,南京农业大学资源与环境科学学院/江苏省固体有机废弃物资源化研究重点实验室,南京210095The Potential and Related Mechanisms of Increasing Rice Yield by Reducing Chemical Nitrogen Application in Jiangsu Province
GUO JunJie, CHAI YiXiao, LI Ling, GAO LiMin, XIE KaiLiu, LING Ning, GUO ShiWei,College of Resources and Environmental Sciences, Nanjing Agricultural University/Jiangsu Provincial Key Laboratory of Solid Organic Waste Utilization, Nanjing 210095通讯作者:
收稿日期:2018-07-6接受日期:2018-12-17网络出版日期:2019-03-01
| 基金资助: |
Received:2018-07-6Accepted:2018-12-17Online:2019-03-01
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郭俊杰, 柴以潇, 李玲, 高丽敏, 谢凯柳, 凌宁, 郭世伟. 江苏省水稻减肥增产的潜力与机制分析[J]. 中国农业科学, 2019, 52(5): 849-859 doi:10.3864/j.issn.0578-1752.2019.05.007
GUO JunJie, CHAI YiXiao, LI Ling, GAO LiMin, XIE KaiLiu, LING Ning, GUO ShiWei.
0 引言
【研究意义】水稻是中国最主要的粮食作物之一,其产量的提高对于保障中国乃至全世界的粮食安全至关重要。氮素作为决定水稻产量的一个关键因素,是水稻生产投入的主要部分[1]。化肥养分尤其是氮肥投入的增加,为水稻的持续增产发挥了重要的作用[2]。但是,由于农户对氮肥增产的盲目信赖,导致当前中国与世界其他水稻主产国相比氮肥施用量偏高而利用率则显著偏低[2]。作为中国主要的水稻生产优势集中区,江苏省的稻田种植同样存在氮肥过量施用的现象,其氮肥平均施用量超过300 kg·hm-2,水稻氮肥利用效率普遍偏低[3,4,5,6]。因此,当前江苏省水稻生产中的氮肥利用状况以及氮肥减量管理改良措施是国家和社会关注的焦点问题。【前人研究进展】位于江苏省内的一些长期定位试验的研究结果证实,在当地农户施肥水平下（270—300 kg·hm-2）,水稻季氮肥用量减量20%—30%是可行的,对产量没有显著影响[7,8]。JU等[9]研究同样表明,通过采用最佳氮肥施用技术,可以在不损失水稻产量的基础上减少1/3的氮肥投入量。此外,国际水稻研究所（IRRI）提出的实地氮肥管理（SSNM）系统已被证明在氮肥效率提高和籽粒产量增加方面具有显著作用,其可以在降低氮肥施用量10%—16%的同时实现产量提高14.4%,农学利用率提高64.1%[10]。黄进宝等[11]通过田间试验与15N微区试验相结合,研究表明该地区水稻的经济生态适宜施氮量应该在219—255 kg·hm-2。宁运旺等[12]依据肥料效应函数法,推荐江苏省水稻最佳经济施氮量为（246.8±42.5）kg·hm-2,而当采用兼顾作物产量、效益和生态环境的氮素归还指数法时,其推荐施氮量则继续下调为（216.9±27.3）kg·hm-2。【本研究切入点】以往针对稻田氮肥减量施用的研究主要是基于一个或几个长期定位试验而进行的分析,角度比较单一,缺乏普遍的区域指导意义。本研究从宏观区域尺度出发,以江苏省为研究重点,采用农户调研结合整合分析的方法,进行大样本数据的综合定量分析,研究水稻实际生产过程中氮肥施用现状与问题,同时评价氮肥减量施用对水稻产量形成和氮素吸收利用的整体影响及其可行性。【拟解决的关键问题】本研究立足于江苏省,通过农户问卷调研以及对已发表文献数据的收集与整合分析,定量评价水稻化学氮肥减量施用的可行性以及最佳减量施用条件,从而为江苏省水稻生产管理提供科学的施肥措施和决策依据。1 材料与方法
1.1 农户调研
农户调研采用分层抽样的方法,根据江苏省的区域气候环境条件和经济发展特征,由北向南共选取约30个市（县）,每市（县）选取1—2个乡（镇）,每乡（镇）选择选取1—2个村,每村随机选取 6—8家农户进行问卷调查。农户调研数据必须包括农户的基本信息、农户在水稻生产过程中的化学氮肥投入量以及水稻产量情况。调研时间为2008—2014年,最终共筛选出有效问卷1 502份。1.2 水稻化学氮肥减量效应的数据库构建
通过中国知网（CNKI）、谷歌学术（Google Scholar）等数据库,基于“水稻（rice）”和（and）“减氮（reducing nitrogen）、优化施氮（optimizing nitrogen）、氮肥管理（nitrogen management）”等关键词,检索2000年1月至2017年7月期间已发表的关于水稻氮肥减量的同行评审文献。文献筛选标准如下：（1）试验地点为江苏省内区域;（2）必须是田间试验,排除室内盆栽或模拟试验等;（3）试验设有对照组（当地传统/常规施氮量）与试验组（氮肥减量）,且至少有3次重复;（4）对照组与试验组均有明确的氮肥施用量;（5）排除缓（控）释肥、硝化抑制剂、脲酶抑制剂、机械深施等特殊施肥技术的施肥试验;（6）数据至少含有水稻产量、产量构成（穗数、穗粒数、结实率、千粒重）、氮素吸收量、氮肥偏生产力等指标中的一项;（7）不同发表文献中的同一试验数据只纳入一次;（8）只考虑化学氮肥的减量。最终通过标准筛选出49篇符合要求的试验性研究文献。利用搜集的文献,建立水稻化学氮肥减量效应数据库。所有指标参数的相关数据直接从文献中获取。对于数据以图形展示的文献,通过GetData Graph Digitizer 2.24 软件,将图形数值化后再提取。为了比较不同因素对水稻氮肥减量效应的影响,根据水稻品种（粳稻和籼稻）、减量方式（直接减量、减量+养分运筹、减量+增施有机肥（秸秆）、减量+增施有机肥（秸秆）+养分运筹）、减量比例（≤25%、25%—50%、>50%）。此外,根据土壤基础地力[13]的定义,以不施（氮）肥区水稻产量作为表征土壤基础地力的数据,将数据按<5.5、5.5—7、>7 t·hm-2分为低、中、高土壤基础地力。
1.3 农户调研数据分析
农户水稻生产过程中的施氮量按其所用化肥产品的实际含氮量折算,最终以纯氮量（kg·hm-2）表示。氮肥效率用氮肥偏生产力（PFPN,Partial factor productivity of applied nitrogen）（kg·kg-1）,即单位面积水稻籽粒产量与单位面积施氮量的比值表示,该指标适用于农户调研数据中化肥效率的分析[14]。1.4 水稻化学氮肥减量效应meta分析
使用响应比（response ratio,简称RR ）的自然对数（lnRR ）作为水稻氮肥减量相关考虑指标的效应值（L ）[15]：L =lnRR =ln(Xt/Xc) （1）
式中,Xt和Xc是某一指标试验组和对照组的平均值。
通过以下公式计算加权累积效应值（RR++）[16]：
RR++=$\sum\limits_{i=\text{1}}^{j}{{{w}_{i}}{{L}_{i}}\text{/}}\sum\limits_{i=\text{1}}^{j}{{{w}_{i}}}$ （2）
式中,j 是试验组和对照组成对比较的总数,w 是单个数据对效应值的权重,L 是单个数据效应值。由于本研究中所搜集的文献绝大多数未展示平均值的标准差或者标准误,因此效应值的权重（w ）基于样本重复数进行计算[17]：
w =(Nt×Nc)/(Nt+Nc) （3）
式中,Nt和Nc是试验组和对照组的样本重复数。
利用 MetaWin 2.1中的重取样（resampling tests）和靴襻法（bootstrap CI）（4 999次迭代次数）[18,19],确定95%置信区间（CI）,并用偏差校正法（bias- corrected method） 进行校正。同时使用随机检验法（randomization test）,判断组间差异的显著性。
为了便于解释,将 lnRR 的分析结果转化成变化百分比（percentage changes）[16]：
Percentage changes =（RR -1)×100% （4）
式中,若 RR =1,即变化百分比为 0,表明试验组和对照组没有差异;若 RR >1,则说明产生了正效应,氮肥减量导致相关指标的增加; 若 RR <1, 则说明产生了负效应,氮肥减量导致相关指标的减少。
2 结果
2.1 江苏省水稻生产与化学氮肥施用现状
如图1所示,江苏省农户调研所获得的水稻产量（图1-a）、施氮量（图1-b）及氮肥偏生产力（图1-c）的数据符合偏正态分布。江苏省农户水稻产量为 （8 273± 1 062）kg·hm-2,变化范围在3 571—12 998 kg·hm-2,变异系数为12.83%;水稻施氮量为（358.10±98.73）kg·hm-2,变化范围在94.88—699.75 kg·hm-2,变异系数为27.57%;水稻氮肥偏生产力为（25.12±8.90）kg·kg-1,变化范围在8.14—88.93 kg·kg-1,变异系数为35.44%。图1
新窗口打开|下载原图ZIP|生成PPT图1江苏省农户水稻产量（a）、施氮量（b）、氮肥偏生产力（c）的分布
曲线表示数据的正态分布,虚线表示数据的上、下内限（即上、下四分位至1.5倍四分位距的点的值）,Mean表示数据的算术平均值,SD表示数据的标准差,C.V.表示数据的变异系数,Sk表示数据的偏度,Bk表示数据的峰度,n表示数据的样本量
Fig. 1Distribution of rice yield (a), nitrogen rate (b) and PFPN (c) of farmer’s practice in Jiangsu Province
The solid line is normal distribution, and the dashed line is the upper and lower limit lines of data. The value of Mean, SD, C.V., Sk, Bk and n denote the mean, standard deviation, variable coefficient, skewness, kurtosis and sample numbers of data, respectively
2.2 化学氮肥减量对水稻产量及产量构成的影响
总体而言,与当地传统/常规施氮量相比,氮肥减量能够显著提高水稻产量（图2）,增幅为4.2%（CI=2.8%—5.7%）。对于不同水稻品种而言,氮肥减量均显著提高其水稻产量,但是氮肥减量对籼稻产量（6.8%）的促进作用显著高于粳稻（3.6%）。不同减量方式下,氮肥减量对水稻产量的影响存在显著差异。氮肥直接减量会导致水稻产量显著降低（-2.3%）,但是减量的基础上增施有机肥（秸秆）可以维持水稻产量甚至有所提高（3.6%）。而氮肥减量并调控氮肥运筹或者在减量基础上同时调控运筹与增施有机肥,分别可使水稻产量显著提高5.4%和8.0%。对于不同减量比例而言,随着氮肥减量比例的增加,水稻产量的增幅呈现显著下降趋势。水稻产量在氮肥减量比例≤25%和25%—50%时分别增加6.3%和2.8%,而在减量比例>50%时增产不显著。对于不同土壤基础地力而言,当基础地力<5.5 t·hm-2时,氮肥减量对水稻的增产不显著。当基础地力为5.5—7或者>7 t·hm-2时,氮肥减量分别提高水稻产量6.8%和6.6%。图2
新窗口打开|下载原图ZIP|生成PPT图2化学氮肥减量对水稻产量的影响
n为观察样本量。下图同 n is numbers of experimental observation. The same as
Fig. 2Changes in rice yield induced by the application of reducing chemical nitrogen rate
整合分析还表明,氮肥减量显著影响水稻的产量构成因素（图3）。整体而言,与当地传统/常规施氮量相比,氮肥减量会导致水稻的穗数显著下降3.6% （CI=-2.09%—-5.46%）,而水稻的穗粒数、结实率与千粒重则分别提高了5.36%（CI=3.96%—6.79%）、2.92%（CI=2.00%—3.88%）和 1.50%（CI=0.89%— 2.10%）。对于不同水稻品种而言,除了籼稻的千粒重无显著变化外,粳、籼稻的产量构成因素均受到氮肥减量的影响,其变化趋势与整体变化相似。其中氮肥减量对籼稻穗粒数（9.42%）的促进效应显著强于粳稻（4.51%）,而对粳稻千粒重（1.8%）的增幅则显著高于籼稻（0.2%）。不同的减量方式对水稻穗数和结实率的影响不显著,但会显著改变氮肥减量对水稻穗粒数以及千粒重的调控。氮肥直接减量会导致穗粒数显著降低（-6.24%）。氮肥减量基础上增施有机肥（秸秆）则能够使水稻籽粒的千粒重显著提高3.46%。相比之下,无论是否增施有机肥（秸秆）,氮肥减量后通过调控养分运筹,均可以提高水稻的穗粒数和千粒重（减量+养分运筹下水稻千粒重除外）。除了结实率以外,不同减量比例显著影响氮肥减量后的水稻穗数、穗粒数与千粒重。与对照相比,水稻穗数在氮肥减量比例≤25%时无显著差异,但随着减量比例的增加,水稻穗数呈现明显下降趋势。与穗数的趋势不同,穗粒数随着减量比例的增加而增加,而千粒重则呈现先增加后下降趋势。不同土壤基础地力下的氮肥减量显著影响水稻的穗粒数,随着土壤基础地力增加,穗粒数呈现先增加后减少的趋势。
