Effects of conservation tillage practices on winter wheat water-use efficiency and crop yield on the Loess Plateau,China

In the semi-humid to arid loess plateau areas of North China, water is the limiting factor for rain-fed crop yields. Conservation tillage has been proposed to improve soil and water conservation in these areas. From 1999 to 2005, we conducted a field experiment on winter wheat (Triticum aestivum L.) to investigate the effects of conservation tillage on soil water conservation, crop yield, and water-use efficiency. The field experiment was conducted using reduced tillage (RT), no tillage with mulching (NT), subsoil tillage with mulching (ST), and conventional tillage (CT). NT and ST improved water conversation, with the average soil water storage in 0–200 cm soil depth over the six years increased 25.24 mm at the end of summer fallow periods, whereas RT soil water storage decreased 12 mm, compared to CT. At wheat planting times, the available soil water on NT and ST plots was significantly higher than those using CT and RT. The winter wheat yields were also significantly affected by the tillage methods. The average winter wheat yields over 6 years on NT or ST plots were significantly higher than that in CT or RT plots. CT and RT yields did not vary significantly between them. In each study year, NT and ST water-use efficiency (WUE) was higher than that of CT and RT. In the dry growing seasons of 1999–2000, 2004–2005 and the low-rainfall fallow season of 2002, the WUE of NT and ST was significantly higher than that of CT and RT, but did not vary significantly in the other years. For all years, CT and RT showed no WUE advantage. In relation to CT, the economic benefit of RT, NT, and ST increased 62, 1754, and 1467 yuan ha⁻¹, respectively, and the output/input ratio of conservation tillage was higher than that of CT. The overall results showed that NT and ST are the optimum tillage systems for increasing water storage and wheat yields, enhancing WUE and saving energy on the Loess Plateau.     

Evaluation of post-rainy season crops with residual soil moisture and different tillage methods in rice fallow of eastern India

In eastern India, farmers grow rice during rainy season (June-September) and land remains fallow after rice harvest in the post-rainy season (November-May) due to lack of sufficient rainfall or irrigation facilities. But in lowland areas of eastern India, sufficient carry-over residual soil moistures are available in rice fallow in the post-rainy season (November-March), which can be utilized for growing second crops in the region. During the post-rainy season when irrigation facilities are not available and rainfall is meager, effective utilization of carry-over residual soil moisture and conservation agriculture become imperative for second crop production after rice. Implementation of suitable tillage/seeding methods and other agro-techniques are thus very much important to achieve this objective. In this study four pulse crops (lathyrus, blackgram, pea, and greengram) were sown utilizing carry-over residual soil moisture and with different tillage/seeding methods viz. relay cropping (RC)/farmers’ practice, reduced tillage (only two ploughing) (RT), conventional tillage (CT) and zero tillage (ZT). Study revealed that the highest grain yields of 580, 630, 605 and 525 kg ha⁻¹ were obtained from lathyrus, blackgram, pea and green gram, respectively, with RT treatment. On the other hand, with conventional tillage, 34-44% lower yields were obtained than that of RT. Crops with reduced tillage performed better than that with zero tillage or relay cropping also. Impacts of different tillage methods on important soil physical properties like infiltration, bulk density were also studied after harvesting first crop (rice) and before growing second crops (pulses) in rice fallow. The lowest mean bulk density (1.42) was recorded in the surface soils of CT treatment while the corresponding value under ZT treatment was 1.54 Mg m⁻³.     

关于长春地区保护性耕作培训班学习后的几点思考

随着资源与环境问题逐渐凸显,我国对于农业生产中的秸秆类生物质资源的利用要求逐渐提高,国家和地区的多项政策都提出禁止秸秆的随意处置,要求建立秸秆的科学利用机制.保护性耕作是秸秆利用的可行模式,不仅能够就地利用农作物秸秆,还有利于改善农业土壤环境,提高农作物产量.基于此,利用2021年6月开展的长春地区保护性耕作技术培训,...     

