作物水分胁迫指数监测红壤农田短期干旱的分析

Analysis of Monitoring Short-term Drought of Farmland in Red Soil Using Crop Water Stress Index

在南方红壤区,设置化肥(NPK)、有机肥(M)以及不施肥(CK)3个不同施肥水平和3个不同灌水处理的水肥耦合试验,对作物水分胁迫指数(CWSI)在该区监测农田作物发生短期干旱时的使用效果进行了分析。结果表明,在红壤区农田发生短期干旱时,土壤表层水分降低迅速,深层水分变化缓慢;不同施肥处理条件下建立的夏玉米CWSI下基线各不相同,其中施NPK处理下基线明显低于其他两个处理,从而导致不同施肥处理玉米CWSI上基线也存在差异;CWSI与农田表层土壤含水量呈显著的负相关关系,与20 cm土层土壤含水量相关性最好(P<0.01),并且CWSI值还与作物最终产量具有极显著的线性关系(P<0.01)。本研究结果说明,在南方红壤区可以使用CWSI监测农田短期干旱,并可利用该指标对农田水分状况及作物产量进行反映和估计,但是在计算作物CWSI值时,需要根据不同的施肥条件建立相应施肥水平下作物CWSI上下基线。

In red soil area of southern Chin a, a water and fertilizer coupling test is carried out with 3 levels of fertilizers including chemical fertilizer （NPK）, manure （M） and nil fertilizer （CK）, as well as 3 levels of irrigation. The effect of using crop water stress index （CWSIO to monitor short-term drought in farmland of red soil area is analyzed. The results show that the surface layer soil water contents decrease quickly whereas deep layer soil water contents change slowly as a short-term drought happens in red soil area. The low baselines of summer maize CWSI in different fertilization treatments are not completely identical, as that of NPK is obviously lower than the other treatments. Therefore, the upper baselines of CWSI under different amendments different from each other. CWSI is significantly negatively correlated to soil water content in surface soil layer, and is correlated best with water content at 20 cm soil depth （P 〈 0.01）. Furthermore, CWSI is extremely significantly correlated to the final crop yield （P 〈 0.01）. The present study concludes that CWSI can be used to monitor the short-term drought in farmland of red soil area, and estimate the water status and final yield of maize. However, the calculation of CWSI should be based on the upper and low baselines under different fertilizer amendments.