玉米作物水分胁迫指数(CWSI)基线差异原因初探

Preliminary Investigation on Difference of Crop Water Stress Index Baseline for Maize

为了探讨相同作物水分胁迫指数(CWSI)基线,在不同试验条件下存在差异的原因,于2010年及2011年连续2年在南方红壤区进行了不同施肥处理的玉米小区试验。结果表明,不同的氮素处理,玉米形态学指标及叶龄存在差异,其中不施氮的处理与施氮的处理差异显著(P<0.05),施氮多和施氮少的处理差异较小。在玉米不同的生育期,CWSI下基线不完全相同。施肥能够影响玉米冠气温差的降低程度,施用氮肥越多,冠气温差降幅越大,从而可使不同施肥处理的CWSI下基线产生差异。此外,在作物发生干旱时,施用不同类型的肥料还能够影响作物冠气温差的增加程度,其中施用化肥处理玉米冠气温差要比施用有机肥和不施肥的处理高,施用有机肥处理的玉米冠气温差也较不施肥的处理高。研究结果认为,相同作物CWSI基线的差异与作物本身品种,以及不同生长条件下作物生长状况之间的差异密切相关,而气候条件是造成这种差异的辅助因素。

Crop water stress index（CWSI） is an useful tool to quickly assess water status of crop.For usage of CWSI with same baselines for specific crop in different areas under different climate types,we investigated the reason of difference for crop water stress index baseline of summer maize at different treatments.The summer maize field experiments were carried out in red soil areas of south China under different fertilizer treatments during two consecutive years.The results showed that,the morphological indices and leaf age of maize under different nitrogenous fertilizer treatments were different.The low baselines of maize at different growing stage were not same.Fertilization had an effect on low baseline of maize.Nitrogen fertilization reduced the low baselines of maize.The low baseline decreased as the amount of nitrogen fertilization increased.Fertilization also had an effect on upper baseline of maize under severe water stress conditions.The results indicated that,the main reason of difference of CWSI baselines for same crop was the growing conditions and growing stage of crop.The weather condition was the second factor to impact baseline of CWSI.