Soil texture, climate and management effects on plant growth, grain yield and water use by rainfed maize–wheat cropping system: Field and simulation study

In sub-mountain tract of Punjab state of India, maize (Zea mays, L.) and wheat (Triticum aestivum L.) crops are grown as rainfed having low crop and water productivity. To enhance that, proper understanding of the factors (soil type, climate, management practices and their interactions) affecting it is a pre-requisite. The present study aims to assess the effects of tillage, date of sowing, and irrigation practices on the rainfed maize–wheat cropping system involving combined approach of field study and simulation. Field experiments comprising 18 treatments (three dates of sowing as main, three tillage systems as subplot and two irrigation regimes as the sub-subplot) were conducted for two years (2004–2006) and simulations were made for 15 years using CropSyst model. Field and simulated results showed that grain yields of maize and wheat crops were more in early July planted maize and early November planted wheat on silt loam soil. Different statistical parameters (root mean square error, coefficient of residual mass, model efficiency, coefficient of correlation and paired t-test) indicated that CropSyst model did fair job to simulate biomass production and grain yield for maize–wheat cropping system under varying soil texture, date of planting and irrigation regimes.     

秋耕覆盖对马铃薯生长及水分利用效率的影响

在宁南旱区,采用免耕、深松、翻耕结合秸秆、地膜等覆盖耕作措施,以翻耕不覆盖为对照,研究覆盖耕作模式下休闲期土壤的蓄水保墒效果、马铃薯生育期土壤水分的变化特征及对作物生长、产量及水分利用效率的影响.结果表明:在休闲末期,不同覆盖耕作处理下0~200 cm土层土壤蓄水量均比休闲初期明显提高.与翻耕不覆盖处理相比,免耕覆盖地膜、深松覆盖地膜和翻耕覆盖地膜处理0~200 cm土层土壤蓄水量分别比对照处理提高7.6%,9.3%和8.0%.马铃薯生育前期,覆盖地膜结合不同耕作措施下0~200 cm土层土壤蓄水量最高,生育中后期覆盖秸秆结合不同耕作处理对0~200 cm土层土壤保水效果最佳.覆盖地膜结合不同耕作处理能促进马铃薯生育前期的生长,生育中后期以覆盖秸秆结合不同耕作处理促进作用最为显著.不同覆盖耕作处理均能提高马铃薯的产量和水分利用效率,增产效果以免耕覆盖秸秆、深松覆盖秸秆和翻耕覆盖秸秆处理最为显著,分别较对照组增产51.2%,42.8%和35.3%,水分利用效率分别比对照组提高50.0%,42.3%和32.3%.可见,覆盖秸秆结合不同耕作处理的增产效果和提高水分利用效率最高.     

Yield and soil system changes from conservation tillage in dryland farming: A case study from North Eastern Tanzania

Yield levels in smallholder farming systems in semi-arid sub-Saharan Africa are generally low. Water shortage in the root zone during critical crop development stages is a fundamental constraining factor. While there is ample evidence to show that conservation tillage can promote soil health, it has recently been suggested that the main benefit in semi-arid farming systems may in fact be an in situ water harvesting effect. In this paper we present the result from an on-farm conservation tillage experiment (combining ripping with mulch and manure application) that was carried out in North Eastern Tanzania from 2005 to 2008. Special attention was given to the effects of the tested treatment on the capacity of the soil to retain moisture. The tested conservation treatment only had a clear yield increasing effect during one of the six experimental seasons (maize grain yields increased by 41%, and biomass by 65%), and this was a season that received exceptional amounts of rainfall (549 mm). While the other seasons provided mixed results, there seemed to be an increasing yield gap between the conservation tillage treatment and the control towards the end of the experiment, and cumulatively the yield increased with 17%. Regarding soil system changes, small but significant effects on chemical and microbiological properties, but not on physical properties, were observed. This raises questions about the suggested water harvesting effect and its potential to contribute to stabilized yield levels under semi-arid conditions. We conclude that, at least in a shorter time perspective, the tested type of conservation tillage seems to boost productivity during already good seasons, rather than stabilize harvests during poor rainfall seasons. Highlighting the challenges involved in upgrading these farming systems, we discuss the potential contribution of conservation tillage towards improved water availability in the crop root zone in a longer term perspective.     

