极端气候事件对1978-2017年广西农作物的灾损影响

为了降低极端气候事件对农作物产量与经济的损失,本文基于灾害学理论,运用数理统计的趋势分析等方法,分析了1978-2017年旱灾、水灾、风雹灾与低温成灾4种极端气候事件对广西区农作物成灾、受灾面积的影响.并用极端气候事件的气候因素响应频率来近似代替一定区域极端气候发生的概率,结合1978-2017年4种极端气候事件灾损评...     

粮食作物AM真菌研究进展

综述了近年来粮食作物根际AM真菌多样性研究进展,包括粮食作物根际AM真菌资源及种类,AM真菌对粮食作物的侵染及影响因素;以及AM真菌对粮食作物生长发育、矿质营养吸收、植物抗逆性和抗病性等方面影响的研究现状;并展望了粮食作物AM真菌的应用前景。     

基于不同夏作物-冬小麦种植制度的黄土高原东部农田土壤物理质量研究

黄土高原东部农田土壤物理质量下降是限制该地区农业生产的重要因素之一,合理的种植制度能够改善土壤物理质量。本试验于2016年设置连续夏绿豆-冬小麦(MB-WW,T₁)、2年夏玉米-冬小麦+2年夏绿豆-冬小麦(2 a SC-WW+2 a MB-WW,T₂)及连续夏休闲-冬小麦(SF-WW,T₃) 3种种植制度,分析实施第3和4年的土壤物理质量,以探索潜在的适宜于改善研究区土壤物理质量的种植制度。结果表明：T₁处理下冬小麦收获后0~30 cm各土层毛管孔隙度较T₂和T₃处理分别显著提高了19.20~28.49%和18.86~31.86%。此外T₁处理夏播作物收获后,10~20 cm土层土壤储水量较T₂显著增加了6.37%,20~30 cm土层土壤质量含水量和储水量较T₂处理分别显著增加了7.87%和4.70%。相较于T₃,冬小麦和夏播作物收获后T₁和T₂处理下土壤容重、总孔隙度和土壤固、液、气三相比偏离值没有得到明显的改善。综上所述,绿豆-冬小麦种植制度对土壤物理质量有一定的改善,采用连续夏绿豆-冬小麦种植制度可能是改善黄土高原东部农田土壤物理质量潜在的措施之一。     

作物对水分胁迫的响应及水分利用效率的研究进展

作物对水分胁迫的响应及水分利用效率的研究是节水农业的重要方面,为此,对水分胁迫下作物形态、生理生化响应,作物水分利用效率的内涵、测定计算方法及提高作物水分利用效率途径等国内外的相关研究进行了回顾,并在此基础上,提出了我国目前在该领域研究和应用中存在的问题.     

Water management and crop production for food security in China: A review

Food security is a high priority issue on the Chinese political agenda. China’s food security is challenged by several anthropogenic, sociopolitical and policy factors, including: population growth; urbanization and industrialization; land use changes and water scarcity; income growth and nutritional transition; and turbulence in global energy and food markets. Sustained growth in agricultural productivity and stable relations with global food suppliers are the twin anchors of food security. Shortfalls in domestic food production can take their toll on international food markets. Turbulence in global energy markets can affect food prices and supply costs, affecting food security and poverty. Policy safeguards are needed to shield food supply against such forces. China must make unremitting policy responses to address the loss of its fertile land for true progress towards the goal of national food security, by investing in infrastructure such as irrigation, drainage, storage, transport, and agricultural research and institutional reforms such as tenure security and land market liberalization. The links between water and other development-related sectors such as population, energy, food, and environment, and the interactions among them require reckoning, as they together will determine future food security and poverty reduction in China. Climate change is creating a new level of uncertainty in water governance, requiring accelerated research to avoid water-related stresses.     

