A Passive Drip Irrigation Controller for Efficient Water Use

在全球范围内，农业灌溉控制通常是通过对作物需水量的粗略估计、农民的直觉，或使用基于计时器的控制器按时间表进行的。这往往导致浇水过多或不足，导致植物生长下降和个人收入损失，特别是对缺水地区的小农而言。土壤湿度传感器是存在的，但它们并没有被广泛采用，而且它们仍然需要农民亲自访问每一种作物来控制灌溉。此外，农村地区普遍缺乏电力基础设施，因此难以使用电动灌溉设备（计时器、执行阀、抽水设备）。这里正在开发的被动灌溉控制器（PIC）在不需要电力或外部控制信号的情况下自动调节灌溉网络的水量。它通过机械测量土壤水势（衡量土壤干燥程度的一种方法）来感知作物对水的需求，并直接使用这种机械测量来打开或关闭水控制阀。PIC的开发处于后期原型设计阶段。之前，我们已经在实验室环境中验证了PIC可以在预先确定的土壤水势设定值下可靠且一致地打开。我们已经对设计进行了几次迭代，目前正在将PIC的灌溉性能与在温室中种植西红柿的基于定时器的控制器进行比较。ICARDA和圭尔夫大学（University of Guelph）的技术开发人员都对实施这项技术有浓厚的兴趣。这个Lab2Market计划将使我们能够定位技术以产生最大的影响。

Globally, irrigation control for agriculture is typically done using rough estimations of a crop's water needs, a farmer's intuition, or on a schedule using a timer-based controller. This often leads to over- or underwatering, resulting in decreased plant growth and a loss of personal income, particularly for small farmers in regions experiencing water scarcity. Soil moisture sensors exist, but they are not widely adopted, and they still require the farmer to physically visit each crop to control the irrigation. Also, the general lack of electrical infrastructure in rural areas makes the use of electrically powered irrigation equipment (timers, actuation valves, pumping equipment) difficult to implement. The passive irrigation controller (PIC) being developed here automatically regulates the flow of water to an irrigation network without the need of electricity or an external control signal. It senses the crop's need for water by mechanically measuring the soil water potential, a measure of how dry a soil is, and directly uses this mechanical measurement to open or close the water control valve. The development of the PIC is in late-stage prototyping. Previously, we have validated in a laboratory setting that the PIC can open reliably, and consistently, at pre-determined soil water potential setpoints. We have made several iterations on the design and are currently comparing the irrigation performance of the PIC against a timer-based controller for growing tomatoes in a greenhouse. There is strong interest in implementation from technology developers at both ICARDA and the University of Guelph. This Lab2Market program will enable us to position the technology for maximum impact.