保护耕作研究进展及前景展望

阐述了国内外保护耕作技术的研究进展,分析了保护耕作对作物产量、土壤性状、土壤水分利用的效应以及对作物病虫草害的影响和控制水土流失的作用,提出我国推行保护耕作应注意的关键问题。     

Effects of tillage and traffic on crop production in dryland farming systems: II. Long-term simulation of crop production using the PERFECT model

Soil water conservation is critical to long-term crop production in dryland cropping areas in Northeast Australia. Many field studies have shown the benefits of controlled traffic and zero tillage in terms of runoff and soil erosion reduction, soil moisture retention and crop yield improvement. However, there is lack of understanding of the long-term effect of the combination of controlled traffic and zero tillage practices, as compared with other tillage and traffic management practices.In this study, a modeling approach was used to estimate the long-term effect of tillage, traffic, crop rotation and type, and soil management practices in a heavy clay soil. The PERFECT soil–crop simulation model was calibrated with data from a 5-year field experiment in Northeast Australia in terms of runoff, available soil water and crop yield; the procedure and outcomes of this calibration were given in a previous contribution. Three cropping systems with different tillage and traffic treatments were simulated with the model over a 44-year-period using archived weather data.Results showed higher runoff, and lower soil moisture and crop production with conventional tillage and accompanying field traffic than with controlled traffic and zero tillage. The effect of traffic is greater than the effect of tillage over the long-term. The best traffic, tillage and crop management system was controlled traffic zero tillage in a high crop intensity rotation, and the worst was conventional traffic and stubble mulch with continuous wheat. Increased water infiltration and reduced runoff under controlled traffic resulted in more available soil water and higher crop yield under opportunity cropping systems.     

Effect of conservation tillage on crop yield and soil organic carbon in Northeast China: A meta-analysis

Northeast China, the important grain-producing region in China, is under threat from soil degradation because of long-term conventional tillage (CT). The adoption of conservation tillage is anticipated to restore soil fertility, maintain crop yields and enhance sustainability. However, the integrated effects of conservation tillage practice on crop yields and soil organic carbon (SOC) remain unclear. In this meta-analysis of peer-reviewed studies conducted in the Northeast China region, we assess crop yields and SOC values under no-till, ridge tillage and subsoiling tillage practices. The results indicate that in areas with mean annual temperatures (MAT) below 3°C, crop yields were significantly (p < .05) higher under ridge tillage (0.8%) and subsoiling tillage (13.1%) compared with CT, whereas yields reduced under no-till (−3.7%). Ridge tillage generally had a similar effect on crop yield as no-till, without the negative impact in colder regions. We also report that no-till practice increased SOC concentrations by 24.1%, 43.9% and 17.4% in areas of higher temperature (MAT > 6°C), low mean annual precipitation (MAP) (<500 mm) and continuous cropping conditions, respectively. Ridge tillage and subsoiling tillage also had positive effects on SOC concentrations (to a lesser degree than no-till), indicating that conservation tillage can enhance SOC in Northeast China. Overall, the implementation of different conservation tillage measures in Northeast China was found to enhance crop yields and sequester carbon. We recommend that ridge tillage is used in colder areas and that subsoiling tillage is used in rotation with other tillage measures to maintain crop yields.     

玉米-小麦一年两熟保护性耕作体系试验研究

采用将夏玉米、冬小麦两季作物作为整体来研究适合华北一年两熟地区保护性耕作技术体系，确定了耕作和覆盖两个因素，包括免耕、深松、耙地、翻耕4种耕作方法，以及100%秸秆覆盖，50%秸秆覆盖和0覆盖3种秸秆覆盖水平。筛选设计了8种保护性耕作和2种传统翻耕共10种体系的试验方案。试验中测定了土壤含水量、容重、地温等参数和根系、产量等作物指标。试验结果表明，我国华北地区实施保护性耕作有利于节约用水，提高水分利用效率，增加作物产量。试验得出最适合的两种保护性耕作体系是：玉米-小麦全程免耕100%秸秆覆盖体系、玉米深松100%秸秆覆盖+小麦免耕100%秸秆覆盖体系。     

