,1, 翟丽梅1, 雷秋良1, 武淑霞1, 任天志2Responses of Crop Yields, Soil Carbon and Nitrogen Stocks to Additional Application of Organic Materials in Different Fertilization Years
GAI XiaPu1, LIU HongBin1, YANG Bo1, WANG HongYuan,1, ZHAI LiMei1, LEI QiuLiang1, WU ShuXia1, REN TianZhi2通讯作者:
收稿日期:2018-07-24接受日期:2018-09-25网络出版日期:2019-02-16
| 基金资助: |
Received:2018-07-24Accepted:2018-09-25Online:2019-02-16
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盖霞普,E-mail：
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盖霞普, 刘宏斌, 杨波, 王洪媛, 翟丽梅, 雷秋良, 武淑霞, 任天志. 不同施肥年限下作物产量及土壤碳氮库容对增施有机物料的响应[J]. 中国农业科学, 2019, 52(4): 676-689 doi:10.3864/j.issn.0578-1752.2019.04.009
GAI XiaPu, LIU HongBin, YANG Bo, WANG HongYuan, ZHAI LiMei, LEI QiuLiang, WU ShuXia, REN TianZhi.
0 引言
【研究意义】土壤有机碳、氮库是土壤中最重要的组成部分,土壤有机碳、氮库的特性能够直接或者间接决定土壤的质量和健康（如土壤结构的稳定性、土壤肥力等）,并与作物高产等密切相关[1,2]。土壤碳库的增加,能够提供微生物营养循环的能量和改善土壤的物理化学性质,因此利于作物生产;反过来,作物净初级生产力的增加可以产生更大量的地上和地下部植物残体,返还到农田土壤后,也有利于土壤碳的固持[3]。此外,提高土壤氮素固定可以降低氮肥施用量和施肥成本,提高土壤供氮潜力,保护环境免受氮素流失的负面影响[4]。【前人研究进展】 增施有机肥和秸秆还田是提高作物产量和土壤碳氮库容的有效措施[5,6,7,8]。LI等[8]在黄淮海平原区开展长期定位试验结果表明,与试验初始值相比,连续9年NPK+有机肥、NPK+秸秆还田处理,小麦产量提高9.9%、13.2%,0—20 cm耕层土壤有机碳含量提高25.3%、31.82%,全氮含量提高6.7%、10%。施肥不同年限对作物产量和土壤碳氮库容的增加效果也不同。例如,王飞等[9]分析长期定位施肥试验数据发现,连续15年增施有机肥（NPKM）与秸秆还田（NPKS）的水稻产量比单施化肥（NPK）分别提高7.9%—10.9%与1.7%—10.8%,连续增施32年,分别提高12.6%—21.7%与11.6%— 16.3%。相似的,连续10年和16年NPKM处理,玉米和水稻产量分别比NPK处理提高7.3%和25.4%[10]。笔者及同组成员等[6,11]通过定位试验发现,和试验初始值相比,增施有机肥1年,0—20 cm耕层土壤有机碳（SOC）和全氮（TN）含量分别增加4.2%和27.3%;连续增施27年后,耕层SOC和TN分别增加62.6%—141.5%和31.3%—132.5%。此外,有机肥及秸秆还田对不同土壤剖面层的养分含量增加的强度不同。例如,和60—90 cm深层土壤相比,长期施用有机肥可使0—30 cm土层中SOC和TN均增加2.3倍,在30—60 cm土层中均增加3倍[12]。尽管目前施用有机肥及秸秆还田对作物产量及土壤养分含量的提升有了比较深入的了解,但其对深层土壤C、N分布及库容的影响,尤其是施用年限的影响作用强度认识不足。【本研究切入点】中国土壤C、N库容变化趋势为黑土中C、N库下降,土壤退化[13];水稻土C库增加[14];而在潮褐土旱地土壤中存在争议性,有的认为增加[11],有的认为降低[15]。提高土壤C、N库容是保产减肥的重要措施,华北平原是我国粮食主产区,潮褐土是主要土壤类型,土壤养分含量较低,硝化速率较高,是养分容易流失的一类土壤[16,17]。提升土壤肥力是提高作物产量的一个重要措施,有机肥及秸秆还田等有机物料添加是提高土壤肥力的有效手段。外源有机物料的添加对土壤C、N库增强的潜力还不明确,尤其是高量增施有机肥以及低量秸秆还田对低肥力潮褐土剖面土壤肥力提升潜力的研究较少。【拟解决的关键问题】以农业农村部昌平潮褐土生态环境重点野外科学观测试验站为平台,探讨增施有机肥及秸秆还田对作物产量及土壤碳氮库容强度的影响,为提升作物产量和更好地培肥土壤提供科学依据。1 材料与方法
1.1 试验区概况与试验设计
本研究在农业农村部昌平潮褐土生态环境重点野外科学观测试验站中进行。研究基地位于北京市昌平区,北纬40°13′,东经116°14′,海拔高度43.5 m,年平均温度11℃,≥10℃积温4 500℃,年降雨量600 mm,年蒸发量1 065 mm,无霜期210 d,灾害性天气主要是春旱和夏季暴雨。长期肥料定位试验始于1990年,种植制度主要为冬小麦（Triticum aestivum L.）-夏玉米（Zea mays L.）。土壤母质为黄土性物质,属潮褐土。试验开始时表层（0—20 cm）土壤理化性质为：SOC含量为7.5 g·kg-1,全氮0.5 g·kg-1,全磷0.6 g·kg-1,碱解氮49.7 mg·kg-1,速效磷3.8 mg·kg-1,有效钾65.3 mg·kg-1,缓效钾503.7 mg·kg-1,pH =8.12。
试验设有4个处理：（1）氮磷钾（NPK）;（2）氮磷钾+22.5 t·hm-2有机肥（NPKM）;（3）氮磷钾+33.75 t·hm-2有机肥（NPKM+）;（4）氮磷钾+秸秆还田（NPKS）。每处理小区选取3个作物长势均匀一致的试验区域3 m2 （2.0 m×1.5 m）作为试验微区,试验共12个微区,在微区周围设置30 cm缓冲区域,在作物采收前,严禁进入微区进行试验操作。处理中N、P、K分别代表每季作物施N 150 kg·hm-2、P2O5 75 kg·hm-2、K2O 45 kg·hm-2;M为有机肥（含水量28%）;M+为过量有机肥（含水量28%,用量为M的1.5倍）;S为玉米秸秆或小麦秸秆,其中有机肥为猪粪,含N为1.5%（干基）,小麦秸秆中含N为0.49%（干基）、玉米秸秆含N为0.91%（干基）,各处理施肥量如表1所示。氮、磷、钾化肥于播种前一次性施入,猪粪和秸秆还田每年施用1次,于小麦播种前做基肥。氮肥为尿素,磷肥为过磷酸钙,钾肥为氯化钾。田间管理按大田丰产要求进行。
Table 1
表1
表1各处理施肥量
Table 1
| 处理 Treatments | 小麦 Wheat | 玉米 Maize | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | P2O5 | K2O | 有机肥 Manure | 小麦秸秆Wheat straw | N | P2O5 | K2O | 有机肥 Manure | 玉米秸秆 Maize straw | |
| NPK | 150 | 75 | 45 | 0 | 0 | 150 | 75 | 45 | 0 | 0 |
| NPKM | 150 | 75 | 45 | 22500 | 0 | 150 | 75 | 45 | 0 | 0 |
| NPKM+ | 150 | 75 | 45 | 33750 | 0 | 150 | 75 | 45 | 0 | 0 |
| NPKS | 150 | 75 | 45 | 0 | 2170 | 150 | 75 | 45 | 0 | 2170 |
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1.2 取样及样品处理
土壤样品：以农业农村部昌平潮褐土生态环境重点野外科学观测试验站为平台,分别于2000年（长达11年）和2016年（长达27年）小麦季收获后,采集2个不同施肥年限的土壤样品,在各处理微区均随机取3点采集0—200 cm（间隔20 cm）土层土样品,剔除石砾和植物残根等杂物,混合制样,样品风干后过0.25 mm筛测定土壤SOC、TN含量等。植物样品：分别于2000年和2016年的6月小麦收获时、10月玉米收获时将各微区全部收获测产。
有机肥及秸秆样品：将新鲜猪粪及秸秆自然风干后,采用H2SO4-H2O2消煮,凯氏定氮法测定有机肥及秸秆中的全氮含量。
1.3 土壤样品的测定方法及计算
土壤SOC测定采用重铬酸钾-外加热容量法;土壤TN采用浓H2SO4消煮-半微量开氏法,采用全自动开氏定氮仪（KDY—9830,北京）。土壤C、N库容的计算公式如下[11]：
S=C×B×H×10-1
式中,S表示土壤SOC和TN库容（Mg·hm-2）;C表示土壤SOC和TN含量（g·kg-1）;B表示土壤容重（g·cm-3）;H表示土层深度（cm）。
多个土层累积C、N库容的计算,如果某一土体的剖面由k层组成,那么该剖面的土壤中SOC或者TN库容Smass的计算公式为：
Smass=$\sum^{k}_{i=1}$ CiBiHi×10-1
式中,Smass表示土壤中累积SOC和TN库容（Mg·hm-2）;C表示土壤SOC和TN含量（g·kg-1）;B表示土壤容重（g·cm-3）;H表示土层深度（cm）。在我们的研究中,没有直接测定容重B,采用以下公式进行估算[18]：
B=-0.0048×lnSOC+1.377
式中,SOC表示土壤有机碳含量（g·kg-1）。
分别计算2000年和2016年6月小麦收获时、10月玉米收获时两种作物的氮肥偏生产力,计算公式如下：
氮肥偏生产力（partial factor productivity of nitrogen, PFPN, kg·kg-1）=施氮区产量/施氮量,指投入单位氮肥所生产的作物产量。
1.4 数据分析
采用Excel 2013软件作图,所有数据采用SPSS软件进行（version 19.0）多因素方差分析（one—way ANOVA）,统计分析施肥类型、土层深度、施肥年限的交互作用对增施有机肥及秸秆还田中土壤碳氮库容的影响,多重比较采用LSD法（P=0.05）,平均值在P<0.05水平下的任何差异具有统计学意义。2 结果
2.1 作物产量和氮肥偏生产力
由图1-a、1-b可知,增施有机肥（NPKM、NPKM+）和秸秆还田（NPKS）均能够提高小麦和玉米产量,且施肥年限的延长会强化增产效应。施肥11年后,NPKM处理的小麦产量最高,达3 592 kg·hm-2,比NPK处理提高18.6%,其次为NPKM+和NPKS处理,比NPK处理分别提高15.8%和3.5%,NPKM与NPKS处理间差异不显著（P>0.05）。随着施肥年限的延长,NPKM+处理小麦产量最高,达5 122 kg·hm-2,比NPK处理提高51.5%,其次为NPKM和NPKS处理,小麦产量分别为4 753、4 163 kg·hm-2, 比NPK处理分别提高41%、23%,且NPKM+与NPKS处理间差异显著（P<0.05）。在玉米产量方面,不同年限中均表现为NPKM和NPKM+处理较高,为5 837—5 968、8 162—8 288 kg·hm-2,显著高于NPK和NPKS,但两处理间均表现为差异不显著（P>0.05）。与NPK处理相比,增产幅度分别达到39%—42%、31%—33%。同时,NPKS处理玉米产量高于NPK处理,施肥11年、27年后,增幅分别为35%、58%,表明随着施肥年限的延长,秸秆还田的增产效应逐渐加强。图1
新窗口打开|下载原图ZIP|生成PPT图1增施有机肥及秸秆还田对作物产量和氮肥偏生产力的影响
每个柱状图上的不同小写（连续施肥11年后）和大写（连续施肥27年后）字母表示差异显著
Fig. 1Response of crop yields and partial factor productivity of nitrogen (PFPN) to additional application of organic manure and straw incorporation
Different lowercase (11 years fertilization) or uppercase (27 years fertilization) letters above each bar indicate significant differences, P<0.05
在本文中,NPKM、NPKM+中每年有机肥用量分别为22.5、33.75 t·hm-2（含水量28%）,结合有机肥的含N量,计算得到每年NPKM、NPKM+中总N投入量分别为542.6、663.8 kg·hm-2;NPKS中每年小麦、玉米秸秆还田量均为2.17 t·hm-2,结合小麦、玉米秸秆的含N量,计算得到每年NPKS中总N投入量为330.2 kg·hm-2。采用施氮区产量与施氮量之比作为衡量氮肥偏生产力（PFPN）的指标发现,不同施肥年限中增施有机肥及秸秆还田均明显降低了PFPN（图1-c、1-d）。在小麦和玉米生长季中,连续施肥11年后PFPN从大到小均表现为：NPK>NPKM>NPKM+、NPKS;而27年后PFPN从大到小均表现为：NPK>NPKM>NPKM+>NPKS,NPK与NPKM、NPKM+、NPKS处理均达到显著关系（P<0.05）,这与有机肥及秸秆本身带入大量氮素有关。
2.2 土壤有机碳库及其剖面分布特征
由图2-a—2-c可以看出,随着施肥年限的延长,增施有机肥及秸秆还田均能够提升0—200 cm土层SOC水平,具体表现为连续施用11年后各处理SOC库容为25—114 Mg·hm-2,27年后为29—146 Mg·hm-2。随着土壤剖面的加深,不同年限各处理中SOC库容均表现为先逐渐增加后逐渐降低的趋势,均在80 cm处达到峰值。连续施用11年后各处理SOC库容峰值为110—114 Mg·hm-2;27年后NPK、NPKM、NPKM+、NPKS处理SOC库容峰值分别为102、128、146、123 Mg·hm-2。连续施用11年后各处理对整个剖面SOC库容影响差异不显著（P>0.05）,而随着施肥年限的延长,各处理在60—80 cm土层对SOC库容的影响均达到了显著性差异水平（P<0.05）。经多因素主体间效应检验可知（表2）,施肥类型、土层深度和施肥年限的交互作用显著影响土壤碳库水平（P<0.01）。以0—20 cm表层SOC库容为例,与NPK（29 Mg·hm-2）相比,NPKM、NPKM+、NPKS处理SOC库容增幅为62%、121%、9%;在60—80 cm峰值处,NPKM、NPKM+、NPKS处理SOC库容增幅为26%、43%、20%,说明长期增施有机肥及秸秆还田能够增加表层及深层土壤碳库,且增施有机肥对SOC的提升效果强于秸秆还田。同时,增施有机肥及秸秆还田对土壤碳库的增强效应在80 cm深层土壤强于表层土壤,说明随着土层的加深,土壤碳含量不断向下迁移,增强深层土壤碳库。由图2-c中可以看出,各施肥处理土壤碳库变化量表现为随着土壤剖面的加深,呈现先降低后增加,随后逐渐降低的趋势。在各个土层中,土壤碳库变化量均表现为NPKM+>NPKM>NPKS>NPK。这说明增施有机肥及秸秆还田能够增加SOC库容变化量,且施用有机肥的提升效果强于秸秆还田。图2
新窗口打开|下载原图ZIP|生成PPT图2增施有机肥及秸秆还田对土壤有机碳库容及其变化量剖面分布的影响
同一图的不同小写字母代表差异显著（P<0.05）,重复数=3。下同。“a”表示连续施肥11年后土壤碳库;“b”表示连续施肥27年后土壤碳库;“c”表示有机碳库变化量（有机碳库b-有机碳库a）
Fig. 2Responses of soil organic carbon (SOC) stocks and variations to additional application of organic manure and straw incorporation
Different letters indicate significant difference for the results in the same column (P<0.05). Three replicates in the study. The same as below. “a” represent SOC stocks after 11 years fertilizations; “b” represent SOC stocks after 27 years fertilizations; “c” represent variations of SOC stocks (SOC stocks b-a)
