气候变化下黄土高原耕作系统演变与适应性管理

耕作系统主要包括土壤系统、作物系统和区域气候系统等几个相对独立、但又紧密关联的组成部分,涉及作物栽培模式、作物类型、杂草和病虫害及农田水土资源管理等方面,在黄土高原生态系统管理和农业可持续发展中占有重要地位。过去50a (1951-2000年),黄土高原的年平均气温升高了1.1℃,且其变率逐渐增加,降雨和热量资源分布呈现复杂的时空异质性。作物种植区域的变迁、熟制制度的演变和农田灾害的加剧促使农田管理模式不断寻求改变,对当地农业耕作系统产生了深远影响。本文总结了黄土高原过去多年的气候变化（气温、降水量、积温）特征和发展趋势,气候变化下耕作系统（种植区、耕作制度、土壤环境）和作物系统（需水量、物候、品种、产量）的演变规律,作物与土壤互作关系,以及气象灾害对黄土高原耕作系统的影响,并提出气候变化下耕作系统适应性管理途径和策略。旨在为黄土高原耕作技术和田间管理提供新的理论,寻求气候变化下区域农业可持续发展应对策略。     

Soil quality and other factors influencing maize yield in northern Ghana

Food security is a crucial issue in sub‐Saharan Africa as a consequence of unreliable rainfall, marginal soil fertility and a low level of inputs leading to declining crop yields. As a case study, we investigated the most important variables affecting maize yield in northern Ghana. We combined a soil quality index on a continuous scale with a social data set to model maize yield using linear multiple regression. Five significant variables have been identified (P < 0.05): soil quality index, fertilizer use, household size, distance from main market, and the interaction between fallow length and soil quality index. The effect of the interaction between soil quality and fallow on maize yield is negative, suggesting the influence of litter quality and N immobilization in the soils. Research and policy should focus on the development of site‐specific, legume‐based cropping, and the integration of crop and livestock farming in Northern Ghana and similar areas in sub‐Saharan Africa.     

Tillage methods and soil and water conservation in Australia

Tillage in Australia has evolved from ‘imported’ European practices to tillage systems more in tune with ‘older’ fragile soils and more severe climatic conditions. Cereal yields are commonly limited by water supply and the native fertility of many soils is poor. Crop/pasture rotations involving pasture legumes have been the mainstay of cereal production in the winter rainfall areas while production in much of the summer rainfall area has relied more on exploiting native fertility. Soil erosion and structural decline are still considered major issues facing long-term production. The general trend in tillage methods is for less tillage and greater retention of crop residues for soil and water conservation.

Tillage experiments have shown that management strategies involving retention of crop residues (stubble), reduced tillage and crop rotation can reduce erosion and improve yield. Results from experimentation are highly variable, both in magnitude and direction of responses to tillage treatments. Much of this variation is due to variation in seasonal conditions. Simulation models are being used to examine management options and to design experiments based on a knowledge of climate variability and physical and biological processes.     

Soil erosion from sugar beet in Central Europe in response to climate change induced seasonal precipitation variations

This study estimates the implications of projected seasonal variations in rainfall quantities caused by climate change for water erosion rates by means of a modeling case study on sugar beet cultivation in the Central European region of Upper-Austria. A modified version of the revised Morgan–Morgan–Finney erosion model was used to assess soil losses in one conventional and three conservation tillage systems. The model was employed to a climatic reference scenario (1960–89) and a climate change scenario (2070–99). Data on precipitation changes for the 2070–99 scenario were based on the IPCC SRES A2 emission scenario as simulated by the regional climate model HadRM3H. Weather data in daily time-steps, for both scenarios, were generated by the stochastic weather generator LARS WG 3.0. The HadRM3H climate change simulation did not show any significant differences in annual precipitation totals, but strong seasonal shifts of rainfall amounts between 10 and 14% were apparent. This intra-annual precipitation change resulted in a net-decrease of rainfall amounts in erosion sensitive months and an overall increase of rainfall in a period, in which the considered agricultural area proved to be less prone to erosion. The predicted annual average soil losses under climate change declined in all tillage systems by 11 to 24%, which is inside the margins of uncertainty typically attached to climate change impact studies. Annual soil erosion rates in the conventional tillage system exceeded 10 t ha^− 1 a^− 1 in both climate scenarios. Compared to these unsustainably high soil losses the conservation tillage systems show reduced soil erosion rates by between 49 and 87%. The study highlights the importance of seasonal changes in climatic parameters for the discussion about the impacts of global climate change on future soil erosion rates in Central Europe. The results also indicate the high potential of adaptive land-use management for climate change response strategies in the agricultural sector.     

