Effects of Straw Strip Returning on Spring Maize Yield, Soil Moisture, Nitrogen Contents and Root Distribution in Northeast China
ANJun-Peng通讯作者:
收稿日期:2017-09-29
接受日期:2018-03-19
网络出版日期:2018-03-19
版权声明:2018作物学报编辑部作物学报编辑部
基金资助:
作者简介:
-->
展开
摘要
关键词:
Abstract
Keywords:
-->0
PDF (5587KB)元数据多维度评价相关文章收藏文章
本文引用格式导出EndNoteRisBibtex收藏本文-->
秸秆还田是一项有助于改善农田水土条件, 增加土壤有机质含量的保护性耕作措施[1,2]。在提高作物产量、增加土壤水分和养分有效性等方面的作用已被许多研究证实[3,4]。目前, 东北春玉米产区是中国最大的玉米商品粮基地, 该区年玉米秸秆量(约6800万吨)占全国总量的31.0%, 但秸秆还田比例仅为11.2%, 远远低于全国17.6%的平均水平[5]。由于该地区冬季温度较低, 秸秆还田后分解缓慢, 严重影响了第2年春玉米播种和出苗质量[6]。另有研究指出, 秸秆分解过程中的反硝化作用可能导致微生物与作物争夺土壤中的氮素, 进而影响作物生长发育及产量[7,8]。
针对传统秸秆还田方式的不足, 近些年出现一种新的还田方式, 即秸秆条带还田。目前, 秸秆条带还田主要包括条带覆盖、条带旋耕和条带沟埋等[9,10,11]。该措施由于避免了作物与秸秆的直接接触, 一定程度上解决了传统还田方式下播种和出苗困难问题[12]; 土壤容重显著降低, 疏松的土壤条件有利于促进根系生长发育[13]; 利于增加水分蓄纳和入渗能力, 提高田间土壤含水量[14]; 可以有效滞留氮素, 减少土壤氮的淋失[15]。然而, 关于秸秆条带还田影响农田土壤水分、氮素和作物根系空间分布及提高土壤水氮资源利用效率的机制尚不清楚。
东北春玉米产区传统的浅耕和犁耕引发了农田土壤犁底层厚度与紧实度增加等耕层结构性问题[16]。另一方面, 忽视有机物料投入与大量使用化肥的重用轻养生产方式造成了该区农田板结和耕性变差等功能性问题[17]。现有条件下, 秸秆还田仍然是改变该区农田土壤结构和功能障碍的最佳途径。本研究于2015—2016年在辽河平原中西部春玉米地区, 模拟旋耕处理下不同秸秆条带还田方式, 探讨其对春玉米产量的影响, 及对农田土壤水分、氮素和春玉米根系空间分布的调控效应。旨在为解决东北春玉米产区秸秆还田提供科学依据。
1 材料与方法
1.1 试验地概况
辽宁省铁岭市张庄试验站(42°49′N, 124°16′E)位于辽河平原中西部, 属于温带半湿润半干旱气候区。多年平均气温6.3℃, 降雨量675 mm, 日照时数2700 h, 无霜期146 d。试验地土壤类型为棕壤土, 主要耕作方式为旋耕。2015年0~20 cm土层含有机质19.66 g kg-1、有效氮132.80 mg kg-1、速效磷33.26 mg kg-1和速效钾161.50 mg kg-1。其中, 0~20 cm、20~40 cm和40~60 cm土层全氮含量分别为0.92、0.75和0.63 g kg-1。2015年和2016年春玉米全生育期累计降水量分别为355.3 mm和829.0 mm (图1)。显示原图|下载原图ZIP|生成PPT
图12015年和2016年春玉米生长季日平均气温与降雨量
-->Fig. 1Precipitation and daily mean temperature during spring maize growing seasons in 2015 and 2016 at the Tieling experimental station
-->
1.2 试验设计和田间管理
试验区春玉米播种方式为平播, 供试玉米品种为郑单958, 株行距为25 cm × 60 cm, 平均种植密度约为6.75万株 hm-2。在垄间人工开10 m (长)×30 cm (宽)×15 cm (深)沟槽, 沟槽间距分为30 cm (模拟行行旋耕)和90 cm (模拟隔行旋耕)两种(图2-a)。在两种沟槽内, 分别设置秸秆还田(各试验小区秸秆均取自上一茬该区作物秸秆或临近田块秸秆, 还田量均调整为12 t hm-2, 近似于上茬玉米秸秆全量还田)与秸秆不还田处理。前者将秸秆与土壤混拌均匀后原位还入沟槽内(图2-b), 后者将秸秆全部移出。设垄间旋耕+秸秆还田(RR+S)、垄间旋耕(RR)、隔行垄间旋耕+秸秆还田(IR+S)和隔行垄间旋耕(IR) 4个处理, 3次重复。2015年5月17日和2016年5月2日播种, 同时施入氮75 kg hm-2、P2O5 75 kg hm-2和K2O 225 kg hm-2, 拔节期追施氮150 kg hm-2。其他栽培管理措施按照一般高产田进行, 2015年10月2日和2016年9月28日收获。显示原图|下载原图ZIP|生成PPT
图2田间试验设计(a)、沟槽挖掘(b)以及土壤取样(c)示意和实景图
RR+S: 垄间旋耕秸秆还田; RR: 垄间旋耕; IR+S: 隔行垄间旋耕秸秆还田; IR: 隔行垄间旋耕。
-->Fig. 2Schematic diagram of field design (a), photo of trench excavation (b), and soil sampling (c)
RR+S: the ridges of rotary tillage with straw returning; RR: the ridges of rotary tillage without straw returning; IR+S: interlaced ridges of rotary tillage with straw returning; IR: interlaced ridges of rotary tillage without straw returning.