Table 2
表2
表2施肥类型、土层深度和施肥年限对土壤碳库、氮库和碳氮比影响的主体间效应检验（n=240）
Table 2
| 变异来源 Variation source | 因变量 Dependent variables | Ш型平方和 Quadratic sum of squares | Df Degree of freedom | F | Sig. Significance level |
|---|---|---|---|---|---|
| 施肥类型 Fertilization types (T) | 土壤碳库SOC stocks | 12245.007 | 3 | 79.734 | <.001 |
| 土壤氮库TN stocks | 98.287 | 3 | 85.845 | <.001 | |
| 碳氮比Ratios of C to N | 107.216 | 3 | 15.832 | <.001 | |
| 土层深度 Soil depth (D) | 土壤碳库SOC stocks | 141872.456 | 9 | 307.938 | <.001 |
| 土壤氮库TN stocks | 630.196 | 9 | 183.473 | <.001 | |
| 碳氮比Ratios of C to N | 547.745 | 9 | 26.961 | <.001 | |
| 施肥年限 Fertilization years (Y) | 土壤碳库SOC stocks | 21584.778 | 1 | 421.653 | <.001 |
| 土壤氮库TN stocks | 4.216 | 1 | 11.047 | <.001 | |
| 碳氮比Ratios of C to N | 138.014 | 1 | 61.140 | <.001 | |
| 施肥类型×土层深度 T×D | 土壤碳库SOC stocks | 2305.072 | 27 | 1.668 | <.05 |
| 土壤氮库TN stocks | 39.807 | 27 | 3.863 | <.001 | |
| 碳氮比ratios of C to N | 60.212 | 27 | 0.988 | >.05 | |
| 施肥类型×施肥年限 T×Y | 土壤碳库SOC stocks | 2341.579 | 3 | 15.247 | <.001 |
| 土壤氮库TN stocks | 39.058 | 3 | 34.113 | <.001 | |
| 碳氮比Ratios of C to N | 52.189 | 3 | 7.707 | <.001 | |
| 土层深度×施肥年限 D×Y | 土壤碳库SOC stocks | 4273.625 | 9 | 9.276 | <.001 |
| 土壤氮库TN stocks | 86.500 | 9 | 25.183 | <.001 | |
| 碳氮比Ratios of C to N | 271.041 | 9 | 13.341 | <.001 | |
| 施肥类型×土层深度×施肥年限 T×D×Y | 土壤碳库SOC stocks | 2182.463 | 27 | 1.579 | <.05 |
| 土壤氮库TN stocks | 33.137 | 27 | 3.216 | <.001 | |
| 碳氮比Ratios of C to N | 117.867 | 27 | 1.934 | <.01 |
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2.3 土壤氮库及其剖面分布特征
由图3-a—3-c可以看出,与土壤SOC库容变化规律相一致,增施有机肥和秸秆还田均能够随着施肥年限的延长提升土壤TN库水平,具体表现为连续施用11年后各处理土壤TN库容为2.2—9.0 Mg·hm-2,27年后为2.5—12.1 Mg·hm-2。随着土壤剖面的加深,不同年限下土壤TN库均表现为先逐渐增加后逐渐降低的趋势,除连续施用11年后NPKS处理外,其余处理均在80 cm处达到峰值。在80 cm土层峰值处,连续施肥11年后NPK、NPKM、NPKM+、NPKS处理土壤TN库容分别为6.7、7.2、8.2、8.4 Mg·hm-2;27年后NPK、NPKM、NPKM+、NPKS处理土壤TN库容分别为8.3、9.7、 12.1、9.1 Mg·hm-2。连续施用11年后,除80—100、160—180 cm土层外,各施肥处理对其余土层TN库容影响差异均不显著（P>0.05）,而随着施肥年限的延长,各处理在0—20、80—100、140—160、180—200 cm土层土壤氮库容的影响均达到了显著性差异水平（P<0.05）。经多因素主体间效应检验可知（表2）,施肥类型、土层深度和施肥年限的交互作用显著影响土壤氮库水平（P<0.01）。以0—20 cm表层土壤TN库容为例,与NPK（2.5 Mg·hm-2）相比,NPKM、NPKM+、NPKS氮库容分别增加105%、184%、16%;在60—80 cm土层处,NPKM、NPKM+、NPKS处理比NPK分别提高17%、46%、9%,说明长期增施有机肥及秸秆还田能够增加表层及深层土壤TN库容,且增施有机肥对TN的提升效果强于秸秆还田。随着土层的加深,土壤TN库容呈现先增加后降低的变化趋势,说明施肥处理能够提升深层TN库容。由图3-c中可以看出,各施肥处理土壤TN库容变化量表现为随着土壤剖面的加深,呈现先降低后增加,随后逐渐降低的趋势。在0—40 cm土层内,土壤TN库容变化量表现为NPKM+>NPKM>NPKS>NPK;而在40—200 cm土层内,表现为NPKM+>NPKM, NPKS>NPK。这说明增施有机肥及秸秆还田均能够增加0—40 cm表层土壤TN的变化量。同时,增施有机肥对深层土壤TN库容变化量强于表层土壤。值得注意的是,在0—60 cm土层,秸秆还田氮库容增加量为正值,而在底层60—200 cm土层,增加量为负值,说明秸秆还田在表层土壤中具有固氮作用。图3
新窗口打开|下载原图ZIP|生成PPT图3增施有机肥及秸秆还田对土壤氮库容及其变化量剖面分布的影响
“a”表示连续施肥11年后土壤氮库;“b”表示连续施肥27年后土壤氮库;“c”表示土壤氮库变化量（氮库b-氮库a）
Fig. 3Response of soil total nitrogen (TN) stocks and variations to additional application of organic manure and straw incorporation
“a” represent TN stocks after 11 years fertilizations; “b” represent TN stocks after 27 years fertilizations; “c” represent variations of TN stocks (TN stocksb-a)
2.4 土壤碳氮比剖面分布特征
由图4-a—4-b可以看出,和NPK相比,不同年限中增施有机肥及秸秆还田均降低了不同土层的土壤碳氮比（C/N）。对整个土壤剖面而言,连续施用11年后各处理土壤C/N为6.5—14.7,27年后各处理土壤C/N为9.1—14.8,表明随着施肥年限的延长,土壤C/N趋于稳定。连续施用11年后,随着0—140 cm土壤剖面的加深,各处理土壤C/N表现为先缓慢增加,后逐渐降低;随着土层的进一步加深（140—200 cm）,土壤C/N再次升高,随后降低,直至稳定。在>80 cm土层处,各处理土壤C/N表现为NPK>NPKM+、NPKM>NPKS。而27年后,随着土壤深度的增加,土壤C/N由0—80 cm土层的稳定水平逐渐降低,随后逐渐达到稳定状态。在C/N较稳定的>140 cm土层处,各处理土壤C/N表现为NPK>NPKS>NPKM+、NPKM。经多因素主体间效应检验可知（表2）,除施肥类型×土层深度外,施肥类型×施肥年限、土层深度×施肥年限及施肥类型×土层深度×施肥年限的交互作用显著影响土壤碳氮比（P<0.05）。图4
新窗口打开|下载原图ZIP|生成PPT图4增施有机肥及秸秆还田对土壤碳氮比剖面分布的影响
“a”表示连续施肥11年后土壤碳氮比;“b”表示连续施肥27年后土壤碳氮比
Fig. 4Response of ratios of C to N to additional application of organic manure and straw incorporation
“a”=soil C/N after 10 years fertilizations; “b”=soil C/N after 27 years fertilizations
2.5 土壤累积碳氮库
由表3可知,随着施肥年限的延长,各处理0—200 cm土层土壤累积碳、氮库均呈现增加趋势,在土壤累积碳库方面,和NPK相比,连续施肥11年后,NPKM、NPKM+、NPKS处理土壤累积碳库分别提升5.2%、11.2%、9.2%;27年后NPKM、NPKM+、NPKS处理土壤累积碳库分别提升26.3%、41.1%、21.8%。这说明随着施肥年限的延长,施用有机肥对土壤累积碳库的提升高于秸秆还田的趋势愈加明显。在土壤累积氮库方面,和NPK相比,连续施肥11年后,NPKM、NPKM+、NPKS处理土壤累积氮库分别提高21.2%、26.6%%、38.8%;27年后NPKM、NPKM+、NPKS处理土壤累积氮库分别提升26.2%、44.9%、4.0%。Table 3
表3
表3增施有机肥及秸秆还田对0—200 cm土层土壤累积碳、氮库的影响
Table 3
| 施肥处理 Treatments | 累积碳库 Cumulative SOC stocks (Mg·hm-2) | 累积库氮 Cumulative TN stocks (Mg·hm-2) | ||
|---|---|---|---|---|
| 连续施肥11年 11 years fertilizations | 连续施肥27年 27 years fertilizations | 连续施肥11年 11 years fertilizations | 连续施肥27年 27 years fertilizations | |
| NPK | 440 ±21 b | 530.7±43 c | 41±4 b | 43± 3 c |
| NPKM | 463±23 ab | 671±51 b | 50±5 ab | 54±2 b |
| NPKM+ | 490±34 a | 749±40 a | 52±4 a | 63±4 a |
| NPKS | 481±29 a | 646±35 b | 58±3 a | 45±1 c |
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3 讨论
3.1 增施有机肥及秸秆还田对作物产量的影响
在本研究中,长期增施有机肥及秸秆还田等外源有机物料的添加能够显著提高昌平地区小麦和玉米产量（P<0.05）,这与国内外其他****的研究报道相一致。例如,ZHANG等[19]通过长达11年的8个试验点的长期定位试验发现,和NPK相比,在NPK基础上增施有机肥能够提高小麦、玉米产量分别为3.1%、2.4%。相似的,在长达31年长期定位试验中的研究结果表明,增施猪粪、秸秆还田比NPK能够提高小麦产量分别为11.5%、8.0%;提高大豆籽粒产量分别为27.7%、17.2%[20]。K?RSCHENS等[21]总结了欧洲20个长期定位试验数据（10—61年）发现,和NPK相比,有机无机配施处理作物产量平均提高6%,而LEHTINEN等[22]采用meta分析的方法报道了和秸秆不还田相比,秸秆还田提高作物产量平均也为6%。长期施用有机肥料和秸秆还田等外源有机物料对作物产量有积极效应,一方面是由于有机肥及秸秆还田增加了土壤有机碳含量及养分循环,从而提高了作物产量[23,24,25,26];另一方面有机物料的施用提高了养分利用效率[27],增加土壤内在养分的供应能力,改善土壤健康,减轻不利环境因素引起的作物产量的波动,进而提高作物生长活力[8]。在本研究中,有机肥对作物产量的提升作物强于秸秆还田,一方面是由于有机肥中含有更多的作物易利用态有机碳;另一方面是由于有机肥本身所含养分含量高于秸秆,且随着施肥年限的延长,这种增产作用愈加明显,这与土壤肥力随施肥年限延长而逐渐增加有关。
3.2 增施有机肥及秸秆还田对土壤剖面碳氮库容的影响
有机肥及秸秆还田一直被提倡和实践用来改善土壤肥力,提升土壤碳、氮库容。在本研究中,连续27年的长期定位施肥试验结果发现,与NPK相比,增施有机肥及秸秆还田均能够显著增加土壤累积碳、氮库容,主要归因于我们的研究地点,其年平均降雨量为534 mm,且82%的降雨发生在玉米生长季节（6—9月）[28]。降雨使碳、氮向下迁移,随着土壤深度的增加,因此土壤碳、氮含量呈现累积现象[29]。增施有机肥及秸秆还田对土壤碳、氮库容的提升效应与前人的研究结果相一致, 例如, HUA等[20]发现在31年长期定位试验中,与NPK相比,增施猪粪、增施牛粪、秸秆还田能够使0—100 cm土壤碳库提升31.8%、51.6%、18.2%。ZHANG等[19]通过8个试验点的长期定位试验发现,1990—2000年近11年NPK处理的SOC从26 t C·hm-2增长到30 t C·hm-2,而NPKM处理碳固持率从27 t·C hm-2增长到36 t C·hm-2。与之相似,31年长期增施有机肥处理碳固持率比NPK提高27.0%—64.4%[30]。而MAILLARD等[31]和LEHTINEN等[22]采用Meta分析分别估算了长期定位实验中有机肥及秸秆还田的碳固持效率分别为12%、6%—14%。施用有机肥及秸秆还田能够显著提高土壤固碳能力和SOC含量,这与其他田间试验的研究结果相一致[32,33]。已有大量长期试验揭示了生物量碳输入与SOC含量的正相关关系[23,31,34]。外源有机物料的添加,包括猪粪和秸秆,不仅能够直接向土壤中输入碳,而且通过作物残茬、凋落物及根系等较高的植物生物量的方式间接向土壤中输入碳[34,35]。有机肥是土壤N和P元素的重要来源,施用有机肥能够减少N和P对作物生长及构建SOC的限制[36,37]。且有机肥对土壤有机碳的保护作用随其施用年限的增加而增加[38,39]。在本文中,有机肥的固碳作用强于秸秆还田,一方面归因于有机肥比秸秆（秸秆中存在较多的纤维素、半纤维素和木质素等顽固态有机碳）中含有更多的可利用态碳;另一方面归因于有机肥比秸秆还田具有更高的C投入[30]。
土壤C/N的变化可以反映微生物群落对N的固持能力[40],也能够反映土壤C和N循环的相互作用和土壤有机质的稳定性[41]。外源C、N的施用来源和施用量影响土壤C/N。例如,有机肥中含有大量的活性C和N,利于土壤N固定;而化肥的施用能够促进土壤N矿化[42],但矿化养分在C限制的条件下不能立即再固定。即有机无机配施（如有机肥、秸秆还田等）有利于提高土壤的C/N,单施化肥,将显著降低土壤的C/N[43]。本研究与上述观点不一致,与NPK相比,化肥配施有机肥及秸秆还田均降低了土壤C/N,表明施用有机肥能够提高土壤N矿化率,较低的土壤C/N表明在作物种植系统中C源供应不足,这可能限制土壤微生物固定N素[44],并易导致较高的N损失[45];而高C/N的秸秆施入土壤后,会通过固定作用将无机氮转化为有机氮[46],从而减少氮矿化过程[47],提升土壤氮水平。
在本文中,随着土层的加深,增施有机肥及秸秆还田等外源有机物料的添加能够提高土壤碳氮库容,在80 cm处达到峰值,后逐渐降低的趋势。表层土壤输入有机物有利于产生可溶性有机碳,这些有机碳可以被输入到底层土壤,这有利于底层土壤碳库的构建[48],这与LONG等[49]的研究结果相一致,发现长期施用有机物料后,土壤可溶性碳氮含量可向深层土壤的迁移至80 cm。深层土壤碳氮库含量较低的原因可归结为根系生物量、根系分泌物和植物残体的积累量较少的缘故[50]。有趣的是,不同年限土壤C/N均随着土层加深呈现降低趋势,与DIEKOW等[51]在巴西的长期定位试验中的研究结果相一致,发现在不同的作物体系和施肥水平下,随着土壤深度的增加,土壤C/N在下降,与此同时,土壤粘粒质量分数是随着土壤深度的增加而增加,这跟粘粒矿物含有更多的固定态铵有关系。
