桂平富硒土地改良效果初步对比研究

桂平富硒土地中大量含有As、Cd、Pb等有毒有害元素,对于如何降低有毒有害元素含量和提高Se的利用率,成为了生态农业和土地改良中所关注的焦点。此次土地改良是使用石灰加有机肥相混合的方式,通过对桂平地区水稻、花生、火龙果等种植区土地改良前后的土壤和植物样品进行分析,结果显示：(1)改良后植物组织及果实中的Se含量均有所提高;(2)植物组织及果实对As、Cd、Pb的吸收量减少。As、Cd更多地被固定在土壤中,它们在土壤中的含量增加,而土壤中的Pb含量变化不大。这表明,桂平富硒土地通过改良能较好地提高硒的利用率,并为大规模富硒产业的培育提供技术保障。     

上海地区滩涂土地整治改良方法探讨

介绍了土地整治改良的方法、上海地区滩涂资源的特点和改良思路,认为上海地区滩涂土地的改良除了固化、脱盐外,还应综合多种措施提高土地的品质。     

农村低产田开发掀高潮

沂蒙山区平邑县是典型的山区农业大县,近百万亩粮食作物耕地中,20％的山区、丘陵为低产田。对此,该县16个乡镇,认真普查低产田现状,及时拿出低产田开发意见,合理调整农村劳动力结构,分3个层次进行综合开发：首先是瘠薄丘陵低产田的开发,采取乡镇劳动力集中会战的办法,分年、分段逐步治理。     

Using a Modified Soil-Plant-Atmosphere Scheme （MSPAS） to Simulate the Interaction between Land Surface Processes and Atmospheric Boundary Layer in Semi-Arid Regions

This paper uses a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to study the interaction betweenland surface and atmospheric boundary layer processes. The scheme is composed of two main parts:atmospheric boundary layer processes and land surface processes. Compared with SiB and BATS, which arefamous for their detailed parameterizations of physical variables, this simplified model is more convenientand saves much more computation time. Though simple, the feasibility of the model is well proved inthis paper. The numerical simulation results from MSPAS show good agreement with reality. The schemeis used to obtain reasonable simulations for diurnal variations of heat balance, potential temperature ofboundary layer, and wind field, and spatial distributions of temperature, specific humidity, vertical velocity,turbulence kinetic energy, and turbulence exchange coefficient over desert and oasis. In addition, MSPAS isused to simulate the interaction between desert and oasis at night, and again it obtains reasonable results.This indicates that MSPAS can be used to study the interaction between land surface processes and theatmospheric boundary layer over various underlying surfaces and can be extended for regional climate andnumerical weather prediction study.     

农业地质与土壤调查

土壤是农业生态系统中的物质基础,是农业地质研究的主要对象,土壤调查按研究的目的不同,可分为[农业土壤学调查,环境土壤学调查和地球化学土壤学调查,作者扼要阐述了不同土壤调查。     

守牢中国“饭碗田”

我国幅员辽阔,拥有历史悠久的农耕文明,其赖以支撑的土地资源类型多样,有被称为“耕地中的大熊猫”的东北黑土地,有从黄河盐碱地转变而来的良田,有以淤泥为基础的洞庭湖区农田,也有紫色土丰富的四川盆地……近年来,我国采取有效的土地保护政策,大力推进土地改良工程,走可持续发展道路,保护现有耕地。