污水灌溉系统中氮素转化运移的数值模拟分析

本文研究了不同类型氮素在二维饱和-非饱和土壤中运动及转化的数学模型,概化和简化了氮素集合体的划分,给出了氮素转化和运移的对流、弥散、硝化、反硝化、挥发、作物吸收、深层渗漏、固持和矿化等转化运移方式和控制方程。通过野外两个灌溉季节的污水灌溉试验,利用第一灌溉季节的试验数据进行参数求解,利用第二个灌溉季节的数据对该数值模型的实际应用进行检验。数值模拟的内容包括地下水位,排水中铵态氮、硝态氮的浓度变化三个部分,研究结果表明,模型正确可靠,预测结果可信,可用于实际污水灌溉的模拟分析。     

大柳树灌区作为国家商品粮后备基地可行性研究

论证了大柳树水利枢纽周边灌区作为国家商品粮后备基地的需求与可行性.通过对土地资源潜力、开发前景和未来水土资源匹配态势的系统分析,以及其周边区域对粮食的需求的探讨,认为在大柳树水利枢纽工程和南水北调工程建成后,可以保证新增的(150～200)×103hm2粮食播种面积自流和低扬程灌溉的水源,从而满足增产100×104t以上粮食的目的.     

铜川市节水灌溉的经验与发展对策

水资源短缺、干旱缺水,已成为制约农业生产再上台阶和社会经济发展的主要因素.在分析、总结铜川市“九五”期间,将节水灌溉建设作为一项革命性措施来实施,大力发展节水灌溉方面的经验与作法的基础上,提出了“十五”的发展对策.     

Soil Hydraulic Properties Affecting Discharge Uniformity of Gravity-Fed Subsurface Drip Irrigation Systems

The use of subsurface drip irrigation (SDI) is increasing for many reasons, including its many agronomic advantages and the ability for safe application of wastewater to crops. In contrast to surface drip irrigation, soil hydraulic properties may affect SDI performance, particularly for new SDI systems designed to operate under low pressure (e.g., 2?m of head). This work introduces a new approach for solving problems of predicting discharge in SDI laterals. We accomplish this by coupling models of head loss in laterals and soil impacts on dripper discharge. The coupled model enables an evaluation of the performance of SDI laterals while changing inputs, such as the lateral diameter, length and slope, dripper nominal discharge and exponent, inlet pressure head, soil hydraulic properties, and soil spatial variability. This model is used to determine the coefficient of variation of discharge for two numerical comparisons.     

ERT法在树干水分运移监测中的运用

以生长中的树木为研究对象,通过在树干布置电极,利用电阻率与含水量之间的关系,探讨了树干中水份的运移特性.提出了针对圆柱体的电阻率修正方法,以解决圆柱体中电阻率计算问题,并将该方法应用于对树干电阻率的修正.结果表明,在降雨发生时,水份迅速进入亏空的木质部导管,由于水势突变,导管内会有气泡的产生.水分在树干中的传输并非呈面状推进,而是存在优势通道.     

集散控制系统在保护地微灌中的应用

集散控制系统（DCS）在保护地微灌中的应用推广,满足了随机供水、按量收费、自动灌溉、科学用水的要求,使工程管理和受益农户从中得到相应的利益。     

沧州市节水灌溉发展现状及对策

文中对沧州节水灌溉发展状况进行了回顾,提出了几种适用的节水灌溉技术和今后应采取的对策。     

Effect of row space and irrigation on seed composition of Turkish sesame (Sesamum indicum L.)

The effect of row space (RS) and irrigation (IR) on total protein, total oil, and fatty acid composition of Harran-grown sesame seed was studied. Total oil content of sesame varied from 46.4 to 51.5%. The oil and protein contents were significantly different among treatments (P<0.01) in 1998 and 1999. IR affected oil content significantly (P<0.01) in both years, and RS had no significant effect. The protein content was significantly influenced by RS and IR at P<0.05 and P<0.01, respectively. RS 70 cm had the highest protein content followed by RS 60, 50, and 40 cm, respectively. IR every 24th day resulted in the highest level of protein, followed by 18th-, 12th-, and 6th-day irrigation, respectively. Correlation coefficients between protein and oil content were −0.34 in 1998 and −0.59 in 1999. RS (P<0.05) and IR (P<0.01) influenced oleic and linoleic acid contents significantly. Interactions of RS and IR were also found to be significant (P<0.05) over the oleic and linoleic acid levels.     

新疆下坂地水利枢纽建设规模分析论证

主要论述在确定下坂地水利枢纽工程建设规模中,如何充分发挥、利用已建水利水电工程的作用,通过流域内的径流水文补偿,跨流域的电力补偿及充分利用下游平原水库的反调节作用。为分析论证多年调节水库的建设规模与地区经济发展提供有益的思考方法。     

灌溉水经济价值与粮棉作物种植布局

以我国十大区域灌溉需求指数为切入点,灌溉水经济价值为主要研究内容,在系统整编2000—2005年4种主要农产品成本收益资料的基础上,采用扣除非水成本法计算得出了十大区域4种主要作物灌溉水经济价值,研究了作物适应性种植的地域性特征和规律性,提出粮棉作物种植的优势地区、种植布局以及政策扶持和倾斜的品种,可为粮棉种植决策和维护国家粮食安全提供水资源方面的科学依据。