-->
1.3 测定项目与方法
1.3.1 产量及其构成因素 玉米收获前, 从各小区收取中间4行果穗, 于田间称其总穗重。同时计算平均穗重, 根据平均穗重选取10穗, 观测穗行数、行粒数和千粒重。利用谷物水分测定仪(PM-8188-A, 日本凯特公司)测定籽粒含水量, 换算成14%含水量的玉米产量。1.3.2 土壤水分、全氮和春玉米根系空间分布
在春玉米吐丝期, 从各处理选取3株代表性植株, 采用 “Monilith 3D空间取样法” 测定土壤水分、收集土壤及根系样品[18]。具体方法见图2-c。利用土壤水分测定仪(ML3, 英国Delta-T公司)测定各块土体含水量, 采集各土体样品, 同时使用3 mm孔径筛子和镊子收集根系于自封袋中。利用根系扫描仪(Epson Perfection V700, Indonesia Inc.)对根系扫描, 使用根系分析系统(Win RHIZO Program, Regent Instruments Inc.)获得根长、根表面积等数据。扫描后的根系经105℃杀青, 80℃烘干至恒重后称重, 获得根干重数据。利用凯氏定氮仪(Kjeltec 8400, 丹麦Foss Inc.)测定土壤全氮含量。
1.3.3 水分利用效率
作物耗水量[19]ET = R1+U - R - F - ΔW (1)
式中, R1为作物生育期降水量, mm; U为地下水补给量, mm; R为径流量, mm; F为土壤水分渗漏量, mm; ΔW为收获后和播种前土壤根层储水量的变化, mm, 其中土壤储水量以2 m土层含水量计算; 因为试验小区土地平坦, 故地表径流和土壤水分渗漏量可以忽略不计; 地下水埋深较大, 多在几十米以下, 地下水的补充可以忽略不计。
据此, 式(1)可简化为
ET = R - ΔW (2)
WUEgy = GY/ ET (3)
式中WUEgy为籽粒(经济)产量水分利用效率, kg hm-2 mm-1, GY为玉米籽粒产量。
1.4 数据分析
采用SPSS 18.0 (SPSS, Inc.)进行数据显著性检验(显著性水平为P<0.05), 采用Origin 9.0 (OriginLab, Inc.)和Surfer 8.0 (Golden Software, Inc.)制图。2 结果与分析
2.1 秸秆条带还田对产量及其构成因素的影响
秸秆还田处理可以显著提高春玉米产量, 但还田方式与两者互作均无显著影响(表1)。RR+S和IR+S处理的春玉米产量均显著高于不还田处理, 分别提高6.7%和8.2%, 尤其是在干旱年份(2015年),增产幅度更大, 分别为11.4%和14.3%。秸秆还田可以显著提高穗粒数, 还田方式和两者互作均无显著影响, 在2015年, RR+S和IR+S处理穗粒数较不还田处理显著提高28.3%和45.6%, 处理间千粒重差异不显著。RR+S和IR+S处理均通过增加穗粒数来显著提高产量, 且两者产量差异不显著。Table 1
表1
表1秸秆条带还田对春玉米产量及其构成因素的影响
Table 1Yield and yield components of spring maize in different treatment
年份 Year | 处理 Treatment | 穗粒数 Grain number (per ear) | 千粒重 1000-kernel weight (g) | 产量 Yield (kg hm-2) | 收获指数 Harvest index |
---|---|---|---|---|---|
2015 | RR+S | 466.83±24.66 b | 307.12±16.64 a | 7412.99±211.71 a | 0.42±0.06 ab |
RR | 363.85±20.60 c | 304.04±42.93 a | 6655.35±326.94 b | 0.33±0.10 b | |
IR+S | 511.88±13.99 a | 275.34±34.27 a | 7234.28±103.94 a | 0.49±0.02 a | |
IR | 351.53±26.40 c | 277.20±20.87 a | 6331.27±247.10 b | 0.32±0.09 b | |
2016 | RR+S | 514.80±38.66 ab | 345.90±18.02 ab | 12120.94±145.29 a | 0.56±0.02 a |
RR | 465.46±28.88 b | 366.07±9.81 a | 11655.48±186.20 bc | 0.55±0.01 a | |
IR+S | 535.15±34.18 a | 321.81±18.58 b | 12052.68±351.78 ab | 0.49±0.03 b | |
IR | 485.64±2.01 ab | 363.13±5.80 a | 11494.58±159.99 c | 0.55±0.01 a | |
显著性分析(F值) Interaction analysis of yield and yield components (F-value) | |||||
S | 41.055** | 1.455 | 28.286** | 4.268 | |
M | 1.680 | 2.939 | 2.103 | 0.100 | |
S×M | 1.036 | 0.273 | 0.222 | 0.100 |
新窗口打开
2.2 秸秆条带还田对春玉米根系空间分布的影响
在0~30 cm土层中, 2015年RR+S和IR+S处理的根长密度明显低于不还田处理, 2016年趋势相反, RR+S和IR+S处理的根长密度分别提高26.3%和12.3%。在30~60 cm土层中, RR+S和IR+S处理的根长密度均显著高于不还田处理, 2015年分别提高36.8%和24.6%, 2016年分别提高21.9%和20.7% (图3)。根表面积规律同根长密度(图4)。显示原图|下载原图ZIP|生成PPT
图3不同处理0~60 cm春玉米根长密度的空间分布
RR+S: 垄间旋耕秸秆还田; RR: 垄间旋耕; IR+S: 隔行垄间旋耕秸秆还田; IR: 隔行垄间旋耕。
-->Fig. 3Spatial distribution of root length density in 0-60 cm soil layers under different treatments
RR+S: the ridges of rotary tillage with straw returning; RR: the ridges of rotary tillage without straw returning; IR+S: interlaced ridges of rotary tillage with straw returning; IR: interlaced ridges of rotary tillage without straw returning.
-->
显示原图|下载原图ZIP|生成PPT
图4不同处理0~60 cm春玉米根表面积的空间分布
RR+S: 垄间旋耕秸秆还田; RR: 垄间旋耕; IR+S: 隔行垄间旋耕秸秆还田; IR: 隔行垄间旋耕。
-->Fig. 4Spatial distribution of root surface area in 0-60 cm soil layers under different treatments
RR+S: the ridges of rotary tillage with straw returning; RR: the ridges of rotary tillage without straw returning; IR+S: interlaced ridges of rotary tillage with straw returning; IR: interlaced ridges of rotary tillage without straw returning.
-->
2.3 秸秆条带还田对春玉米根冠比的影响
秸秆条带还田处理的根冠比低于不还田处理(表2), 其中, 2016年IR+S处理、2015年RR+S和IR+S处理分别较秸秆不还田处理降低24.6%、36.5%和39.7%, 且均达到显著水平。IR+S与RR+S处理根冠比差异不显著。由表2可知, 秸秆处理对2015年和2016年根冠比有极显著影响, 还田方式对2016年根冠比有极显著影响, 秸秆处理和还田方式互作对2016年根冠比有极显著影响, 分析认为, 秸秆条带还田对雨水充沛年份(2016)根冠比的效应更为显著。Table 2
表2
表2吐丝期不同处理对春玉米根干重及根冠比的影响
Table 2Effects of different treatments on root dry weight and root shoot ratio at silking stage
处理 Treatment | 2015 | 2016 | |||
---|---|---|---|---|---|
根干重 Root biomass (g plant-1) | 根冠比 Root shoot ratio | 根干重 Root biomass (g plant-1) | 根冠比 Root shoot ratio | ||
RR+S | 12.61±0.43 b | 0.040±0.001 b | 15.71±0.66 b | 0.047±0.002 b | |
RR | 17.12±0.30 a | 0.063±0.001 a | 14.60±0.55 b | 0.047±0.002 b | |
IR+S | 11.22±0.82 c | 0.038±0.003 b | 15.71±0.64 b | 0.046±0.002 b | |
IR | 16.89±0.86 a | 0.063±0.003 a | 18.81±1.07 a | 0.061±0.003 a | |
显著性分析(F值) Interaction analysis of root biomass and root shoot ratio (F-value) | |||||
S | 184.430** | 304.516** | 5.135 | 30.550** | |
M | 4.668 | 2.037 | 23.067** | 18.690** | |
S×M | 2.410 | 0.066 | 23.033** | 29.627** |
新窗口打开
2.4 秸秆条带还田对土壤水氮空间分布的影响
秸秆条带还田对土壤水分空间分布的影响见图5-A。在0~30 cm土层中, 秸秆条带还田与不还田处理土壤水分含量差异不明显; 在30~60 cm土层中, RR+S和IR+S处理分别较秸秆不还田处理增加7.8%和6.1%。秸秆条带还田土壤氮素含量均高于不还田处理(图5-B), 其中在0~20 cm土层, RR+S和IR+S处理分别较秸秆不还田处理提高6.9%和4.5%, 均达到显著水平。显示原图|下载原图ZIP|生成PPT
图52016年不同处理0~60 cm土层中水分(A)和全氮含量(B)的空间分布
RR+S: 垄间旋耕秸秆还田; RR: 垄间旋耕; IR+S: 隔行垄间旋耕秸秆还田; IR: 隔行垄间旋耕。
-->Fig. 5Spatial distribution of moisture (A) and total nitrogen (B) in different soil layers in 2016
RR+S: the ridges of rotary tillage with straw returning; RR: the ridges of rotary tillage without straw returning; IR+S: interlaced ridges of rotary tillage with straw returning; IR: interlaced ridges of rotary tillage without straw returning.