长期深耕秸秆还田配施生物炭对砂姜黑土团聚体及小麦-玉米产量的影响

为探究耕作方式、秸秆还田和生物炭添加结合对土壤团聚体粒径分布、团聚体养分特征、养分库储量及小麦-玉米周年产量的影响,本研究采用3因素2水平试验设计,分别为耕作方式：常规旋耕（CT）,深翻耕作（DT）;秸秆处理：秸秆还田（S）、秸秆不还田（NS）;生物炭：生物炭添加（B）、无生物炭添加（NB）,共8个处理。结果表明：无生物炭添加时,旋耕秸秆还田显著提高了0~15 cm土层团聚体稳定性及土壤养分库储量,而深耕秸秆还田显著改善了>15~30 cm土层土壤团粒组成,提升土壤肥力,促进作物增产。相关性分析表明,砂姜黑土中作物产量的提升更依赖于深层（>15~30 cm）土壤物理结构的改善和土壤肥力的提升。配施生物炭后如DT-S-B（深耕秸秆还田配施生物炭）较CT-NS-NB（旋耕秸秆不还田无生物炭）处理尤其使>15~30 cm土层团聚体稳定性显著增强,>2 mm粒级团聚体比例、重量平均直径和几何平均直径值分别增加165.88%、62.37%和119.81%,显著提高>2 mm粒级团聚体有机碳、全氮和全磷含量,提高了>2 mm粒级团聚体有机碳和养分固持能力,降低了<2 mm粒级团聚体有机碳和养分固持能力,使>15~30 cm土层土壤有机碳库储量、全氮、全磷和全钾库储量分别显著提升37.41%、38.99%、41.26%和9.84%,促使2年作物周年产量平均增加22.96%,但在深耕秸秆还田的基础上配施生物炭在短期内增产效果不显著。综上,深耕秸秆还田配施生物炭能够显著改善黄淮海南部砂姜黑土深层土壤团聚体粒径分布和稳定性,提升了土壤肥力和作物周年产量,保障了农田高效绿色可持续生产。     

Is conservation tillage suitable for organic farming? A review

Conservation tillage covers a range of tillage practices, mostly non‐inversion, which aim to conserve soil moisture and reduce soil erosion by leaving more than one‐third of the soil surface covered by crop residues. Organic farmers are encouraged to adopt conservation tillage to preserve soil quality and fertility and to prevent soil degradation – mainly erosion and compaction. The potential advantages of conservation tillage in organic farming are reduced erosion, greater macroporosity in the soil surface due to larger number of earthworms, more microbial activity and carbon storage, less run‐off and leaching of nutrients, reduced fuel use and faster tillage. The disadvantages of conservation tillage in organic farming are greater pressure from grass weeds, less suitable than ploughing for poorly drained, unstable soils or high rainfall areas, restricted N availability and restricted crop choice. The success of conservation tillage in organic farming hinges on the choice of crop rotation to ensure weed and disease control and nitrogen availability. Rotation of tillage depth according to crop type, in conjunction with compaction control measures is also required. A high standard of management is required, tailored to local soil and site conditions. Innovative approaches for the application of conservation tillage, such as perennial mulches, mechanical control of cover crops, rotational tillage and controlled traffic, require further practical assessment.     

Effects of tillage and traffic on crop production in dryland farming systems: I. Evaluation of PERFECT soil-crop simulation model