图3
新窗口打开|下载原图ZIP|生成PPT图3化学氮肥减量对水稻穗数（a）、穗粒数（b）、结实率（c）和千粒重（d）的影响
Fig. 3Changes in panicles number (a), grains per panicle (b), seed setting rate (c) and 1000-grain weight (d) of rice induced by the application of reducing chemical nitrogen rate
2.3 化学氮肥减量对水稻氮素吸收与利用的影响
图4表明,与当地传统/常规施氮量相比,氮肥减量使水稻地上部氮素吸收量平均降低了9.5%（CI= -5.8%—-14.0%）,却显著提高了水稻的氮肥偏生产力（63.9%,CI=52.4%—77.0%）。对于不同品种而言,氮肥减量均显著降低水稻的氮素吸收量,同时提高其氮肥偏生产力。但是,氮肥减量对籼稻氮素吸收量的降低（-19.6%）比粳稻（-6.6%）更显著。而氮肥偏生产力则是籼稻的增幅（117.1%）显著高于粳稻（43.7%）。对于不同减量方式而言,氮肥直接减量以及在此基础上进行养分运筹调控均会显著降低水稻地上部氮素吸收量,但是增施有机肥（秸秆）能够维持甚至增加水稻的氮素吸收量,变幅-3.6%— 8.7%。此外,所有减量方式均能够在不同程度上显著提高水稻的氮肥偏生产力。对于不同减量比例而言,与对照相比,水稻氮素吸收量在氮肥减量比例≤25%时无显著差异,但随着减量比例的增加,水稻氮素吸收量显著下降。相反,随着氮肥减量比例的增加,水稻的氮肥偏生产力呈现明显上升趋势。对于不同基础地力而言,氮肥减量对水稻氮素吸收与利用的效应无明显差异。图4
新窗口打开|下载原图ZIP|生成PPT图4化学氮肥减量对水稻氮素吸收量（a）和氮肥偏生产力（b）的影响
Fig. 4Changes in total nitrogen uptake (a) and PFPN (b) of rice induced by the application of reducing chemical nitrogen rate
2.4 水稻化学氮肥减量模式
基于整合分析数据库的相关数据,构建水稻化学氮肥减量效应示意图。如图5所示,传统/常规施氮处理的基肥、分蘖肥与穗肥平均施用量分别为127.66、73.88和92.48 kg·hm-2,而氮肥减量处理的基肥、分蘖肥与穗肥平均施用量则分别降低38.10%、39.74%和13.85%。氮肥的减施主要集中在基肥与分蘖肥上,减量比例约占传统/常规施氮处理总施氮量的26.56%,是主要的氮肥减量方向。此外,试验中专家氮肥推荐的减施量均值为90.81 kg·hm-2,占传统/常规施氮处理总施氮量的30.89%。从分配比例上看,传统/常规施氮中的基肥、分蘖肥与穗肥比例约为4﹕3﹕3,而氮肥减量处理则为4﹕2﹕4,即氮肥减量的同时运筹比例也进行了调整。示意图还表明,氮肥减量主要通过影响水稻的氮素吸收量（-5.8%—-14.0%）,一定程度上抑制了穗数的产生（-2.09%—-5.46%）,同时调控穗粒数（3.96%— 6.79%）、结实率（2.00%—3.88%）以及千粒重（0.89%—2.10%）的增加,进而提高水稻产量（2.8%—5.7%）与氮肥偏生产力（52.4%—77.0%）。图5
新窗口打开|下载原图ZIP|生成PPT图5水稻化学氮肥减量效应示意图
在虚线箭头上的数值表示各施肥时期的基于传统总施氮量的氮肥减量比例。在实线箭头上的数值表示氮肥减量对箭头所指指标的影响,括号中加号（+）表示正效应,减号（-）表示负效应
Fig. 5The schematic diagram of response of rice yield formation and nitrogen utilization to reducing chemical nitrogen application
The value close to the dotted arrow indicated that the reduction rate of corresponding fertilization stage based on the total conventional nitrogen application. The value close to the implementation arrow indicates the effect of reducing nitrogen application on the variable in which the arrow points. The (+) indicates the positive effect and the (-) indicates negative effect
3 讨论
农户调研数据表明,当前江苏省农户间水稻氮肥施用不足与过量的现象并存,其中以过量施肥尤为突出。WU等[20]通过研究表明,全国农户水稻生产的平均产量、施氮量以及氮肥偏生产力分别为7 140 kg·hm-2、214.00 kg·hm-2和 37.00 kg·kg-1。对比本研究中农户调研的数据（图1）可以发现,江苏省水稻单产比全国农户平均水平高16.52%,然而其施氮量是全国平均水平的1.67倍,导致氮肥偏生产力显著偏低,这与前人的研究结果相一致[4-5, 21]。这主要是由于在中国农民的传统观念中,高氮肥投入就意味着高产量,因此农户常常为了片面追求产量而过量偏施氮肥[22]。江苏省发达的经济水平与较高的农业集约化程度,也可能是导致现阶段高投入、高产出局面的原因之一。此外,长期不合理的化肥施用也可能会削弱土壤对养分匮乏的缓冲能力,进而迫使农户不得不过量施肥以维持作物产量[23],导致肥料利用率降低。过量的施肥不仅会极大地降低施肥的经济效益,还可能引发病虫害或倒伏,给农民造成沉重的经济负担,同时也容易导致一系列严重的环境问题[24]。总之,为了促进农业的可持续发展和减轻环境污染的风险,减少氮肥施用量是当务之急。基于49篇文献的整合分析发现,江苏省稻季氮肥的减量施用能够显著增加水稻产量（2.8%—5.7%）与氮肥偏生产力（52.4%—77.0%）。XIA等[25]的研究表明,单独使用一种氮肥优化管理技术（包括优化氮肥施用量、缓控释肥、脲酶抑制剂、硝化抑制剂等技术）,可以显著提高中国三大主要粮食作物的产量,增幅1.3%—10%,这与本文研究的结果相似。此外,研究表明,如果综合地应用这些氮肥优化管理技术,则能够显著地增加粮食产量18%—35%[26]。不同的是,XIA等[25] 基于所有氮肥优化管理技术对水稻的影响总结得出,产量的增加主要归因于水稻更多的氮素吸收量和更高的氮素利用率。而本研究主要是关于水稻氮肥施用量的减量优化,结果表明氮肥减量会导致水稻氮素吸收量显著降低5.8%—14.0%,因此产量的增加显然不是由于氮素吸收累积的提高而导致的。进一步分析表明,本研究中水稻的增产可能是由于氮肥用量的改变导致水稻各主要生育时期氮素的吸收与分配的改变,进而使各时期氮素的功能发生变化,调控了水稻的产量构成因素,最终实现产量的增加与氮肥效率的提高[6]。LONGNECKER 等[27]研究表明,在分蘖期,叶片的氮素浓度会影响植株分蘖的发生及存活。叶面积指数也会影响分蘖数目,而高叶面积指数同样需要高的叶片氮素浓度以维持分蘖的存活,反之亦然[28]。因此对于传统/常规施氮而言,水稻前期（基、蘖肥）施氮量大,前期较高的氮素含量会造成分蘖数目及无效分蘖数的增加,最终导致穗数偏高。此外,过量的分蘖还会导致穗粒数减少,籽粒灌浆不足,结实率降低[6]。而氮肥减量优化可以通过降低水稻的基、蘖肥的施用,进而减少分蘖的产生,一定程度上抑制水稻穗数的形成。SUN等 [29]的研究结果表明,随着后期氮肥比例的增加,水稻穗粒数的增加。另外,有研究指出,小穗分化期前穗粒数与氮吸收量之间的关系非常紧密[30]。而水稻籽粒产量的形成大多受限于最终的穗粒数[31]。因此,通过氮肥减量优化,可以提高后期穗肥的比例,保证花后较高的绿叶面积从而提高生物量[32],同时能够维持叶片氮代谢相关酶类活性,促进水稻后期光合作用[33],进行籽粒灌浆,提高结实率与千粒重最终提高水稻产量。
不同的水稻品种显著影响水稻氮肥减量的效果。研究表明,籼稻的氮素吸收效率高于粳稻而氮素需求低于粳稻[34,35],这可能导致氮肥减量对籼稻的产量和氮肥效率的提高均要高于粳稻。不同的减量方式和比例同样会影响产量和氮肥利用效率对氮肥减量优化的响应。当氮肥直接减量而不进行其他调控措施,虽然能够减少化学肥料的投入,但穗数以及穗粒数均显著下降,最终导致减产。而在减量基础上调控氮肥运筹,则可以优化水稻各主要生育期的氮素供应,满足水稻生长的氮素需求,实现氮素供应与作物需求同步,进而达到减氮增产增效的目的[36]。当在氮肥减量基础上增施有机物料,则有利于提高土壤的微生物活性[37],改善土壤肥力,维持土壤养分的持续供应[38]。就减量比例而言,当减量比例≤25%时,产量不但没有降低,反而显著增加,说明水稻生产中适当的氮肥减量是可行的。而当减量比例大于50%时,虽然氮肥偏生产力能够显著地提升,但是水稻产量却出现了降低趋势,因此氮肥的减量应在合理范围之内。本研究的结果表明,江苏省区域专家推荐的氮肥减量比例约为31%,属于较为适宜的减量范围,这与前人的研究基本一致[7,8,9]。需要注意的是,研究表明氮肥的施用导致江苏省农田土壤氮素出现盈余现象[39],进而提高土壤氮素的供应能力,这可能间接地增加了水稻的氮肥减量潜力。因此,当前的氮肥减量空间是基于现阶段施肥过量以及土壤氮盈余的前提,一味地减施可能会导致土壤养分匮乏,降低作物生产系统的稳定性,影响作物产量[40]。此外,不同的基础土壤地力也会影响水稻氮肥减量的效果。在高基础地力土壤上进行氮肥减量对水稻产量的负面影响小于低基础地力土壤,这主要是由于高基础地力稻田的外源氮肥贡献率低于低基础地力稻田[41]。
4 结论
尽管当前江苏省的水稻生产处于领先水平,但是其过量的氮肥施用仍然制约着水稻高产高效的实现,水稻氮肥施用量的降低势在必行。水稻氮肥减量可行,其推荐减量空间为31%,主要减少基肥和分蘖肥。氮肥减量能够同时实现水稻增产2.8%—5.7%和氮肥偏生产力提高52.4%—77.0%。氮肥减量优化的实现主要是通过影响水稻的氮素吸收量（-5.8%—-14.0%）,调控各生育时期氮素的功能,在一定程度上抑制了穗数的产生（-2.09%—-5.46%）,同时促进穗粒数（3.96%—6.79%）、结实率（2.00%—3.88%）以及千粒重（0.89%—2.10%）的形成。在进行氮肥减量时,还应考虑水稻品种间差异,优先选择中或高基础地力（≥5 t·hm-2）的土壤,在适宜的减量比例（≤25%）下,合理调控减量后的化肥运筹以及有机无机养分的协同。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:10.3321/j.issn:0578-1752.2002.09.012URLMagsci [本文引用: 1]
介绍了中国水稻生产氮肥使用及利用率概况。中国氮肥消费量占世界氮肥总量的 30 %,水稻生产所消耗的氮肥占世界水稻氮肥总消耗量的 37%。与主要产稻国相比 ,中国水稻生产氮肥施用量较高而利用率较低 ;介绍了国际上公认的氮肥利用率的概念和相应的定量方法 ;总结了国内外水稻氮肥的施用方法 ,肥料种类 ,计算机推荐施肥以及实时施氮管理模式等对降低氮素损失 ,提高氮肥利用率的研究概况和研究进展 ;从水稻品种耐肥性、土壤供肥能力、施肥技术及水分管理等多方面分析了中国水稻氮肥利用率低的可能原因 ;提出了通过改善水稻品种对氮肥的敏感反应 ,以作物氮素状况为指导适时和适量施用氮肥 ,以及合理调节土壤背景氮来降低氮素损失 ,提高水稻的氮肥利用率的研究策略。
DOI:10.3321/j.issn:0578-1752.2002.09.012URLMagsci [本文引用: 1]
介绍了中国水稻生产氮肥使用及利用率概况。中国氮肥消费量占世界氮肥总量的 30 %,水稻生产所消耗的氮肥占世界水稻氮肥总消耗量的 37%。与主要产稻国相比 ,中国水稻生产氮肥施用量较高而利用率较低 ;介绍了国际上公认的氮肥利用率的概念和相应的定量方法 ;总结了国内外水稻氮肥的施用方法 ,肥料种类 ,计算机推荐施肥以及实时施氮管理模式等对降低氮素损失 ,提高氮肥利用率的研究概况和研究进展 ;从水稻品种耐肥性、土壤供肥能力、施肥技术及水分管理等多方面分析了中国水稻氮肥利用率低的可能原因 ;提出了通过改善水稻品种对氮肥的敏感反应 ,以作物氮素状况为指导适时和适量施用氮肥 ,以及合理调节土壤背景氮来降低氮素损失 ,提高水稻的氮肥利用率的研究策略。
DOI:10.1626/pps.12.3URL [本文引用: 2]
Rice production in China has more than tripled in the past five decades mainly due to increased grain yield rather than increased planting area. This increase has come from the development of high-yielding varieties and improved crop management practices such as nitrogen fertilization and irrigation. However, yield stagnation of rice has been observed in the past ten years in China. As its popu...