-->
RR+S处理的土壤水、氮在空间上均呈“植株中心两侧含量较为对称”的分布状态, 而IR+S处理则呈“植株中心两侧含量不对称”的分布状态。两者相比, 水氮分布特性差异显著, 但均明显提高了土壤深层水分和耕层土壤氮素含量。说明RR+S和IR+S均可优化土壤结构, 改善农田土壤水氮分布特性。
2.5 秸秆条带还田对玉米水分利用效率的影响
除播种前RR+S处理外, 播种前和收获后秸秆条带还田处理的土壤贮水量均显著高于不还田处理(表3)。与不还田处理相比, RR+S和IR+S耗水量分别降低3.6%和1.6%, 玉米水分利用效率分别显著提高7.8%和7.0%。秸秆处理对播前和收获后土壤贮水量、耗水量和水分利用效率有极显著影响。Table 3
表3
表32016年秸秆条带还田对春玉米耗水量和水分利用效率的影响
Table 3Evapotranspiration of field (ET), grain yield, and water use efficiency (WUE) of spring maize in 2016
处理 Treatment | 播前土壤贮水量 Pre-planting soil water storage(mm) | 收获后土壤贮水量 Soil water storage after harvest (mm) | 耗水量 ET (mm) | 水分利用效率 WUE (kg hm-2 mm-1) |
---|---|---|---|---|
RR+S | 430.7±4.3 b | 383.6±12.2 a | 876.1±6.2 b | 13.8±0.5 a |
RR | 420.0±3.9 b | 340.1±3.7 c | 908.9±15.9 a | 12.8±0.5 b |
IR+S | 443.2±11.5 a | 397.2±8.9 a | 874.9±7.7 b | 13.8±0.3 a |
IR | 424.5±2.2 c | 354.0±15.1 b | 889.4±3.8 b | 12.9±0.4 b |
显著性分析(F值) Interaction analysis of ET and WUE (F-value) | ||||
S | 15.183** | 48.006** | 18.390** | 14.440** |
M | 5.076 | 4.830 | 3.522 | 0.040 |
S×M | 1.124 | 0.001 | 2.753 | 0.040 |
新窗口打开
3 讨论
目前, 秸秆还田对作物产量影响的研究报道相对较多, 且均指出积极增产的效果。殷文等[20]研究表明, 秸秆还田2年后, 玉米籽粒增产11.3%~ 17.5%。赵亚丽等[21]研究发现, 2年的秸秆全量还田, 周年作物(玉米、小麦)产量分别提高了18.0%和19.3%。这与本研究结果一致, 秸秆还田显著提高了春玉米产量, 特别是干旱年份增产效果更明显。秸秆还田对穗粒数和产量的提高有极显著的影响, 还田方式(秸秆还田带间隔距离改变)影响不显著, 穗粒数的提高是秸秆条带还田增产的直接原因。发达的深层根系是作物获得高产的关键因素[22]。与不还田处理相比, 秸秆条带还田在干旱年份(2015年)和丰水年份(2016年)均改变了根系空间分布, 明显增加土壤深层根长密度和根表面积, 显著降低根冠比, 可能是秸秆条带还田下良好的土壤结构及适宜的水氮环境有利于春玉米深层根系的生长发育, 进而降低根冠比, 提高地上部物质积累[23]。玉米根系的生长对农田土壤含水量和土壤全氮的空间分布可能存在反向调控作用[24]。
秸秆条带还田较不还田处理显著改变了农田土壤水分、土壤氮素空间分布特征。RR+S和IR+S处理可以增加深层(30~60 cm)土壤含水量, 分析认为秸秆还田处理部位相当于混拌秸秆的暗沟, 有效降低了地表径流、增加了雨水入渗、减少表层土壤水分蒸发[25,26]。秸秆条带还田显著提高了耕层(0~20 cm)土壤全氮含量, 可能是因为秸秆有效滞留了土壤中施用的氮肥并减缓了土壤氮素淋失[27], 同时秸秆腐解可能增加表层土壤中全氮含量[28]。还田初期秸秆腐解容易造成土壤微生物与春玉米争氮[7,8], 本研究中较高的土壤全氮含量可能部分来源于前一年(2015年)秸秆腐解所释放的氮。RR+S和IR+S处理下土壤水氮分布存在差异, 但均可显著提高土壤深层水分含量和耕层氮素含量, 这也可能是RR+S和IR+S处理下春玉米产量无显著差异的主要原因。
4 结论
不同秸秆条带还田方式下, 垄间旋耕+秸秆还田与隔行垄间旋耕+秸秆还田均能显著提高玉米产量, 秸秆还田处理较秸秆不还田处理玉米根长密度显著增加29.4%和22.7%, 水分利用效率提高7.8%和7.0%。垄间与隔行垄间处理显著影响水氮空间分布, 垄间处理(RR+S和RR)的土壤水、氮在空间上呈“植株中心两侧含量对称分布”状态, 而隔行垄间处理(IR+S和IR)则呈“植株中心两侧含量不对称分布”状态。表明秸秆条带还田通过优化耕层土壤结构, 改善土壤水氮分布, 提高水分利用效率和籽粒产量。为东北春玉米高产高效和秸秆综合利用提供有益的借鉴。The authors have declared that no competing interests exist.
作者已声明无竞争性利益关系。
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
[1] | ., Field experiments were conducted on a sandy clay loam soil (deep aquic ustorthent) for five consecutive seasons from wet season (WS) 1998 to WS 2000 with a permanent layout at the Directorate of Rice Research (DRR) farm, ICRISAT campus, India, to study the influence of incorporation of rice straw residues alone or in combination with in situ grown green manure (GM) and straw burning on soil fertility, irrigated rice productivity and pest incidence in comparison with only fertiliser application (control). The residue treatments received uniform doses of N, K, Zn at the same level as that in control plots. The crop residue treatments favourably influenced some of the soil parameters over control. Recycling of crop residues by incorporation or burning increased soil available K and organic carbon significantly over control, while total N content increased by residue incorporation. Bulk density decreased with residue incorporation as compared to control and burning treatments. Yellow stem borer was the only pest observed, with higher white ear damage recorded during wet seasons ranging from 14.2 31.3% in 1999 and 16.8 29.7% in 2000. The damage was higher with straw + green manure, apparently reflecting the quantum of N applied through crop residues and fertilisers. The influence of crop residue treatments on yield parameters like panicle and spikelet number was more apparent after two cycles of residue incorporation, recording significant effects on rice productivity in the dry and wet seasons of 2000. Rice yield increased by 1.0 to 1.2 t/ha in DS and 0.4 to 0.8 t/ha in WS. |