黑土区田块尺度下地形影响作物长势机理分析

为揭示作物长势及水肥运移的空间分异规律,探究田块尺度内作物长势与地形变化的关系,以东北典型黑土区东兴农机合作社为研究区,沿南北垄向提取高精度数字高程模型(Digital elevation model,DEM)与归一化植被指数(Normalized differential vegetation index,NDVI)信息,构建地形指标,分析NDVI的空间变异性。结果表明,坡型凸凹程度越明显,NDVI的空间变异性越大;同类坡型中阴坡NDVI的空间变异性与坡型凸凹程度呈负相关;坡度在±0.03范围内,作物长势好,空间变异性低;以坡度绝对值高于0.04的坡度均值与其对应直线距离所占整条直线的比值作为自变量,构建多元逐步回归模型,进行回归分析,可以解释大豆NDVI决定系数为0.965 2、高粱NDVI决定系数为0.888 3的空间变异性。不同地理空间的地形与成土母质差异显著,通过分析研究区内地形对作物长势的影响规律,可为田块尺度地形的分析提供借鉴,有助于指导农户合理地进行水肥分配。     

我国农作物生产机械化发展阶段分析

农作物生产机械化是农业机械化的核心。本文构建了农作物生产机械化发展进程阶段划分指标体系,提出将农作物生产机械化发展进程划分为四个阶段,建立了相应的判断数学模型,并运用此模型研究了机械化生产方式与传统生产方式在农作物生产中的力量对比变化,揭示出农作物生产机械化发展进程不同阶段的基本特征。     

Cover crop evapotranspiration under semi-arid conditions using FAO dual crop coefficient method with water stress compensation

Cover cropping is a common agro-environmental tool for soil and groundwater protection. In water limited environments, knowledge about additional water extraction by cover crop plants compared to a bare soil is required for a sustainable management strategy. Estimates obtained by the FAO dual crop coefficient method, compared to water balance-based data of actual evapotranspiration, were used to assess the risk of soil water depletion by four cover crop species (phacelia, hairy vetch, rye, mustard) compared to a fallow control. A water stress compensation function was developed for this model to account for additional water uptake from deeper soil layers under dry conditions. The average deviation of modelled cumulative evapotranspiration from the measured values was 1.4% under wet conditions in 2004 and 6.7% under dry conditions in 2005. Water stress compensation was suggested for rye and mustard, improving substantially the model estimates. Dry conditions during full cover crop growth resulted in water losses exceeding fallow by a maximum of +15.8% for rye, while no substantially higher water losses to the atmosphere were found in case of evenly distributed rainfall during the plant vegetation period with evaporation and transpiration concentrated in the upper soil layer. Generally the potential of cover crop induced water storage depletion was limited due to the low evaporative demand when plants achieved maximum growth. These results in a transpiration efficiency being highest for phacelia (5.1 g m⁻² mm⁻¹) and vetch (5.4 g m⁻² mm⁻¹) and substantially lower for rye (2.9 g m⁻² mm⁻¹) and mustard (2.8 g m⁻² mm⁻¹). Taking into account total evapotranspiration losses, mustard performed substantially better. The integration of stress compensation into the FAO crop coefficient approach provided reliable estimates of water losses under dry conditions. Cover crop species reducing the high evaporation potential from a bare soil surface in late summer by a fast canopy coverage during early development stages were considered most suitable in a sustainable cover crop management for water limited environments.     

病虫害状态下作物叶片表观模拟方法

为了解决农作物病害三维场景难以模拟的问题,该文提出一种病虫害条件下叶片表观的模拟算法。该方法首先利用细胞纹理基函数控制病斑的形状、分布及扩散方式;之后为了模拟病斑在叶片上的堆积效果,采用shell模型进行模拟,并针对病斑的特点,对病斑的颗粒感、高度变化以及周边叶色的变化情况均进行建模。试验结果表明,该方法可以真实地模拟植物叶片在病害状态下的表观,可以容易地与病害知识进行结合,实现基于环境数据驱动的白粉病病情变化过程模拟,为数字农业设计及农业科普培训动画的制作提供有力工具。