笔者[4,28]在同一试验点对同一年的长期定位施肥试验数据分析表明,在施用NPK的基础上配施有机肥,能够促进硝态氮（NO3--N）向深层土壤的迁移,增加了NO3--N淋溶的风险,且增施过量有机肥处理存在更大的NO3--N淋溶风险;而在施用NPK的基础上进行秸秆还田,对土壤NO3--N具有一定的固持作用。DISE等[52]研究了英国针叶林土壤C/N与土壤NO3--N淋失的关系证明,土壤C/N可以作为NO3--N淋失的一个指标。GUNDERSENA等[53]研究了丹麦33个温带针叶林土壤,得出了同样的结果,随着土壤C/N的增加,NO3--N的淋失量在下降。这与本文中在NPK基础上配施有机肥降低了土壤C/N,却增加了氮素淋失风险的结果相吻合。
4 结论
4.1
我国华北平原小麦-玉米轮作模式下,长期增施有机肥及秸秆还田能够提高作物产量、提升土壤肥力,且随着施肥年限的延长,提升作用增强。同时,长期施用有机肥对作物产量、土壤碳、土壤氮储量的提升效果强于秸秆还田,但增施有机肥及秸秆还田均降低了氮肥偏生产力。4.2
多因素方差分析表明,施肥类型、土层深度和施肥年限的交互作用显著影响土壤碳、氮库及碳氮比。随着土壤剖面的加深,增施有机肥及秸秆还田土壤碳、氮库均表现为先逐渐增加后逐渐降低的趋势,均在80 cm处达到峰值。和单施化肥相比,不同施肥年限下增施有机肥及秸秆还田均降低了不同土层的土壤碳氮比。同时,随着施肥年限的延长,土壤C/N越稳定。4.3
随着施肥年限的延长,各施肥处理土壤累积碳、氮库均呈现增加趋势,且施用有机肥对土壤累积碳储量的提升高于秸秆还田的趋势愈加明显,而对土壤累积氮储量的提升效果低于秸秆还田。（责任编辑 李云霞）
参考文献 原文顺序
文献年度倒序
文中引用次数倒序
被引期刊影响因子
DOI:10.1016/j.agee.2008.04.006URL [本文引用: 1]
Disposal of poultry litter, a widely available organic manure in the southeastern USA because of a large-scale poultry industry, is a major concern because of its contamination in surface- and groundwater through N leaching and P runoff. Application of poultry litter in no-tilled intensive cropping system could increase soil C and N sequestration compared with the conventional-tilled system with inorganic N fertilization and reduce environmental contamination. We evaluated the 10-year effects of tillage, cropping systems, and N fertilizer sources on crop residue (stems + leaves) production and soil bulk density, organic C (SOC), and total N (STN) at the 0–20 cm depth in Decatur silt loam (clayey, kaolinitic, thermic, and Typic Paleudults) in northern AL, USA. Treatments were incomplete factorial combinations of three tillage practices [no-till (NT), mulch till (MT), and conventional till (CT)], two cropping systems [cotton ( Gossypium hirsutum L.)–cotton–corn ( Zea mays L.) and rye ( Secale cereale L.)/cotton–rye/cotton–corn], and two N fertilization sources and rates (0 and 100 kg N ha 611 from NH 4NO 3, and 100 and 200 kg N ha 611 from poultry litter) in randomized complete block with three replications. Rye was grown as winter cover crop and corn as residual crop without tillage and fertilization. Mean crop residue returned to the soil from 1997 to 2005 was greater in rye/cotton–rye/cotton–corn than in cotton–cotton–corn and greater with NH 4NO 3 than with poultry litter at 100 kg N ha 611. While SOC and STN concentrations at 10–20 cm after 10 years were not influenced by treatments, SOC and STN contents at 0–20 cm were greater with poultry litter than with NH 4NO 3 in NT and CT. These resulted in a C sequestration rate of 510 kg C ha 611 year 611 and N sequestration rates of 41–49 kg N ha 611 year 611 with poultry litter compared with 61120 to 147 kg C ha 611 year 611 and 6123 to 613 kg N ha 611 year 611, respectively, with NH 4NO 3. Cropping and fertilization sequestered C at 730 kg C ha 611 year 611 and N at 67 kg N ha 611 year 611 compared with fallow and no-fertilization in NT. Tillage and cropping system did not influence SOC and STN. Long-term poultry litter application or continuous cropping can sequester C and N in the soil compared with inorganic N fertilization or fallow, thereby increasing soil quality and productivity and reducing the potentials for N leaching and greenhouse gas emission.
DOI:10.1038/515351aURL [本文引用: 1]
DOI:10.1016/j.agee.2008.10.008URL [本文引用: 1]
The role of soil organic matter (SOM) in agricultural systems has been widely studied in conjunction with the potential for greenhouse gas mitigation. However, the link between SOM accumulation in croplands, crop productivity and yield stability has not yet been clearly established. In this paper, we collected data on provincial yearly crop productivity (yields, total cropland area) during 1949–1998 and the average SOM contents in croplands sampled and determined from the National Soil Survey in 1979–1982 of mainland China. The cereal productivity was assessed both with an overall mean of 1949–1998 and with the mean values for different time periods within this overall time, respectively. The yield variability within a single stabilizing stage, and between the fluctuating years, was calculated as a negative measure of yield stability. The correlation between SOM and cereal productivity was very significant for most provinces, but the relationship has become less significant as we approach the present. Moreover, the average yield variability was very significantly and negatively correlated with the cropland SOM level. The findings support our previous hypothesis from case studies, that C sequestration in China's croplands may provide win–win benefits, by enhancing crop productivity and stabilizing yield. This offers a sound basis as a greenhouse gas mitigation strategy by promoting C sequestration in croplands, and enhancing food security in China's agriculture.
DOI:10.3864/j.issn.0578-1752.2018.12.010URL [本文引用: 2]
【目的】研究长期增施有机肥/秸秆还田对作物产量及土壤氮素淋失风险的影响,旨在为华北平原冬小麦-夏玉米轮作区增强土壤肥力、提高作物产量及降低农业面源污染风险提供依据。【方法】以国家褐潮土肥力与肥料效益监测基地的长期肥料试验为平台,研究长达27年不同施肥处理对冬小麦-夏玉米产量、土壤肥力、氮素淋失风险和土壤氮素剖面分布的影响,试验共设置5个施肥处理,即:对照(CK);氮磷钾(NPK);氮磷钾+有机肥(NPKM);氮磷钾+过量有机肥(NPKM+);氮磷钾+秸秆还田(NPKS)。【结果】(1)在27年的不同施肥处理中,长期增施有机肥/秸秆还田均能使作物增产,改善土壤肥力。其中,增施有机肥处理尤为显著,与NPK相比,NPKM、NPKM+处理提高小麦和玉米产量分别为41%—50%和30%—32%;增加0—20 cm表层土壤有机碳(SOC)和全氮(TN)含量分别为62%—121%、107%—187%;但降低小麦、玉米氮肥偏生产力(PFPN)分别达22%—32%、27%—41%。而NPKS处理对作物增产及提升土壤肥力的作用低于增施有机肥处理,对小麦产量、玉米产量、SOC、TN含量的增幅分别为24%、6%、9%、97%,但提高小麦季PFPN为216%、降低玉米季PFPN为40%。(2)长期增施有机肥/秸秆还田处理中,0—20 cm表层土壤SOC、TN、硝态氮(NO3—-N)、可溶性碳氮等养分含量以及氮矿化速率、硝化潜势等微生物学过程显著高于20—200 cm,说明长期增施有机肥/秸秆还田等外源碳的添加对土壤养分及微生物学过程的影响主要发生在表层。(3)与NPK相比,NPKM处理能够显著增加100—200 cm深层土壤中NO3--N含量,NO3--N平均含量为17.8—26.1 mg·kg-1;而NPKS处理在一定程度上能够增加0—100 cm土层NO3--N含量,NO3--N平均含量为3.6—13.4 mg·kg-1,表明增施有机肥会促进土壤NO3--N的向下迁移,而秸秆还田对土壤NO3--N具有一定的固持作用。此外,由于有机肥和秸秆带入的氮素,NPKM、NPKM+、NPKS处理氮盈余比NPK处理增加312%、1 037%、953%,大大增加了土壤氮素淋失风险。【结论】在氮磷钾化肥基础上增施有机肥/秸秆还田会提高作物产量、增强土壤肥力,但会提高土壤氮盈余量,提高氮素淋失风险,尤其是增施有机肥会大大增加氮素淋失风险。
DOI:10.3864/j.issn.0578-1752.2018.12.010URL [本文引用: 2]
【目的】研究长期增施有机肥/秸秆还田对作物产量及土壤氮素淋失风险的影响,旨在为华北平原冬小麦-夏玉米轮作区增强土壤肥力、提高作物产量及降低农业面源污染风险提供依据。【方法】以国家褐潮土肥力与肥料效益监测基地的长期肥料试验为平台,研究长达27年不同施肥处理对冬小麦-夏玉米产量、土壤肥力、氮素淋失风险和土壤氮素剖面分布的影响,试验共设置5个施肥处理,即:对照(CK);氮磷钾(NPK);氮磷钾+有机肥(NPKM);氮磷钾+过量有机肥(NPKM+);氮磷钾+秸秆还田(NPKS)。【结果】(1)在27年的不同施肥处理中,长期增施有机肥/秸秆还田均能使作物增产,改善土壤肥力。其中,增施有机肥处理尤为显著,与NPK相比,NPKM、NPKM+处理提高小麦和玉米产量分别为41%—50%和30%—32%;增加0—20 cm表层土壤有机碳(SOC)和全氮(TN)含量分别为62%—121%、107%—187%;但降低小麦、玉米氮肥偏生产力(PFPN)分别达22%—32%、27%—41%。而NPKS处理对作物增产及提升土壤肥力的作用低于增施有机肥处理,对小麦产量、玉米产量、SOC、TN含量的增幅分别为24%、6%、9%、97%,但提高小麦季PFPN为216%、降低玉米季PFPN为40%。(2)长期增施有机肥/秸秆还田处理中,0—20 cm表层土壤SOC、TN、硝态氮(NO3—-N)、可溶性碳氮等养分含量以及氮矿化速率、硝化潜势等微生物学过程显著高于20—200 cm,说明长期增施有机肥/秸秆还田等外源碳的添加对土壤养分及微生物学过程的影响主要发生在表层。(3)与NPK相比,NPKM处理能够显著增加100—200 cm深层土壤中NO3--N含量,NO3--N平均含量为17.8—26.1 mg·kg-1;而NPKS处理在一定程度上能够增加0—100 cm土层NO3--N含量,NO3--N平均含量为3.6—13.4 mg·kg-1,表明增施有机肥会促进土壤NO3--N的向下迁移,而秸秆还田对土壤NO3--N具有一定的固持作用。此外,由于有机肥和秸秆带入的氮素,NPKM、NPKM+、NPKS处理氮盈余比NPK处理增加312%、1 037%、953%,大大增加了土壤氮素淋失风险。【结论】在氮磷钾化肥基础上增施有机肥/秸秆还田会提高作物产量、增强土壤肥力,但会提高土壤氮盈余量,提高氮素淋失风险,尤其是增施有机肥会大大增加氮素淋失风险。
DOI:10.1016/j.catena.2016.04.007URL [本文引用: 1]
61Low rates of straw plus NPK increased Nminand MBC concentrations andqMIC.61High amounts of organic manure plus NPK increased most of the selected parameters.61High rates of manure application accelerated carbon mineralization.61Low rates of organic amendments are recommended to improve soil quality.