Agricultural production systems are complex involving variability in climate, soil, crop, tillage management and interactions between these components. The traditional experimental approach has played an important role in studying crop production systems, but isolation of these factors in experimental studies is difficult and time consuming. Computer simulation models are useful in exploring these interactions and provide a valuable tool to test and further our understanding of the behavior of soil–crop systems without repeating experimentation.Productivity erosion and runoff functions to evaluate conservation techniques (PERFECT) is one of the soil–crop models that integrate the dynamics of soil, tillage and crop processes at a daily resolution. This study had two major objectives. The first was to calibrate the use of the PERFECT soil–crop simulation model to simulate soil and crop responses to changes of traffic and tillage management. The second was to explore the interactions between traffic, tillage, soil and crop, and provide insight to the long-term effects of improved soil management and crop rotation options. This contribution covers only the first objective, and the second will be covered in a subsequent contribution.Data were obtained from field experiments on a vertisol in Southeast Queensland, Australia which had controlled traffic and tillage treatments for the previous 5 years. Input data for the simulation model included daily weather, runoff, plant available water capacity, and soil hydraulic properties, cropping systems, and traffic and tillage management. After model calibration, predicted and measured total runoffs for the 5-year period were similar. Values of root mean square error (RMSE) for daily runoff ranged from 5.7 to 9.2 mm, which were similar to those reported in literature. The model explained 75–95% of variations of daily, monthly and annual runoff, 70–84% of the variation in total available soil water, and 85% of the variation in yield. The results showed that the PERFECT daily soil–crop simulation model could be used to generate meaningful predictions of the interactions between crop, soil and water under different tillage and traffic systems.Ranking of management systems in order of decreasing merit for runoff, available soil water and crop yield was (1) controlled traffic zero tillage, (2) controlled traffic stubble mulch, (3) wheeled zero tillage, and (4) wheeled stubble mulch.     

Trends in tillage practices in relation to sustainable crop production with special reference to temperate climates

The concept and some definitions of sustainable agriculture are reviewed. Most of these definitions include economic, environmental and sociological aspects. The finite area of land emphasizes the need for consideration of soil conservation and of soil quality in relation to sustainability. An important element of soil quality is rooting depth. Therefore loss of soil by erosion is a dominant factor in long-term sustainability. The effects of tillage on soil parameters in minimum data sets that have been proposed to describe soil quality are reviewed. Soil organic matter may be one of the most important soil quality characteristics in relation to tillage because of its influence on other soil physical, chemical and biological properties. Conservation tillage practices can increase the organic matter content, aggregate stability and cation exchange capacity (CEC) of the topsoil. However, bulk density and penetrometer resistance are also increased, especially with zero tillage. Although such soil quality parameters may form a basis for describing some of the consequences of particular tillage practices, they do not provide a basis for predicting the outcome in terms of crop growth and yield. This is both because critical values of soil quality parameters have not been defined and because in some soils biopore formation in zero or minimally tilled land can modify the soil for water movement and for root growth and function.

The effects of tillage on crop growth and yield in long-term experiments are reviewed. The review only includes experiments in North America, Europe and New Zealand that have lasted 10 years or more to allow for seasonal variation in weather, possible progressive changes in soil conditions and the learning phase often experienced when new tillage methods are used. While there is a good deal of variation in the results of these tillage experiments some patterns have emerged. In long-term experiments, yields of maize in Europe and the US and soybeans in the US have been similar after ploughing and no-tillage, especially on well-drained soils. In Europe, yields of winter cereals have also been similar after traditional and simplified tillage but yields of spring cereals have sometimes been less after direct drilling than ploughing.

Trends in tillage practices are reviewed. Conservation tillage in the US is increasing and is used on about 30% of cropland, including no-till on about 10% of cropland. This increase in use of conservation tillage is mainly attributed to the legal requirement for farmers who are in government price support programs to adopt conservation plans which may involve conservation tillage. However, the allowable rates of erosion in these plans are likely to be in excess of rates of erosion for long-term sustainability. Survey information on tillage practices needs to be considered in relation to predictions on suitability of conservation tillage based on experimental results. In the semi-arid prairies of Canada there is a trend toward fewer cultivation operations, but in eastern Canada the mouldboard plough is still the dominant tillage method. In Europe although erosion is less obvious it is believed to be increasing, but minimum tillage is not widely used. This is because of the need to remove at least some straw for successful minimum tillage in sequential winter wheat and barley crops, but there are few economic uses for straw, and burning is illegal in many countries. In the more moist cooler conditions of Europe grass weed proliferation is another constraint, at least with present technology. So far, the overall success of conservation tillage has not been limited by the growing problem of genetic resistance of weeds to herbicides. Societal attitudes to the continued use of herbicides may pose longer-term problems for some conservation tillage practices.     

