基于土壤基质势的灌溉预报及自动控制系统设计

Design of irrigation forecast and automatic control system based on soil matric potential

为了使灌溉预报及自动控制系统简单、投资成本低且便于推广应用,设计了一套基于土壤基质势的灌溉预报及自动控制系统.通过利用电接点压力表测量负压计中的压力,设定不同作物、不同生育期、不同灌水方式的灌水下限和上限.当土壤基质势达到灌水上下限时,通过电接点压力表和自动控制电路,实现灌溉预报和自动控制.灌水过程中,通过单片机、远传水表和液晶显示屏,可以实现灌水时间、灌水量和灌水次数的记录与存储.经室内试验验证表明基于土壤基质势的灌溉预报及自动控制系统合理可行,对于粉砂壤土可以将灌水上限的土壤基质势设置为-8 k Pa左右.

An irrigation forecast and automatic control system was designed based on soil matric potential to make the system simple, cheap and widely applicable. By using pressure gauge with electric contact to measure the pressure of tensiometer, the irrigation upper and lower limits can be easily set with the knob on the pressure gauge for different crops, growth stages, and irrigation methods based on the soil matric potential. When the soil matric potential reaches the upper and lower limits, the auto- matic irrigation can be achieved with the pressure gauge and automatic control circuit. The irrigation duration, amount, and fi＇equency can be recorded and stored with single chip microcomputer and displayed by remote -transmitting water meter and liquid crystal display during irrigation. The laboratory test show that this irrigation forecast and automatic control system is reliable and feasible. Moreover, based on the soil matric potential, the irrigation upper limit is approximately equal to -8 kPa for silt loam soil.