DOI:10.1016/j.agee.2011.05.005URL [本文引用: 1]
China consumes 32% of the world's total synthetic fertilizer nitrogen (N). Overuse of fertilizer N has become widespread, resulting in severe environmental problems. Based on a set of statistical models, we quantified the optimum N rates for rice production in terms of economic and ecological benefits. Model fitting results suggested that the dependence of rice yield, N uptake and N loss on fertilizer N application rates can be well determined by a quadratic polynomial function, a logistic function and a power function, respectively. Using these functions, the economically optimum and ecologically optimum N rates in south-eastern China were estimated to be 180–285 kg ha 611 and 90–150 kg ha 611, respectively, depending on rice subspecies, varieties and cropping systems. A case study in Jiangsu Province, where single rice with conventional japonica varieties is dominated, suggested that current N rates (65390 kg ha 611) could be cut by 26% and 61% when the economically and ecologically optimum N rates, respectively, are adopted, saving 189 × 10 3 and 442 × 10 3 metric tons per year, respectively. Cutting one-third of the N use would not reduce rice yield but is expected to mitigate negative environmental impact in this province.
URL [本文引用: 2]
为了解江苏省水稻施肥现状及其影响因素,采用农户调查数据和专家田间试验统计数据相结合的方法,实地调研了江苏省30个市(县)水稻肥料施用现状,并通过回归模型探讨影响农户施肥的主要因素.结果表明:苏北、苏中、苏南3个地区分别有57%、55%和54%的农户氮肥施用过量,氮肥生产力偏低.农户人均收入水平和主要劳动力年龄结构对氮肥用量的影响不显著；主要劳动力受教育年限、是否施用有机肥、是否参加过培训和土地所有形式等分别在不同显著水平上影响氮肥的施用.
URL [本文引用: 2]
为了解江苏省水稻施肥现状及其影响因素,采用农户调查数据和专家田间试验统计数据相结合的方法,实地调研了江苏省30个市(县)水稻肥料施用现状,并通过回归模型探讨影响农户施肥的主要因素.结果表明:苏北、苏中、苏南3个地区分别有57%、55%和54%的农户氮肥施用过量,氮肥生产力偏低.农户人均收入水平和主要劳动力年龄结构对氮肥用量的影响不显著；主要劳动力受教育年限、是否施用有机肥、是否参加过培训和土地所有形式等分别在不同显著水平上影响氮肥的施用.
DOI:10.1016/j.fcr.2005.05.004URL [本文引用: 2]
Irrigated rice in China accounts for nearly 30% of global rice production and about 7% of global nitrogen (N) consumption. The low agronomic N use efficiency (AE N, kg grain yield increase per kg N applied) of this system has become a threat to the environment. The objective of this study was to determine the possibility to improve the AE N of irrigated rice in China by comparing the farmers’ N-fertilizer practices with other N management strategies such as real-time N management (RTNM) and fixed-time adjustable-dose N management (FTNM). Field experiments were conducted in farmers’ fields in four major rice-growing provinces in China in 2001 and 2002. The same experiment was repeated at the International Rice Research Institute (IRRI) farm in the dry seasons of 2002 and 2003. Agronomic N use efficiency was determined by the “difference method” using an N-omission plot. Maximum yield was achieved mostly at 60–120 kg N ha 611, which was significantly lower than the 180–240 kg N ha 611 applied in farmers’ practices at the Chinese sites. With the modified farmers’ fertilizer practice, a 30% reduction in total N rate during the early vegetative stage did not reduce yield but slightly increased yield and doubled AE N compared with the farmers’ practice at the Chinese sites. The total N rate in RTNM and FTNM ranged from 30 to 120 kg ha 611 at the Chinese sites, but their yields were similar to or higher than that of the farmers’ practice. Compared with the modified farmers’ practice, RTNM and FTNM further increased AE N at the Chinese sites. Overall, FTNM performed better than RTNM at the Chinese sites because the total N rate of FTNM was closer to the optimal level than RTNM. A quantum leap in AE N is possible in the intensive rice-growing areas in China by simply reducing the current N rate and by allocating less N at the early vegetative stage.
DOI:10.1016/j.fcr.2013.06.012URL [本文引用: 3]
Recently, many optimized nutrient management strategies have been applied to improve rice yield and nitrogen use efficiency (NUE) in China, most of which achieved higher yield and NUE than farmers' usual fertilizer practices. The objective of this study was to investigate the aboveground biomass, nitrogen (N) accumulation and contribution of yield factors (i.e., number of effective panicles, number of spikelets per panicle, and grain weight) on rice yield regulated by optimized nitrogen application at different growth stages. Field experiments were conducted in 2009 and 2010 at 7 different sites, and three optimized N treatments (OPT) were compared with local farmers' fertilizer practices (FFP). Rice yields of the optimized treatments increased 8.2-12.6% over the farmers' fertilizer practices. Recovery efficiency of N (REN), agronomic N use efficiency (AE(N)) and partial factor productivity of applied N (PFPN) for OPT1 and OPT2 were all significantly higher than those obtained using the farmers' fertilizer practices. The aboveground biomass and nitrogen accumulation of OPTs were lower than FFP at the vegetative and earlier reproductive growth stages, but the accumulation rate became faster than FFP at the later reproductive stage. In our result, grain yield was positively correlated with the panicles per unit area for OPTs, but not for FFP. Spikelets per panicles had negative correlation with panicles per unit area but the slop of OPTs was slower than the slope of FFP. We found that the OPTs treatments could mitigate the contradiction between yield formation factors. According to yield responses to the treatments, we defined two dominant yield-promotion stages: the primary nutrient contribution stage and the advanced nutrient contribution stage. Our results illustrated that at the primary nutrient contribution stage, the main promotion factor for yield was panicle number, which was mainly promoted by high N application at the early vegetative stage, and at the advanced nutrient contribution stage, the yield increase depended upon resolving the contradiction between number of effective panicles and spikelet number per panicle, which resulted from appropriate adjustments to the proportions of added N applied at different growth stages. In conclusion, our results indicated that adjusting the proportion of N application at different growth stages may reform the source-sink contradiction of yield, thus further increasing rice yield. (C) 2013 Elsevier B.V. All rights reserved.
DOI:10.1088/1748-9326/9/11/115010URL [本文引用: 2]
In the Tailake region of China, heavy nitrogen (N) loss of rice–wheat rotation systems, due to high fertilizer-N input with low N use efficiency (NUE), was widely reported. To alleviate the detrimental impacts caused by N loss, it is necessary to improve the fertilizer management practices. Therefore, a 3 yr field experiments with different N managements including organic combined chemical N treatment (OCN, 390 kg N ha611yr611, 20% organic fertilizer), control–released urea treatment (CRU, 390 kg N ha611yr611, 70% resin-coated urea), reduced chemical N treatment (RCN, 390 kg N ha611yr611, all common chemical fertilizer), and site-specific N management (SSNM, 333 kg N ha611yr611, all common chemical fertilizer) were conducted in the Taihu Lake region with the ‘farmer’s N’ treatment (FN, 510 kg N ha611yr611, all common chemical fertilizer) as a control. Grain yield, plant N uptake (PNU), NUE, and N losses via runoff, leaching, and ammonia volatilization were assessed. In the rice season, the FN treatment had the highest N loss and lowest NUE, which can be attributed to an excessive rate of N application. Treatments of OCN and RCN with a 22% reduced N rate from FN had no significant effect on PNU nor the yield of rice in the 3 yr; however, the NUE was improved and N loss was reduced 20–32%. OCN treatment achieved the highest yield, while SSNM has the lowest N loss and highest NUE due to the lowest N rate. In wheat season, N loss decreased about 28–48% with the continuous reduction of N input, but the yield also declined, with the exception of OCN treatment. N loss through runoff, leaching and ammonia volatilization was positively correlated with the N input rate. When compared with the pure chemical fertilizer treatment of RCN under the same N input, OCN treatment has better NUE, better yield, and lower N loss. 70% of the urea replaced with resin-coated urea had no significant effect on yield and NUE improvement, but decreased the ammonia volatilization loss. Soil total N and organic matter content showed a decrease after three continuous cropping years with inorganic fertilizer application alone, but there was an increase with the OCN treatment. N balance analysis showed a N surplus for FN treatment and a balanced N budget for OCN treatment. To reduce the environmental impact and maintain a high crop production, proper N reduction together with organic amendments could be sustainable in the rice–wheat rotation system in the Taihu Lake region for a long run.
DOI:10.1016/j.agee.2017.03.002URL [本文引用: 2]
Abstract To increase the rice yield and nitrogen (N) use efficiency (NUE), an integrated agronomic practice, including rapeseed cake addition, increased fertilizer frequency, improved irrigation and crop cultivation management, was adopted in the Taihu Lake region of China. The environmental impacts of the whole rice–wheat rotation system have not yet been fully evaluated. Here, a two-rotation field trail system was used to assess the effects of the improved practice adopted in rice season on crop yield and nitrate (NO363-N) leaching in the rice–wheat rotation. Four treatment conditions were used—control (CK), conventional (CT), reduced N (RT), and improved (IP). During the rice season, the leaching losses of NO363-N in the IP treatment group (2.29–3.88 kg N ha6301) were lower than those in the CT treatment group (4.11–5.38 kg N ha6301), and the former had a 28.55% higher crop yield than the latter. Similarly, the RT treatment had lower N leaching loss and a 9.32% higher rice crop yield than the CT treatment. In the wheat seasons, the CT treatment had 41.83% and 38.03% higher NO363-N leaching than the RT and IP treatments, respectively, despite the three treatments having the same fertilizer application and field management; and N leaching was strongly affected by chemical N surplus in rice season. The RT treatment had the lowest wheat yield, which was 18.72% and 32.06% lower than the CT and IP treatments, respectively; and wheat yield appeared an exponentially increasing response to N surplus that included organic fertilizer N from rice production. These results indicated that management practices applied in rice season had subsequent effect on N leaching and crop yield of the following wheat season. During the whole rice–wheat rotation system, the IP treatment produced 23.56% higher crop yield and 30.87% lower TN leaching than the CT treatment. The IP treatment also increased chemical NUE by 24.67–31.22% and agronomic efficiency of applied chemical N (AEN) by 17.71–33.4% compared with the CT and RT treatments. Thus, compared with traditional practice and reduced N use management, the improved practice management was more in line with the target of food increase and environmental protection.