DOI:10.1016/j.scitotenv.2018.03.069URL [本文引用: 2]
The impacts of manure application on soil ammonia (NH 3 ) volatilization and greenhouse gas (GHG) emissions are of interest for both agronomic and environmental reasons. However, how the swine manure addition affects greenhouse gas and N emissions in North China Plain wheat fields is still unknown. A long-term fertilization experiment was carried out on a maize-wheat rotation system in Northern China ( Zea mays L - Triticum aestivum L.) from 1990 to 2017. The experiment included four treatments: (1) No fertilizer (CK), (2) single application of chemical fertilizers (NPK), (3) NPK plus 22.502t/ha swine manure (NPKM), (4) NPK plus 33.702t/ha swine manure (NPKM+). A short-term fertilization experiment was conducted from 2016 to 2017 using the same treatments in a field that had been abandoned for decades. The emissions of NH 3 and GHGs were measured during the wheat season from 2016 to 2017. Results showed that after long-term fertilization the wheat yields for NPKM treatment were 710502kg/ha, which were higher than NPK (388002kg/ha) and NPKM+ treatments (551802kg/ha). The wheat yields were similar after short-term fertilization (6098–688702kg/ha). The NH 3 -N emission factors (EF amm ) for NPKM and NPKM+ treatments (1.1 and 1.1–1.4%, respectively) were lower than NPK treatment (2.2%) in both the long and short-term fertilization treatments. In the long- and short-term experiments the nitrous oxide (N 2 O) emission factors (EF nit ) for NPKM+ treatment were 4.2% and 3.7%, respectively, which were higher than for the NPK treatment (3.5% and 2.5%, respectively) and the NPKM treatment (3.6% and 2.2%, respectively). In addition, under long and short-term fertilization, the greenhouse gas intensities for the NPKM+ treatment were 33.7 and 27.002kg CO 2 -eq/kg yield, respectively, which were higher than for the NPKM treatment (22.8 and 21.102kg CO 2 -eq/kg yield, respectively). These results imply that excessive swine manure application does not increase yield but increases GHG emissions.
DOI:10.1016/j.apsoil.2016.06.001URL [本文引用: 1]
Nitrogen (N) fertilizer is commonly excessive in vegetable production, which greatly increases the risk of N loss and may eventually lead to the contamination of adjacent surface and ground water bodies. We assessed the effects of different fertilizer treatments on vegetable yields and soil biochemical properties, with the aim to develop best fertilizer management strategy for vegetable production. A five-year study (from 2008 to 2012) was conducted on a vegetable field in Jiangsu Province, southern China, with six fertilizer treatments: no fertilizer (control; CK), mineral fertilizer (NPK), chicken manure (OM), manure combined with mineral N fertilizer (OPT), OPT plus additional N fertilizer (OPT+N) and OPT plus additional phosphorus (P) fertilizer (OPT+P). Vegetable yields were measured each year, multiple soil (0 20cm) chemical and biochemical characteristics were analyzed at the end of the study. Moreover, the soil ammonia-oxidizing microbial community structure was analyzed based on the PCR-DGGE method. Results showed that all fertilizer treatments produced higher economic vegetable yields than CK, with the highest yields in OPT. Combined application of manure and mineral fertilizer (OPT, OPT+N and OPT+P) produced higher yields than OM and NPK that had similar yields. All treatments with manure promoted soil carbon, N and P levels and reduced the potential of soil acidity. The OPT+P treatment performed best in enhancing soil fertility, which, for example, increased the concentrations of soil total-N, nitrate-N and microbial biomass N by 15.8%, 51.0% and 53.5%, respectively, compared to OPT. In addition, the OPT+P treatment had the highest abundance and diversity of ammonia-oxidizing archaea (AOA), which was positively correlated to the soil ammonium-N and nitrate-N concentrations. Possibly, the additional P in OPT+P could stimulate soil microbial activity, with positive implications for N fertility. However, the OPT+P treatment may also increase the risk of N loss due to an increasing soil nitrate-N, making it a less desirable fertilizer management strategy. In conclusion, the combined application of organic and chemical fertilizers without additional N or P (OPT) is suggested to be the best fertilizer management strategy that can improve soil fertility and vegetable yields, and meanwhile reduces the potential of N loss from soil.
DOI:10.1016/S2095-3119(17)61740-4URL [本文引用: 3]
We investigated the soil microbiologic characteristics, and the yield and sustainable production of winter wheat, by conducting a long-term fertilization experiment. A single application of N, P and K （NPK） fertilizer was taken as the control （CK） and three organic fertilization treatments were used： NPK fertilizer＋pig manure （T1）, NPK fertilizer＋straw return （T2）, NPK fertilizer＋pig manure＋straw return （T3）. The results showed that all three organic fertilization treatments （T1, T2 and T3） significantly increased both soil total N （STN） and soil organic carbon （SOC） from 2008 onwards. In 2016, the SOC content and soil C/N ratios for T1, T2 and T3 were significantly higher than those for CK. The three organic fertilization treatments increased soil microbial activity. In 2016, the activity of urease （sucrase） and the soil respiration rate （SRS） for T1, T2 and T3 were significantly higher than those under CK. The organic fertilization treatments also increased the content of soil microbial biomass carbon （SMBC） and microbial biomass nitrogen （SMBN）, the SMBC/SMBN ratio and the microbial quotient （qMB）. The yield for T1, T2 and T3 was significantly higher than that of CK, respectively. Over the nine years of the investigation, the average yield increased by 9.9, 13.2 and 17.4% for T1, T2 and T3, respectively, compared to the initial yield for each treatment, whereas the average yield of CK over the same period was reduced by 6.5%. T1, T2, and T3 lowered the coefficient of variation （CV） of wheat yield and increased the sustainable yield index （SYI）. Wheat grain yield was significantly positively correlated with each of the soil microbial properties （P〈0.01）. These results showed that the long-term application of combined organic and chemical fertilizers can stabilize crop yield and make it more sustainable by improving the properties of the soil.
DOI:10.11674/zwyf.2015.0609URLMagsci [本文引用: 1]
<p><strong>目的</strong> 探讨南方丘陵黄泥田不同施肥对耕层土壤有机碳固存及生产力的影响,促进区域农田固碳减排和作物高产。<strong>方法</strong> 基于32年的长期定位试验,研究不施肥(CK)、 单施化肥(NPK)、 化肥+牛粪(NPKM)、 化肥+全部稻草还田(NPKS)处理下,历年水稻产量、 代表性年份耕层土壤有机碳含量及固碳速率的变化。<strong>结果</strong> NPK、 NPKM、 NPKS处理下水稻历年平均产量分别较CK高67.1%、 88.1%和84.2%,差异显著,且NPKM、 NPKS处理与NPK处理间亦具有显著差异。NPK、 NPKM与NPKS处理耕层土壤有机碳历年平均含量比CK高8.9%~36.8%,其中NPKM最高且亦显著高于NPKS与NPK处理。与初始土壤相比,各处理有机碳含量增加1.84~5.26 g/kg。以每10年为评价周期,NPKM、 NPKS处理的固碳速率与CK及NPK差异均显著,其中双季稻年份NPKM与NPKS处理固碳速率分别是CK的2.38倍和1.98倍,是NPK处理的1.59倍与1.32倍,但NPK处理与CK间差异不显著。稻田系统年均有机碳输入与有机碳固存间存在极显著幂函数关系,施肥土壤有机碳含量变化与籽粒产量变化间亦呈极显著正相关。<strong>结论</strong> 南方黄泥田化肥配施有机肥或配合秸秆还田较单施化肥稳步提升水稻产量。长期不施肥土壤有机碳仍可维持低幅度增长,随着土壤有机碳含量升高,固碳效率逐步降低。化肥配施有机肥或配合秸秆还田较单施化肥明显提高了土壤的固碳速率,二者均是提高黄泥田生产力与固碳能力的双赢措施。</p>
DOI:10.11674/zwyf.2015.0609URLMagsci [本文引用: 1]
<p><strong>目的</strong> 探讨南方丘陵黄泥田不同施肥对耕层土壤有机碳固存及生产力的影响,促进区域农田固碳减排和作物高产。<strong>方法</strong> 基于32年的长期定位试验,研究不施肥(CK)、 单施化肥(NPK)、 化肥+牛粪(NPKM)、 化肥+全部稻草还田(NPKS)处理下,历年水稻产量、 代表性年份耕层土壤有机碳含量及固碳速率的变化。<strong>结果</strong> NPK、 NPKM、 NPKS处理下水稻历年平均产量分别较CK高67.1%、 88.1%和84.2%,差异显著,且NPKM、 NPKS处理与NPK处理间亦具有显著差异。NPK、 NPKM与NPKS处理耕层土壤有机碳历年平均含量比CK高8.9%~36.8%,其中NPKM最高且亦显著高于NPKS与NPK处理。与初始土壤相比,各处理有机碳含量增加1.84~5.26 g/kg。以每10年为评价周期,NPKM、 NPKS处理的固碳速率与CK及NPK差异均显著,其中双季稻年份NPKM与NPKS处理固碳速率分别是CK的2.38倍和1.98倍,是NPK处理的1.59倍与1.32倍,但NPK处理与CK间差异不显著。稻田系统年均有机碳输入与有机碳固存间存在极显著幂函数关系,施肥土壤有机碳含量变化与籽粒产量变化间亦呈极显著正相关。<strong>结论</strong> 南方黄泥田化肥配施有机肥或配合秸秆还田较单施化肥稳步提升水稻产量。长期不施肥土壤有机碳仍可维持低幅度增长,随着土壤有机碳含量升高,固碳效率逐步降低。化肥配施有机肥或配合秸秆还田较单施化肥明显提高了土壤的固碳速率,二者均是提高黄泥田生产力与固碳能力的双赢措施。</p>
DOI:10.11838/sfsc.20170305URL [本文引用: 1]
为了解西南黄壤性水稻土长期施肥效应,通过连续19年长期定位试验,分析了西南黄壤性水稻土单施化肥（NPK）、单施有机肥（M）、1/2有机肥和1/2化肥配施（0.5MNPK）、全量有机肥和全量化肥配施（MNPK）4种施肥模式对作物产量、氮肥利用率的影响及变化特征。结果表明：长期施用化肥或有机肥可显著增加作物产量,NPK、M、0.5MNPK、MNPK比CK分别显著增产56.2%、57.8%、65.0%、74.0%;各施肥处理氮肥偏生产力（PFP_N）、氮肥内部利用率（IE_N）、氮肥回收利用率（RE_N）、氮肥累积利用率（ARE_N）分别为10.9~20.7kg·kg~（-1）、44.7~53.8 kg·kg~（-1）、13.6%~19.6%、12.0%~16.9%,均以0.5MNPK最高,MNPK最低,高量氮肥施用导致氮肥利用率较低;长期单施化肥处理氮肥利用率随时间保持持平或呈下降趋势,施用有机肥的各处理氮肥利用率随时间呈显著上升趋势,尤其是氮肥累积利用率呈极显著上升趋势。长期施用有机肥尤其是有机无机配施作物产量稳定且氮肥利用率稳步提高。因此,常年高量施氮的黄壤性水稻土可适量减少氮肥用量,相应的进行有机无机肥料的合理配施是提高作物产量和肥料利用率的有效措施。
DOI:10.11838/sfsc.20170305URL [本文引用: 1]
为了解西南黄壤性水稻土长期施肥效应,通过连续19年长期定位试验,分析了西南黄壤性水稻土单施化肥（NPK）、单施有机肥（M）、1/2有机肥和1/2化肥配施（0.5MNPK）、全量有机肥和全量化肥配施（MNPK）4种施肥模式对作物产量、氮肥利用率的影响及变化特征。结果表明：长期施用化肥或有机肥可显著增加作物产量,NPK、M、0.5MNPK、MNPK比CK分别显著增产56.2%、57.8%、65.0%、74.0%;各施肥处理氮肥偏生产力（PFP_N）、氮肥内部利用率（IE_N）、氮肥回收利用率（RE_N）、氮肥累积利用率（ARE_N）分别为10.9~20.7kg·kg~（-1）、44.7~53.8 kg·kg~（-1）、13.6%~19.6%、12.0%~16.9%,均以0.5MNPK最高,MNPK最低,高量氮肥施用导致氮肥利用率较低;长期单施化肥处理氮肥利用率随时间保持持平或呈下降趋势,施用有机肥的各处理氮肥利用率随时间呈显著上升趋势,尤其是氮肥累积利用率呈极显著上升趋势。长期施用有机肥尤其是有机无机配施作物产量稳定且氮肥利用率稳步提高。因此,常年高量施氮的黄壤性水稻土可适量减少氮肥用量,相应的进行有机无机肥料的合理配施是提高作物产量和肥料利用率的有效措施。
DOI:10.1016/j.agwat.2018.07.002URL [本文引用: 3]
DOI:10.2136/sssaj2016.04.0107URL [本文引用: 1]
Long-term studies are extremely beneficial to understand and evaluate changes in soil quality and sustainability of specific management practices. The objectives of this study were to evaluate the effects of 70 yr of moldboard plowing with manure (M) and commercial fertilizer (F) additions on soil organic C (SOC), soil total N (STN), particulate organic matter (POM) and its associated C (POM-C), and mineral-associated organic matter C (MAOM-C). The Knorr-Holden plots were initiated in 1912 on a Tripp sandy loam (coarse-silty, mixed, superactive, mesic Aridic Haplustolls) with furrow irrigated, continuous-corn (Zea mays L.) production. In 2011, soil samples were collected from the 0-5, 5-10, 10-15, 15-30, 30-60, and 60-90 cm depths. Treatments were evaluated for the form of stability and distribution of SOC as POM, POM-C, and MAOM-C. On a fixed depth basis (FD), SOC and STN in the 0-30 cm layer increased by 2.3 fold compared with 30-60 cm layer and by 3 fold compared with 60-90 cm layer. Similar differences in SOC and STN were observed when calculated on an equivalent mass (ESM) basis. Compared with 90 and 180 kg N ha-1, application of manure with fertilizer (F+ M) increased POM content in 0-30 cm depth by 36% and 52% with 90+M and 180+M respectively. In the 0-15 cm soil depth, the relative POM-C to SOC content was 43% greater than in 15-30 cm soil depth. In the 15-30 cm depth, MAOM-C was 7% higher than the surface 0-15 cm depth. The MAOM-C represented 69% of SOC content associated with different treatments Positive and significant correlations were found among SOC, POM-C, and MAOM-C. Overall, manure-based amendments, with or without F, enhanced SOC and its distribution by depth between soil C pools investigated.
