精量灌溉决策定量指标研究现状与进展

按照土壤 植物 大气连续体(SPAC)理论,灌溉决策的指标可分为三类:土壤水分、作物水分生理状况和气象因素。对这三方面的研究现状与进展作了详细的阐述。在土壤水分监测技术方面,时域反射仪(TDR)技术、微波技术、近红外辐射等的应用,使监测更加准确和便利;用于灌溉决策的作物水分生理信息监测包括:细胞液浓度、叶/水势、茎果微变化、生理电阻电容、声发射等,从目前国际上研究情况来看,叶冠层温度和茎流变化是指示作物水分状况较好的指标;在估算大气蒸发力方面,以参考作物蒸散量为指标,估计作物参考蒸散量的方法以联合国粮农组织(FAO)最新推荐的Penman-Monteith方法较为精细。并对目前灌溉决策指标的综合运用情况进行了总结。讨论了作为精准农业重要组成部分的"精量控制灌溉"今后的发展方向,建议以通过对作物、土壤、气象复合系统的分析和判断,指导灌溉的适时和适量。

Review of indices for precision irrigation decision-making

According to the theory of soil-plant-atmosphere continuum, there are three types of indices for precision irrigation decision-making, including soil moisture, plant water status and weather conditions. This paper reviews the researches and developments in these regards. The technologies for soil water monitoring and measurement have lately made great progress, such as time domain reflectometry, microwave, near infra-red radiation, etc. The plant water status, indicated by the leaf temperature, shrinking or swelling of stems or fruits, the capacitance or resistance of crop stem, etc, has been used as indicators for irrigation decision-making. And the temperature difference between canopy and its ambience, including the sap flow of plant, will be a better method to study the crop water status from the literature reviews. The crop reference evapotranspiration, estimated from meteorological data with methods such as the Penman-Monteith method recommended by FAO, is useful for precision irrigation decision-making. And it is concluded that the combination of the applied multi-indices can be used for irrigation management. In this paper, the development of precision irrigation control, as an important part of precision agriculture, is also discussed. The factors, which should be considered for irrigation application at the "proper time" and "adequate quantity" for these purposes, are crop, soil moisture and weather conditions.