DOI:10.1073/pnas.0813417106URL [本文引用: 2]
DOI:10.2135/cropsci2012.06.0360URL [本文引用: 1]
A major challenge in rice (Oryza sativa L.) production is to achieve the dual goal of increasing food production and resource use efficiency. This study aimed to investigate if an improved crop management (ICM) could increase grain yield, N use efficiency (NUE), and water use efficiency (WUE). Three rice cultivars were field grown at either Yangzhou or Lianyungang, China. in 2009 and 2010. Three treatments, local farmers' practice (LFP), ICM, and N omission, were conducted. The ICM adopted two new techniques, that is, site-specific N management and irrigation using alternate wetting and moderate drying. Compared with the LFP, the ICM significantly increased percentage of productive tillers, crop growth rate, and contents of cytokinins in plants at mid and late growth stages, nonstructural carbohydrate accumulation in the stem at the heading time, and root oxidation activity, leaf area duration, photosynthetic rate of the flag leaf, and activities of key enzymes involved in sucrose-to-starch conversion in grains during grain filling. On average, the ICM increased grain yield by 14.4%, agronomic NUE (kg grain yield increase per kg N applied) by 64.1%, and WUE for irrigation (grain yield over amount of irrigation water) by 36.4% when compared with the LFP. We conclude that the ICM could increase not only grain yield but also NUE and WUE. Improved physiological performances at latter growth stages contribute to increases in grain yield and resource use efficiency.
DOI:10.3321/j.issn:1000-0933.2007.02.021URLMagsci [本文引用: 1]
通过田间试验对不同施肥水平下太湖地区黄泥土壤水稻的氮肥吸收规律和氮肥利用效率进行了研究，并应用15N微区试验测定不同氮肥水平下氮肥损失数量。在此研究数据基础上，引入数学的微积分原理和环境经济学的Coase原理，对该地区水稻田氮肥施用的经济效益和环境效益进行评价，求得219~255 kg hm<SUP>-2</SUP>为太湖地区黄泥土上目前生产条件下，兼顾生产、生态和经济三效益比较合理的水稻施肥量，相应的经济、生态适宜产量为8601～8662 kg hm<SUP>-2</SUP>。
DOI:10.3321/j.issn:1000-0933.2007.02.021URLMagsci [本文引用: 1]
通过田间试验对不同施肥水平下太湖地区黄泥土壤水稻的氮肥吸收规律和氮肥利用效率进行了研究，并应用15N微区试验测定不同氮肥水平下氮肥损失数量。在此研究数据基础上，引入数学的微积分原理和环境经济学的Coase原理，对该地区水稻田氮肥施用的经济效益和环境效益进行评价，求得219~255 kg hm<SUP>-2</SUP>为太湖地区黄泥土上目前生产条件下，兼顾生产、生态和经济三效益比较合理的水稻施肥量，相应的经济、生态适宜产量为8601～8662 kg hm<SUP>-2</SUP>。
DOI:10.11766/trxb201405150234URL [本文引用: 1]
Based on nitrogen (N) balance in soil system, a new N fertilization recommendation method, i.e. “N return index (NRI)” method, was introduced. The NRI concept was brought forth by the Nutrient Return Doctrines, and means how much N must be returned to soil in order to maintain soil N balance when one kilogram N is taken off by crop harvesting. On the assumption that other than N fertilization, the N inflow via atmosphere deposition, irrigation and seeding (N biofixation and N in straw incorporation exclusive) and the N outflow via erosion, runoff, leaching, volatilization, and nitrification-denitrification, are constant, an equation for calculation of NRI (NRI=161⊿E/F) was deduced, where ⊿E stands for increase in N output from soil to environment induced by N application; F for N input with fertilizer applied, and ⊿E/F is net N loss. With the target yield (Y) of the fields most farmers are familiar with set as the only variable to distinguish fields different in soil fertility, an equation for NRI-based recommendation of N fertilization was worked out, i.e. RNR= RNRI×N×Y/100”, where RNR stands for recycled N rate, RNRI for the regional NRI, which is a relatively stable constant in a specific farming area, N for N uptake by one hundred kilogram grains, which is in a significant linear relationship with crop yield. By taking into account the actual production practices, the equation was finally amended as "RNR=RNRI×N×Y/10061W", where W stands for N input via biofixation and straw incorporation. To verify effectiveness of NRI, two regions in Lixiahe Plain and Taihu Lake Basin in Jiangsu Province were selected as for the study. Based on the soil N budgeting data of the study areas during the rice growing season, RNRI was worked out to be 1.52, based on traits of rice cultivars, N was 8.67×10 Y+1.161 (=0.828 0**) and based on N biofization and straw incorporation, WN was N 52.3 kg hm , then the equation of “RNR=1.32×10 Y 1.76×10 Y6152.3” for recommendation of N fertilization for rice in the study areas was figured out. Based on the data of the fertilization experiment on 45 cultivars of japonica rice in recent years, comparison was performed between N fertilization recommendations using different methods, the fertilizer effective function (FEF), NRI and theoretical N rate (TNR) in effectiveness. Results show that the optimal economic N application rate (OENR) recommended by FEF, the N-recycling N application rate (RNR) by NRI and the theoretic N application rate (TNR) by TNR was N 246.8±42.5 kg hm , 216.9±27.3 kg hm and 176.9±22.3 kg hm respectively. Compared with OENR, RNR was 2.4% less in rice grain yield and 500 yuan hm in economic benefits, but saved N 29.9 kg hm and 10.3 kg hm , respectively, from N application and soil-N net loss and moreover kept soil-N in a rough balance. The new method can be used to make recommendation for N fertilization with target yield being the only variable and without the need to go through field experiment, however, further study is still required to see whether RNRI will remain relatively stable for long, and whether long-term use of the method would lead to soil-N surplus or not.
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DOI:10.11766/trxb201405150234URL [本文引用: 1]
Based on nitrogen (N) balance in soil system, a new N fertilization recommendation method, i.e. “N return index (NRI)” method, was introduced. The NRI concept was brought forth by the Nutrient Return Doctrines, and means how much N must be returned to soil in order to maintain soil N balance when one kilogram N is taken off by crop harvesting. On the assumption that other than N fertilization, the N inflow via atmosphere deposition, irrigation and seeding (N biofixation and N in straw incorporation exclusive) and the N outflow via erosion, runoff, leaching, volatilization, and nitrification-denitrification, are constant, an equation for calculation of NRI (NRI=161⊿E/F) was deduced, where ⊿E stands for increase in N output from soil to environment induced by N application; F for N input with fertilizer applied, and ⊿E/F is net N loss. With the target yield (Y) of the fields most farmers are familiar with set as the only variable to distinguish fields different in soil fertility, an equation for NRI-based recommendation of N fertilization was worked out, i.e. RNR= RNRI×N×Y/100”, where RNR stands for recycled N rate, RNRI for the regional NRI, which is a relatively stable constant in a specific farming area, N for N uptake by one hundred kilogram grains, which is in a significant linear relationship with crop yield. By taking into account the actual production practices, the equation was finally amended as "RNR=RNRI×N×Y/10061W", where W stands for N input via biofixation and straw incorporation. To verify effectiveness of NRI, two regions in Lixiahe Plain and Taihu Lake Basin in Jiangsu Province were selected as for the study. Based on the soil N budgeting data of the study areas during the rice growing season, RNRI was worked out to be 1.52, based on traits of rice cultivars, N was 8.67×10 Y+1.161 (=0.828 0**) and based on N biofization and straw incorporation, WN was N 52.3 kg hm , then the equation of “RNR=1.32×10 Y 1.76×10 Y6152.3” for recommendation of N fertilization for rice in the study areas was figured out. Based on the data of the fertilization experiment on 45 cultivars of japonica rice in recent years, comparison was performed between N fertilization recommendations using different methods, the fertilizer effective function (FEF), NRI and theoretical N rate (TNR) in effectiveness. Results show that the optimal economic N application rate (OENR) recommended by FEF, the N-recycling N application rate (RNR) by NRI and the theoretic N application rate (TNR) by TNR was N 246.8±42.5 kg hm , 216.9±27.3 kg hm and 176.9±22.3 kg hm respectively. Compared with OENR, RNR was 2.4% less in rice grain yield and 500 yuan hm in economic benefits, but saved N 29.9 kg hm and 10.3 kg hm , respectively, from N application and soil-N net loss and moreover kept soil-N in a rough balance. The new method can be used to make recommendation for N fertilization with target yield being the only variable and without the need to go through field experiment, however, further study is still required to see whether RNRI will remain relatively stable for long, and whether long-term use of the method would lead to soil-N surplus or not.
DOI:10.1371/journal.pone.0074617URLPMID:3776784 [本文引用: 1]
Abstract OBJECTIVE: China's food production has increased 6-fold during the past half-century, thanks to increased yields resulting from the management intensification, accomplished through greater inputs of fertilizer, water, new crop strains, and other Green Revolution's technologies. Yet, changes in underlying quality of soils and their effects on yield increase remain to be determined. Here, we provide a first attempt to quantify historical changes in inherent soil productivity and their contributions to the increase in yield. METHODS: The assessment was conducted based on data-set derived from 7410 on-farm trials, 8 long-term experiments and an inventory of soil organic matter concentrations of arable land. RESULTS: Results show that even without organic and inorganic fertilizer addition crop yield from on-farm trials conducted in the 2000s was significantly higher compared with those in the 1980s - the increase ranged from 0.73 to 1.76 Mg/ha for China's major irrigated cereal-based cropping systems. The increase in on-farm yield in control plot since 1980s was due primarily to the enhancement of soil-related factors, and reflected inherent soil productivity improvement. The latter led to higher and stable yield with adoption of improved management practices, and contributed 43% to the increase in yield for wheat and 22% for maize in the north China, and, 31%, 35% and 22% for early and late rice in south China and for single rice crop in the Yangtze River Basin since 1980. CONCLUSIONS: Thus, without an improvement in inherent soil productivity, the 'Agricultural Miracle in China' would not have happened. A comprehensive strategy of inherent soil productivity improvement in China, accomplished through combining engineering-based measures with biological-approaches, may be an important lesson for the developing world. We propose that advancing food security in 21st century for both China and other parts of world will depend on continuously improving inherent soil productivity.
DOI:10.3321/j.issn:0564-3929.2008.05.018URL [本文引用: 1]
总结了近年来在全国粮食主产区进行的1 333个田间试验结果,分析了目前条件下中国主要粮食作物水稻、小麦和玉米氮磷钾肥的偏生产力、农学效率、肥料利用率和生理利用率等,发现水稻、小麦和玉米的氮肥农学效率分别为10.4 kg kg-1、8.0 kg kg-1和9.8 kg kg-1,氮肥利用率分别为28.3%、28.2%和26.1%,远低于国际水平,与20世纪80年代相比呈下降趋势。造成肥料利用率低的主要原因包括高产农田过量施肥,忽视土壤和环境养分的利用,作物产量潜力未得到充分发挥以及养分损失未能得到有效阻控等。要大幅度提高肥料利用率就必须从植物营养学、土壤学、农学等多学科联合攻关入手,充分利用来自土壤和环境的养分资源,实现根层养分供应与高产作物需求在数量上匹配、时间上同步、空间上一致,同时提高作物产量和养分利用效率,协调作物高产与环境保护。
DOI:10.3321/j.issn:0564-3929.2008.05.018URL [本文引用: 1]
总结了近年来在全国粮食主产区进行的1 333个田间试验结果,分析了目前条件下中国主要粮食作物水稻、小麦和玉米氮磷钾肥的偏生产力、农学效率、肥料利用率和生理利用率等,发现水稻、小麦和玉米的氮肥农学效率分别为10.4 kg kg-1、8.0 kg kg-1和9.8 kg kg-1,氮肥利用率分别为28.3%、28.2%和26.1%,远低于国际水平,与20世纪80年代相比呈下降趋势。造成肥料利用率低的主要原因包括高产农田过量施肥,忽视土壤和环境养分的利用,作物产量潜力未得到充分发挥以及养分损失未能得到有效阻控等。要大幅度提高肥料利用率就必须从植物营养学、土壤学、农学等多学科联合攻关入手,充分利用来自土壤和环境的养分资源,实现根层养分供应与高产作物需求在数量上匹配、时间上同步、空间上一致,同时提高作物产量和养分利用效率,协调作物高产与环境保护。
DOI:10.2307/177062URL [本文引用: 1]
Meta-analysis provides formal statistical techniques for summarizing the results of independent experiments and is increasingly being used in ecology. The response ratio (the ratio of mean outcome in the experimental group to that in the control group) and closely related measures of proportionate change are often used as measures of effect magnitude in ecology. Using these metrics for meta-analysis requires knowledge of their statistical properties, but these have not been previously derived. We give the approximate sampling distribution of the log response ratio, discuss why it is a particularly useful metric for many applications in ecology, and demonstrate how to use it in meta-analysis. The meta-analysis of response-ratio data is illustrated using experimental data on the effects of increased atmospheric CO2 on plant biomass responses.