[2] | . , 保护性耕作具有提高作物水分利用效率、减少能耗等优点,但能否将该技术集成应用于间作套种,尚需理论研究和具体实验依据。本研究通过2011至2012年度的田间定位试验,探讨不同耕作和秸秆还田方式对小麦间作玉米作物群体竞争、互补作用及产量的影响。试验设3种秸秆还田处理,分别是小麦带25 cm高茬收割立茬免耕(NTSS)、小麦带25 cm高茬等量秸秆覆盖免耕(NTS)及小麦带高茬等量秸秆还田翻压(TIS),以传统耕作(CT)为对照。秸秆还田后少耕间作的土地当量比高于传统耕作间作,且大于1,说明少耕小麦秸秆还田有利于提高间作优势;少耕秸秆还田降低了共生期小麦相对于玉米的竞争力,以NTS处理对小麦竞争力的影响最大,NTSS、NTS和TIS的小麦全生育期相对竞争力分别降低37%~54%、109%~141%和22%~24%。与单作玉米相比,NTSS、NTS、TIS和CT处理间作玉米的相对生长率分别高54%~59%、66%~71%、61%~63%和71%~78%,其中小麦秸秆还田间作处理中NTS更有利于发挥玉米的恢复效应。间作条件下,3种秸秆还田处理的产量较对照高6%~10%(2011年度)和4%~12%(2012年度),其中NTS增产显著。总体来看,间作群体籽粒产量与小麦相对于玉米全生育期的平均竞争力呈二次相关关系,当该竞争力在0.24~0.27时利于获得间作高产。本研究表明,秸秆还田配合少耕是调控种间竞争力的可行途径,其中小麦等量秸秆(小麦留茬25 cm)还田覆盖是优化小麦玉米竞争力的理想耕作措施。 ., 保护性耕作具有提高作物水分利用效率、减少能耗等优点,但能否将该技术集成应用于间作套种,尚需理论研究和具体实验依据。本研究通过2011至2012年度的田间定位试验,探讨不同耕作和秸秆还田方式对小麦间作玉米作物群体竞争、互补作用及产量的影响。试验设3种秸秆还田处理,分别是小麦带25 cm高茬收割立茬免耕(NTSS)、小麦带25 cm高茬等量秸秆覆盖免耕(NTS)及小麦带高茬等量秸秆还田翻压(TIS),以传统耕作(CT)为对照。秸秆还田后少耕间作的土地当量比高于传统耕作间作,且大于1,说明少耕小麦秸秆还田有利于提高间作优势;少耕秸秆还田降低了共生期小麦相对于玉米的竞争力,以NTS处理对小麦竞争力的影响最大,NTSS、NTS和TIS的小麦全生育期相对竞争力分别降低37%~54%、109%~141%和22%~24%。与单作玉米相比,NTSS、NTS、TIS和CT处理间作玉米的相对生长率分别高54%~59%、66%~71%、61%~63%和71%~78%,其中小麦秸秆还田间作处理中NTS更有利于发挥玉米的恢复效应。间作条件下,3种秸秆还田处理的产量较对照高6%~10%(2011年度)和4%~12%(2012年度),其中NTS增产显著。总体来看,间作群体籽粒产量与小麦相对于玉米全生育期的平均竞争力呈二次相关关系,当该竞争力在0.24~0.27时利于获得间作高产。本研究表明,秸秆还田配合少耕是调控种间竞争力的可行途径,其中小麦等量秸秆(小麦留茬25 cm)还田覆盖是优化小麦玉米竞争力的理想耕作措施。 |
[3] | . , ., |
[4] | . , 为揭示周年秸秆还田量对小麦高产优质栽培的影响机理,在大田条件下,设置稻麦秸秆均不还田(CK)、25%稻麦秸秆均还田、50%稻麦秸秆均还田、75%稻麦秸秆均还田、100%稻麦秸秆均还田、100%麦季稻秸还田、100%稻季麦秸还田等7个秸秆处理,经过三年田间定位试验,分析了周年秸秆还田量对三年麦田土壤养分及小麦产量的影响.结果表明,周年秸秆还田后三年土壤养分和有机质含量均不同程度地提高,且随秸秆还田量的增加呈先增后减的趋势,效果最好的还田量主要集中在50%和75%.其中,第一年以50%秸秆还田量对土壤养分和有机质含量影响最明显;到第三年以75%还田量影响最显著,土壤全氮、有效磷、速效钾和有机质含量分别比CK提高了2.61%、4.05%、18.25%和5.90%.在前两年,不同秸秆还田处理对小麦均有增产效果,但在第三年,100%稻麦秸秆均还田和100%麦季稻秸还田处理略微减产.6个秸秆还田处理中只有50%稻麦秸秆均还田对小麦的增产效果在三年中均达到显著水平,增产幅度分别为11.23%、14.74%和14.29%.综合来看,50%稻麦秸秆均还田最适宜当地小麦高产栽培. ., 为揭示周年秸秆还田量对小麦高产优质栽培的影响机理,在大田条件下,设置稻麦秸秆均不还田(CK)、25%稻麦秸秆均还田、50%稻麦秸秆均还田、75%稻麦秸秆均还田、100%稻麦秸秆均还田、100%麦季稻秸还田、100%稻季麦秸还田等7个秸秆处理,经过三年田间定位试验,分析了周年秸秆还田量对三年麦田土壤养分及小麦产量的影响.结果表明,周年秸秆还田后三年土壤养分和有机质含量均不同程度地提高,且随秸秆还田量的增加呈先增后减的趋势,效果最好的还田量主要集中在50%和75%.其中,第一年以50%秸秆还田量对土壤养分和有机质含量影响最明显;到第三年以75%还田量影响最显著,土壤全氮、有效磷、速效钾和有机质含量分别比CK提高了2.61%、4.05%、18.25%和5.90%.在前两年,不同秸秆还田处理对小麦均有增产效果,但在第三年,100%稻麦秸秆均还田和100%麦季稻秸还田处理略微减产.6个秸秆还田处理中只有50%稻麦秸秆均还田对小麦的增产效果在三年中均达到显著水平,增产幅度分别为11.23%、14.74%和14.29%.综合来看,50%稻麦秸秆均还田最适宜当地小麦高产栽培. |
[5] | . , 推广秸秆还田对于改善土壤条件、促进农业可持续发展意义重大.但与美国等发达国家相比,我国玉米秸秆直接还田比例仍较低,地域差异明显.本文旨在从技术和经济两个方面,掌握玉米秸秆直接还田的现状,理清未来推广的重点和思路.为此,采用实地调查、文献资料查阅和专家访谈等研究方法,首先利用技术参数对我国玉米秸秆的资源总量及其使用结构进行估计,从总体上把握玉米秸秆的资源状况和还田发展水平;其次依据文献和调研信息,从积极和消极两个方面系统分析了玉米秸秆直接还田技术应用的经济环境影响,从技术和经济两个角度分析了现阶段推广该技术面临的主要瓶颈;再次结合美国推广的成功经验,论证了我国未来推广玉米秸秆直接还田技术的可行性,并明确了未来推广的关键;最后从政策、技术、舆论和调研四个方面提出了政策建议. ., 推广秸秆还田对于改善土壤条件、促进农业可持续发展意义重大.但与美国等发达国家相比,我国玉米秸秆直接还田比例仍较低,地域差异明显.本文旨在从技术和经济两个方面,掌握玉米秸秆直接还田的现状,理清未来推广的重点和思路.为此,采用实地调查、文献资料查阅和专家访谈等研究方法,首先利用技术参数对我国玉米秸秆的资源总量及其使用结构进行估计,从总体上把握玉米秸秆的资源状况和还田发展水平;其次依据文献和调研信息,从积极和消极两个方面系统分析了玉米秸秆直接还田技术应用的经济环境影响,从技术和经济两个角度分析了现阶段推广该技术面临的主要瓶颈;再次结合美国推广的成功经验,论证了我国未来推广玉米秸秆直接还田技术的可行性,并明确了未来推广的关键;最后从政策、技术、舆论和调研四个方面提出了政策建议. |
[6] | . , ., |
[7] | ., A pot experiment was conducted to study the availability of soil and fertilizer N to wetland rice as influenced by wheat straw amendment (organic amendment) and to establish the relative significance of the two sources in affecting crop yield. Straw was incorporated in soil at 0.1, 0.2, and 0.3% before transplanting rice. Inorganic N as 15 N-ammonium sulphate was applied at 30, 60, and 90 渭g g -1 soil either alone or together with wheat straw in different combinations. After harvesting the rice, the plant and soil samples were analyzed for total N and 15 N. Straw incorporation significantly decreased the dry matter and N yield of rice, the decrease being greater with higher rates of straw. The reduction in crop yield following the straw incorporation was attributed mainly to a decrease in the uptake of soil N rather than fertilizer N. The harmful effects of organic matter amendment were mitigated by higher levels of mineral N addition. The uptake of applied N increased and its losses decreased due to the straw incorporation. Mineral N applied alone or together with organic amendment substantially increased the uptake of unlabelled soil N. The increase was attributed to a real added N interaction. |
[8] | . , ., |
[9] | . , ., |
[10] | . , ., |
[11] | . , 通过大田试验,采用秸秆机械集中沟埋和常规还田方式,将上季作物秸秆进行全量还田(秸秆沟埋量2.1kg/m)。设置沟埋深度为20cm(D2),30cm(D3),常规还田(CK)3个处理。利用West提出的净碳排放方程对CK、D2、D3农田各项投入造成的碳排放和土壤碳累积及农作物碳吸收进行比较。结果表明:CK、D2、D3稻麦轮作各项农田投入造成的碳排放量分别为9 018.19,6 459.9,7 162.86kg/(hm2.a),表层0-28cm土壤的碳储量分别为8 375.98,15 854.42,10 954.36kg/(hm2.a),农作物年碳吸收量分别为10 912.42,12 863.95,12 585.51kg/(hm2.a);农田净碳排放量分别为-10 270.2,-22 258.5,-16 377.0kg/(hm2.a),与CK相比,D2、D3的相对净碳排放量分别为-11 988.30,-6 106.81kg/(hm2.a);D2、D3农业投入的碳减排量2 558.29,1 855.33kg/(hm2.a)分别为碳增汇量28 718.4,23 539.9kg/(hm2.a)的8.91%,7.88%,秸秆集中沟埋还田对农田储碳减排能能力较常规还田强,其贡献优先排序是D2〉D3〉CK。 ., 通过大田试验,采用秸秆机械集中沟埋和常规还田方式,将上季作物秸秆进行全量还田(秸秆沟埋量2.1kg/m)。设置沟埋深度为20cm(D2),30cm(D3),常规还田(CK)3个处理。利用West提出的净碳排放方程对CK、D2、D3农田各项投入造成的碳排放和土壤碳累积及农作物碳吸收进行比较。结果表明:CK、D2、D3稻麦轮作各项农田投入造成的碳排放量分别为9 018.19,6 459.9,7 162.86kg/(hm2.a),表层0-28cm土壤的碳储量分别为8 375.98,15 854.42,10 954.36kg/(hm2.a),农作物年碳吸收量分别为10 912.42,12 863.95,12 585.51kg/(hm2.a);农田净碳排放量分别为-10 270.2,-22 258.5,-16 377.0kg/(hm2.a),与CK相比,D2、D3的相对净碳排放量分别为-11 988.30,-6 106.81kg/(hm2.a);D2、D3农业投入的碳减排量2 558.29,1 855.33kg/(hm2.a)分别为碳增汇量28 718.4,23 539.9kg/(hm2.a)的8.91%,7.88%,秸秆集中沟埋还田对农田储碳减排能能力较常规还田强,其贡献优先排序是D2〉D3〉CK。 |
