灌溉

Better seeds, crop rotation, irrigation and access to markets all help farmers.

对农场主帮助更大的，是采用更优良的种子、更好的农作物轮作方式、更好的灌溉方法，建立更顺畅的市场渠道。

The researchers note that only four percent of the cropland in sub-Saharan Africa is irrigated.

研究人员注意到，在下撒哈拉地区只有4%的农田得到灌溉。

This paper used Elman neural network to establish the model of irrigation water use prediction, having four importing units and exporting units. The determination of concealed level neural single number used the cut-and-try method, ten units were used.

运用神经网络中Elman反馈型神经网络建立了灌溉用水量预测模型，模型输入层神经元数目为4，输出层神经元数目为1，隐含层神经元数目确定采用试验法，最终确定为10。

The purpose of the dam was to provide irrigation and power.

这座水坝的功能是提供灌溉和电力。

Compared to the dater border, 44mm irrigation water and 20kg/hm^2 N are lost in the longer border.

试验研究不同灌溉畦长对灌水量、灌水均匀度与土壤NO(上标–下标 3)-N分布的影响。

Water deficiency sensitive index; water production function; optimal irrigation schedule; dynamic planning model; non-linear model

农业科技，农业基础科学，农业数学缺水敏感指数；水分生产函数；灌溉制度优化；动态规划模型；非线性规划

The yield increased as the ecapotranspiration,while it comes to a certain,the yield won't increase,it may decline. 2According to the non-full irrigation experimental datum of spring wheat and flax in Liangzhou and Gulang city of Shiyang River Basin,calculating the crop water deficiency sensitive index or coefficient by using crop water production function models of Jensen,Blank,Stewart and Minhas.

产量随着耗水量的增加而增加，当达到一定数值将不再增加，反而有下降的趋势。2 依据石羊河流域凉州和古浪春小麦和亚麻非充分灌溉试验资料，利用现有的Jensen 、Blank、Stewart 和Minhas 水分生产函数模型求解作物的缺水敏感指数。

2According to the non-full irrigation experimental datum of spring wheat and flax in Liangzhou and Gulang city of Shiyang River Basin,calculating the crop water deficiency sensitive index or coefficient by using crop water production function models of Jensen,Blank,Stewart and Minhas.

依据石羊河流域凉州和古浪春小麦和亚麻非充分灌溉试验资料，利用现有的Jensen 、Blank、Stewart 和Minhas 水分生产函数模型求解作物的缺水敏感指数。

This paper studies the main geometrical parameter such as angle, height, width, stagger and the upper width in dentation and trapezoid flow path, firstly, uses the single-phase numerical simulation of the computational fluid dynamics technique to analyse the influence of different geometrical parameter on discharge coefficient and flow state exponent of drip emitter. Secondly, uses the two-phases numerical simulation of CFD (1% sand content ) to analyse the influence of the above mentioned geometrical parameter on the contribution regulation of sand and anti-clogging performance. Thirdly, uses the PIV （ particle Tracking Velocimetry ） technique which can see the small-scale flow path to observe and test the trajectories and velocities of solid particles in labyrinth flow path, and analyses the basic factors which can influence the movement characteristic of solid particles and the flow state in flow path.

本文以齿形流道、梯形流道为主要研究对象，以流道转角、流道高，流道宽、偏差量及梯形流道上底宽为主要结构参数，首先应用 CFD 单相流数值模拟技术对不同结构参数灌水器流道水力性能进行模拟，分析了不同结构参数对流态指数和流量系数的影响，其次，应用 CFD 两相流（含沙量为1%）数值模拟技术分析了结构参数对含沙量分布规律和抗堵塞性能的影响，然后，应用 PIV 可视化测试方法测试了固体颗粒在流道内运行轨迹及速度，分析了影响固体颗粒运动特性及流道内流体流态的基本因素，最后，对上述流道结构形式通过模具加工及滴灌带试制，进行了标准化测试（ GB/T 17187-1997 农业灌溉设备滴头技术规范和试验方法与 ISO 标准 ISO /TC23 /SC18 /WG5N4短周期堵塞测试程序），测试结果验证了 CFD 模拟结果，并提出了迷宫结构流道灌水器的抗堵塞设计方法。

In this paper, the principle and the method of the discrete time Markou Decision Programming have been used for the MDP model of irrigating the crop field.

本文应用离散时间的马尔可夫决策规划的原理和方法，建立了农田灌溉的MDP模型。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。