DOI:10.1111/gcb.12517URLPMID:24395454 [本文引用: 2]
Straw return has been widely recommended as an environmentally friendly practice to manage carbon (C) sequestration in agricultural ecosystems. However, the overall trend and magnitude of changes in soil C in response to straw return remain uncertain. In this meta-analysis, we calculated the response ratios of soil organic C (SOC) concentrations, greenhouse gases (GHGs) emission, nutrient contents and other important soil properties to straw addition in 176 published field studies. Our results indicated that straw return significantly increased SOC concentration by 12.8 ± 0.4% on average, with a 27.4 ± 1.4% to 56.6 ± 1.8% increase in soil active C fraction. CO2 emission increased in both upland (27.8 ± 2.0%) and paddy systems (51.0 ± 2.0%), while CH4 emission increased by 110.7 ± 1.2% only in rice paddies. N2O emission has declined by 15.2 ± 1.1% in paddy soils but increased by 8.3 ± 2.5% in upland soils. Responses of macro-aggregates and crop yield to straw return showed positively linear with increasing SOC concentration. Straw-C input rate and clay content significantly affected the response of SOC. A significant positive relationship was found between annual SOC sequestered and duration, suggesting that soil C saturation would occur after 12 years under straw return. Overall, straw return was an effective means to improve SOC accumulation, soil quality, and crop yield. Straw return-induced improvement of soil nutrient availability may favor crop growth, which can in turn increase ecosystem C input. Meanwhile, the analysis on net global warming potential (GWP) balance suggested that straw return increased C sink in upland soils but increased C source in paddy soils due to enhanced CH4 emission. Our meta-analysis suggested that future agro-ecosystem models and cropland management should differentiate the effects of straw return on ecosystem C budget in upland and paddy soils.
DOI:10.1111/j.1365-2486.2012.02758.xURLPMID:24501062 [本文引用: 1]
Abstract Understanding nitrogen (N) removal and replenishment is crucial to crop sustainability under rising atmospheric carbon dioxide concentration ([CO2 ]). While a significant portion of N is removed in grains, the soil N taken from agroecosystems can be replenished by fertilizer application and N2 fixation by legumes. The effects of elevated [CO2 ] on N dynamics in grain crop and legume pasture systems were evaluated using meta-analytic techniques (366 observations from 127 studies). The information analysed for non-legume crops included grain N removal, residue C : N ratio, fertilizer N recovery and nitrous oxide (N2 O) emission. In addition to these parameters, nodule number and mass, nitrogenase activity, the percentage and amount of N fixed from the atmosphere were also assessed in legumes. Elevated [CO2 ] increased grain N removal of C3 non-legumes (11%), legumes (36%) and C4 crops (14%). The C : N ratio of residues from C3 non-legumes and legumes increased under elevated [CO2 ] by 16% and 8%, respectively, but the increase for C4 crops (9%) was not statistically significant. Under elevated [CO2 ], there was a 38% increase in the amount of N fixed from the atmosphere by legumes, which was accompanied by greater whole plant nodule number (33%), nodule mass (39%), nitrogenase activity (37%) and %N derived from the atmosphere (10%; non-significant). Elevated [CO2 ] increased the plant uptake of fertilizer N by 17%, and N2 O emission by 27%. These results suggest that N demand and removal in grain cropping systems will increase under future CO2 -enriched environments, and that current N management practices (fertilizer application and legume incorporation) will need to be revised. 2012 Blackwell Publishing Ltd.
[本文引用: 1]
DOI:10.1890/0012-9658(1997)078[1277:RTFMAO]2.0.CO;2URL [本文引用: 1]
DOI:10.1088/1748-9326/10/9/095011URL [本文引用: 1]
A lack of basic information on optimal nitrogen (N) management often results in over- or under-application of N fertilizer in small-scale intensive rice farming. Here, we present a new database of N input from a survey of 6611 small-scale rice farmers and rice yield in response to added N in 1177 experimental on-farm tests across eight agroecological subregions of China. This database enables us to evaluate N management by farmers and develop an optimal approach to regional N management. We also investigated grain yield, N application rate, and estimated greenhouse gas (GHG) emissions in comparison to N application and farming practices. Across all farmers, the average N application rate, weighted by the area of rice production in each subregion, was 210 kg haand ranged from 30 to 744 kg haacross fields and from 131 to 316 kg haacross regions. The regionally optimal N rate (RONR) determined from the experiments averaged 167 kg haand varied from 114 to 224 kg N hafor the different regions. If these RONR were widely adopted in China, approximately 56% of farms would reduce their use of N fertilizer, and approximately 33% would increase their use of N fertilizer. As a result, grain yield would increase by 7.4% from 7.14 to 7.67 Mg ha, and the estimated GHG emissions would be reduced by 11.1% from 1390 to 1236 kg carbon dioxide (CO) eq Mggrain. These results suggest that to achieve the goals of improvement in regional yield and sustainable environmental development, regional N use should be optimized among N-poor and N-rich farms and regions in China.
DOI:10.3969/j.issn.1005-4944.2009.03.003URL [本文引用: 1]
抽样选择毗邻太湖的常州市武进区雪堰镇3个村,调查当地种植结构及变化,肥料、农药过量施用情况,以及农民对农业面源污染的认识。结果显示,肥料投入总量依次为:蔬菜水蜜桃葡萄稻麦轮作稻油轮作柑橘茶叶;稻-麦轮作、水蜜桃和柑橘3种主要种植模式都存在肥料过量施用,稻-麦轮作N投入过量,水稻和小麦过量的比例分别为40.00%和53.57%,水蜜桃和柑橘则是P2O5投入过量,比例分别为85.71%和25.00%。因此,太湖地区减量施肥的潜力较大。农药投入近年来有所下降,但绝对投入量仍较大,远高于10~15年前的使用量,也有较大的减量空间。当地农民对农业面源污染缺乏认识,急需宣传提高。
DOI:10.3969/j.issn.1005-4944.2009.03.003URL [本文引用: 1]
抽样选择毗邻太湖的常州市武进区雪堰镇3个村,调查当地种植结构及变化,肥料、农药过量施用情况,以及农民对农业面源污染的认识。结果显示,肥料投入总量依次为:蔬菜水蜜桃葡萄稻麦轮作稻油轮作柑橘茶叶;稻-麦轮作、水蜜桃和柑橘3种主要种植模式都存在肥料过量施用,稻-麦轮作N投入过量,水稻和小麦过量的比例分别为40.00%和53.57%,水蜜桃和柑橘则是P2O5投入过量,比例分别为85.71%和25.00%。因此,太湖地区减量施肥的潜力较大。农药投入近年来有所下降,但绝对投入量仍较大,远高于10~15年前的使用量,也有较大的减量空间。当地农民对农业面源污染缺乏认识,急需宣传提高。
DOI:10.1021/es5007127URLPMID:24742316 [本文引用: 1]
To achieve food and environmental security, closing the gap between actual and attainable N-use efficiency should be as important as closing yield gaps. Using a meta-analysis of 205 published studies from 317 study sites, including 1332 observations from rice, wheat, and maize system in China, reactive N (Nr) losses, and total N2O emissions from N fertilization both increased exponentially with increasing N application rate. On the basis of the N loss response curves from the literature meta-analysis, the direct N2O emission, NH3 volatilization, N leaching, and N runoff, and total N2O emission (direct + indirect) were calculated using information from the survey of farmers. The PFP-N (kilogram of harvested product per kilogram of N applied (kg (kg of N)(-1))) for 6259 farmers were relative low with only 37, 23, and 32 kg (kg of N)(-1) for rice, wheat, and maize systems, respectively. In comparison, the PFP-N for highest yield and PFP-N group (refers to fields where the PFP-N was within the 80-100th percentile among those fields that achieved yields within the 80-100th percentile) averaged 62, 42, and 53 kg (kg of N)(-1) for rice, wheat, and maize systems, respectively. The corresponding grain yield would increase by 1.6-2.3 Mg ha(-1), while the N application rate would be reduced by 56-100 kg of N ha(-1) from average farmer field to highest yield and PFP-N group. In return, the Nr loss intensity (4-11 kg of N (Mg of grain)(-1)) and total N2O emission intensity (0.15-0.29 kg of N (Mg of grain)(-1)) would both be reduced significantly as compared to current agricultural practices. In many circumstances, closing the PFP-N gap in intensive cropping systems is compatible with increased crop productivity and reductions in both Nr losses and total N2O emissions.