[12] | . , 免耕秸秆覆盖是中国北方干旱半干旱区一种重要的保护性耕作模式。 为明确宽行覆盖窄行深松交错种植条件下覆盖带适宜的秸秆覆盖量和覆盖方式,2012-2013年在河北省廊坊市进行了春玉米的田间试验。选用郑单958为 试验材料,采用80 cm+40 cm宽窄行种植,宽行间覆盖秸秆,窄行间进行苗带深松,设置8.42 t hm-2覆盖量下粉碎覆盖(100SC)、整秆覆盖(100SP)、4.21 t hm-2覆盖量下粉碎覆盖(50SC)、整秆覆盖(50SP)和不覆盖(CK)处理,测定土壤水分和温度、出苗状况、物质积累、产量及产量构成。结果表 明,秸秆覆盖与深松结合条件下,4种覆盖处理与对照相比均提高了土壤含水量,其中50SC处理在花前0~15 cm土壤降温幅度最小,其他覆盖处理显著降低花前土壤温度。各覆盖处理明显提高了苗期整齐度,秸秆覆盖对苗期的生育期天数略有推迟。与 CK 相比,50SC 提高了春玉米地上部生物量,促进花后干物质积累,千粒重和穗粒重分别提高10.9%(P<0.05)和6.5%(P<0.05),产量提高 4.78%,达12243 kg hm-2。50SC条件下产量与全生育期干物质积累(DMA)、花后/花前DMA呈极显著正相关。说明宽行覆盖窄行深松交错种植有利于缓和秸秆覆盖对出苗 的物理阻碍,其中秸秆以4.21 t hm-2的覆盖量粉碎覆盖效果最好,该处理可为玉米提供稳定有利的土壤水分和温度条件,提高了生育后期的物质积累以及籽粒产量。 ., 免耕秸秆覆盖是中国北方干旱半干旱区一种重要的保护性耕作模式。 为明确宽行覆盖窄行深松交错种植条件下覆盖带适宜的秸秆覆盖量和覆盖方式,2012-2013年在河北省廊坊市进行了春玉米的田间试验。选用郑单958为 试验材料,采用80 cm+40 cm宽窄行种植,宽行间覆盖秸秆,窄行间进行苗带深松,设置8.42 t hm-2覆盖量下粉碎覆盖(100SC)、整秆覆盖(100SP)、4.21 t hm-2覆盖量下粉碎覆盖(50SC)、整秆覆盖(50SP)和不覆盖(CK)处理,测定土壤水分和温度、出苗状况、物质积累、产量及产量构成。结果表 明,秸秆覆盖与深松结合条件下,4种覆盖处理与对照相比均提高了土壤含水量,其中50SC处理在花前0~15 cm土壤降温幅度最小,其他覆盖处理显著降低花前土壤温度。各覆盖处理明显提高了苗期整齐度,秸秆覆盖对苗期的生育期天数略有推迟。与 CK 相比,50SC 提高了春玉米地上部生物量,促进花后干物质积累,千粒重和穗粒重分别提高10.9%(P<0.05)和6.5%(P<0.05),产量提高 4.78%,达12243 kg hm-2。50SC条件下产量与全生育期干物质积累(DMA)、花后/花前DMA呈极显著正相关。说明宽行覆盖窄行深松交错种植有利于缓和秸秆覆盖对出苗 的物理阻碍,其中秸秆以4.21 t hm-2的覆盖量粉碎覆盖效果最好,该处理可为玉米提供稳定有利的土壤水分和温度条件,提高了生育后期的物质积累以及籽粒产量。 |
[13] | . , 采用翻转犁开沟的方式,在秋收后将秸秆集中深还田,探讨该模式实施两年后对土壤主要理化性质及玉米根系的影响。结果表明,随着秸秆还田量的增加,各层次土壤容重较CK处理降低了2.42%~10.67%;土壤含水量较CK处理增加了3.99%~14.68%;土壤有机质及全氮含量较CK处理均有显著提高,提高幅度分别为4.34%~97.97%、1.53%~44.36%;玉米根系总根长、总根表面积、总根体积以及平均根系直径均大于CK处理,以12000 kg·hm-2处理效果最为显著。综上,秸秆集中深还田对降低土壤容重,提高土壤蓄水量、有机质和氮素含量,促进根系生长效应明显。 ., 采用翻转犁开沟的方式,在秋收后将秸秆集中深还田,探讨该模式实施两年后对土壤主要理化性质及玉米根系的影响。结果表明,随着秸秆还田量的增加,各层次土壤容重较CK处理降低了2.42%~10.67%;土壤含水量较CK处理增加了3.99%~14.68%;土壤有机质及全氮含量较CK处理均有显著提高,提高幅度分别为4.34%~97.97%、1.53%~44.36%;玉米根系总根长、总根表面积、总根体积以及平均根系直径均大于CK处理,以12000 kg·hm-2处理效果最为显著。综上,秸秆集中深还田对降低土壤容重,提高土壤蓄水量、有机质和氮素含量,促进根系生长效应明显。 |
[14] | . , ., |
[15] | ., Ditch-buried straw return (DBSR) is a novel farming system that not only efficiently eliminates the need to burn straw, but also shows positive effects on soil carbon sequestration and crop yields. Implementation of DBSR, however, may penetrate the tillage pan, increasing the risk of N leaching losses. We therefore determined whether N retention could be increased by DBSR in order to reduce the risk of N loss to the environment. A four-year field experiment and a complementary greenhouse experiment were conducted to test the effects of DBSR on N retention in a rice-wheat rotation system. We found that DBSR altered the spatial distribution of fertilizer N. N content was significantly increased above but reduced below the straw layer in the field experiment. The greenhouse experiment further confirmed the N retention effects by the straw layer. In theory, a maximum of 9.09mg urea-N could be adsorbed by one gram dry wheat straw. Our results suggest that DBSR has the potential to increase N retention in the soil, thus increasing crop uptake and minimizing leaching N loss in the rice-wheat rotation system. |
[16] | . , 针对农田耕层现状及存在的问题,从耕层变薄犁底层增厚,有机质减少地力下降地表裸露水(风)蚀严重等3个方面,分析农田土壤退化及不合理耕层形成的原因,通过总结前人研究结果,明确耕层构造的概念及类型,结合笔者多年研究提出"苗带紧行间松"合理耕层的概念及建立合理耕层构造的重要意义,以期为东北黑土保育、持续高效耕作及确保国家粮食安全提供一定理论参考依据。 ., 针对农田耕层现状及存在的问题,从耕层变薄犁底层增厚,有机质减少地力下降地表裸露水(风)蚀严重等3个方面,分析农田土壤退化及不合理耕层形成的原因,通过总结前人研究结果,明确耕层构造的概念及类型,结合笔者多年研究提出"苗带紧行间松"合理耕层的概念及建立合理耕层构造的重要意义,以期为东北黑土保育、持续高效耕作及确保国家粮食安全提供一定理论参考依据。 |
[17] | . , 本文提出了我国东北地区玉米秸秆还田现状与存在问题,从玉米秸秆还田腐解规律、玉米秸秆还田对土壤物理性状、土壤有机质(碳)、土壤微团聚体、土壤微生物的影响等方面,总结了东北地区玉米秸秆还田培肥机理研究进展,阐述了玉米秸秆还田对玉米生长发育的影响及玉米秸秆还田技术研究进展,并提出了今后东北地区玉米秸秆还田领域的研究方向与重点。 ., 本文提出了我国东北地区玉米秸秆还田现状与存在问题,从玉米秸秆还田腐解规律、玉米秸秆还田对土壤物理性状、土壤有机质(碳)、土壤微团聚体、土壤微生物的影响等方面,总结了东北地区玉米秸秆还田培肥机理研究进展,阐述了玉米秸秆还田对玉米生长发育的影响及玉米秸秆还田技术研究进展,并提出了今后东北地区玉米秸秆还田领域的研究方向与重点。 |