东北垄作滚动圆盘式耕播机

基于垄作栽培制度的高留茬秸秆覆盖耕播是东北地区保护性耕作的主流模式,研制了适合于这种模式的双圆盘螺旋线型清垄部件、圆锥台形垄作导向装置,通过试验优选出3种滚动圆盘式破茬犁刀。设计了以小型四轮拖拉机为动力的垄作滚动圆盘式耕播机。     

Soil water storage and drainage under cotton-based cropping systems in a furrow-irrigated Vertisol

Comparative studies of drainage and leaching under tillage systems in irrigated tropical and sub-tropical Vertisols are sparse. The objective of this study was to quantify drainage under cotton-based cropping systems sown on permanent beds in an irrigated Vertisol. Drainage and soil water storage were measured with the chloride mass balance method and neutron moisture meter, respectively, during the 2002-03, 2004-05, 2006-07 and 2008-09 cotton seasons in an on-going experiment in a Vertisol in NW NSW. The experimental treatments were: cotton monoculture sown either after conventional tillage or on permanent beds, and a cotton-wheat rotation on permanent beds where the wheat stubble was retained as in situ mulch into which the following cotton crop was sown. Subject to in-crop rainfall, irrigation frequency varied between 7 and 14 days for cotton and 2-3 months for wheat. In 2005, a split-plot design was superimposed on the existing experiment such that the main-plot treatments were irrigation frequency (“frequent”, 7-14-day irrigation interval; “infrequent”, 14-21-day irrigation interval), and sub-plot treatments were the historical tillage system/crop rotation combinations. In comparison with cotton monoculture sown either after conventional tillage or on permanent beds, soil water storage, particularly during the early part of growing season when rainfall provided the major proportion of crop water requirements, and drainage were greatest when a cotton-wheat rotation was sown on permanent beds. Seasonal drainage out of the 1.2 m depth, averaged among all seasons, was of the order of 25 mm, 33 mm and 70 mm with cotton monoculture sown either after conventional tillage or on permanent beds, and a cotton-wheat rotation on permanent beds, respectively. Soil water storage and drainage were also greater when irrigation frequency was greater. Seasonal drainage out of the 1.2 m depth, averaged between the 2006-07 and 2008-09 seasons, was 54 mm with “frequent irrigation”, and 28 mm with “infrequent” irrigation. Infiltration was less in management systems which resulted in wetter soil; viz. frequent irrigation or a cotton-wheat rotation on permanent beds with in situ stubble retention. Drainage water losses in a furrow-irrigated Vertisol may be reduced and soil water storage increased (i.e. water conservation improved) by sowing a cotton-wheat rotation with in situ stubble retention under less frequent irrigation.     

Soil management and traffic effects on infiltration of irrigation water applied using sprinklers

Zero tillage and controlled traffic have been proposed as means for more productive and sustainable irrigated farming. Both practices affect soil infiltration characteristics and, therefore, should have effects on sprinkler irrigation performance. This study compared water infiltration and runoff in three sprinkler irrigation tests performed on an alluvial loam soil at different times during a maize (Zea mays L.)–cotton (Gossypium hirstium L.) rotation under two soil managements: permanent beds with crop residue retention (PB: planting beds maintained unaltered from year to year) and conventional beds with residues incorporated with tillage (CB: disc and chisel ploughing followed by rotavator pass and bed forming every year). Traffic was controlled and two types of furrows were distinguished in both tillage systems: with (+T) and without (−T) wheel traffic. The irrigation tests were performed on maize at full cover, on bare soil just before cotton sowing and on cotton with 50% ground cover. Infiltration and runoff were affected notably by both traffic and soil management. The soil under PB infiltrated more water than under CB, and −T furrows more than +T furrows. Considering the combined treatments, −T furrows in the CB system infiltrated more water than +T furrows in the PB system. A sprinkler irrigation model for simulating water application and soil infiltration and runoff was formulated. The model was used to analyse irrigation performance under infiltration characteristic of the CB and PB systems in trafficked and non-trafficked furrows. Five irrigation performance indicators were used to assess the various combinations of tillage and traffic: Wilkox–Swailes coefficient of uniformity; application efficiency; deep percolation ratio; tail water ratio; and adequacy. The model was used to develop operation diagrams and provided guidelines for making irrigation decisions in the new controlled traffic/permanent bed system and in a standard conventional system.     