DOI:10.11674/zwyf.2014.0401URLMagsci [本文引用: 1]
<p>氮素在作物产量和品质形成中起着关键作用。本文综述了什么是合理施氮，包括施氮量、 施氮方法和时期，也包括与有机肥和秸秆还田措施的配合等。指出我国农田氮肥施用的主要问题是施肥过程和施肥后的严重损失。依据农户调查所获得的田块尺度施氮量，与田间试验合理施氮量对比分析表明，过量施氮田块占总调查田块的大约33%。依据区域尺度单位播种面积平均施氮量，与作物平均推荐施氮量对比分析表明，全国过量施氮面积占播种面积20%、 合理面积占70%、 不足面积占10%。总体而言，过量施氮现象还相当普遍，特别是在蔬菜和果树等经济作物上。本文提出了一种估算国家尺度氮肥需求量的方法，可估算出全国合理需氮量范围，称之为氮肥需求量估算法。用三种不同方法估算的我国19802010年间的氮肥需求量与实际氮肥使用量比较表明，如仍然依照现在的粗放施肥习惯，应该为现在的实际氮肥使用量，5年平均为N 27.9×10<sup>6</sup> t 左右，正好处于合理需氮量范围的中线。在改善施肥技术基础上，我国2006~2010年间5年氮肥平均使用量应该在N 19.6×10<sup>6</sup> t 左右；用五种方法预测的我国未来氮肥需求量表明，如果改善施肥技术，我国2020、 2030、 2050年合理氮肥需求量分别为N 21.0×10<sup>6</sup> t、 21.7×10<sup>6</sup> t、 23.1×10<sup>6</sup> t；如施肥技术得不到实质性改善，依然粗放施氮，则氮肥需求量应处于合理使用量范围的中线，分别为N 30.4×10<sup>6</sup> t、 31.4×10<sup>6</sup> t、 33.4×10<sup>6</sup> t。进一步分析了我国粮食产量和氮肥施用量与美国和西欧的差异，我国农田有机肥和碳投入对增加土壤有机碳氮库的重要性。</p>
DOI:10.11674/zwyf.2014.0401URLMagsci [本文引用: 1]
<p>氮素在作物产量和品质形成中起着关键作用。本文综述了什么是合理施氮，包括施氮量、 施氮方法和时期，也包括与有机肥和秸秆还田措施的配合等。指出我国农田氮肥施用的主要问题是施肥过程和施肥后的严重损失。依据农户调查所获得的田块尺度施氮量，与田间试验合理施氮量对比分析表明，过量施氮田块占总调查田块的大约33%。依据区域尺度单位播种面积平均施氮量，与作物平均推荐施氮量对比分析表明，全国过量施氮面积占播种面积20%、 合理面积占70%、 不足面积占10%。总体而言，过量施氮现象还相当普遍，特别是在蔬菜和果树等经济作物上。本文提出了一种估算国家尺度氮肥需求量的方法，可估算出全国合理需氮量范围，称之为氮肥需求量估算法。用三种不同方法估算的我国19802010年间的氮肥需求量与实际氮肥使用量比较表明，如仍然依照现在的粗放施肥习惯，应该为现在的实际氮肥使用量，5年平均为N 27.9×10<sup>6</sup> t 左右，正好处于合理需氮量范围的中线。在改善施肥技术基础上，我国2006~2010年间5年氮肥平均使用量应该在N 19.6×10<sup>6</sup> t 左右；用五种方法预测的我国未来氮肥需求量表明，如果改善施肥技术，我国2020、 2030、 2050年合理氮肥需求量分别为N 21.0×10<sup>6</sup> t、 21.7×10<sup>6</sup> t、 23.1×10<sup>6</sup> t；如施肥技术得不到实质性改善，依然粗放施氮，则氮肥需求量应处于合理使用量范围的中线，分别为N 30.4×10<sup>6</sup> t、 31.4×10<sup>6</sup> t、 33.4×10<sup>6</sup> t。进一步分析了我国粮食产量和氮肥施用量与美国和西欧的差异，我国农田有机肥和碳投入对增加土壤有机碳氮库的重要性。</p>
DOI:10.1073/pnas.0708013104URL [本文引用: 1]
DOI:10.1111/gcb.13455URLPMID:27506858 [本文引用: 2]
Abstract Knowledge-based nitrogen (N) management, which is designed for a better synchronization of crop N demand with N supply, is critical for global food security and environmental sustainability. Yet, a comprehensive assessment on how these N management practices affect food production, greenhouse gas emission (GHG), and N pollution in China is lacking. We compiled the results of 376 studies (1166 observations) to evaluate the overall effects of seven knowledge-based N management practices on crop productivity, nitrous oxide (N 2 O) emission, and major reactive N (Nr) losses (ammonia, NH 3 ; N leaching and runoff), for staple grain (rice, wheat, and corn) production in China. These practices included the application of controlled-release N fertilizer, nitrification inhibitor (NI) and urease inhibitor (UI), higher splitting frequency of fertilizer N application, lower basal N fertilizer (BF) proportion, deep placement of N fertilizer, and optimal N rate based on soil N test. Our results showed that, compared to traditional N management, these knowledge-based N practices significantly increased grain yields by 1.3-10.0%, which is attributed to the higher aboveground N uptake (5.1-12.1%) and N use efficiency in grain (8.0-48.2%). Moreover, these N management practices overall reduced GHG emission and Nr losses, by 5.4-39.8% for N 2 O emission, 30.7-61.5% for NH 3 emission (except for the NI application), 13.6-37.3% for N leaching, and 15.5-45.0% for N runoff. The use of NI increased NH 3 emission by 27.5% (9.0-56.0%), which deserves extra-attention. The cost and benefit analysis indicated that the yield profit of these N management practices exceeded the corresponding input cost, which resulted in a significant increase of the net economic benefit by 2.9-12.6%. These results suggest that knowledge-based N management practice can be considered an effective way to ensure food security and improve environmental sustainability, while increasing economic return. 2016 John Wiley & Sons Ltd.
DOI:10.1038/nature13609URLPMID:25186728 [本文引用: 1]
Agriculture faces great challenges to ensure global food security by increasing yields while reducing environmental costs. Here we address this challenge by conducting a total of 153 site-year field experiments covering the main agro-ecological areas for rice, wheat and maize production in China. A set of integrated soil-crop system management practices based on a modern understanding of crop ecophysiology and soil biogeochemistry increases average yields for rice, wheat and maize from 7.2 million grams per hectare (Mg ha(-1)), 7.2 Mg ha(-1) and 10.5 Mg ha(-1) to 8.5 Mg ha(-1), 8.9 Mg ha(-1) and 14.2 Mg ha(-1), respectively, without any increase in nitrogen fertilizer. Model simulation and life-cycle assessment show that reactive nitrogen losses and greenhouse gas emissions are reduced substantially by integrated soil-crop system management. If farmers in China could achieve average grain yields equivalent to 80% of this treatment by 2030, over the same planting area as in 2012, total production of rice, wheat and maize in China would be more than enough to meet the demand for direct human consumption and a substantially increased demand for animal feed, while decreasing the environmental costs of intensive agriculture.
DOI:10.2135/cropsci1993.0011183X003300010028xURL [本文引用: 1]
DOI:10.1081/PLN-120020365URL [本文引用: 1]
Relative tillering rate (RTR) increases linearly as leaf nitrogen concentration (NLV) increases in rice (Oryza sativa L.) plants. Leaf area index (LAI) has a negative effect on the emergence and survival of tillers. The objectives of this paper were to quantify the interactive effect of NLV and LAI on tillering in irrigated rice. Field experiments were conducted at Philippine Rice Research Institute (PRRI) and International Rice Research Institute (IRRI), Philippines during the dry seasons of 1995 and 1998. Two indica cultivars, IR72 and IR68284H, were subjected to various nitrogen (N) treatments. Number of tillers (including main stems), leaf area, and tissue N concentration were measured. The NLV explained a large part of variation in number of tillers m612 among treatments. However, the residual, defined as the difference between observed and estimated number of tillers m612, was negatively correlated with LAI (P02<020.01). When LAI was considered in addition to NLV, the model explained the variation in number of tillers m612 much better, and the correlation between the residual and LAI declined and became insignificant (P02>020.05). The critical NLV and critical LAI for tillering to stop were interrelated; higher NLV was needed to prevent tillers from dying when LAI was high, and vice versa. Use of stem or shoot N concentration instead of NLV gave similar results. Results suggest that LAI, in addition to NLV, should be considered in predicting tillers in rice crop.
DOI:10.1016/j.fcr.2011.11.015URL [本文引用: 1]
The water and nitrogen (N) managements play a vital role in hybrid rice production aimed at high yield, high nitrogen use efficiency (NUE), and water-saving irrigation. In order to optimize N application and understand how the different combinations of water and N management affect yield and the relative physiological parameters, we designed three irrigation regimes, standing irrigation (W1), alternation irrigation (W2), and dry cultivation (W3), combined with different N application managements at 180kgha611 of total N condition in our study. The relationship between yield or NUE and ammonia assimilation enzyme activities, photosynthetic rate and root activity were respectively investigated. Our data revealed that there were obvious interacting effects of irrigation regime and N application strategies on grain yield and NUE as well. Our correlation analysis revealed that the grain yield or NUE was significantly related to ammonium assimilation enzyme activities, photosynthetic rate, and root activity, respectively, at several rice growth stages. Our correlation analysis also revealed that the grain yield was significantly related to the N uptake and utilization, and that the root activity was significantly related to the ammonium assimilation enzymes and photosynthetic rate. Further more, we found that the ammonium assimilation enzyme activities and the photosynthetic rate in flag leaves, or root activity at heading stage was able to be used as indicators for grain yield, total N accumulation, and NUE as well. These results suggest that the N application strategy should be adjusted according to different irrigation regimes in order to obtain the highest yield and the best NUE. Under standing irrigation, on the basis of 40–60% base-tiller N fertilizer, panicle N-fertilizer should account for 40–60% applied equally at 4th and 2nd leaves emerged or 3rd and 1st leaves emerged from the top. Under alternation irrigation, the N application ratio should be split into 30% base, 30% tillering, and 40% panicle fertilizer with the last being applied equally at 4th and 2nd leaves emerged from the top. Under dry cultivation, however, panicle N-fertilizer should account for 20–40% applied equally at 5th and 3rd leaves emerged from the top.
DOI:10.1626/jcs.70.34URL [本文引用: 1]
DOI:10.1626/pps.4.9URL [本文引用: 1]
Spikelet number per unit area is a strong determinant of rice yield, and spikelet differentiation must be promoted to increase spikelet number. Nitrogen has been considered to be the most critical factor in promoting spikelet differentiation and the role of non-structural carbohydrates (NSCs) in spikelet differentiation is unclear. To reveal the relation between NSCs and the number of differentiated spikelets, we conducted a field experiment in Matsue, Shimane, Japan, using two japonica cultivars Koshihikari and Nipponbare. The NSC content was changed by shading and thinning during the early reproductive stage. These treatments did not change the amount of nitrogen per hill in the leaves and stems. The number of differentiated spikelets, which was defined as the sum of the numbers of surviving spikelets and vestiges of degenerated spikelets, was not influenced by NSC content in rice plants; neither was the number of primary rachis-branches, which is considered to determine spikelet number per panicle. The ratio of dry matter allocation to leaves and the rest of the plants was changed, but the morphological characteristics such as tiller number and plant length were not influenced by the treatments. It is concluded that the differentiation of spikelets was not influenced by the NSC content within the range examined in the present experiment. The role of NSC in the mechanism of spikelet differentiation is discussed.
DOI:10.1016/S1875-2780(09)60057-2URL [本文引用: 1]
Super rice yanfeng 47 was used as materials,using plot contrast test method to investigate the effects of the different rate of nitrogen base-tiller and panicle fertilizer on development and yield of rice in coastal rice region.The results showed that the rate of base-tiller and panicle fertilizer was 2:5:3 in the B treatment got 625.0kg/667m2 per unit yield,comparing with the treatment of A(2:4:4)、C(2:6:2) and CK(2:8:0),the yield increased 0.6%、3.4% and 5.6%;The effective panicle number and spikelet numbers per unit area,biomass and dry matter accumulation at heading to maturity stage was higher than the treatment of A、C and CK.With the increasing proportion of panicle fertilizer,high effective leaf area of rice population at full heading stage and SPAD value of functional leaves increased gradually,the SPAD value of functional leaves at milk stage、dough stage and yellow ripe stage still maintained a high level.
