The Dynamic Change of Soil Microorganism and Enzyme Activity in the Whole Procreative Process of the Tarim Island Cotton

对塔里木海岛棉生育全程土壤微生物与酶活性的动态变化进行了检测,测试结果表明：（1）塔河种业高产海岛棉田土壤养分比塔河滩地高出6.58%~37.42%,特别是全钾、速效钾比塔河滩地高出29.02%~37.42%。（2）微生物数量变化呈现如下变化趋势：细菌类群在夏季有生长高峰,秋季略有回升;真菌在春季存在生长高峰,夏季处于低谷,秋季生物活性开始回升;放线菌生长高峰位于夏季,春秋季处于低谷。在土壤微生物区系构成中,细菌占据绝对优势,暗示土壤养分的转化主要靠细菌完成。（3）塔河种业高产海岛棉田土壤酶中的过氧化氢酶、     

土壤机械阻力的连续测定及空间变异结构分析

设计了一个土壤机械阻力连续测定系统。利用试验所得数据,初步探讨了土壤机械阻力的空间变异性和分形特征。结果表明,土壤机械阻力表现出空间变异结构,在一定范围内存在空间相关现象,用半方差法和功率谱密度法计算出土壤机械阻力的分维值分别为1.79~1.91和2.12~2.30。     

Effect of soil matric potential on tomato yield and water use under drip irrigation condition

Field experiment was carried out to investigate the effect of soil matric potential (SMP) on tomato yield, evapotranspiration (ET), water use efficiency (WUE) and irrigation water use efficiency (IWUE) under drip irrigation condition in North China Plain. The experiment included five treatments, which controlled SMP at 0.2 m depth immediately under drip emitter higher than −10 (S1), −20 (S2), −30 (S3), −40 (S4) and −50 kPa (S5), respectively, after tomato plant establishment. The results showed that different SMP affected irrigation amount and tomato ET. Irrigation amount decreased from 185 mm (S1) to 83.6 mm (S5) in 2004, and from 165 mm (S1) to 109 mm (S5) in 2005, respectively. The ET decreased from 270 mm (S1) to 202 mm (S5) in both years. However, it was found that SMP did not affect the tomato yield significantly, for the range of SMP investigated. Both WUE and IWUE increased as SMP decreased. The maximum WUE (253 and 217 kg/ha mm) and IWUE (620 and 406 kg/ha mm) were for S5 in 2 years, whereas the minimum WUE (178 and 155 kg/ha mm) and IWUE 261 and 259 kg/ha mm) were for S1 in 2004 and 2005. Based on the above results, therefore, it is recommended that if the tomatoes are well irrigated (SMP is higher than −20 kPa) during establishment, controlling SMP higher than −50 kPa at 0.2 m depth immediately under drip emitter can be used as an indicator for drip irrigation scheduling during following period of tomato growth in North China Plain.     

小流域的综合治理

1984年以来,舒城县采取工程和生物措施相结合的办法,对胡家河等6个小流域进行了综合治理。本文扼要地将在治理和管护工作中积累的经验、方法以及其成效、研究资料介绍给大家,以供参考。     

高盐度有机废水处理研究进展

海水直接利用后排放的废水以及制药和染料化工等工业废水，由于含盐量高，单一废水生物处理法具有一定的难度，本文结合高盐度有机废水的特点介绍了生物法与其他工艺组合以及电化学处理法处理此类废水的研究进展。     

松软地面机器系统研究进展

松软地面机器系统的理论研究,对农业、林业、矿业和军事等领域作业机械的发展具有重要的科学意义和工程应用价值。本文总结了松软地面机器系统基础理论,以及松软干沙地面轮壤关系最新研究进展;从土壤动物形态、结构和柔性方面阐述仿生脱附减阻机理,综述了地面机械触土部件的仿生理论基础;概括了用于地面力学特性测试的技术方法和地面机器系统研究的土槽测试系统;分析归纳了数值模拟方法在地面机器系统研究中的进展;进而对松软地面机器系统理论方法在触土部件和车辆行走机构中的应用研究进行了展望。     

Irrigated land retirement

Land retirement is ceasing irrigation withthe goal of reducing load, in general, ofdissolved constituents and, in particular,of trace elements, present in subsurfacedrainage generated from irrigated lands. Retirement is achieved through a process ofgoal setting, strategy development anddetermining effects, developing landselection criteria, implementation, andmonitoring. In this study, effects of landretirement are evaluated using hydrologic,soil and economic models as well as resultsfrom a field demonstration study. From themodeling and field monitoring, a process isdeveloped to meet the goals of a landretirement program in the San JoaquinValley of California.Potential negative effects listed for landretirement included loss of agriculturalproductivity, perhaps permanently, and lossof revenue to surrounding communities. Uncertainties included those associatedwith reuse of retired lands as wildlifehabitat, with retired-land maintenanceincluding dust control, with potentialpreservation of retired lands in reservefor future re-introduction to irrigated ordry-land agriculture, and withinstitutional changes concerning repaymentof federal and state water contracts. Benefits would accrue from economic returnto the landowner from the sale of property,the sale or lease of irrigation watersupply, the reduced cost of handlingdrainage, and allocation of freed-up waterto beneficial uses, and the reduced risk ofselenium exposure to fish and wildlife.A recommended sequential approach to selectand manage retired land is to identifyprimary objectives; formulate and implementarea-specific land retirement scenarios;measure biologic, hydrologic, soils andeconomic consequences in the short term andthe long term and manage and monitorretired lands based on dynamic biologic,hydrologic and soil conditions.     

耕作土壤表面不平度分析

利用激光式不平度测试仪测定犁耕耕地地面、圆盘耙耙地地面和驱动耙耙地地面的不平度，测定地面不平度沿着3个方向进行，即平行、倾斜和垂直于耕作方向。对每一种地面不平度的RMS高度、自相关长度和自相关函数进行了分析，结果表明：对于短的地块，可用单一尺度来表征地表不平度的特征，地表不平度特征属于指数相关函数，RMS高度和自相关长度具有明显的相关性；对于长的地块，平整的农业地表不平度具有分形性或多尺度性，其自相关函数是一种分形过程。     

基于GIS的精确农业合理采样与施肥间距研究

在GIS软件平台下对采样点进行行列删减,人为减小采样密度,运用地统计学方法制作养分分布图,并与原始采样方案进行形状和面积对比,选取合理的删减方案作为土壤养分的合理采样方案.碱解氮、速效磷和速效钾的合理采样间距分别为64 m×51 m、32 m×76 m和32 m×25 m.为综合考虑多种养分,提出3条综合采样测土原则.提出了调整施肥间距的实现方法,自动变量施肥宜采用"大网格采样、小网格施肥",手动变量施肥则宜采用"小网格采样、大网格施肥".试验表明提出的方法实现了定性与定量相结合来研究土壤采样间距.     

咸水灌溉下土壤水盐变化的试验研究

2002年在内蒙古河套灌区红卫节水示范园进行了咸水灌溉试验,分析试验结果得出:咸水灌溉下的土壤经过秋浇后含盐量可以降到咸水灌溉前水平。以荷兰Wageningen农业大学等单位开发的土壤水分大气作物系统模拟软件SWAP为工具,应用示范园的土壤、水、盐分试验资料对模型的参数进行了率定和验证,模型模拟结果和田间试验结果符合较好。