适宜耕作模式提高黄淮海平原冬小麦产量并改善土壤水肥状况

为了探索黄淮海小麦生产适宜的耕作模式,该研究设计长期定位试验（2017年—2022年）对比了简化耕作模式深耕（deep tillage, DT）、轮耕（rotational tillage, RT）和免耕（no-tillage, NT）对冬小麦产量和土壤水肥状况的影响。结果表明：RT处理显著提高了冬小麦苗期0～20 cm土层土壤水分吸收利用情况,冬小麦孕穗期、灌浆期RT处理0～20、>20~40 cm土层土壤含水量显著高于DT、NT处理。RT处理0～20、>20～40 cm土壤全氮、有机质含量和碳氮比含量较DT、NT处理显著提高, 2021—2022年0～20 cm土壤全氮、有机质含量、碳氮比RT处理较DT和NT处理分别显著提高40.45%和31.58%、56.66%和45.34%、11.62%和9.91%。2020—2021年和2021—2022年RT处理冬小麦产量较DT、NT处理分别显著提高20.20%、13.39%和20.35%、18.74%。RT处理显著增加了冬小麦千粒质量,其产量变异系数最低,产量可持续指数最高,说明RT处理有助于增加冬小麦生产力稳定性和可持续性,可以实现黄淮海冬小麦高产稳产。研究可为黄淮海平原冬小麦生产应用一年深耕、两年免耕的轮耕耕作模式提供理论指导与技术支撑。     

The adoption of annual subsoiling as conservation tillage in dryland maize and wheat cultivation in northern China

Soil compaction caused by random traffic or repetitive tillage has been shown to reduce water use efficiency, and thus crop yield due to reduced porosity, decreased water infiltration and availability of nutrients. Conservation tillage coupled with subsoiling in northern China is widely believed to reduce soil compaction, which was created after many years of no-till. However, limited research has been conducted on the most effective time interval for subsoiling, under conservation tillage. Data from conservation tillage demonstration sites operating for 10 years in northern China were used to conduct a comparative study of subsoiling interval under conservation tillage. Three modes of traditional tillage, subsoiling with soil cover and no-till with soil cover were compared using 10 years of soil bulk density, water content, yield and water use efficiency data. Cost benefit analysis was conducted on subsoiling time interval under conservation tillage. Yield and power consumption were assessed by based on the use of a single pass combine subsoiler and planter. Annual subsoiling was effective in reducing bulk density by only 4.9% compared with no-till treatments on the silty loam soils of the Loess plateau, but provided no extra benefit in terms of soil water loss, yield increase or water utilization. With the exception of bulk density, no-till and subsoiling with cover were vastly superior in increasing water use (+10.5%) efficiency and yield (+12.9%) compared to traditional tillage methods. Four years of no-till followed by one subsoiling reduced mechanical inputs by 62%, providing an economic benefit of 49% for maize and 209% for wheat production compared to traditional tillage. Annual subsoiling reduced inputs by 25% with an increased economic benefit of 23% for maize and 135% for wheat production. Yield and power consumption was improved by 5% and 20%, respectively, by combining subsoiling with the planting operation in one pass compared with multipass operations of subsoiling and planting. A key conclusion from this is that annual subsoiling in dryland areas of northern China is uneconomical and unwarranted. Four years of no-till operations followed by 1 year subsoiling provided some relief from accumulated soil compaction. However, minimum soil disturbance and maximum soil cover are key elements of no-till for saving water and improving yields. Improved yields and reduced farm power consumption could provide a significant base on which to promote combined planter and subsoiling operations throughout northern China. Further research is required to develop a better understanding of the linkages between conservation tillage, soil quality and yield, aimed at designing most appropriate conservation tillage schemes.     