Soil and Water Assessment Tool Soil Loss Simulation at the Sub‐Basin Scale in the Alt Penedès–Anoia Vineyard Region (Ne Spain) in the 2000s

This paper evaluates soil loss due to water erosion in an area of 32,362 ha with a predominant land use of vineyards (Alt Penedès–Anoia region, Catalonia, Spain). The Soil and Water Assessment Tool (SWAT) was used incorporating daily climatic data for the period 2000–2010 and also detailed soil and land use maps. Particular attention was given to the universal soil loss equation cover and management factor (C factor) of vineyards, with a minimum value of 0·15 being determined for this crop. The model was calibrated using daily flow data for the year 2010, which yielded satisfactory results. Even so, significant differences were obtained on days with high‐intensity rainfall events, when the model overestimated runoff and peak discharge. In these vineyards, the simulated average soil losses per sub‐basin ranged between 0·13 and 9·73 Mg ha⁻¹ y⁻¹, with maximum values of between 26·32 and 42·60 Mg ha⁻¹ y⁻¹ registered in fine‐loamy soils developed on unconsolidated Tertiary marls. Other findings were related to problems associated with SWAT calibration under Mediterranean conditions characterised by major climate variability and high‐intensity rainfall events. Copyright © 2013 John Wiley & Sons, Ltd.     

WOFOST模型的发展及应用

作物生长模拟模型已经成为一门新兴的科学,可以为农业资源的管理利用、农业最大收益的获取提供科学的依据。WOFOST(W orld Food Stud ies)模型是荷兰瓦根宁农业大学和世界粮食研究中心共同开发研制的,是模拟特定的土壤和气候条件下一年生作物生长的动态的、解释性模型。WOFOST模型已经在欧洲、非洲以及亚洲的一些地区得到了运用和验证,可用于水稻、玉米、小麦等多种一年生作物的模拟。WOFOST模型可用来分析作物产量风险,不同年份产量的变化,土壤类型及气候变化对产量变化的影响;确定播种策略以及农业机械使用的关键时期;该模型还可用于估计某种作物最大潜在产量,提高灌溉和施肥的增产效益,对生长在不利条件以及地区的作物产量进行预测等。该模型对可持续农业的发展具有积极的指导作用。     

略论气候与农业生产发展的关系

本文分析研究了气候对农业生产发展的影响。我国气候变率大,是引起农业生产不稳定的主要因素,每年农业受害面积的60％是干旱造成的,不明显的潜在影响(如低温)能使粮食产量减少500万吨以上。在5％的产量波动水平下,本世纪80年代的粮食绝对产量的波动损失比50年代大得多。在同样的政策、种子、农业技术条件下,粮食产量主要受气候的影响。随着农业生产的发展,气候与农业生产的关系不是愈来愈小,而是愈来愈密切。今后制定农业发展战略计划时应考虑气候不稳定的特点。     

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.     