保护性耕作下土壤水分变化特征模拟研究

为了对陇中黄土高原沟壑区不同保护性耕作措施下的土壤含水率进行差异性分析,利用长期定位试验,设置春小麦/豌豆、豌豆/春小麦轮作序列下传统耕作、免耕、传统耕作秸秆覆盖和免耕覆盖4种耕作措施,以当地月平均气温、月降水量、月平均辐射量、月平均蒸发量、月作物耗水量作为输入,以0～200 cm 土层土壤含水率作为输出,建立基于长短...     

水土保持耕作对黑土玉米氮素利用与温室气体排放影响

为探明不同水土保持耕作技术对东北黑土坡耕地玉米氮素利用和温室气体排放的影响，以大田试验为基础，设置7个耕作处理：等高耕作(Transverse slope planting, TP)、垄向区田(Ridge to the district field, RF)、深松耕(Subsoiling tillage, SF)、等高耕作+深松耕(Transverse slope planting+subsoiling tillage, TP-S)、垄向区田+深松耕(Ridge to the district field+subsoiling tillage, RF-S)、等高耕作+垄向区田(Transverse slope planting+ridge to the district field, TP-R)、常规耕作(Down-slope cultivation, CK),探究水土保持耕作技术对东北黑土坡耕地土壤养分状况、温室气体排放、氮素吸收利用和产量的影响。结果表明：在玉米全生育期内，水土保持耕作处理显著提高了玉米产量、器官氮素转运率以及氮肥利用率，部分水土保持耕作措施也可以显著降低N     

Crop rotations in Argentina: Analysis of water balance and yield using crop models

Cropping schemes have developed in east-central Argentina for rainfed soybean (Glycine max Merr.) production that invariably employ no-tillage management. Often these schemes include growing soybean in a sequence of crops including wheat (Triticum aestivum L.) and maize (Zea mays L.). The full impact of various rotation schemes on soil water balance through a sequence of seasons has not been explored, although the value of these rotations has been studied experimentally. The objective of this work was to investigate through simulations, potential differences in temporal soil water status among rotations over five years. In this study, mechanistic models of soybean (Soy), maize (Maz), and wheat (Wht) were linked over a five-years period at Marcos Juárez, Argentina to simulate soil water status, crop growth, and yield of four no-till rotations (Soy/Soy, Soy/Wht, Soy/Maz, and Soy/Maz/Wht). Published data on sowing dates and initial soil water contents in the first year from a no-till rotation experiment were used as inputs to the model. After the first year, soil water status output from the model was used to initiate the next crop simulation in the sequence. The results of these simulations indicated a positive impact on soil water balance resulting from crop residue on the soil surface under no-till management. Continuous soybean and the two-year soybean/maize rotation did not efficiently use the available water from rainfall. Residue from maize was simulated to be especially effective in suppressing soil evaporation. Thus, the Soy/Maz simulation results indicated that this rotation resulted in enhanced soil water retention, increased deep water percolation, and increased soybean yields compared with continuous soybean crops. The simulated results matched well with experimental observations. The three-crop rotation of Soy/Maz/Wht did not increase simulated soybean yields, but the additional water retained as a result of decreased soil evaporation resulting from the maize residue allowed the addition of a wheat crop in this two-year rotation. Simulated soybean yields were poorly correlated with both the amount of soil water at sowing and the rainfall during the cropping period. These results highlight the importance of temporal distribution of rainfall on final yield. These models proved a valuable tool for assessing the consequences of various rotation schemes now being employed in Argentina on temporal soil water status, and ultimately crop yield.     