DOI:10.1016/j.still.2016.07.002URL [本文引用: 1]
Appropriate fertilizer management can effectively restrain decreases in soil carbon (C) and nitrogen (N) in agricultural Mollisols in northeast China. A 22-yr-old field experiment was employed to explore the effects of fallow, chemical fertilizer N, phosphorus (P), potassium (K), or straw or manure combined with NPK (SNPK, MNPK), and 1.5 times the N rate of MNPK (1.5MNPK) application on soil C and N pools. Soil organic C (SOC), total N (TN), inorganic C (IC), and mineral N (NO3-N, NH4-N) to 100cm soil depth and C and N in particulate organic matter (POC, PON), soil microbial biomass (MBC, MBN), and dissolved organic matter (DOC, DON) to 40cm soil depth were determined. In all treatments, the 1.5MNPK treatment had the significantly highest (P<0.05) SOC and TN concentrations above 40cm soil depth and the SNPK treatment had the significantly highest (P<0.05) IC concentration at 40–60 and 60–80cm soil depths. Comparing the other treatments to 40cm soil depth, in most cases 1.5MNPK and MNPK treatments at each depth had significantly higher (P<0.05) POC, PON concentration, POC/SOC and PON/TN. SNPK treatment had significantly higher (P<0.05) MBN and MBN/TN at 10–20 and 20–40cm soil depths and the fallow treatment had significantly higher (P<0.05) MBC and DOC concentrations and higher DOC/SOC ratio at each soil depth. The optimum combination of manure, straw and NPK therefore favored C and N storage in this agricultural Mollisol.
DOI:10.1016/j.scitotenv.2017.06.226URLPMID:28810521 [本文引用: 1]
The accumulation of soil organic carbon (SOC) in agricultural soils is critical to food security and climate change. However, there is still limited information on the dynamic trend of SOC sequestration following changes in cropping systems. Paddy soils, typical of temperate region of southern China, have a large potential for carbon (C) sequestration and nitrogen (N) fixation. It is of great importance to study the impacts of changes in cropping systems on stocks of SOC and total nitrogen (TN) in paddy soils. A six-year field experiment was conducted to clarify the dynamics of SOC and TN stocks in the paddy topsoil (0鈥20聽cm) when crop rotation of rice ( Oryza sativa L.) -garlic ( Allium sativum ) (RG) was changed to rice-fava ( Vicia faba L.) (RF), and to examine how the dynamics were affected by two N management strategies. The results showed that SOC stocks increased by 24.9% in the no N (control) treatment and by 18.9% in the treatment applied with conventional rate of N (CON), when RG was changed to RF. Correspondingly, TN stocks increased by 8.5% in the control but decreased by 2.6% in the CON. Compared with RG, RF was more conducive to increase the contents of soil microbial biomass C and N. Moreover, changing the cropping system from RG to RF increased the year-round N use efficiency from 21.6% to 34.4% and reduced soil N surplus in the CON treatment from 547 kg/ha to 93 kg/ha. In conclusion, changes in the cropping system from RG to RF could markedly increase SOC stocks, improve N utilization, reduce soil N surplus, and thus reduce the risk of N loss in the paddy soil. Overall, this study showed the potential of paddy agro-ecological systems to store C and maintain N stocks in the temperate regions.
URL [本文引用: 1]
以重庆市北碚区5种土地利用方式为研究对象,研究了土壤剖面有机碳和有机碳密度对土地利用方式变化的响应.结果表明：（1）土壤有机碳平均含量的多少顺序表现为水田变菜地,旱地变菜地,水田变果园,水田变旱地,旱地变果园;（2）水田变旱地、旱地变为果园后有机碳含量呈降低趋势,而旱地变为菜地后有机碳含量呈增加的趋势;（3）表层（020cm）土壤有机碳密度大小顺序表现为旱地变菜地,水田变菜地,水田变果园,旱地变果园,水田变旱地;而2060cm厚度土壤有机碳密度表现为变化前为水田的土壤有机碳密度大于变化前为旱地的土壤有机碳密度.
URL [本文引用: 1]
以重庆市北碚区5种土地利用方式为研究对象,研究了土壤剖面有机碳和有机碳密度对土地利用方式变化的响应.结果表明：（1）土壤有机碳平均含量的多少顺序表现为水田变菜地,旱地变菜地,水田变果园,水田变旱地,旱地变果园;（2）水田变旱地、旱地变为果园后有机碳含量呈降低趋势,而旱地变为菜地后有机碳含量呈增加的趋势;（3）表层（020cm）土壤有机碳密度大小顺序表现为旱地变菜地,水田变菜地,水田变果园,旱地变果园,水田变旱地;而2060cm厚度土壤有机碳密度表现为变化前为水田的土壤有机碳密度大于变化前为旱地的土壤有机碳密度.
DOI:10.1016/j.scitotenv.2017.09.183URLPMID:29054672 [本文引用: 1]
Abstract Optimizing the nitrogen (N) application rate can increase crop yield while reducing the environmental risks. However, the optimal N rates vary substantially when different targets such as maximum yield or maximum economic benefit are considered. Taking the wheat-maize rotation cropping system on the North China Plain as a case study, we quantified the variation of N application rates when targeting constraints on yield, economic performance, N uptake and N utilization, by conducting field experiments between 2011 and 2013. Results showed that the optimal N application rate was highest when targeting N uptake (240kgha -1 for maize, and 326kgha -1 for wheat), followed by crop yield (208kgha -1 for maize, and 277kgha -1 for wheat) and economic income (191kgha -1 for maize, and 253kgha -1 for wheat). If environmental costs were considered, the optimal N application rates were further reduced by 20-30% compared to those when targeting maximum economic income. However, the optimal N rate, with environmental cost included, may result in soil nutrient mining under maize, and an extra input of 43kgNha -1 was needed to make the soil N balanced and maintain soil fertility in the long term. To obtain a win-win situation for both yield and environment, the optimal N rate should be controlled at 179kgha -1 for maize, which could achieve above 99.5% of maximum yield and have a favorable N balance, and at 202kgha -1 for wheat to achieve 97.4% of maximum yield, which was about 20kgNha -1 higher than that when N surplus was nil. Although these optimal N rates vary on spatial and temporal scales, they are still effective for the North China Plain where 32% of China's total maize and 45% of China's total wheat are produced. More experiments are still needed to determine the optimal N application rates in other regions. Use of these different optimal N rates would contribute to improving the sustainability of agricultural development in China. Copyright 2017 Elsevier B.V. All rights reserved.
DOI:10.1016/j.fcr.2017.03.002URL [本文引用: 1]
North China Plain is the bread basket for Chinese. However, the over-use of N fertilizer has resulted serious environmental pollution and even threat the food security owing to the soil degradation in North China Plain. It is essential to develop a suit of optimal regional nitrogen application threshold. In this study, we attempted to build the threshold by using dataset of literature review and field experiments. Results showed that the optimal N fertilizer rate should be around 18502kg02N02ha 611 for the wheat cultivation with achieved yield at 700002kg02ha 611 . Both literatures reviewed and field experiments agreed well on this threshold. The wheat yield under this optimal N fertilizer rate was about 2% lower than the theory maximum achievable yield (720302kg02ha 611 ) in this region; however, the N rate could be reduced by 25% compared to the N rate under the maximum yield. This threshold entailed decreases of 25.25%, 20.17%, 27.89% and 38.80% in nitrogen application rates, residual inorganic soil nitrogen (0–10002cm), nitrate leaching and ammonia volatilization, respectively, on the regional scale. In addition, reducing theory maximum achievable yield by 2% was not statistically significant and would not result in additional risks because fluctuations in wheat yields over time (6157.07% to 34.73%) and space (6123.78% to 33.07%) were higher than 2% in this area.
DOI:10.1007/s10533-004-2222-3URL [本文引用: 1]
Topsoil is very sensitive to human disturbance under the changing climate. Estimates of topsoil soil organic carbon (SOC) pool may be crucial for understanding soil C dynamics under human land uses and soil potential of mitigating the increasing atmospheric CO60 by soil C sequestration. China is a country with long history of cultivation. In this paper, we present an estimate of topsoil SOC pool and cultivation-induced pool reduction of China soils based upon the data of all the soil types identified in the 2nd national soil survey conducted during 1979-1982. The area of cultivated soils of China amounted to 138 × 1068 ha while the uncultivated soils occupied 740 × 1068 ha in 1980. Topsoil SOC density ranged from 0.77 to 1489 t$\text{Cha}^{-1}$in uncultivated soils and 3.52 to 591 t$\text{Cha}^{-1}$in cultivated soils with the average being 50 ± 47 t$\text{Cha}^{-1}$and 35 ± 32 t$\text{Cha}^{-1}$, respectively. Geographically, the maximum mean topsoil SOC density was found in northeastern China, being of 70 ± 104 t$\text{Cha}^{-1}$for uncultivated soils and of 57 ± 54 t$\text{Cha}^{-1}$for cultivated soils, respectively. The lowest topsoil SOC density for uncultivated soils was found in East China, being of 38 ± 33 t$\text{Cha}^{-1}$and that for cultivated soils in North China, being of 30 ± 30 t$\text{Cha}^{-1}$. There is still uncertainty in estimating the total topsoil SOC of uncultivated soils because a large portion of them was not surveyed during the 2nd Soil Survey. However, an estimate of total SOC for cultivated soils amounted to 5.1 Pg. On average, cultivation of China's soils had induced a decrease of SOC density of 15 t$\text{Cha}^{-1}$giving rise to an overall pool reduction at 2 Pg. This is significantly smaller than the total SOC pool decline of 7 Pg due to cultivation of natural soils in China reported by Wu et al. (Glob, Change Biol, 2003, 9: 305-315), who made a pool estimation of whole soil profile assuming 1 m depth for all soils. As the mean topsoil SOC density of China was lower than the world average value given by Batjes (J. Soil Sci. 1996, 47: 151-163), China may be considered as a country with low SOC density and may have great potential for C sequestration under well defined management. However, the dynamics of topsoil C storage in China agricultural soils since 1980's and the effects of modern agricultural developments on C dynamics need further study for elucidating the role of China agriculture in global climatic change.
DOI:10.1016/j.scitotenv.2018.01.090URLPMID:29426159 [本文引用: 2]
Abstract This study analyzes the influence of various fertilizer management practices on crop yield and soil organic carbon (SOC) based on the long-term field observations and modelling. Data covering 1162years from 8 long-term field trials were included, representing a range of typical soil, climate, and agro-ecosystems in China. The process-based model EPIC (Environmental Policy Integrated Climate model) was used to simulate the response of crop yield and SOC to various fertilization regimes. The results showed that the yield and SOC under additional manure application treatment were the highest while the yield under control treatment was the lowest (30%-50% of NPK yield) at all sites. The SOC in northern sites appeared more dynamic than that in southern sites. The variance partitioning analysis (VPA) showed more variance of crop yield could be explained by the fertilization factor (42%), including synthetic nitrogen (N), phosphorus (P), potassium (K) fertilizers, and fertilizer NPK combined with manure. The interactive influence of soil (total N, P, K, and available N, P, K) and climate factors (mean annual temperature and precipitation) determine the largest part of the SOC variance (32%). EPIC performs well in simulating both the dynamics of crop yield (NRMSE62=6232% and 31% for yield calibration and validation) and SOC (NRMSE62=6213% and 19% for SOC calibration and validation) under diverse fertilization practices in China. EPIC can assist in predicting the impacts of different fertilization regimes on crop growth and soil carbon dynamics, and contribute to the optimization of fertilizer management for different areas in China.