陇东地区几种旱作作物产量对降水与气温变化的响应

研究作物产量对气候变化的响应,对于指导区域农业生产,保障粮食安全和生态安全具有一定的理论指导意义。结合大田试验与农业生产系统模拟模型(Agricultural Production Systems Simulator,APSIM),在验证模拟研究区冬小麦、玉米和紫花苜蓿产量可靠性的基础上,分析5个降水变化梯度(降水量不变、降低10%和20%、升高10%和20%)和5个气温变化梯度(不变、降低1.5和1℃、升高1.5和1℃)组合情景下3种作物的产量变化趋势。结果表明:APSIM模型在试验点对3种作物籽粒产量和生物量的模拟精度较高,决定系数R2在0.80~0.93之间,归一化均方根误差在11.35%~22.48%之间,模型有效系数在0.53~0.91之间。冬小麦、玉米和紫花苜蓿在气温升高、降水量减少的情景下减产,减产的最大幅度分别为38.7%、40.3%和41.8%;冬小麦、紫花苜蓿的在气温降低、降水量增加时增产,增产的最大幅度分别为29.8%和51.7%;玉米在降水量增加、温度不变的情景下增产幅度最大,为22.0%。总之,在研究范围内,3种作物的产量随降水的增加而增高;玉米的产量随气温升高先增高后降低,另2种作物的产量随气温的升高而降低;紫花苜蓿适应气候变化的能力最强。结果对明确黄土高原地区主要作物的生产走势,制订农业布局、管理措施等具有一定意义。     

Spatial patterns and effects of soil organic carbon on grain productivity assessment in China

In this paper, we present an assessment of the content and effects of cropland soil organic carbon (SOC) on grain productivity at the national scale in China using a Web‐based Land Evaluation System. Homogeneous 5 km × 5 km grid data sets of climate, crop, soil and management parameters were created and grain production in 2005 was simulated. Attempts were made to incorporate SOC into the land evaluation procedure and to quantify the potential effects of SOC deficiency on grain productivity. Results were statistically analysed and the modelling approach was validated. National cropland SOC maps were generated. At the national scale, the cropland SOC content averaged 1.20, 0.58, 0.41, 0.31 and 0.26% for the five 20‐cm sections consecutively from the surface downwards. At the regional scale it tended to decline slightly from northeast (1.63%) to southwest (1.11%). On average, 64% of grain yield was lost due to SOC deficiency for the humid provinces and 7% for the arid and sub‐arid ones. Soil management options are suggested based on the simulation results.     

Modeling crop yield potential of Eastern Anatolia by using geographically weighted regression

Wheat is a very important cereal crop in Eastern Anatolia in terms of acreage and production. It is a staple food and plays an important role in people's livelihood. Drought often occurs in the region and it dramatically influences wheat yield. The yield also depends upon prevailing climatic conditions, rainfall, temperature and humidity. Crop-modeling studies to forecast crop yield are important not only for people now but for planning studies and precautionary measures for the future. Traditional decision support systems based on crop simulation models are normally site-specific. In order to address the effect of spatial variability of weather variables on crop production, we modeled wheat yield potential on certain climatic conditions by using Geographically Weighted Regression and Geographical Information Systems in Eastern Anatolia in Turkey.     

Biochar application to soil for climate change mitigation by soil organic carbon sequestration