渭北旱塬玉米田保护性轮耕土壤固碳效果与增产增收效应

针对渭北旱塬降水少、季节性差异大及长期采用单一土壤耕作制度等制约作物增产增收的因素,该研究探索有利于提高旱作农田土壤质量及作物生产能力的轮耕模式。2007-2012年在陕西合阳实施了渭北旱塬春玉米连作田6种不同轮耕模式的长期定位试验,设置以免耕(NT,no-tillage)、深松(ST,sub-soiling)和翻耕(CT,continuous tillage)3种耕作处理组合集成的6种轮耕模式(NT?ST、ST?CT、CT?NT、NT?NT、ST?ST和CT?CT),测定各轮耕模式下春玉米田土壤容重和有机碳储量,分析各轮耕模式下春玉米籽粒产量、水分利用效率和经济效益的变化规律。结果表明:1)在疏松土壤、减少耕作机械碾压次数,改善土壤结构和降低容重等方面,6种轮耕模式以NT?ST表现最佳,ST?ST次之,差异显著(P0.05)。2)6种轮耕模式在0~60 cm土层土壤有机碳平均储量较试验前均增加幅度6.6%~17.4%。NT?NT轮耕模式对增加表层土壤有机碳储量具有优势,且与各处理间差异显著(P0.05)。NT?ST轮耕模式可改变耕层土壤有机碳储量分布特征,进而使土壤营养均匀分布。3)6种轮耕模式5年春玉米籽粒产量、水分利用效率和经济效益综合评价分析,NT?ST轮耕模式最高,分别为9 338.8 kg/hm2、22.6 kg/(hm2·mm)和7 600.5元/hm2;其次是ST?CT,其中NT?ST轮耕模式下春玉米籽粒产量、水分利用效率和经济效益较其他处理增加幅度分别为3.7%~15.7%、17.6%~45.8%和10.1%~40.4%,差异显著(P0.05);且5种轮耕模式下作物籽粒产量、水分利用利用效率和经济效益均高于传统CT?CT模式。综上所述,在6种轮耕模式下,以NT?ST(免耕与深松逐年轮换)轮耕模式下土壤容重和有机碳储量最佳,生产能力最强,水分利用率最高,是渭北旱塬地区春玉米连作田最佳适宜轮耕模式,其次是ST?CT(深松与翻耕逐年轮换)轮耕模式。     

黄土高原地区耕作技术效益研究

黄土高原地区地形破碎,坡地所占比例大,水土流失严重。调查和试验表明,在坡耕地上,因地制宜地采取各种水土保持耕作技术措施,对改变坡面微地貌,减少水土流失,增加土壤抗蚀、蓄水、保土性能;培肥地力和提高作物产量,都具有显著作用。该文着重分析了效果明显的8种耕作技术及其特征,供决策部门在制订规划时参考。     

Effect of long-term conservation tillage on soil biochemical properties in Mediterranean Spanish areas

In semi-arid Mediterranean areas, studies of the performance of conservation tillage systems have largely demonstrated advantages in crop yield, soil water storage and soil protection against wind and water erosion. However, little attention has been given to interactions between soil biochemical properties under different tillage practices. Biochemical properties are useful tools to assess changes caused by different soil tillage systems in long-term field experiments. This study deals with the effect of long-term tillage practices (reduced tillage and no-tillage vs. traditional tillage) on soil chemical properties and microbial functions in three different sites of Spain (two of them located in the Northeast and one in the Southwest) under semi-arid Mediterranean conditions. Soil biological status, as index of soil quality, was evaluated by measuring microbial biomass carbon (MBC) and dehydrogenase (an oxidoreductase) and protease (a hydrolase) activities at three soil depths (0–5, 5–10 and 10–25 cm). In the three experimental areas, increases in soil organic matter content, MBC and enzymatic activities were found at the superficial layers of soil under conservation tillage (reduced tillage and no-tillage) in comparison with traditional tillage. Values of the stratification ratio of some biochemical properties were significantly correlated with yield production in Northeast sites.Conservation tillage has proven to be an effective strategy to improve soil quality and fertility in Mediterranean areas of Spain.     

Tillage effects on microbial biomass and nutrient distribution in soils under rain-fed corn production in central-western Mexico