DOI:10.1080/09064710.2018.1436722URL [本文引用: 2]
The availability of soil phosphorus (P) is one of the key factors that regulate crop productivity. Fertilization practices with P fertilizers carry a high risk of non-point environmental pollution due to water run-off and leaching. The present work discusses data from a 29–year (1982–2011) fertilization experiment with wheat–soybean rotation. Its aim was to quantify and evaluate the dynamic of... [Show full abstract]
DOI:10.1080/03650340.2012.704548URL [本文引用: 1]
DOI:10.1111/sum.2014.30.issue-4URL [本文引用: 2]
DOI:10.1007/s11104-017-3470-zURL [本文引用: 2]
react-text: 338 Enhance at the sustainability of inland Pacific Northwest cereal systems under changing climates and contribute to mitigation of greenhouse gas emissions from these systems. Supporting goals are (1…" /react-text react-text: 339 /react-text [more]
DOI:10.2134/agronj2007.0027cURL [本文引用: 1]
This article is a history of dryland (L.) farming in the low-precipitation (<300 mm annual) region on the Columbia Plateau of the Inland Pacific Northwest (PNW) of the United States. Numerous technological advances, environmental problems, and sociological factors influenced farming since its inception in 1880. The -based economy traces back to the pioneers who faced many challenges that included scarcity of and wood, unprecedented wind , drought, and minimal equipment. Throughout the years, major technological breakthroughs include: (i) () farming to crude crawler tractors to the 350+ power tractors of today, (ii) transition from sacked grain to bulk grain handling, (iii) fertilizer and herbicides, (iv) the rotary rodweeder, and (v) the deep furrow split-packer drill to allow early planting of winter into stored soil . Cultural practices have evolved from repeated passes with high-soil-disturbance tillage implements to today's conservation tillage management. The 2-yr winter ummer fallow rotation continues as the dominant cropping system as it is less risky and more profitable than alternative systems tested so far. Improved cultivars for deep furrow planting continue to be developed with good emergence, disease resistance, winter hardiness, grain quality, and other values. In the past 125 yr, average farm size has grown from 65 to 1400 ha and grain yield increased from <1.0 to 3.4 Mg ha-1. Since the 1930s, government farm programs have provided unwavering support that, in the last several decades, accounts for about 40% of gross farm income.
DOI:10.2136/sssaj2012.0184URL [本文引用: 1]
ABSTRACT The amount and type of C-containing amendments applied to soil can have an influence on soil organic carbon (SOC) levels. To test the hypothesis that amendment type is more important than amount, we applied 250 g C m-2 as manure, legume foliage, wheat (Triticum aestivum L.) residue, municipal biosolid, wood sawdust, brassica (Brassica napus L.) residue, composted wheat residue, sucrose, and cotton linters to both fallow soil and an annual winter wheat crop for five consecutive years. After an additional 3.5 yr with no inputs and all plots being fallow, the SOC of biosolid, manure, and wood amended plots were significantly (P < 0.0001) greater than the unamended check. The application of biosolid increased SOC 492 g m-2, and manure increased SOC 316 g m-2, over the fallow check plots in the top 300 kg m -2 of soil (approximately 0-25 cm). The increase in SOC relative to the check ranged from 0 to 39% of the amendment C applied. The SOC content was 482 g m-2 greater under continuous winter wheat than under fallow. The amendment and wheat crop effects on soil C and N changed little during the 3.5 yr after treatments ended, indicating that decomposition occurred soon after application. Wood sawdust was unique in that it increased SOC even though it was low in N content, and it changed the soil C/N ratio from 12.3 to 13.4. This field research demonstrated that amendments applied at the same C rate can have variable effects on SOC accretion.
DOI:10.1371/journal.pone.0103901URLPMID:4121199 [本文引用: 1]
Changes in soil microbiotic properties such as microbial biomass and community structure in response to alternative management systems are driven by microbial substrate quality and substrate utilization. We evaluated irrigated crop and forage production in two separate four-year experiments for differences in microbial substrate quality, microbial biomass and community structure, and microbial substrate utilization under conventional, organic, and reduced-tillage management systems. The six different management systems were imposed on fields previously under long-term, intensively tilled maize production. Soils under crop and forage production responded to conversion from monocropping to crop rotation, as well as to the three different management systems, but in different ways. Under crop production, four years of organic management resulted in the highest soil organic C (SOC) and microbial biomass concentrations, while under forage production, reduced-tillage management most effectively increased SOC and microbial biomass. There were significant increases in relative abundance of bacteria, fungi, and protozoa, with two- to 36-fold increases in biomarker phospholipid fatty acids (PLFAs). Under crop production, dissolved organic C (DOC) content was higher under organic management than under reduced-tillage and conventional management. Perennial legume crops and organic soil amendments in the organic crop rotation system apparently favored greater soil microbial substrate availability, as well as more microbial biomass compared with other management systems that had fewer legume crops in rotation and synthetic fertilizer applications. Among the forage production management systems with equivalent crop rotations, reduced-tillage management had higher microbial substrate availability and greater microbial biomass than other management systems. Combined crop rotation, tillage management, soil amendments, and legume crops in rotations considerably influenced soil microbiotic properties. More research will expand our understanding of combined effects of these alternatives on feedbacks between soil microbiotic properties and SOC accrual.
DOI:10.1007/s10661-018-6486-9URLPMID:29404781 [本文引用: 1]
The ever shrinking agricultural land availability and the swelling demand of food for the growing population fetch our attention towards utilizing partially reclaimed sodic soils for cultivation. In...
DOI:10.1016/j.scitotenv.2018.09.275URL [本文引用: 2]
DOI:10.1016/j.agwat.2018.08.036URL [本文引用: 1]
DOI:10.1007/s10705-018-9920-zURL [本文引用: 2]
Cultivation practices and nutrients management have a profound influence on soil productivity and the sequestration of soil organic carbon (SOC). However, there have been few integrated studies on...
DOI:10.1111/gcb.12438URLPMID:24132954 [本文引用: 2]
The impact of animal manure application on soil organic carbon (SOC) stock changes is of interest for both agronomic and environmental purposes. There is a specific need to quantify SOC change for use in national greenhouse gas (GHG) emission inventories. We quantified the response of SOC stocks to manure application from a large worldwide pool of individual studies and determined the impact of explanatory factors such as climate, soil properties, land use and manure characteristics. Our study is based on a meta-analysis of 42 research articles totaling 49 sites and 130 observations in the world. A dominant effect of cumulative manure-C input on SOC response was observed as this factor explained at least 53% of the variability in SOC stock differences compared to mineral fertilized or unfertilized reference treatments. However, the effects of other determining factors were not evident from our data set. From the linear regression relating cumulative C inputs and SOC stock difference, a global manure-C retention coefficient of 12% 卤 4 (95% Confidence Interval, CI) could be estimated for an average study duration of 18 years. Following an approach comparable to the Intergovernmental Panel on Climate Change, we estimated a relative SOC change factor of 1.26 0.14 (95% CI) which was also related to cumulative manure-C input. Our results offer some scope for the refinement of manure retention coefficients used in crop management guidelines and for the improvement of SOC change factors for national GHG inventories by taking into account manure-C input. Finally, this study emphasizes the need to further document the long-term impact of manure characteristics such as animal species, especially pig and poultry, and manure management systems, in particular liquid vs. solid storage.
DOI:10.1002/2013GB004746URL [本文引用: 1]
We determined the historical change in soil organic carbon (SOC) stocks from long-term inorganic fertilizer and/or organic manure trials (maize and wheat dominated rotations) that represent major soil types and climatic conditions of northern China. Soil carbon (RothC, Rothamsted, UK) and general circulation models (BCCR, Bjerknes Centre for Climate Research, Norway, and IPSL, Institute Pierre Simon Laplace, France) were validated using these field trial data sets. We then applied these models to predict future change in SOC stocks to 2100 using two net primary production (NPP) carbon input scenarios (i.e., current NPP or 1% yr-1 NPP increase). Here we show that the conversion rate of plant residues to SOC was higher in single-cropping sites than in double-cropping sites. The prediction of future SOC sequestration potential indicated that these soils will be a net source of carbon dioxide (CO2) under no fertilizer inputs. Even when inorganic nutrients were applied the additional carbon input from increased plant residues could not meet the depletion of SOC in parts of northern China. Manure or straw application could however improve the SOC sequestration potential at all study sites. The SOC sequestration potential in northern China was estimated to be 4.3 to 18.2 t C ha-1 by 2100. The effect of projected climate change on the annual rate of SOC change did not differ significantly between climate scenarios. The average annual rate of SOC change under current and increased NPP scenarios (when using the IPSL and BCCR models at 850 ppm CO2) was ca. 0.136 t C ha-1 yr-1
DOI:10.1016/j.scitotenv.2016.03.193URLPMID:27100005 [本文引用: 1]
61617.4–13.1% of total C input over 20–30years was accumulated as soil organic C in the top 20cm of soil6161SOC had relatively little impact on crop yield and its stability in northern China6161SOC significantly improved crop yield and its stability in southern China6161In south of China yield and its stability increased with SOC stocks up to a value of ~35Mg C ha611
[本文引用: 2]
DOI:10.1016/j.agee.2012.05.009URL [本文引用: 1]
Soil organic carbon is considered to be of central importance in maintaining soil quality. We assessed the effects of a range of commonly applied organic and inorganic amendments on soil quality in a rice–wheat cropping system in the Indo-Gangetic plains of eastern India and evaluated the carbon sequestration potential of such management approaches using a 25 year old long-term fertility experiment. Results showed that there were significant increases in soil nutrient availability with the application of farm yard manure (FYM @ 7.5tha611), paddy straw (PS @ 10tha611) and green manure (GM @ 8tha611) along with inorganic fertilizer. Both microbial biomass C and mineralizable C increased following the addition of the organic inputs. Continuous cultivation, without application of organic inputs, significantly depleted total C content (by 39–43%) compared with treatments involving the addition of organic amendments. A significant increase in the non-labile C fraction resulted from both organic and inorganic amendments, but only 26, 18 and 6% of the C applied through FYM, PS and GM, respectively was sequestered in soils. A significant increase in yield of kharif rice was observed as a result of the addition of these organic amendments.
DOI:10.1016/j.soilbio.2008.11.011URL [本文引用: 1]
The efficiency of agricultural management practices to store SOC depends on C input level and how far a soil is from its saturation level (i.e. saturation deficit). The C saturation hypothesis suggests an ultimate soil C stabilization capacity defined by four SOM pools capable of C saturation: (1) non-protected, (2) physically protected, (3) chemically protected and (4) biochemically protected. We tested if C saturation deficit and the amount of added C influenced SOC storage in measurable soil fractions corresponding to the conceptual chemical, physical, biochemical, and non-protected C pools. We added two levels of 13C-labeled residue to soil samples from seven agricultural sites that were either closer to (i.e., A-horizon) or further from (i.e., C-horizon) their C saturation level and incubated them for 2.5 years. Residue-derived C stabilization was, in most sites, directly related to C saturation deficit but mechanisms of C stabilization differed between the chemically and biochemically protected pools. The physically protected C pool showed a varied effect of C saturation deficit on 13C stabilization, due to opposite behavior of the POM and mineral fractions. We found distinct behavior between unaggregated and aggregated mineral-associated fractions emphasizing the mechanistic difference between the chemically and physically protected C-pools. To accurately predict SOC dynamics and stabilization, C saturation of soil C pools, particularly the chemically and biochemically protected pools, should be considered.
DOI:10.5194/bg-7-409-2010URL [本文引用: 1]
Soil carbon sequestration is a complex process influenced by agricultural practices, climate and soil conditions. This paper reports a study of long-term fertilization impacts on soil organic carbon (SOC) dynamic from six long-term experiments. The experiment sites are located from warm-temperate zone with a double-cropping system of corn (Zea mays L.) ??? wheat (Triticum Aestivium L.) rotation, to mild-temperate zones with mono-cropping systems of continuous corn, or a three-year rotation of corn-wheat-wheat. Mineral fertilizer applications result in an increasing trend in SOC except in the arid and semi-arid areas with the mono-cropping systems. Additional manure application is important to maintain SOC level in the arid and semi-arid areas. Carbon conversion rate is significant lower in the warm-temperate zone with double cropping system (6.8%???7.7%) than that in the mild-temperate areas with mono-cropping systems (15.8%???31.0%). The conversion rate is significantly correlated with annual precipitation and active accumulative temperature, i.e., higher conversion rate under lower precipitation and/or temperature conditions. Moreover, soil high in clay content has higher conversion rate than soils low in clay content. Soil carbon sequestration rate ranges from 0.07 to 1.461 t ha 1 year 1 in the upland of northern China. There is significantly linear correlation between soil carbon sequestration and carbon input at most sites, indicating that these soils are not carbon-saturated thus have potential to migrate more CO2 from atmosphere.