Pyrogenic carbon (C) is produced by incomplete combustion of fuels including organic matter (OM). Certain ranges in the combustion continuum are termed ‘black carbon' (BC). Because of its assumed persistence, surface soils in large parts of the world contain BC with up to 80% of surface soil organic C (SOC) stocks and up to 32% of subsoil SOC in agricultural soils consisting of BC. High SOC stocks and high levels of soil fertility in some ancient soils containing charcoal (e.g., terra preta de Índio) have recently been used as strategies for soil applications of biochar, an engineered BC material similar to charcoal but with the purposeful use as a soil conditioner (1) to mitigate increases in atmospheric carbon dioxide (CO₂) by SOC sequestration and (2) to enhance soil fertility. However, effects of biochar on soils and crop productivity cannot be generalized as they are biochar‐, plant‐ and site‐specific. For example, the largest potential increases in crop yields were reported in areas with highly weathered soils, such as those characterizing much of the humid tropics. Soils of high inherent fertility, characterizing much of the world's important agricultural areas, appear to be less likely to benefit from biochar. It has been hypothesized that both liming and aggregating/moistening effects of biochar improved crop productivity. Meta‐analyses of biochar effects on SOC sequestration have not yet been reported. To effectively mitigate climate change by SOC sequestration, a net removal of C and storage in soil relative to atmospheric CO₂ must occur and persist for several hundred years to a few millennia. At deeper soil depths, SOC is characterized by long turnover times, enhanced stabilization, and less vulnerability to loss by decomposition and erosion. In fact, some studies have reported preferential long‐term accumulation of BC at deeper depths. Thus, it is hypothesized that surface applied biochar‐C (1) must be translocated to subsoil layers and (2) result in deepening of SOC distribution for a notable contribution to climate change mitigation. Detailed studies are needed to understand how surface‐applied biochar can move to deeper soil depths, and how its application affects organic C input to deeper soil depths. Based on this knowledge, biochar systems for climate change mitigation through SOC sequestration can be designed. It is critically important to identify mechanisms underlying the sometimes observed negative effects of biochar application on biomass, yield and SOC as biochar may persist in soils for long periods of time as well as the impacts on downstream environments and the net climate impact when biochar particles become airborne.     

Effect of subsoiling on soil properties and winter wheat grain yield

A 2‐year field experiment was carried out in loessal soil in a semi‐humid climate to explore the integrative influences of subsoiling on soil properties and winter wheat grain yield. Results showed that it was essential to deepen the plough pan in loessal soil. The sharply increased soil penetration resistance (>7 MPa) in plough pan under dry soil condition was especially harmful for plant growth. In rotary tillage treatment, the waterlogging conditions caused by shallow plough pan slightly produced macropores and preferential water flow. Significantly, higher grain yield was obtained in the subsoiling tillage treatment, increased by 21.9% in 2016 and 11.3% in 2017, respectively. Subsoiling tillage improved the resilience of winter wheat under adverse climate conditions. Subsoiling tillage should be popularized in loessal soil with shallow plough pan in semi‐humid climate. This study may provide valuable information on soil sustainable use and management in loessal soil.     

Changing rainfall,seasonality and erosivity in the hyper‐arid zone of Sudan

A primary cause of soil erosion is the impact of rain. Therefore, understanding the altering rainfall characteristics and their effect on soil erosion is an issue of main concern. This is of utmost importance to contribute to developing suitable adaptation and mitigation strategies for soil and water resources conservation and crop management practices. The rainfall seasonality index (SI), precipitation concentration index (PCI) and modified Fournier index (MFI) for rainfall erosivity have been calculated and analysed in this study for the hyper‐arid region of Sudan. The data used consist of monthly rainfall measurements spanning over 60 years for three index meteorological stations, two on the Nile corridor and one on the Red Sea coast. The region is characterized by high year‐to‐year variability in rainfall leading to extreme seasonality/irregular distribution of rainfall over the year. Although prevalent diminishing rainfall amounts have been witnessed, there are marked tendencies for some months to become wetter, indicating changing intra‐annual rainfall variability and thus monthly rainfall erosivity. No statistically significant trends were observed in rainfall seasonality and concentration during the common data period of 1945–2007. Cases of high and very high erosion powers were detected. A significant decreasing trend in erosivity is shown for one inland station. A brief discussion on the implications of these results for risk of soil erosion, freshwater quality and agriculture is also given. Copyright © 2010 John Wiley & Sons, Ltd.     