Quantifying how tillage systems affect soil microbial biomass and nutrient cycling by manipulating crop residue placement is important for understanding how production systems can be managed to sustain long-term soil productivity. Our objective was to characterize soil microbial biomass, potential N mineralization and nutrient distribution in soils (Vertisols, Andisols, and Alfisols) under rain-fed corn (Zea mays L.) production from four mid-term (6 years) tillage experiments located in central-western, Mexico. Treatments were three tillage systems: conventional tillage (CT), minimum tillage (MT) and no tillage (NT). Soil was collected at four locations (Casas Blancas, Morelia, Apatzingán and Tepatitlán) before corn planting, at depths of 0–50, 50–100 and 100–150 mm. Conservation tillage treatments (MT and NT) significantly increased crop residue accumulation on the soil surface. Soil organic C, microbial biomass C and N, potential N mineralization, total N, and extractable P were highest in the surface layer of NT and decreased with depth. Soil organic C, microbial biomass C and N, total N and extractable P of plowed soil were generally more evenly distributed throughout the 0–150 mm depth. Potential N mineralization was closely associated with organic C and microbial biomass. Higher levels of soil organic C, microbial biomass C and N, potential N mineralization, total N, and extractable P were directly related to surface accumulation of crop residues promoted by conservation tillage management. Quality and productivity of soils could be maintained or improved with the use of conservation tillage.     

Tillage effect on nutrient stratification in narrow- and wide-row cropping systems

Recent research has indicated that conservation systems with narrow-rows have potential for higher crop productivity on southeastern USA Coastal Plains Soil. The objective of this study was to determine how surface tillage and subsoiling affect nutrient distribution in the soil profile in narrow- and wide-row systems. A secondary objective was to determine the effect of row position on soil pH and nutrient concentrations in the wide-row system. Soil samples were collected in 1996 from plots that had been growing soybean (Glycine max (L.) Merr.) double cropped with wheat (Tritiucum aestivum L.) for 3 years and then again in 1999 after 3 years of continuous corn (Zea mays L.). Narrow-row spacing was 19 cm for soybean and 38 cm for corn. Wide-row spacing was 76 cm for both soybean and corn. Wheat was grown in 19 cm wide-rows. Soil samples were randomly collected from throughout the plots in the narrow-row culture. In the wide-row culture, separate samples were collected from the row and from between rows. Treatments were surface tillage (disc tillage (DT) and no surface tillage (NT)), with different frequencies of subsoiling. The soil type was Goldsboro loamy sand (fine-loamy, siliceous, thermic, Aquic Kandiudult). Soil samples from four depths (the surface 5 cm of the A horizon, the remainder of the A horizon, the E horizon, and the top 7.5 cm of the B horizon) were analyzed for pH, P, K, Ca, and Mg. Nutrient concentrations and pH differed little between row spacings at any depth after either 3 or 6 years. Differences due to subsoiling appeared mainly due to nutrient removal as the treatments with more intense subsoiling had higher yield and lower concentrations of nutrients (except K). Concentrations of P, Mg, and Ca at the soil surface tended to be higher in NT than in DT, especially in the mid-rows of the 76 cm wide-row systems. The data suggest only small differences in soil nutrient stratification can be expected as growers adopt narrow-row crop production systems with intensive subsoiling.     

秸秆还田和保护性耕作对砂姜黑土有机质和氮素养分的影响

通过田间试验,分别采集小麦成熟期、玉米成熟期和小麦播种期耕层土样,研究不同的秸秆还田方式(秸秆还田、焚烧还田和火粪还田)与保护性耕作(减耕和免耕)对砂姜黑土有机质和氮素养分的影响,以期得到培肥砂姜黑土的最佳方式。结果表明:作物秸秆还田可以增加砂姜黑土有机质和全氮的含量,但是对速效氮含量影响不大。在不同的秸秆还田和保护性耕作处理中,秸秆火粪还田和免耕条件下的秸秆还田对砂姜黑土有机质和全氮含量的增加效果最为明显。与对照相比,秸秆火粪还田后土壤有机质和全氮含量分别平均提高4.45 g/kg和0.131 g/kg;免耕条件下的秸秆还田其土壤有机质和全氮含量分别平均提高3.36 g/kg和0.095 g/kg;减耕条件下的秸秆还田和秸秆粉碎还田对增加砂姜黑土有机质和全氮含量的效果不显著;秸秆焚烧不能增加砂姜黑土有机质和全氮的含量。秸秆还田和保护性耕作不会大幅度提高砂姜黑土C/N进而影响土壤氮素养分的供应,同时秸秆还田能有效提高土壤微生物量碳氮,但微生物量的碳氮比却保持在适宜的范围内。     

Effects of tillage on productivity of a winter wheat-vetch rotation under dryland Mediterranean conditions