DOI:10.3724/SP.J.1006.2009.01672URLMagsci [本文引用: 1]
<p><span >以代表性品种为材料，研究了水稻实地氮肥管理</span><span lang="EN-US" >(SSNM)</span><span >的氮肥利用效率及其生理机制。结果表明，</span><span lang="EN-US" >SSNM</span><span >的施氮量较常规施肥方法</span><span lang="EN-US" >(FFP)</span><span >降低了</span><span lang="EN-US" >48.1%~63.0%</span><span >，产量提高了</span><span lang="EN-US" >0.1%~9.3%</span><span >。</span><span lang="EN-US" >SSNM</span><span >的氮肥吸收利用率和农学利用率分别较</span><span lang="EN-US" >FFP</span><span >提高了</span><span lang="EN-US" >31.4%~56.8%</span><span >和</span><span lang="EN-US" >143.6%~166.0%</span><span >。水稻氮吸收高峰出现在穗分化期至抽穗期，此阶段</span><span lang="EN-US" >SSNM</span><span >处理氮的吸收量和其占最终总吸收量的比例均明显高于</span><span lang="EN-US" >FFP</span><span >。抽穗后</span><span lang="EN-US" >SSNM</span><span >水稻的吸氮量也明显高于</span><span lang="EN-US" >FFP</span><span >。</span><span >自幼穗分化期开始，</span><span lang="EN-US" >SSNM</span><span >水</span><span >稻根系重量和根系活力</span><span >(</span><span >尤其是单茎占有的根系活性</span><span >)</span><span >逐步超过</span><span lang="EN-US" >FFP</span><span >。</span><span lang="EN-US" >SSNM </span><span >明显提高了幼穗分化期和抽穗期水稻叶片中谷氨酰胺合成酶、硝酸还原酶和</span><span lang="EN-US" >Fd-</span><span >谷氨酸合酶的活性。抽穗后</span><span lang="EN-US" >SSNM</span><span >处理水稻剑叶的光合速率高于</span><span lang="EN-US" >FFP</span><span >，上述结果表明</span><span lang="EN-US" >SSNM</span><span >有利于促进水稻中后期根系生长，提高物质生产和养分吸收，从而提高氮肥的利用效率。</span></p>
DOI:10.3724/SP.J.1006.2009.01672URLMagsci [本文引用: 1]
<p><span >以代表性品种为材料，研究了水稻实地氮肥管理</span><span lang="EN-US" >(SSNM)</span><span >的氮肥利用效率及其生理机制。结果表明，</span><span lang="EN-US" >SSNM</span><span >的施氮量较常规施肥方法</span><span lang="EN-US" >(FFP)</span><span >降低了</span><span lang="EN-US" >48.1%~63.0%</span><span >，产量提高了</span><span lang="EN-US" >0.1%~9.3%</span><span >。</span><span lang="EN-US" >SSNM</span><span >的氮肥吸收利用率和农学利用率分别较</span><span lang="EN-US" >FFP</span><span >提高了</span><span lang="EN-US" >31.4%~56.8%</span><span >和</span><span lang="EN-US" >143.6%~166.0%</span><span >。水稻氮吸收高峰出现在穗分化期至抽穗期，此阶段</span><span lang="EN-US" >SSNM</span><span >处理氮的吸收量和其占最终总吸收量的比例均明显高于</span><span lang="EN-US" >FFP</span><span >。抽穗后</span><span lang="EN-US" >SSNM</span><span >水稻的吸氮量也明显高于</span><span lang="EN-US" >FFP</span><span >。</span><span >自幼穗分化期开始，</span><span lang="EN-US" >SSNM</span><span >水</span><span >稻根系重量和根系活力</span><span >(</span><span >尤其是单茎占有的根系活性</span><span >)</span><span >逐步超过</span><span lang="EN-US" >FFP</span><span >。</span><span lang="EN-US" >SSNM </span><span >明显提高了幼穗分化期和抽穗期水稻叶片中谷氨酰胺合成酶、硝酸还原酶和</span><span lang="EN-US" >Fd-</span><span >谷氨酸合酶的活性。抽穗后</span><span lang="EN-US" >SSNM</span><span >处理水稻剑叶的光合速率高于</span><span lang="EN-US" >FFP</span><span >，上述结果表明</span><span lang="EN-US" >SSNM</span><span >有利于促进水稻中后期根系生长，提高物质生产和养分吸收，从而提高氮肥的利用效率。</span></p>
DOI:10.1016/S0378-4290(03)00067-4URL [本文引用: 1]
The identification of the factors that determine grain yield and nitrogen utilization in rice production systems is necessary to optimize their productivity and reduce the pollution risk for the environment. A field study was conducted to analyze the various component traits that cause variation in grain yield, grain nitrogen yield and nitrogen utilization efficiency (NUE) of direct water-seeded Indica and Japonica rice, using yield and yield component analysis. Five rice cultivars, Olympiada and L-202 (Indica type) and Ispaniki A , Melas and Dion (Japonica type), with contrasting traits were grown in a silty loam soil (Aquic Xerofluvents) in 1999 and 2000. Grain yield ranged from 6045 (Melas) to 8310 kg/ha (Olympiada). More than 50% of the total variation in grain yield among cultivars was explained by the variation in panicles per square meter, suggesting the importance of tillering ability of a given cultivar in obtaining high yields. The relative contribution of grains per panicle was moderate (35.2% in 1999 and 34.1% in 2000), while that of grain weight the lowest. Grain yield was significantly correlated with N concentration in vegetative parts at anthesis. NUE for biomass accumulation during grain filling period was generally similar or lower compared to that during vegetative period. Indica cultivars had lower NUE for biomass accumulation and higher nitrogen utilization efficiency for grain yield (NUE g) compared to Japonica cultivars, mainly due to the higher NHI. For a reliable comparison among cultivars, the agronomic traits of each cultivar should be taken into account. Short and late maturing cultivars had significantly higher NUE g than the tall and early or mid-season cultivars, respectively. NUE g was negatively correlated with grain and straw N concentration at maturity, suggesting that low grain or straw N concentrations may be indications of higher NUE g.
DOI:10.11674/zwyf.2014.0402URLMagsci [本文引用: 1]
<p>【目的】目前我国选育和认定的超级稻品种很多，但如何发挥其高产潜力至关重要。氮素是影响水稻生长发育、 产量和品质形成的最活跃因素之一，因此，深入分析籼、 粳超级稻氮素吸收、 利用与转运特征及其与产量形成的关系，从氮素营养层面上阐明超级粳稻高产形成机理，以期为超级稻品种的合理利用以及增产潜力的挖掘提供参考。【方法】2011~2012年在江苏苏中地区，以主体且具有代表性的5个超级杂交籼稻组合和5个常规粳型超级稻品种为试验材料，对稻-麦两熟制条件下籼、 粳超级稻主要生育期植株含氮率和氮素积累量、 氮素阶段吸收速率和阶段吸收量、 氮素利用效率，以及抽穗至成熟期叶、 茎、 鞘氮素转运量、 表观转运率和转运贡献率等进行了系统的比较研究。【结果】1）粳稻平均实收产量、 氮素吸收总量和百公斤籽粒吸氮量分别达10.89 t/hm<sup>2</sup>、 224.50 kg/hm<sup>2</sup>和2.79 kg，分别较籼稻高13.21%、 32.74%和17.45%，差异极显著。2）移栽有效分蘖临界叶龄期、 拔节抽穗期和抽穗成熟期， 粳稻氮素积累量显著或极显著高于籼稻，而有效分蘖临界叶龄期拔节期粳稻极显著低于籼稻。氮素阶段吸收速率表现的趋势与氮素阶段吸收量一致。3）抽穗期和成熟期粳稻植株各器官以及整个生育期整株的含氮率均显著或极显著高于籼稻。4）粳稻氮素吸收利用率和农学利用率略高于籼稻，但氮素生理利用率、 籽粒生产效率、 干物质生产效率和氮肥偏生产力，除氮素生理利用率外，均显著或极显著低于籼稻。5）成熟期，粳稻叶、 茎、 鞘含氮量所占比例均极显著地高于籼稻，但穗中含氮量所占比例极显著低于籼稻，因此，籼稻氮素收获指数极显著高于粳稻。6）抽穗成熟期，粳稻叶、 茎、 鞘氮素转运量、 表观转运率和转运贡献率均小于籼稻，除鞘的氮素转运贡献率外其他指标均达显著或极显著水平。7）籼稻籽粒氮主要依靠抽穗前源器官中贮积的氮素的输出与转运，粳稻主要依靠生育中后期(拔节成熟期)氮素的高速吸收。【结论】在稳定生育前期(移栽拔节期)氮素吸收的基础上，大幅提高生育中期和后期(拔节成熟期)氮素吸收速率和氮素积累量，是稳定形成较高的氮素吸收总量及粳稻高产形成的关键。</p>
DOI:10.11674/zwyf.2014.0402URLMagsci [本文引用: 1]
<p>【目的】目前我国选育和认定的超级稻品种很多，但如何发挥其高产潜力至关重要。氮素是影响水稻生长发育、 产量和品质形成的最活跃因素之一，因此，深入分析籼、 粳超级稻氮素吸收、 利用与转运特征及其与产量形成的关系，从氮素营养层面上阐明超级粳稻高产形成机理，以期为超级稻品种的合理利用以及增产潜力的挖掘提供参考。【方法】2011~2012年在江苏苏中地区，以主体且具有代表性的5个超级杂交籼稻组合和5个常规粳型超级稻品种为试验材料，对稻-麦两熟制条件下籼、 粳超级稻主要生育期植株含氮率和氮素积累量、 氮素阶段吸收速率和阶段吸收量、 氮素利用效率，以及抽穗至成熟期叶、 茎、 鞘氮素转运量、 表观转运率和转运贡献率等进行了系统的比较研究。【结果】1）粳稻平均实收产量、 氮素吸收总量和百公斤籽粒吸氮量分别达10.89 t/hm<sup>2</sup>、 224.50 kg/hm<sup>2</sup>和2.79 kg，分别较籼稻高13.21%、 32.74%和17.45%，差异极显著。2）移栽有效分蘖临界叶龄期、 拔节抽穗期和抽穗成熟期， 粳稻氮素积累量显著或极显著高于籼稻，而有效分蘖临界叶龄期拔节期粳稻极显著低于籼稻。氮素阶段吸收速率表现的趋势与氮素阶段吸收量一致。3）抽穗期和成熟期粳稻植株各器官以及整个生育期整株的含氮率均显著或极显著高于籼稻。4）粳稻氮素吸收利用率和农学利用率略高于籼稻，但氮素生理利用率、 籽粒生产效率、 干物质生产效率和氮肥偏生产力，除氮素生理利用率外，均显著或极显著低于籼稻。5）成熟期，粳稻叶、 茎、 鞘含氮量所占比例均极显著地高于籼稻，但穗中含氮量所占比例极显著低于籼稻，因此，籼稻氮素收获指数极显著高于粳稻。6）抽穗成熟期，粳稻叶、 茎、 鞘氮素转运量、 表观转运率和转运贡献率均小于籼稻，除鞘的氮素转运贡献率外其他指标均达显著或极显著水平。7）籼稻籽粒氮主要依靠抽穗前源器官中贮积的氮素的输出与转运，粳稻主要依靠生育中后期(拔节成熟期)氮素的高速吸收。【结论】在稳定生育前期(移栽拔节期)氮素吸收的基础上，大幅提高生育中期和后期(拔节成熟期)氮素吸收速率和氮素积累量，是稳定形成较高的氮素吸收总量及粳稻高产形成的关键。</p>
DOI:10.11674/zwyf.2015.0403URLMagsci [本文引用: 1]