保护性耕作对土壤理化性质和作物产量的影响

应用定位田间试验的方法，研究了不同耕作方式和秸秆还田方式对作物产量和土壤理化性质的影响。研究结果表明，传统翻耕的土壤容重大于进行保护性耕作的土壤容重；随着免耕年限的增加，土壤团聚体不断增大，进行5年保护性耕作的土壤团聚体比进行2年、3年保护性耕作的土壤团聚体有明显增加：进行免耕秸秆覆盖处理的土壤养分除碱解氮外．有机质、全氮、全钾、全磷及速效磷、速效钾均高于免耕无秸秆覆盖和传统翻耕的土壤：在施肥量相同的情况下。进行保护性耕作处理的小麦和水稻产量均比传统翻耕高，其中以半量秸秆还田免耕增产幅度最高，分别达小麦14．45％，水稻6．47％。     

Impact of crop rotation and minimum tillage on water use efficiency of irrigated cotton in a Vertisol

Crop water use efficiency of irrigated cotton was hypothesized to be improved by a combination of minimum tillage and sowing a wheat (Triticum aestivum L.) rotation crop. This hypothesis was evaluated in a Vertisol near Narrabri, Australia from 1997 to 2003. The experimental treatments were: continuous cotton sown after conventional or minimum tillage and minimum-tilled cotton–wheat. Soil water content was measured with a neutron moisture meter, and runoff with trapezoidal flumes. Application efficiency of irrigation water was estimated as the amount of infiltrated water/total amount applied. Plant available water was estimated using the maximum and minimum soil water storage during the growing season. Evapotranspiration was estimated with the water balance method using measured and simulated soil water data. Seasonal evapotranspiration was partitioned into that coming from rainfall, irrigation and stored soil water. Crop water use efficiency was calculated as cotton lint yield per hectare/seasonal evapotranspiration. Rotation of cotton with wheat and minimum tillage improved water use efficiency in some years and application efficiency in all years. Average seasonal evapotranspiration was higher with minimum tillage than with conventional tillage. In years when cotton was sown in all plots, average cotton crop water use efficiencies were 0.23, 0.23 and 0.22 kg (lint)/m³ for minimum-tilled cotton–wheat and continuous cotton, and conventionally tilled continuous cotton, respectively. In-season rainfall efficiency, transpiration and soil evaporation were unaffected by cropping system.     

垄作免耕技术及机具的研究进展

保护性耕作可以减少土壤风蚀与水蚀,提高作物产量,是发展旱作农业的重要措施。推广保护性耕作必须结合不同地域的气候特点及种植制度,形成具有区域特色的保护性耕作技术体系。垄作免耕技术对东北地区发展保护性耕作具有重要意义。为此,列举了几种垄作免耕技术模式,对其优缺点进行了分析,比较了几种垄作免耕播种机的破茬原理,指出了机具的研究重点应放在开发动土量少和功耗小的破茬部件上,以提高免耕播种机的通过性和作业质量。     

秸秆后覆盖小麦播种机设计与试验

针对华北平原麦-玉两熟区,小麦在玉米秸秆覆盖地撒播易出现秸秆堵塞、麦种架空、晾籽等问题,利用正转旋耕抛土模型以形成土壤、秸秆顺序覆盖,设计了一种秸秆后覆盖小麦播种机,可一次完成旋耕、均匀撒播、覆土、覆盖秸秆、镇压等作业。旋耕刀采用对称螺旋线排列;通过抛土运动分析确定了被抛物料运动的最大高度为0.52 m,水平方向最大位移为0.79 m,并确定了导土板的位置参数;通过性能试验优选分种装置与水平方向夹角为35°,分种板间的距离为50 mm。在河北涿州试验站进行了整机田间试验,结果表明:正转旋耕装置能有效抛土、抛秸秆,避免秸秆、根茬堵塞分种装置,耕深稳定在148~152 mm内,耕深稳定性系数为95.5%,多功能行走轮滑移率约为5.3%,机具通过性能符合国家标准(GB/T 20865—2007)要求;机具作业后秸秆覆盖量平均为1.07 kg/m2,达到作业前秸秆覆盖量的80%;播深稳定在30~35 mm内,播深合格率为91.1%,不同位置幅宽内10 cm×25 cm矩形框内麦种数量稳定在29~30粒,符合农艺要求。     

Investigating water availability for introducing an additional crop yield in dry season on hill land at Rubirizi, Rwanda