DOI:10.1111/j.1365-2486.2004.00863.xURL [本文引用: 1]
Eddy covariance was used to measure the net CO 2 exchange (NEE) over ecosystems differing in land use (forest and agriculture) in Thuringia, Germany. Measurements were carried out at a managed, even-aged European beech stand ( Fagus sylvatica , 70–150 years old), an unmanaged, uneven-aged mixed beech stand in a late stage of development ( F. sylvatica , Fraxinus excelsior , Acer pseudoplantanus , and other hardwood trees, 0–250 years old), a managed young Norway spruce stand ( Picea abies , 50 years old), and an agricultural field growing winter wheat in 2001, and potato in 2002. Large contrasts were found in NEE rates between the land uses of the ecosystems. The managed and unmanaged beech sites had very similar net CO 2 uptake rates (6561480 to 61500 g C m 612 yr 611 ). Main differences in seasonal NEE patterns between the beech sites were because of a later leaf emergence and higher maximum leaf area index at the unmanaged beech site, probably as a result of the species mix at the site. In contrast, the spruce stand had a higher CO 2 uptake in spring but substantially lower net CO 2 uptake in summer than the beech stands. This resulted in a near neutral annual NEE (614 g C m 612 yr 611 ), mainly attributable to an ecosystem respiration rate almost twice as high as that of the beech stands, despite slightly lower temperatures, because of the higher elevation. Crops in the agricultural field had high CO 2 uptake rates, but growing season length was short compared with the forest ecosystems. Therefore, the agricultural land had low-to-moderate annual net CO 2 uptake (6134 to 61193 g C m 612 ), but with annual harvest taken into account it will be a source of CO 2 (+97 to +386 g C m 612 ). The annually changing patchwork of crops will have strong consequences on the regions' seasonal and annual carbon exchange. Thus, not only land use, but also land-use history and site-specific management decisions affect the large-scale carbon balance.
DOI:10.2136/sssaj2004.0809URL [本文引用: 1]
In agricultural systems, maintenance of soil organic matter (SOM) has long been recognized as a strategy to reduce soil degradation. No-tillage and manure amendments are management practices that can increase SOM content and improve soil aggregation. We investigated the effects of 10-yr of different tillage systems and N sources on soil aggregate-size distribution and aggregate-associated C and N. The study was a split-plot design replicated four times. The main plot treatment was tillage (no-tillage, NT; conventional tillage, CT) and the subplot treatment was N source (manure, M; NH
DOI:10.1071/SR05156URL [本文引用: 1]
soil organic matter , soil water , modelling , land management , nutrients , soil rehabilitation , soil genesis , soil morphology and classification , minesite rehabilitation , erosion , effluent application , soil fertility and plant nutrition , soil biology and biochemistry , soil health , soil and water management and conservation , soil physics and hydrology , soil chemistry and mineralogy , soil pollution and waste disposal , tropical , Mediterranean , CSIRO , CSIRO PUBLISHING , publications , science , educational , scientific , journal , journals , Australia , Australian , international
DOI:10.1016/j.still.2009.09.003URL [本文引用: 1]
Fertilizer application has the potential to promote the sequestration of carbon (C) and nitrogen (N) in agricultural soils and thus may mitigate the effects of atmospheric greenhouse gases. In this study, the effects of fertilizer practices [i.e., no fertilizer (CK), chemical fertilizer (NPK), and chemical fertilizer plus low or high rates of organic manure (LOM or HOM)] on soil organic carbon (SOC) and total nitrogen (TN) content in the plow layer (0–20 cm) of paddy soils were examined using the data from eight long-term field experimental sites (1986–2003) in Hunan Province, Southern China. The SOC and TN content with the treatments which included N fertilizer (NPK, LOM, and HOM) ranged from 16.2 to 38.6 g kg 611 and from 1.07 to 3.92 g kg 611, respectively. Compared with the CK treatment, the average SOC and TN content were 2.0 and 19.3%, 29.3 and 5.2%, and 19.5 and 27.1% larger, respectively, for NPK, LOM, and HOM. In addition, the average values for SOC with the four treatments (CK, NPK, LOM, and HOM) had increased by 13.1, 15.4, 35.0, and 46.3%, respectively, by 2003; for TN they had increased by 5.0, 10.5, 25.5, and 33.5%, respectively, above the values obtained in 1986. However, the increase in SOC and TN content varied substantially at the different experimental sites. Organic–chemical fertilization gradually increased SOC and TN content and then the values tended to be stable with the LOM and HOM treatments from 1986 to 2003; they also remained stable for the NPK and CK treatments. Soil TN contents were significantly correlated with SOC at each site ( P < 0.001). Soil C/N ratios in 2003 were generally around 10 and usually ranged from 8.5 to 12.0. The soil C/N ratios among the four treatments were not significantly different at the eight sites in 2003. Nevertheless, the average C/N ratio at the eight sites was approximately 1.08 times higher than in 1986. The results indicate that there is a coupling relationship between SOC and TN in paddy soils in the subtropical region of China, a region that could provide C and N sinks under current fertilizer practices (i.e., combined chemical and organic fertilization) and cropping conditions. However, the results do suggest that the application of organic manure is the primary contributor to C and N sequestration.
DOI:10.1016/j.still.2007.06.011URL [本文引用: 1]
An 8-yr (1998–2005) field experiment was conducted on a Gray Luvisol (Boralf) soil near Star City, Saskatchewan, Canada, to determine the effects of tillage (no-tillage – NT and conventional tillage – CT), straw management (straw retained – R and straw not retained – NR) and N fertilizer (0, 40, 80 and 120 kg N ha 611, except no N to pea ( Pisum sativum L.) phase of the rotation) on seed and straw yield, mass of N and C in crop, organic C and N, inorganic N and aggregation in soil, and nitrous oxide (N 2O) emissions for a second 4-yr rotation cycle (2002–2005). The plots were seeded to barley ( Hordeum vulgare L.) in 2002, pea in 2003, wheat ( Triticum aestivum L.) in 2004 and canola ( Brassica napus L.) in 2005. Seed, straw and chaff yield, root mass, and mass of N and C in crop increased with increasing N rate for barley in 2002, wheat in 2004 and canola in 2005. No-till produced greater seed (by 51%), straw (23%) and chaff (13%) yield of barley than CT in 2002, but seed yield for wheat in 2004, and seed and straw yield for canola in 2005 were greater under CT than NT. Straw retention increased seed (by 62%), straw (by 43%) and chaff (by 12%) yield, and root mass (by 11%) compared to straw removal for barley in 2002, wheat in 2004, and seed and straw yield for pea in 2003. No-till resulted in greater mass of N in seed, and mass of C in seed, straw, chaff and root than CT for barley in 2002, but mass of N and C were greater under CT than NT for wheat in 2004 and for canola in 2005 in many cases. Straw retention had greater mass of N and C in seed, straw, chaff and root in most cases compared to straw removal for barley in 2002, pea in 2003 and wheat in 2004. Soil moisture content in spring was higher under NT than CT and with R than NR in the 0–15 cm depth, with the highest moisture content in the NT + R treatment in many cases. After eight crop seasons, tillage and straw management had no effect on total organic C (TOC) and N (TON) in the 0–15 cm soil, but light fraction organic C (LFOC) and N (LFON), respectively, were greater by 1.275 Mg C ha 611 and 0.031 Mg N ha 611 with R than NR, and also greater by 0.563 Mg C ha 611 and 0.044 Mg N ha 611 under NT than CT. There was no effect of tillage, straw and N fertilization on the NH 4-N in soil in most cases, but R treatment had higher NO 3-N concentration in the 0–15 cm soil than NR. The NO 3-N concentration in the 0–15, 15–30 and 30–60 cm soil layers increased (though small) with increasing N rate. The R treatment had 6.7% lower proportion of fine (<0.83 mm diameter) and 8.6% greater proportion of large (>38.0 mm) dry aggregates, and 4.5 mm larger mean weight diameter (MWD) compared to NR treatment. This suggests a lower potential for soil erosion when crop residues are retained. There was no beneficial effect of elimination of tillage on soil aggregation. The amount of N lost as N 2O was higher from N-fertilized (580 g N ha 611) than from zero-N (155 g N ha 611) plots, and also higher in CT (398 g N ha 611) than NT (340 g N ha 611) in some cases. In conclusion, retaining crop residues along with no-tillage improved some soil properties and may also be better for the environment and the sustainability of high crop production. Nitrogen fertilization improved crop production and some soil quality attributes, but also increased the potential for NO 3-N leaching and N 2O-N emissions, especially when applied in excess of crop requirements.
DOI:10.3969/j.issn.1674-5906.2014.10.001 [本文引用: 1]
碳氮共济的概念体现了二者间共同依赖、共同转化、共同协作的关系，将土壤碳和氮均作为改善土壤质量的主动因素，这一概念有别于其它碳氮关系论述时只考虑元素间的被动耦合机制。土壤碳和氮之间存在着相互依存和相互制约的关系，土壤碳、氮在数量上和结构上需要处于什么样的状态才能够实现土壤碳氮的共济关系，土壤碳对氮有多大的承载能力等是值得探讨的问题。文章利用我国长期定位试验中的土壤碳氮数据，分析土壤的碳氮质量分数变化特征、施肥对土壤w（C）/w（N）比的影响、土壤碳对氮素的储存能力、碳氮共济关系及其情景分析，以便为充分挖掘土壤碳氮的生物学潜力、提高土壤生产力、改善环境和实现碳氮的良性循环提供依据。通过检索文献数据库，选取了69篇记载有土壤碳氮数据的有代表性的文章，获得土壤碳氮数据1782项。分析结果表明：土壤碳氮关系可以用yC＝7.66xN＋1.8162（r2＝0.734＊＊, n=737）表达，土壤平均全氮质量分数为1.17 g·kg-1，变化范围在0.08~3.52 g·kg-1之间，土壤平均有机碳质量分数为10.8 g·kg-1，变化范围在0.64~32.08 g·kg-1之间；土壤w（C）/w（N）比集中在7.6~10.7之间，占总样本的80%左右，有机无机配施有利于提高土壤的w（C）/w（N）比，单施化肥，特别是偏施某一种化肥时，将显著降低土壤的w（C）/w（N）比；在土壤氮素储存率为N 20 kg·hm-2·a-1，目标w（C）/w（N）比为9、10、11的情景下，目前已经处于碳饱和的土壤分别占：52.7%、72.1%、87.5%；储存率为N 50 kg·hm-2·a-1的情景下分别占：58.2%、78.2%、91.4%；储存率为N 100 kg·hm-2·a-1的情景下分别占68.7%、87.6%、95.8%。土壤碳氮质量分数变异很大，总体碳氮比稳定在7.66左右，偏施化肥将显著降低土壤的w（C）/w（N）比，较低的土壤w（C）/w（N）比和较高的氮素储
DOI:10.3969/j.issn.1674-5906.2014.10.001 [本文引用: 1]
碳氮共济的概念体现了二者间共同依赖、共同转化、共同协作的关系，将土壤碳和氮均作为改善土壤质量的主动因素，这一概念有别于其它碳氮关系论述时只考虑元素间的被动耦合机制。土壤碳和氮之间存在着相互依存和相互制约的关系，土壤碳、氮在数量上和结构上需要处于什么样的状态才能够实现土壤碳氮的共济关系，土壤碳对氮有多大的承载能力等是值得探讨的问题。文章利用我国长期定位试验中的土壤碳氮数据，分析土壤的碳氮质量分数变化特征、施肥对土壤w（C）/w（N）比的影响、土壤碳对氮素的储存能力、碳氮共济关系及其情景分析，以便为充分挖掘土壤碳氮的生物学潜力、提高土壤生产力、改善环境和实现碳氮的良性循环提供依据。通过检索文献数据库，选取了69篇记载有土壤碳氮数据的有代表性的文章，获得土壤碳氮数据1782项。分析结果表明：土壤碳氮关系可以用yC＝7.66xN＋1.8162（r2＝0.734＊＊, n=737）表达，土壤平均全氮质量分数为1.17 g·kg-1，变化范围在0.08~3.52 g·kg-1之间，土壤平均有机碳质量分数为10.8 g·kg-1，变化范围在0.64~32.08 g·kg-1之间；土壤w（C）/w（N）比集中在7.6~10.7之间，占总样本的80%左右，有机无机配施有利于提高土壤的w（C）/w（N）比，单施化肥，特别是偏施某一种化肥时，将显著降低土壤的w（C）/w（N）比；在土壤氮素储存率为N 20 kg·hm-2·a-1，目标w（C）/w（N）比为9、10、11的情景下，目前已经处于碳饱和的土壤分别占：52.7%、72.1%、87.5%；储存率为N 50 kg·hm-2·a-1的情景下分别占：58.2%、78.2%、91.4%；储存率为N 100 kg·hm-2·a-1的情景下分别占68.7%、87.6%、95.8%。土壤碳氮质量分数变异很大，总体碳氮比稳定在7.66左右，偏施化肥将显著降低土壤的w（C）/w（N）比，较低的土壤w（C）/w（N）比和较高的氮素储
DOI:10.1016/j.soilbio.2004.06.006URL [本文引用: 1]
We investigated the relationship between soil organic matter (SOM) content and N dynamics in three grassland soils (0–10 and 10–20 cm depth) of different age (6, 14 and 50 y-old) with sandy loam textures. To study the distribution of the total C and N content the SOM was fractionated into light, intermediate and heavy density fractions of particulate macro-organic matter (150–2000 μm) and the 50–150 μm and <50 μm size fractions. The potential gross N transformation rates (mineralisation, nitrification, NH 4 + and NO 3 61 immobilization) were determined by means of short-term, fully mirrored 15N isotope dilution experiments (7-d incubations). The long-term potential net N mineralisation and gross N immobilization rates were measured in 70-d incubations. The total C and N contents mainly tended to increase in the 0–10 cm layer with increasing age of the grassland soils. Significant differences in total SOM storage were detected for the long-term (50 y-old) conversion from arable land to permanent grassland. The largest relative increase in C and N contents had occurred in the heavy density fraction of the macro-organic matter, followed by the 50–150 and <50 μm fractions. Our results suggest that the heavy density fraction of the macro-organic matter could serve as a good indicator of early SOM accumulation, induced by converting arable land to permanent grassland. Gross N mineralisation, nitrification, and (long-term) gross N immobilization rates tended to increase with increasing age of the grasslands, and showed strong, positive correlations with the total C and N contents. The calculated gross N mineralisation rates (7-d incubations) and net N mineralisation rates (70-d incubations) corresponded with a gross N mineralisation of 643, 982 and 1876 kg N ha 611 y 611, and a net N mineralisation of 195, 208 and 274 kg N ha 611 y 611 in the upper 20 cm of the 6, 14 and 50 y-old grassland soils, respectively. Linear regression analysis showed that 93% of the variability of the gross N mineralisation rates could be explained by variation in the total N contents, whereas total N contents together with the C-to-N ratios of the <50 μm fraction explained 84% of the variability of the net N mineralisation rates. The relationship between long-term net N mineralisation rates and gross N mineralisation rates could be fitted by means of a logarithmic equation (net m=0.24Ln(gross m)+0.23, R 2=0.69, P<0.05), which reflects that the ratio of gross N immobilization-to-gross N mineralisation tended to increase with increasing SOM contents. Microbial demand for N tended to increase with increasing SOM content in the grassland soils, indicating that potential N retention in soils through microbial N immobilization tends to be limited by C availability.