【目的】水稻是我国主要粮食作物之一,为了进一步满足日益增长的人口对水稻生产的更大需求,需要在现有甚至减少种植面积的前提下提高水稻产量,同时实现高效利用水肥资源和减少对环境的压力。【方法】本研究基于2008～2011年间,在我国长江流域和南方稻区的主要省份 (包括湖南、 湖北、 广东、 安徽、 江苏和重庆)开展的403个田间试验,比较了农民传统技术和最佳作物管理技术下 (主要技术为氮肥总量控制分期调控,磷、钾衡量监控,增加水稻的栽插密度和后期干湿交替灌溉),水稻的施氮量、产量、氮肥利用率(氮肥偏生产力、氮肥农学利用率和氮肥回收利用率)、水稻生长发育的主要时期 (分蘖期、穗分化期、抽穗期和成熟期) 的氮素吸收、干物质累积动态及产量构成。【结果】最佳作物管理技术处理的水稻产量平均为7917.0 kg/hm<sup>2</sup>,显著高于农民传统处理(P<0.05),增产量为690.6 kg/hm<sup>2</sup>,增产率9.6%;而最佳作物管理技术处理的氮肥平均施用量为N 162.7 kg/hm<sup>2</sup>,显著低于农民传统处理 (<i>P</i><0.05),氮肥减少量为N 41.4 kg/hm<sup>2</sup>,减少率20.3%;最佳作物管理技术处理的平均氮肥偏生产力、氮肥农学利用率和氮肥回收利用率分别为50.8 kg/kg、14.9 kg/kg和42.3%,均显著高于农民传统处理(P<0.05),分别增加36.2%、75.3% 和13.6个百分点;农民传统处理的水稻植株在生育前期表现出较大的氮吸收能力和干物质累积量,但从齐穗期开始,最佳作物管理技术处理的作物吸氮量和干物质累积量均大于农民传统处理;到成熟期,农民传统处理和最佳作物管理技术处理的作物吸氮量分别为151.7 kg/hm<sup>2</sup>和165.9 kg/hm<sup>2</sup>,干物质累积量分别为12914.2 kg/hm<sup>2</sup>和13796.1 kg/hm<sup>2</sup> (P<0.05)。同时,农民传统处理和最佳作物管理技术处理的水稻花后干物质积累量表现出显著的差异,分别为4045.2 kg/hm<sup>2</sup>和4654.5 kg/hm<sup>2 </sup>(P<0.05);最佳作物管理技术处理的单位面积穗数、每穗粒数和千粒重分别为243.2、154.2和26.9 g,显著大于农民传统处理的231.7、150.0和26.6 g (P<0.05)。【结论】通过最佳作物管理技术可以在节约水肥的条件下,进一步提高我国长江流域和南方水稻的产量,这一最佳作物管理技术也具有被农民采纳的现实可行性。研究结果可为我国水稻生产实现高产高效提供技术支撑。
DOI:10.11674/zwyf.2015.0403URLMagsci [本文引用: 1]
【目的】水稻是我国主要粮食作物之一,为了进一步满足日益增长的人口对水稻生产的更大需求,需要在现有甚至减少种植面积的前提下提高水稻产量,同时实现高效利用水肥资源和减少对环境的压力。【方法】本研究基于2008～2011年间,在我国长江流域和南方稻区的主要省份 (包括湖南、 湖北、 广东、 安徽、 江苏和重庆)开展的403个田间试验,比较了农民传统技术和最佳作物管理技术下 (主要技术为氮肥总量控制分期调控,磷、钾衡量监控,增加水稻的栽插密度和后期干湿交替灌溉),水稻的施氮量、产量、氮肥利用率(氮肥偏生产力、氮肥农学利用率和氮肥回收利用率)、水稻生长发育的主要时期 (分蘖期、穗分化期、抽穗期和成熟期) 的氮素吸收、干物质累积动态及产量构成。【结果】最佳作物管理技术处理的水稻产量平均为7917.0 kg/hm<sup>2</sup>,显著高于农民传统处理(P<0.05),增产量为690.6 kg/hm<sup>2</sup>,增产率9.6%;而最佳作物管理技术处理的氮肥平均施用量为N 162.7 kg/hm<sup>2</sup>,显著低于农民传统处理 (<i>P</i><0.05),氮肥减少量为N 41.4 kg/hm<sup>2</sup>,减少率20.3%;最佳作物管理技术处理的平均氮肥偏生产力、氮肥农学利用率和氮肥回收利用率分别为50.8 kg/kg、14.9 kg/kg和42.3%,均显著高于农民传统处理(P<0.05),分别增加36.2%、75.3% 和13.6个百分点;农民传统处理的水稻植株在生育前期表现出较大的氮吸收能力和干物质累积量,但从齐穗期开始,最佳作物管理技术处理的作物吸氮量和干物质累积量均大于农民传统处理;到成熟期,农民传统处理和最佳作物管理技术处理的作物吸氮量分别为151.7 kg/hm<sup>2</sup>和165.9 kg/hm<sup>2</sup>,干物质累积量分别为12914.2 kg/hm<sup>2</sup>和13796.1 kg/hm<sup>2</sup> (P<0.05)。同时,农民传统处理和最佳作物管理技术处理的水稻花后干物质积累量表现出显著的差异,分别为4045.2 kg/hm<sup>2</sup>和4654.5 kg/hm<sup>2 </sup>(P<0.05);最佳作物管理技术处理的单位面积穗数、每穗粒数和千粒重分别为243.2、154.2和26.9 g,显著大于农民传统处理的231.7、150.0和26.6 g (P<0.05)。【结论】通过最佳作物管理技术可以在节约水肥的条件下,进一步提高我国长江流域和南方水稻的产量,这一最佳作物管理技术也具有被农民采纳的现实可行性。研究结果可为我国水稻生产实现高产高效提供技术支撑。
DOI:10.1007/s11104-017-3547-8URL [本文引用: 1]
DOI:10.1016/j.agee.2016.03.035URL [本文引用: 1]
Farmers have to combine several measures to balance carbon contents in the top soil to preserve soil quality but potentially increasing the risk for N and P losses by leaching. We studied the effect of a combination of several measures on topsoil C content, nutrient leaching and soil quality in a multi-year field trial. Soil quality was defined as the result of the interaction between chemical, physical and biological soil characteristics, and included an assessment of disease suppressiveness as well. Initially, the soil had a suboptimal C content (i.e. 0.81%). Soil organic carbon (SOC) levels were maintained and slightly increased by applying slurry and good agricultural practices such as the use of cover crops and the incorporation of cereal straw (on average +0.04 percentage point). Only with a yearly extra plant-based farm compost amendment SOC levels were substantially increased after a period of four years (on average +0.17 percentage point). This application of 8.3 Mg C ha 1also improved chemical, physical and biological soil quality. Our research demonstrates that farmers can use compost, for at least 4 years, on top of cattle or pig slurry application to soils with suboptimal C levels to increase C content in the top soil, without inducing higher N and P leaching. Repeated compost application increased the microbial biomass (measured by means of PLFA) and disease suppressiveness againstBotrytis cinereaon lettuce. There was no effect on the abundance of the plant-parasitic nematodePratylenchus penetransin the soil, nor on disease severity caused byDickeya solani,Streptomyces scabiesandRhizoctonia solaniafter a potato cropping. Differences between tillage practices were most obvious in the 0 10cm soil layer as non-inversion tillage (compared to ploughing) resulted in an increase in SOC, Total N, hot-water extractable C and P, plant-available P and K, aggregate stability, earthworm abundance and bacterial and fungal populations in this layer.
DOI:10.7685/jnau.201806030URL [本文引用: 1]
[目的]本文旨在研究江苏省农田土壤全氮含量变化特征及其影响因子.[方法]基于2008和2015年江苏省基本农田质量长期监测点实测数据,运用经典统计学和地统计学分析土壤全氮含量的时空变化,运用多因素方差分析探明成土母质、气候、种植制度、化肥施用等因子对土壤全氮含量变化的影响及不同影响因子间的交互效应.[结果] 2015年江苏农田土壤全氮平均含量为1.47 g·kg-1,比2008年增加了8.9％(P＜0.01).2008和2015年,土壤全氮含量空间分布特征保持相对一致,表现为苏南地区高于苏北地区(里下河地区除外),西部地区高于东部地区,沿海地区最低;土壤全氮含量的变化受氮肥施用及氮肥施用与气候交互效应的影响显著,湿润亚热带地区氮肥低投入时土壤全氮含量增加最多,而半湿润温暖带地区氮肥超高投入时土壤全氮含量增加最多;土壤有机质作为协变量对全氮变化影响显著,且解释率最高.[结论]在氮肥低投入及超高投入2种情况下,气候是土壤全氮含量变化的显著影响因子,建议在生产实践中依据气候条件合理施用氮肥.
DOI:10.7685/jnau.201806030URL [本文引用: 1]
[目的]本文旨在研究江苏省农田土壤全氮含量变化特征及其影响因子.[方法]基于2008和2015年江苏省基本农田质量长期监测点实测数据,运用经典统计学和地统计学分析土壤全氮含量的时空变化,运用多因素方差分析探明成土母质、气候、种植制度、化肥施用等因子对土壤全氮含量变化的影响及不同影响因子间的交互效应.[结果] 2015年江苏农田土壤全氮平均含量为1.47 g·kg-1,比2008年增加了8.9％(P＜0.01).2008和2015年,土壤全氮含量空间分布特征保持相对一致,表现为苏南地区高于苏北地区(里下河地区除外),西部地区高于东部地区,沿海地区最低;土壤全氮含量的变化受氮肥施用及氮肥施用与气候交互效应的影响显著,湿润亚热带地区氮肥低投入时土壤全氮含量增加最多,而半湿润温暖带地区氮肥超高投入时土壤全氮含量增加最多;土壤有机质作为协变量对全氮变化影响显著,且解释率最高.[结论]在氮肥低投入及超高投入2种情况下,气候是土壤全氮含量变化的显著影响因子,建议在生产实践中依据气候条件合理施用氮肥.
DOI:10.3969/j.issn.1002-6819.2011.04.020URLMagsci [本文引用: 1]
为探讨长期施肥条件下作物持续稳产和高产的途径，利用始于1980年的江苏太湖典型稻麦轮作区水稻土长期定位试验，分析水稻和小麦不同年份产量数据和土壤养分数据，研究了长期不同施肥方式对作物产量稳定性的影响，以及作物产量波动和土壤养分变化相关性。结果表明：各处理试验小区水稻和小麦的平均产量均呈锯齿状波动，受气候和其他因素影响不同年份间的产量变动差异较大。数十年期间，各施肥处理包括对照的水稻和小麦产量均有增长趋势，水稻增产趋势较小麦明显，小麦产量年际间的波动较大。有机肥与化肥配施和秸秆还田较单施化肥或有机肥有更明显的增产效果。水稻产量的稳定性高于小麦，各处理水稻产量的变异系数（CV）较小麦低，而稳定性系数（SYI）较高。其中MPK（有机肥+化肥磷钾）处理的产量稳定性最高，而MNPK（有机肥+化肥氮磷钾）的稳定性最低。施化肥尤其是氮肥可能是造成产量稳定性降低的一个因素。氮肥是增产的主要因素，也可能是引起稻田生态系统稳定性降低的因素。水稻和小麦产量与土壤氮素之间的相关性较显著、相比旱季，在稻季条件下，水稻产量稳定性更高，且增产趋势更明显，说明稻田土壤生态系统可能稳定性较高，并且随着耕作年限的延长其稳定性有提高趋势。
DOI:10.3969/j.issn.1002-6819.2011.04.020URLMagsci [本文引用: 1]
为探讨长期施肥条件下作物持续稳产和高产的途径，利用始于1980年的江苏太湖典型稻麦轮作区水稻土长期定位试验，分析水稻和小麦不同年份产量数据和土壤养分数据，研究了长期不同施肥方式对作物产量稳定性的影响，以及作物产量波动和土壤养分变化相关性。结果表明：各处理试验小区水稻和小麦的平均产量均呈锯齿状波动，受气候和其他因素影响不同年份间的产量变动差异较大。数十年期间，各施肥处理包括对照的水稻和小麦产量均有增长趋势，水稻增产趋势较小麦明显，小麦产量年际间的波动较大。有机肥与化肥配施和秸秆还田较单施化肥或有机肥有更明显的增产效果。水稻产量的稳定性高于小麦，各处理水稻产量的变异系数（CV）较小麦低，而稳定性系数（SYI）较高。其中MPK（有机肥+化肥磷钾）处理的产量稳定性最高，而MNPK（有机肥+化肥氮磷钾）的稳定性最低。施化肥尤其是氮肥可能是造成产量稳定性降低的一个因素。氮肥是增产的主要因素，也可能是引起稻田生态系统稳定性降低的因素。水稻和小麦产量与土壤氮素之间的相关性较显著、相比旱季，在稻季条件下，水稻产量稳定性更高，且增产趋势更明显，说明稻田土壤生态系统可能稳定性较高，并且随着耕作年限的延长其稳定性有提高趋势。
DOI:10.3864/j.issn.0578-1752.2012.14.011URLMagsci [本文引用: 1]
【目的】研究江汉平原地区不同基础地力土壤和优化施肥对水稻产量和氮肥利用率的影响。【方法】以江汉平原水稻主推品种丰两优香一号为试验材料，通过3年田间小区试验，考察分析土壤基础地力不同的稻田优化施肥、农民习惯施肥和不施肥处理的产量、氮肥贡献率、土壤氮素依存率和氮肥利用率等的差异。【结果】土壤基础地力不同的稻田均是优化施肥处理的产量最高，与农民习惯施肥处理比较，高地力和低地力稻田优化施肥处理的产量分别平均提高6.9%和5.0%；与不施肥处理比较，产量分别平均提高17.3%和30.3%。与农民习惯施肥处理比较，优化施肥处理的氮肥吸收利用率、农学利用率和偏生产力均大幅度提高。高地力稻田土壤氮素依存率高、氮肥贡献率小、施肥增产的潜力小；低地力稻田土壤氮素依存率低、氮肥贡献率大、施肥增产的潜力大。【结论】优化施肥可以降低水稻产量对土壤基础地力的依赖，提高氮肥利用率。
DOI:10.3864/j.issn.0578-1752.2012.14.011URLMagsci [本文引用: 1]
【目的】研究江汉平原地区不同基础地力土壤和优化施肥对水稻产量和氮肥利用率的影响。【方法】以江汉平原水稻主推品种丰两优香一号为试验材料，通过3年田间小区试验，考察分析土壤基础地力不同的稻田优化施肥、农民习惯施肥和不施肥处理的产量、氮肥贡献率、土壤氮素依存率和氮肥利用率等的差异。【结果】土壤基础地力不同的稻田均是优化施肥处理的产量最高，与农民习惯施肥处理比较，高地力和低地力稻田优化施肥处理的产量分别平均提高6.9%和5.0%；与不施肥处理比较，产量分别平均提高17.3%和30.3%。与农民习惯施肥处理比较，优化施肥处理的氮肥吸收利用率、农学利用率和偏生产力均大幅度提高。高地力稻田土壤氮素依存率高、氮肥贡献率小、施肥增产的潜力小；低地力稻田土壤氮素依存率低、氮肥贡献率大、施肥增产的潜力大。【结论】优化施肥可以降低水稻产量对土壤基础地力的依赖，提高氮肥利用率。