The study explores the potential of introducing an additional crop during dry season in Rwanda, comparing the efficiency of in situ soil moisture conservation techniques to sustain rain-fed agriculture. Comparative study of in situ soil moisture conservation techniques in bench terraces and unterraced field with maize crop had been conducted from June 2007 to October 2007. Bench terrace increased the average soil moisture content in 90 cm soil depth by more than 50% than that of unterraced land. Within the bench terraced field compartment bund and ridges and furrows increased soil moisture by 19.5% and 27.9% higher than plain bed. In terms of efficiency of moisture conservation, ridges and furrows performed well with 85.8% followed by compartment bund with 75.9% in terraced field. Unterraced field conserved moisture very poorly with 13.9% efficiency inferring importance of bench terraces for soil moisture conservation. No maize grain yield was recorded in all the techniques because soil water depleted to 60% and above from the beginning of the cropping period inferring the need of supplementary irrigation. Analysis of rainfall, crop water demand and in situ moisture conservation reveals exciting opportunities for water productivity enhancements by integrating components of water management within the context of rain-fed farming through water harvesting and supplemental or microirrigation for dry spell mitigation. Detailed analysis is needed for feasibility of lift irrigation with different crops under different altitudes to derive suitable policy for hill land irrigation.     

Sustainable recovery of soil desiccation in semi-humid region on the Loess Plateau

Soil desiccation is one of the key factors to influence the sustainable development of crop production on the Loess Plateau of China. Depletion of soil water during growth period and its recovery in the fallow period is influenced by the amount of rainfall, its distribution, the type of crop and its rotation sequence. This study analyzed depletion and restoration of soil water for different cropping systems, based on a series of long-term experimental data at Changwu Agriculture Station from 1985 to 2001. Results of this study indicated that: (1) temporary soil desiccation took place in 1-3 m soil for MM, PWM and MW cropping system. (2) Permanent soil desiccation took place in 1-5 m and 1-10 m soil for APW and AF cropping system respectively. (3) When a rotation system was built to recover soil desiccation, broomcorn millet and potato can be considered first pea and spring maize also can be considered in rainy years or normal years. During fallow period, mulch or canopy can relief the soil desiccation in winter wheat land.     

Effect of tillage and water table control on evapotranspiration,surface runoff,tile drainage and soil water content under maize on a clay loam soil

Two tillage and two water table control treatments under continuous maize cropping were evaluated over a 3-year period (1992–1994) for their effects on evapotranspiration, surface runoff (SR), tile drainage (TD) and soil water content in the root-zone on a clay loam soil in southern Ontario. The tillage treatments included soil saver (SS, reduced tillage) and moldboard plow (MP, conventional tillage). The water table control treatments included controlled drainage-subirrigation (CDS) and regular tile drainage (DR). There was no significant difference (P<0.05) in evapotranspiration estimates between the SS and MP tillage treatments. The SS tillage increased SR compared with MP tillage during the non-cropping periods in 1993 and 1994, but not in 1992. Relative to MP, the SS tillage increased soil profile water content during the cropping period but decreased soil profile water content during the non-cropping period in 1992. The CDS treatment produced significantly higher (P<0.05) evapotranspiration and soil water content than the drainage treatment during the dry 1993 and 1994 years, but not during the wet 1992 year. The CDS treatment also had significantly lower (P<0.05) TD and higher SR than the drainage treatment. For all the treatments, over 65% of SR and TD occurred in the 5 month non-cropping period from November to March. Of the total annual water input (precipitation and/or subirrigation) to the field site, 8% was partitioned to SR, 30% was partitioned to TD, 55% was removed by crop and soil evapotranspiration and 7% was accounted for by changes in soil profile water content.     

东北地区不同耕作方式下土壤温度的动态变化

针对东北地区常见的4种耕作方式(留茬覆盖、留茬无覆盖、旋耕和翻耕起垄),测定了玉米田土壤温度的动态变化.结果表明:留茬覆盖处理土壤温度较低,但并未低于出苗的最低界限温度;由于土壤含水量较高,出苗效果良好,秸秆全量还田,有利于土壤肥力的恢复与提高.