An experiment was conducted to determine the effects of three tillage systems on crop yield in a winter wheat-vetch (Vicia sativa L.) rotation during 3-year growing seasons on a clay-loam soil in the northwest region of Turkey. The three tillage treatments were: (1) conventional tillage (CT); (2) shallow tillage (ST); (3) double disk tillage (DD).The wheat grain yield was significantly affected by tillage when averaged across years. The highest wheat grain yield was obtained with shallow tillage treatment. The year affected wheat grain yield significantly, mainly due to the distribution of rainfall through the growing season and probably due to the wheat-vetch rotation. Heads density and head length increased significantly with shallow tillage when compared with conventional tillage. Tillage practices had no significant influence on thousand kernel weight. Results from this study indicated that for a dryland wheat-vetch rotation cropping system, shallow tillage had higher wheat grain yields than that obtained from conventional tillage. Furthermore, mouldboard ploughing tillage in this crop rotation could be replaced by shallow tillage that would increase yield and would be likely to improve soil properties in the long-term. On the other hand, double disk tillage proved to be a promising soil management practice to improve vetch grain yield when compared with conventional tillage.     

冀北高原土壤干旱及抗旱土壤耕作法研究

本文指出，冀北高原气候干燥、多风少雨、土壤粗骨、松散贫瘠是土壤干旱的基础因素，而人为不合理的耕垦、利用，激发、加剧了土壤的干化过程。采用沟垄种植，垄部覆膜，沟部松耕，立茬越冬的少耕抗旱耕作法可有效拦截降水，阻隔水分蒸发，改善土壤营养条件，促进作物根系发育，作物产量提高18.54-23.51%，2米土体水分利用率由4.05公斤/毫米*公顷提高到4.65公斤/毫米*公顷。     

华北平原一年两熟保护性耕作体系试验研究

冬小麦-夏玉米一年两熟的种植方式在华北地区的农业生产中具有极为重要的地位。但是传统耕作方式使该地区的农业生产不可持续。保护性耕作技术是一种先进的保水保土的生产技术。该文在田间试验的基础上，研究了保护性耕作体系对作物产量、土壤容重、土壤含水率、土壤温度的影响，结果表明：保护性耕作能够提高作物的产量，增加土壤的含水率。其对土壤容重和土壤温度的影响并未对作物的生长产生不利影响。但是，从长远来看，对保护性耕作引起的土壤容重增加、温度降低的问题必须引起足够的重视。结果初步表明：以免耕加覆盖为主的保护性耕作体系可以在华北平原一年两熟地区试验推广。     

Response of Arbuscular Mycorrhizal Fungi in Different Soil Tillage Systems to Long‐Term Swine Slurry Application

Swine slurry is a common agricultural fertilizer in many countries. However, its long‐term use in large amounts can cause excess nutrient accumulation, alter soil compounds, and potentially influence critical microbial populations such as arbuscular mycorrhizal fungi, which have important roles in plant nutrition and soil sustainability. This work determined if arbuscular mycorrhizal status, external mycelium, and glomalin‐related soil protein content were affected by long‐term swine slurry application to different soil tillage systems. The experiment was conducted on a clayey oxisol, in southern Brazil. Swine slurry (0, 30, 60, 90, and 120 m³ ha⁻¹ y⁻¹) was applied for 15 years to conventional tillage and no tillage soil prior to the summer (soybean or maize) and winter (wheat or oats) crop seasons. Swine slurry decreased mycorrhizal root colonization, spore number, and total external mycelium. Swine slurry increased active external mycelium and both easily extractable and total glomalin‐related soil protein. No‐tillage soil had more glomalin‐related soil protein than conventional tillage soil. The most significant response variables were root colonization, easily extractable glomalin‐related soil protein, and total external arbuscular mycorrhizal mycelia. Long‐term application of swine slurry in this environment, even at high rates, did not adversely affect crop yield but did influence arbuscular mycorrhizae fungi and their products in the soil environment. Benefits of swine slurry application for crop nutrition must be weighed against potential adverse consequences for the size, activity, and benefits of the mycorrhizal community to subsequent annual crops. Copyright © 2014 John Wiley & Sons, Ltd.