Sensitivity of crop yield and N losses in winter wheat to changes in mean and variability of temperature and precipitation in Denmark using the FASSET model

Abstract

Sensitivity of wheat yield and soil nitrogen (N) losses to stepwise changes in means and variances of climatic variables were determined using the FASSET model. The LARS-WG was used to generate climate scenarios using observed climate data (1961–90) from two sites in Denmark, which differed in climate and soil conditions. Scenarios involved changes to (i) mean temperature alone, (ii) mean and variability of temperature, (iii) winter and summer precipitation amounts and (iv) duration of dry and wet series.

The model predicted lower grain yield and N uptake in response to increases in mean temperatures, caused by early maturity, with little change in variability. This, however, increased soil mineral N causing increased N losses. On sandy loam, larger temperature variability lowered grain yields and increased N losses coupled with higher variability at all the mean temperature ranges. On coarse sand, grain yields either remained unaltered or were slightly reduced when larger temperature variability was introduced to increase in mean temperatures of up to +2°C above baseline. However, introducing variability to further increase in mean temperatures lowered yields without any change in variability. Larger temperature variability did not affect soil mineral N and N₂O emissions, but increased N leaching on coarse sand.

Large response in grain yield, N uptake and soil N cycling, and in their variability was predicted when summer precipitation was varied, whereas only N leaching responded to changes in winter precipitation. Doubling the duration of dry series lowered grain yield and N removed by grain, but increased N leaching, whereas doubling the duration of wet series showed opposite effect. Predicted responses to changes in precipitation patterns were larger on coarse sand than on sandy loam. This study illustrates the importance of considering effects of changes to mean climatic factors, climatic variability and soil types on both crop yield and soil N losses.     

Daytime,Temporal, and Seasonal Variations of N2O Emissions in an Upland Cropping System of the Humid Tropics

Abstract

Nitrous oxide (N₂O) contributes to global climate change, and its emission from soil–crop systems depend on soil, environmental, and anthropogenic factors. Thus, we evaluated the variability of N₂O emissions measured by microchambers (cross section: 184 cm²) from a groundnut–fallow–maize–fallow cropping system of the humid tropics. The crops received inorganic nitrogen (N) plus crop residues (NC), inorganic N alone as ammonium sulfate (RN), and half of the inorganic N along with crop residues and chicken manure (N_1/2CM), amounting for the crop rotation to 322, 180, and 400 kg N ha^?1 yr^?1, respectively. The N₂O fluxes during the groundnut–maize crop rotation were log‐normally distributed, and the frequency distributions were positively skewed. Daytime changes in N₂O fluxes were inconsistent, and the 50% of total N₂O emission during the 12 h measurement periods was attained earlier under maize (～11∶00 h) than groundnut covers (～13∶00 h). Spatial variability in each treatment with eight gas chambers was large but smaller during the cropping periods than the fallow, indicating masking efficiency of crop covers for the soil heterogeneity that was accelerated presumably by antecedent climatic variables. The temporal variability of N₂O emissions was also large (coefficients of variation, CV, ranged from 60 to 81%), involving both input differences between treatments and measurement periods. As such, the relative deviation from the annual mean of total N₂O emission was high during the period after a large N application with a maximum of +480%, due to addition of chicken manure. The seasonal contribution of summer and monsoon to N₂O emissions was insignificant. However, intensive rainfall negatively (?0.65**) and the amount of added N from either source positively (0.83***) correlated with the integrated N₂O emissions, and those were exponential. Results suggest that around noon (12∶00 h) gas collection could represent well the daily N₂O fluxes, increasing the number or size of the gas chambers could minimize the large variability, and mainly the rainfall and N inputs regulated its emissions in the humid tropics of Malaysia.     