[18] | ., The spatial distribution of root length density (RLD) is important for water and nutrient uptake by plants and biomass allocation in the soil. Experimental root assessment is, however, mostly based on methods that encompass only small fractions of the soil volume. The aim of this study was to characterize the three dimensional (3D) spatial distribution of RLD in the soil of a maize crop for plots of 37.5 and 7502cm row spacing. At each plot, a 3D soil monolith of 7065×654065×6530 (=84,000) cm 3 was completely sampled in form of 84 cubic samples of 1002cm edge length. Roots were washed from the soil and RLD was determined using the line intersect method. In 2004, mean RLD values were 0.4102cm cm 613 for narrow and 0.3402cm cm 613 for wide row spacing at row closure (5502days after planting; DAP) and 0.7402cm cm 613 (1.3702cm cm 613 in 2003) for narrow and 0.7702cm cm 613 (0.9602cm cm 613 in 2003) for wide row spacing at tasseling (104 DAP). The CV values for RLD of 48% to 72% in 2004 were first higher for wide than for narrow row spacing but at the later growth stage (tasseling) lower for wide than for narrow. For individual vertical soil slices, CV values for RLD were about 40–60%, irrespective of the orientation of the slice. The results suggest that RLD was related mainly to the spatial location and the plant row structure, and not governed unambiguously by SBD or SWC. The spatially distributed maize root data suggest that variability of RLD parallel to plant rows is not negligible. Any simplified use of 1D or 2D vertical samples at separate locations may lead to erroneous estimations of RLD profiles. |
[19] | . , 在连续8年田间定位试验的基础上,分析了关中平原冬小麦-夏玉米复种连作系统2008-2009年连续两 个生长季期间不同耕作措施(结合秸秆还田和不还田)对土壤有机碳和水分利用率的影响.结果表明:相对于传统耕作,保护性耕作有利于土壤有机碳、水分利用效 率和作物产量的提高,其中在“深松+秸秆还田”耕作模式下的增幅最高,土壤有机碳含量在0~30 cm土层增幅达到19.5%,水分利用效率和作物产量提高了16.9%和20.5%,而免耕模式则有效提高了0 ~ 10 cm土层有机碳含量.在该地区土壤和气候条件下,深松结合秸秆粉碎还田是最理想的耕作模式,最有利于土壤有机碳累积,并提高水分利用效率和作物产量. ., 在连续8年田间定位试验的基础上,分析了关中平原冬小麦-夏玉米复种连作系统2008-2009年连续两 个生长季期间不同耕作措施(结合秸秆还田和不还田)对土壤有机碳和水分利用率的影响.结果表明:相对于传统耕作,保护性耕作有利于土壤有机碳、水分利用效 率和作物产量的提高,其中在“深松+秸秆还田”耕作模式下的增幅最高,土壤有机碳含量在0~30 cm土层增幅达到19.5%,水分利用效率和作物产量提高了16.9%和20.5%,而免耕模式则有效提高了0 ~ 10 cm土层有机碳含量.在该地区土壤和气候条件下,深松结合秸秆粉碎还田是最理想的耕作模式,最有利于土壤有机碳累积,并提高水分利用效率和作物产量. |
[20] | . , 研究茬口对轮作作物的产量贡献及干物质积累与分配规律的影响,对于优化作物高产高效栽培理论和技术具有重要意义。本研究在甘肃河西绿洲灌区,通过田间试验,研究了前茬小麦不同秸秆还田方式(25 cm高茬收割免耕,NTSS;25 cm高茬等量秸秆覆盖免耕,NTS;25 cm高茬等量秸秆翻压,TIS;低茬收割翻耕,CT)对轮作玉米干物质积累和分配及产量的影响,以期为该区前茬小麦轮作玉米生产模式提供优化依据。结果表明,与CT相比,NTSS、NTS、TIS提高了玉米抽穗后干物质的积累量,两年平均高4.8%~12.7%,NTS较NTSS、TIS具有更高的干物质累积作用;NTSS、NTS、TIS可提高玉米叶、茎、鞘对籽粒的贡献率,提高幅度平均为12.8%~25.0%、6.3%~11.3%、18.3%~78.4%,其中NTS较NTSS、TIS提高作用更突出。NTSS、NTS、TIS提高了玉米的籽粒产量,增幅为11.3%~17.5%,其中NTS两年籽粒产量最高,分别达到13 470 kg hm–2和13 274 kg hm–2,较TIS高5.6%~9.0%;穗粒数增加是小麦秸秆还田提高轮作玉米产量的主要原因。同时NTS获得较高的收获指数,提高比例为6.4%~8.4%,说明NTS较其他处理增产的另一原因是提高了收获指数。本研究表明,其前茬小麦秸秆覆盖结合免耕(NTS)可作为绿洲灌区优化后茬玉米干物质累积规律及获得高产的理想耕作措施。 ., 研究茬口对轮作作物的产量贡献及干物质积累与分配规律的影响,对于优化作物高产高效栽培理论和技术具有重要意义。本研究在甘肃河西绿洲灌区,通过田间试验,研究了前茬小麦不同秸秆还田方式(25 cm高茬收割免耕,NTSS;25 cm高茬等量秸秆覆盖免耕,NTS;25 cm高茬等量秸秆翻压,TIS;低茬收割翻耕,CT)对轮作玉米干物质积累和分配及产量的影响,以期为该区前茬小麦轮作玉米生产模式提供优化依据。结果表明,与CT相比,NTSS、NTS、TIS提高了玉米抽穗后干物质的积累量,两年平均高4.8%~12.7%,NTS较NTSS、TIS具有更高的干物质累积作用;NTSS、NTS、TIS可提高玉米叶、茎、鞘对籽粒的贡献率,提高幅度平均为12.8%~25.0%、6.3%~11.3%、18.3%~78.4%,其中NTS较NTSS、TIS提高作用更突出。NTSS、NTS、TIS提高了玉米的籽粒产量,增幅为11.3%~17.5%,其中NTS两年籽粒产量最高,分别达到13 470 kg hm–2和13 274 kg hm–2,较TIS高5.6%~9.0%;穗粒数增加是小麦秸秆还田提高轮作玉米产量的主要原因。同时NTS获得较高的收获指数,提高比例为6.4%~8.4%,说明NTS较其他处理增产的另一原因是提高了收获指数。本研究表明,其前茬小麦秸秆覆盖结合免耕(NTS)可作为绿洲灌区优化后茬玉米干物质累积规律及获得高产的理想耕作措施。 |
[21] | . , 通过两年田间裂区设计试验,研究了不同土壤耕作方式(常规耕作、深耕、深松)与秸秆还田(秸秆还田、秸秆 不还田)对冬小麦一夏玉米一年两熟农田土壤微生物数量、酶活性和作物产量的影响.结果表明:深松(耕)和秸秆还田不仅降低了土壤容重,提高了土壤有机碳含 量,而且增加了土壤微生物数量、土壤酶活性和作物产量,且二者对夏玉米季的影响大于冬小麦季.与常规耕作+无秸秆还田相比,深耕+秸秆还田、深松+秸秆还 田处理的20~30 cm土壤容重分别降低8.5%和6.6%,土壤有机碳含量分别提高14.8%和12.4%,土壤微生物数量、土壤酶活性分别提高45.9%、33.9%和 34.1%、25.2%,作物产量分别提高18.0%和19.3%,且两处理间无显著差异.说明土壤深松(耕)结合秸秆还田有利于作物产量、土壤微生物数 量和酶活性的提高. ., 通过两年田间裂区设计试验,研究了不同土壤耕作方式(常规耕作、深耕、深松)与秸秆还田(秸秆还田、秸秆 不还田)对冬小麦一夏玉米一年两熟农田土壤微生物数量、酶活性和作物产量的影响.结果表明:深松(耕)和秸秆还田不仅降低了土壤容重,提高了土壤有机碳含 量,而且增加了土壤微生物数量、土壤酶活性和作物产量,且二者对夏玉米季的影响大于冬小麦季.与常规耕作+无秸秆还田相比,深耕+秸秆还田、深松+秸秆还 田处理的20~30 cm土壤容重分别降低8.5%和6.6%,土壤有机碳含量分别提高14.8%和12.4%,土壤微生物数量、土壤酶活性分别提高45.9%、33.9%和 34.1%、25.2%,作物产量分别提高18.0%和19.3%,且两处理间无显著差异.说明土壤深松(耕)结合秸秆还田有利于作物产量、土壤微生物数 量和酶活性的提高. |