DOI:10.1016/S0269-7491(98)80060-2URL [本文引用: 1]
Relationships between nitrogen (N) output with seepage water and forest floor C/N ratios were analysed by use of three independent datasets: (i) a compilation of input-output studies in temperate forest ecosystems in Europe; (ii) a seven-year nationalDanish survey of nitrate concentrations in forest soils; and (iii) a similar one year Dutch survey. Nitrate leaching and nitrate concentrations were negatively correlated with forest floor C/N ratios in all three datasets, though the correlation was weakin the Dutch dataset. Sites with a C/N ratio below 25 leached nitrate or had elevated nitrate concentration in the three datasets. Nitrate was not present in the subsoil at sites with C/N ratios above 30 in the European and Danish data. In the less intensively monitored Dutch forest soils nitrate concentrations at C/N ratios above 30 were variable. Forest floor C/N ratios may be used to assess risk for nitrate leaching in conifer stands using>30, 25 to 30, and <25 to separate low, moderate, and high nitrate leaching risk, respectively.
DOI:10.1016/j.fcr.2014.02.014URL [本文引用: 1]
The aim of this study is to observe the N balance of a summer-maize/winter-wheat double cropping system of the North China Plain (NCP), using data from a static field experiment that was conducted in a previously over-fertilized farmer's field. Two reduced N treatments that were fertilized by adjusting N supply to crop N demand (UREA: urea; ASNDMPP: ammoniumsulphate nitrate+3,4,-dimethylpyrazolephoshate) are compared to common farmers’ practice (FP: urea, 550kgNha611a611) and to a control treatment (CK). Further, this research aims to estimate the importance of N mineralization for N supply in an intensive maize/wheat cropping system in order to better understand seasonal N dynamics in an over-fertilized system. The results of the experiment show that the N surplus (fertilized N61grain N) as well as the N balance (N Input61N Output) after harvest are significantly lower for the optimized treatments (Surplus: 6125kg to 98kgNha611; Balance: 6136 to 102kgNha611) compared to FP (Surplus: 156kg to 187kgNha611; Balance: 56–262kgNha611). This leads to lower residual N in the soil horizon from 0 to 90cm in the reduced treatments (113kgNha611 at end of experiment) compared to FP (293kgNha611). Mineralization of N, which occurs mainly in the spring vegetation period of wheat and during the summer vegetation period of maize, plays a substantial role in N supply to the summer-crop. Apparent net N mineralization of the CK treatment was 161kgNha611 for the first vegetation period of maize in 2009, decreasing to 27kgNha611 over the following two vegetation periods. The two intermittent periods of winter-wheat showed an apparent net mineralization of 64 and 84kgNha611, that did not influence yield formation. It is therefore likely that N mineralized during the spring vegetation period is carried over to the following vegetation period of summer-maize. In contrast to the CK treatment, an apparent net N loss was determined for all vegetation periods of summer maize in the FP treatment and for the first two vegetation periods of maize in the reduced treatments, even though mineralization in excess of the CK treatment was observed in an in situ mineralization experiment. The results show that the N balance in previously over-fertilized farmers’ fields of the NCP can be reduced by estimating crop N demand. Further, mineralization of N is an important factor both for N supply of crops, as well as for the loss of N during the summer vegetation periods and must be taken into consideration if N application rates in the NCP should be further reduced.
DOI:10.1016/j.agee.2005.06.006URL [本文引用: 1]
The efficacy of ‘Good Agricultural Practices’ (GAP) for reducing nitrate pollution is tested on the scale of a small catchment area (187 ha) which is almost entirely under arable agriculture. GAP have been introduced on all fields since 1990. They consist in applying carefully planned N fertiliser recommendations, establishing catch crops (CC) before spring crops and recycling all crop residues. Soil water and mineral nitrogen (SMN) were measured three times each year on 36 sites representative of crops (wheat, sugarbeet, pea, barley, oilseed rape) and soil materials (loam, loamy clay and rocks, sand loam and limestone, sand) during 8 years (1991–1999). These measurements (about 3600 soil samples) were used in LIXIM model to calculate water and nitrogen fluxes below the rooting zone. The model could reproduce satisfactorily the water and SMN contents measured at the end of winter. It simulated reasonably well the nitrate concentration measured in the subsoil (3–10 m deep) of nine fields. The mean calculated amounts of drained water and leached nitrogen below the rooting depth were 231 mm year 611 and 27 kg N ha 611 year 611, corresponding to a nitrate concentration of 49 mg L 611. Leached N varied by a five-, four- and three-fold factor according to the year, crop and soil type, respectively. Nitrate concentration was primarily affected by soil type: it varied from 31 mg L 611 in deep loamy soils to 92 mg L 611 in shallow sandy soils, and was linked to the soil water holding capacity. The sugarbeet–wheat rotation gave the lowest concentration (38 mg L 611) and the pea–wheat rotation the highest one (66 mg L 611). In spite of their moderate growth (mean biomass = 0.8 Mg ha 611), the catch crops allowed to reduce the mean concentration by 50% at the annual scale and 23% at the rotation scale. Straw incorporation was also beneficial since net mineralisation between harvest and late autumn was reduced by 24 kg N ha 611 when straw residues were incorporated. Reducing fertilisation below the recommended rate did not significantly reduce further nitrate leaching. Although GAP were not all optimal and therefore less efficient than in well controlled experiments, they appear essential in intensive agriculture in order to comply with the EU standard for nitrate concentration.
DOI:10.1016/S0065-2113(05)88002-2URL [本文引用: 1]
DOI:10.1016/j.still.2014.09.020URL [本文引用: 1]
Dissolved organic matter (DOM) plays an important role in soil biological activity and transport of pollutants and nutrients in soils, but very little information is available with regard to the long-term impact of agricultural management practices on the dynamics and fate of DOM in acidic soils. The seasonal and inter-annual variation of dissolved organic carbon (DOC) and nitrogen (DON) contents and leaching were investigated in an acidic clay soil (Ferric Acrisol) by a long-term field lysimeter experiment in subtropical China. The experiment was conducted from 2002 to 2010 with 4 fertilization treatments under maize monoculture: no manure (CK), low-rate manure with 150kgNha611y611 (LM), high-rate manure with 600kgNha611y611 (HM), and high-rate manure with 600kgNha611y611 and lime at 3000kg Ca(OH)2ha6113y611 (HML). Manure application resulted in a seasonal variation of soil DOC and DON, and significant effects were observed by manure DOC, microbial biomass and soil water content. Soil DOC, which was mainly determined by soil organic matter and soil water content, increased yearly until the seventh year when it was stabilized. Manure application on acidic clay soil did not alter DOC leaching, whereas DON leaching clearly increased after three years of high manure application of 600kgNha–1y–1. The average annual DON leaching losses under long-term manure application had a range of 3.8–5.4kgha–1, accounting for 6–11% of total nitrogen leached. The addition of lime, combined with manure application, produced no impact on soil dynamics and leaching of DOC and DON, with the exception of increasing emission of CO2.
DOI:10.1016/j.still.2008.05.015URL [本文引用: 1]
The physical quality of the soil, which creates suitable environment for the availability and uptake of the plant nutrients, is generally ignored. Though the effect of organic manures on soil physical quality has been widely appreciated but that of inorganic fertilizers is studied to a lesser extent. The present study carried out during 2004–2005 aims to characterize the soil physical quality in relation to the long-term (32 years) application of farmyard manure (FYM) and inorganic fertilizers in maize ( Zea mays L.) wheat ( Triticum aestivum L.) cropping system. The treatments during both maize and wheat crops were (i) farm yard manure at 20 Mg ha 611 (FYM), (ii) nitrogen at 100 kg ha 611 (N 100), (iii) nitrogen and phosphorus at 100 and 50 kg ha 611 (N 100P 50) and (iv) nitrogen, phosphorus and potassium at 100, 50 and 50 kg ha 611 (N 100P 50K 50) in addition to (v) control treatment, i.e. without any fertilizer and/or FYM addition. The treatments were replicated four times in randomized block design in a sandy loam (Typic Ustipsament, non-saline, slightly alkaline). Bulk density, organic carbon content, structural stability of soil aggregates and water holding capacity of 0–60 cm soil layer were measured. The application of FYM to maize increased the organic carbon by 16% whereas N 100P 50K 50 increased it by 21%. The increased organic matter with both FYM and N 100P 50K 50 increased the total soil porosity and decreased soil bulk density from that in control plots. The mean weight diameter (MWD) was highest in FYM plots of both maize (0.160 mm) and wheat (0.172 mm) closely followed by that in N 100P 50K 50 plots. The effect of FYM in increasing the MWD decreased with soil depth. The average water holding capacity (WHC) was higher with FYM and N 100P 50K 50 application than that in control plots. The MWD, total porosity, OC content and WHC improved with the application of balanced application of fertilizers. The grain yield and uptake of N, P and K by both maize and wheat were higher with the application of FYM and inorganic fertilizers than in control plots. The uptake of N, P and K increased with the application of FYM and N 100P 50K 50.
DOI:10.1016/j.still.2004.05.003URL [本文引用: 1]
Soil organic matter is an ecosystem component with agronomic and environmental functions and is affected by soil management. The objectives of this study were to evaluate (i) soil organic C and N losses during a period of conventional cultivation (1969–1983) that followed on native grassland and (ii) the potential of four long-term (17 years) no-till cereal- and legume-based cropping systems (bare soil, oat ( Avena strigosa Schreb.)/maize ( Zea mays L.), lablab ( Lablab purpureum L. Sweet) + maize and pigeon pea ( Cajanus cajan L. Millsp.)+maize) with different N fertilisation levels (0 and 180 kg N ha 611 year 611) to increase the C and N stocks of a southern Brazilian Acrisol. Samples were taken from 0 to 107.5 cm depth, in 10 soil layers. The C content in the 0–17.5 cm layer of grassland decreased by 22% (8.6 Mg C ha 611) during the period of conventional cultivation. Meanwhile, N decreased by 14% (0.44 Mg N ha 611). Additional C and N losses occurred after the establishment of bare soil and oat/maize (no N). With N fertilisation, the C and N stocks of oat/maize were steady with time. Legume-based cropping systems (lablab + maize and pigeon pea + maize) increased C and N stocks due to the higher residue input. Although the major soil management effects were found in the 0–17.5 cm layer, up to 24% of the overall C losses and up to 63% of the gains of the whole 0–107.5 cm layer occurred below the 17.5 cm depth, reinforcing the importance of subsoil as a C source or sink. The average C sequestration rate of legume-based cropping systems (with N) was 0.83 Mg C ha 611 year 611 in the top 0–17.5 cm layer and 1.42 Mg C ha 611 year 611 in the whole 0–107.5 cm layer, indicating the remarkable potential of legume cover crops and N fertilisation under no-tillage to improve SOM stocks and thus, soil and environmental quality in humid subtropical regions.
DOI:10.1016/S0269-7491(98)80068-7URL [本文引用: 1]
We evaluate the relationship between the carbon-to-nitrogen ratio (C:N) of the soil organic horizon and nitrate leaching in runoff or seepage water from 33 conifer forests across Europe. The sites span a geographical range covering 11 countries from Ireland to western Russia and Finland to the southern Alps, and encompass a wide range in throughfall nitrogen deposition. The aim of the study is to evaluate the hypothesis that the C:N ratio of the organic (OH) horizon can be used to estimate the level of leaching of nitrate from a forest ecosystem. The analysis suggests that C:N ratio can be an indicator of nitrate leaching for conifer forests across Europe if these ecosystems are grouped into broad categories of throughfall nitrogen deposition. At low levels of N deposition (< 10 kg N ha
DOI:10.1016/S0269-7491(98)80060-2URL [本文引用: 1]
Relationships between nitrogen (N) output with seepage water and forest floor C/N ratios were analysed by use of three independent datasets: (i) a compilation of input-output studies in temperate forest ecosystems in Europe; (ii) a seven-year nationalDanish survey of nitrate concentrations in forest soils; and (iii) a similar one year Dutch survey. Nitrate leaching and nitrate concentrations were negatively correlated with forest floor C/N ratios in all three datasets, though the correlation was weakin the Dutch dataset. Sites with a C/N ratio below 25 leached nitrate or had elevated nitrate concentration in the three datasets. Nitrate was not present in the subsoil at sites with C/N ratios above 30 in the European and Danish data. In the less intensively monitored Dutch forest soils nitrate concentrations at C/N ratios above 30 were variable. Forest floor C/N ratios may be used to assess risk for nitrate leaching in conifer stands using>30, 25 to 30, and <25 to separate low, moderate, and high nitrate leaching risk, respectively.