Improved and sustainable agroecosystem,food security and environmental resilience through zero tillage with emphasis on soils of temperate and subtropical climate regions: A review

Tillage is one of the agricultural management practices that significantly impacts agroecosystems, crop production, and the environment. Conventional tillage (CT) practices alter the soil environment and induce organic constituents’ decomposition and the emission of greenhouse gases (GHGs), which contribute to the greenhouse effect and global warming. Low organic matter, biological diversity, aggregate stability, high erosion and degradation of the soil environment, and sequestration strength are additional factors associated with CT, which negatively affect food security and environmental sustainability. As a result, CT is no more beneficial in the long run; consequently, zero tillage (ZT) could be a viable candidate for sustainable agriculture. The review to establish this systematically compared and summarized the effect of tillage systems (i.e. CT and ZT) by synthesizing and interpreting published data (>150 peer-reviewed articles) with >200 observations on soil ecosystem services and properties/agroecosystem, crop yield/food security, GHG emission, and carbon sequestration/environmental resilience. The review established that ZT improves soil structure, aggregate stability, biological diversity, organic matter and nutrients, water and water use efficiency, and reduces soil degradation, erosion, tillage machinery impacts, and GHG emissions. It allows timely seeding and better crop growth, increases yield and food security, improves carbon sequestration, strengthens soil storage potential, and helps to mitigate the adverse effects of climate change on environmental resilience. Based on various latent direct and indirect benefits, resource-saving ability, and broad adoption scope of ZT, it is corroborated that ZT is a practical and potential approach for improved and sustainable agroecosystem, food security, and environmental resilience.     

基于气候带与农业区划的农田生态系统服务权衡及驱动机制

农田生态系统作为重要的陆地生态系统之一,不同气候带与农业区的农田生态系统服务权衡关系与机理尚不明确。该研究定量分析了1990—2019年典型区域淮河流域农田生态系统关键服务食物供给与土壤保持的权衡强度,运用地理探测器方法揭示了不同气候带与农业区划下农田生态系统服务权衡关系的驱动机制,完善与细化了农田生态系统服务权衡机理,为推进淮河流域不同气候区和农业区的粮食安全和生态安全协同和精准施策提供科学依据。结果表明：1）淮河流域食物供给服务总体呈现增长趋势,黄淮海平原食物供给增长幅度显著高于长江中下游。土壤保持服务分区差异较大,在气候带上表现为亚热带增长趋势快于暖温带,在农业区划上表现为长江中下游增长趋势快于黄淮海平原,但黄淮海平原土壤保持平均值高于长江中下游。2）淮河流域农田食物供给与土壤保持两种服务间的权衡关系存在时空分异性,总体呈现加剧态势,权衡强度表现为暖温带长江中下游农业区>亚热带农业区>暖温带黄淮海平原农业区。3）淮河流域农田生态系统食物供给与土壤保持间的权衡关系受自然因素和人为因素共同作用,人为因素尤其是化肥施用量显著增强了食物供给与土壤保持间的权衡;在不同气候带与农...     

Quantitative assessment of rill and interrill soil erosion in Romania

Soil erosion is an important geomorphological process with potential negative consequences especially on land agricultural potential. Unsuitable agricultural practices may increase soil erosion, leading to rapid loss of soil fertility and decrease of crop production. It is therefore important to correctly quantify soil erosion rates in order to adapt agricultural practices and implement proper conservation measures. This study attempts to assess the rill and interrill erosion in Romania, using the Romanian soil erosion model and GIS techniques. The database includes the digital terrain model, the soil map of Romania, the land use map of Romania and the rainfall erosivity regions. The results show that the high and very high erosion risk classes include 4.1% of the Romanian territory (9,627 km²). Most of this land is present in the hilly and plateau areas (Subcarpathians, Moldavian Plateau, Getic Plateau, Western Hills, Dobrogea Plateau). The model was validated by comparison of its predictions with long‐term erosion measurements from different locations in the country. Comparison with previous non‐GIS assessments of soil erosion at national level shows that the total estimated rill and interrill erosion in our study was very close to previous estimates. Comparison with the RUSLE 2015 model computed for Europe as a whole reveals that the two models assign almost 54% of their shared area to the same erosion class, while for 39% of the territory there is one class difference between the models. The results can be used for evaluations of erosion risk at national and regional scales.