[22] | ., The spatial distribution of the root system through the soil profile has an impact on moisture and nutrient uptake by plants, affecting growth and productivity. The spatial distribution of the roots, soil moisture, and fertility are affected by tillage practices. The combination of high soil density and the presence of a soil plow pan typically impede the growth of maize (Zea mays L.).We investigated the spatial distribution coordination of the root system, soil moisture, and N status in response to different soil tillage treatments (NT: no-tillage, RT: rotary-tillage, SS: subsoiling) and the subsequent impact on maize yield, and identify yield-increasing mechanisms and optimal soil tillage management practices. Field experiments were conducted on the Huang-Huai-Hai plain in China during 2011 and 2012. The SS and RT treatments significantly reduced soil bulk density in the top 0-20 cm layer of the soil profile, while SS significantly decreased soil bulk density in the 20-30 cm layer. Soil moisture in the 20-50 cm profile layer was significantly higher for the SS treatment compared to the RT and NT treatment. In the 0-20 cm topsoil layer, the NT treatment had higher soil moisture than the SS and RT treatments. Root length density of the SS treatment was significantly greater than density of the RT and NT treatments, as soil depth increased. Soil moisture was reduced in the soil profile where root concentration was high. SS had greater soil moisture depletion and a more concentration root system than RT and NT in deep soil. Our results suggest that the SS treatment improved the spatial distribution of root density, soil moisture and N states, thereby promoting the absorption of soil moisture and reducing N leaching via the root system in the 20-50 cm layer of the profile. Within the context of the SS treatment, a root architecture densely distributed deep into the soil profile, played a pivotal role in plants' ability to access nutrients and water. An optimal combination of deeper deployment of roots and resource (water and N) availability was realized where the soil was prone to leaching. The correlation between the depletion of resources and distribution of patchy roots endorsed the SS tillage practice. It resulted in significantly greater post-silking biomass and grain yield compared to the RT and NT treatments, for summer maize on the Huang-Huai-Hai plain. |
[23] | ., Field experiments were conducted in 2008–2010 in the Loess Plateau of China to study the effects of straw incorporation on maize growth and biomass water use efficiency (WUE) under semi-arid condition in dark loessial soil. Low (LS 4.5tha611), medium (MS 9.0tha611), and high (HS 13.5 tha611) levels of straw were incorporated into the surface soil combined with fixed levels of inorganic fertilizers (CK) as control. Straw incorporation compared with CK significantly improved biomass yield at the tasseling–maturity stage of maize and WUE at the jointing–ten leaf collar and the tasseling–grain filling stages. WUEs with LS and MS treatments were significantly lower than that with CK at the ten leaf collar–tasseling stage, although the WUEs with MS and HS treatments were significantly higher in the whole growth period. HS treatment compared with LS treatment significantly increased biomass yield at the ten leaf collar–maturity stage and WUE at the jointing–tasseling stage. Meanwhile, MS and HS treatments compared with LS treatment significantly increased the biomass yield at the late grow period. Straw incorporation significantly improved WUE at the sowing–jointing stage and soil organic carbon relative to CK. Biomass yield at the ten leaf collar stage and WUE in whole growth period with LS treatment were significantly higher compared with CK. WUE at the ten leaf collar–tasseling and the grain filling–maturity stages were significantly higher with HS treatment compared with CK. In the long term, the rational straw incorporation level in improving maize biomass yield and WUE was 9.0tha611. |
[24] | . , The incomplete soil exploration by roots is a possible cause of reduced water uptake and the occurrence of strong gradients in water potential between root clusters and the bulk soil. Therefore, the hydraulic or root signal-elicited behaviors of plants might correspond to a lower water content than that of the bulk soil. Evidence supporting this hypothesis is scarce and often circumstantial due to the lack of appropriate techniques. This work studies the relations of root clustering caused by localized soil compaction and the spatial patterns of water uptake in plants grown on stored water. Five soil structure treatments were compared in 100-cm high containers: clay-loam soil (C), sandy-clay soil (S), sandy clay with large clay-loam peds (S + LA), sandy clay with small clay-loam peds (S + SA), and compacted clay-loam soil (CC). Root length density (RLD) and volumetric water content ( v) (time-domain reflectometry) were measured in bulk soil and across peds in 2-cm increments. In the S treatment, plant growth was rapid initially, but green leaf area declined to zero when water was exhausted. Root length density was quite uniform in each layer. In the CC treatment, root density and water uptake were limited and leaf area remained stable throughout the experiment, suggesting that incomplete water extraction was a consequence rather than a cause of reduced plant growth. In the other treatments, when plants had lost all leaves, the water content of peds ranged from 0.23 cm |
[25] | . , ., |
[26] | . , 采用田间试验方法,将玉米秸秆切段、粗粉碎、细粉碎、细粉碎后压粒和细粉碎后氨化处理,研究玉米秸秆深施还田对土壤水分转移及产量的影响。结果表明,秸秆粉碎程度越细,吸水能力越强,深施后土壤渗水速度越快;粉碎的秸秆较其他处理更能促进土壤水分竖直方向转移;各处理的蓄水能力表现为粉碎状秸秆处理段状秸秆处理CK(不施秸秆),且细粉碎、细粉碎后氨化处理在还田初期就能呈现出明显的蓄水效果;秸秆粉碎状态越细,深施后土壤容重减小的速度和幅度越大,细粉碎处理和细粉碎后氨化处理能在还田初期对减小土壤容重产生明显作用,播种后25 d,土壤容重减小幅度最大,分别达0.052和0.045 g/cm3;秸秆深施还田有效提高玉米产量,产量排序为细粉碎细粉碎后氨化处理粗粉碎细粉碎后压粒秸秆切段CK(不施秸秆),其中细粉碎处理对玉米产量的增加影响最明显。 ., 采用田间试验方法,将玉米秸秆切段、粗粉碎、细粉碎、细粉碎后压粒和细粉碎后氨化处理,研究玉米秸秆深施还田对土壤水分转移及产量的影响。结果表明,秸秆粉碎程度越细,吸水能力越强,深施后土壤渗水速度越快;粉碎的秸秆较其他处理更能促进土壤水分竖直方向转移;各处理的蓄水能力表现为粉碎状秸秆处理段状秸秆处理CK(不施秸秆),且细粉碎、细粉碎后氨化处理在还田初期就能呈现出明显的蓄水效果;秸秆粉碎状态越细,深施后土壤容重减小的速度和幅度越大,细粉碎处理和细粉碎后氨化处理能在还田初期对减小土壤容重产生明显作用,播种后25 d,土壤容重减小幅度最大,分别达0.052和0.045 g/cm3;秸秆深施还田有效提高玉米产量,产量排序为细粉碎细粉碎后氨化处理粗粉碎细粉碎后压粒秸秆切段CK(不施秸秆),其中细粉碎处理对玉米产量的增加影响最明显。 |
[27] | ., Soil fertility and leaching losses of nutrients were compared between a Fimic Anthrosol and a Xanthic Ferralsol from Central Amaz么nia. The Anthrosol was a relict soil from pre-Columbian settlements with high organic C containing large proportions of black carbon. It was further tested whether charcoal additions among other organic and inorganic applications could produce similarly fertile soils as these archaeological Anthrosols. In the first experiment, cowpea ( Vigna unguiculata (L.) Walp.) was planted in pots, while in the second experiment lysimeters were used to quantify water and nutrient leaching from soil cropped to rice ( Oryza sativa L.). The Anthrosol showed significantly higher P, Ca, Mn, and Zn availability than the Ferralsol increasing biomass production of both cowpea and rice by 38 45% without fertilization (P<0.05). The soil N contents were also higher in the Anthrosol but the wide C-to-N ratios due to high soil C contents led to immobilization of N. Despite the generally high nutrient availability, nutrient leaching was minimal in the Anthrosol, providing an explanation for their sustainable fertility. However, when inorganic nutrients were applied to the Anthrosol, nutrient leaching exceeded the one found in the fertilized Ferralsol. Charcoal additions significantly increased plant growth and nutrition. While N availability in the Ferralsol decreased similar to the Anthrosol, uptake of P, K, Ca, Zn, and Cu by the plants increased with higher charcoal additions. Leaching of applied fertilizer N was significantly reduced by charcoal, and Ca and Mg leaching was delayed. In both the Ferralsol with added charcoal and the Anthrosol, nutrient availability was elevated with the exception of N while nutrient leaching was comparatively low. |
[28] | . , 秸秆集中沟埋还田(DB-SR)是一种新型土壤耕作方式,能够形成特殊的“秸秆层”结构。通过研究秸秆层及其界面土壤的氮素含量和微生物群落结构,以期阐明秸秆层对土壤氮素分布以及微生物群落的影响。设置秸秆沟埋还田深度为20 cm、40 cm以及对照(秸秆不还田)3个处理,测定秸秆层及其界面土层(依5 cm)的NH+4-N与NO-3-N含量,分析微生物量碳(MBC)及群落结构特征。研究发现,“秸秆层”对氮素具有滞留作用,并能够持续60个月。在20 cm埋深下,秸秆层提高了其界面上下土层的MBC,但对多样性指数的影响不显著;在40 cm埋深下,水稻秸秆层界面土壤MBC随时间先减小后增大,多样性指数随时间延长而增加;小麦秸秆层界面土壤MBC随时间先增大后减小,多样性指数随时间先减小后增大。微生物群落碳源利用主成分分析表明,秸秆层微生物能很好地利用各类碳源,其界面土壤的微生物代谢活性也比CK处理有所提高。对应分析表明,小麦秸秆在20 cm埋深下,NH+4-N、NO-3-N与界面土层微生物群落具有相关性,MBC与秸秆层微生物群落显著相关;在40 cm埋深下,NH+4-N、NO-3-N和MBC与秸秆层微生物群落变异显著相关。综上可知,“秸秆层”能有效滞留氮素,减少土壤氮素淋失,增加土壤微生物群落功能多样性。 ., 秸秆集中沟埋还田(DB-SR)是一种新型土壤耕作方式,能够形成特殊的“秸秆层”结构。通过研究秸秆层及其界面土壤的氮素含量和微生物群落结构,以期阐明秸秆层对土壤氮素分布以及微生物群落的影响。设置秸秆沟埋还田深度为20 cm、40 cm以及对照(秸秆不还田)3个处理,测定秸秆层及其界面土层(依5 cm)的NH+4-N与NO-3-N含量,分析微生物量碳(MBC)及群落结构特征。研究发现,“秸秆层”对氮素具有滞留作用,并能够持续60个月。在20 cm埋深下,秸秆层提高了其界面上下土层的MBC,但对多样性指数的影响不显著;在40 cm埋深下,水稻秸秆层界面土壤MBC随时间先减小后增大,多样性指数随时间延长而增加;小麦秸秆层界面土壤MBC随时间先增大后减小,多样性指数随时间先减小后增大。微生物群落碳源利用主成分分析表明,秸秆层微生物能很好地利用各类碳源,其界面土壤的微生物代谢活性也比CK处理有所提高。对应分析表明,小麦秸秆在20 cm埋深下,NH+4-N、NO-3-N与界面土层微生物群落具有相关性,MBC与秸秆层微生物群落显著相关;在40 cm埋深下,NH+4-N、NO-3-N和MBC与秸秆层微生物群落变异显著相关。综上可知,“秸秆层”能有效滞留氮素,减少土壤氮素淋失,增加土壤微生物群落功能多样性。 |