不同秸秆覆盖量对春玉米冠气温差和叶水势日变化的影响

为了探明不同秸秆覆盖量对春玉米冠气温差(CATD)和叶水势(LWP)日变化的影响,在渭北旱塬设置了3种不同秸秆覆盖量(4 5009、000、13 500 kg/hm2),以不覆盖为对照(CK),研究了孕穗期春玉米冠气温差及叶水势的日变化。结果表明,4 500～13 500 kg/hm2覆盖量处理,较CK均能显著降低CATD、提高LWP(P0.05),尤其中午13:00—15:00效果最为明显。9 000 kg/hm2覆盖量处理综合表现最优,其日平均和14:00的CATD分别为0.79、-0.20℃,较CK依次降低了75.8%、111.4%,差异均显著(P0.05),15:00时LWP为-1.58 MPa,较CK增加7.06%(P0.05);其次为13 500 kg/hm2覆盖量处理,其日平均和14:00的冠气温差与9 000 kg/hm2覆盖量处理无显著差异(P0.05);4 500 kg/hm2覆盖量处理表现最差,与CK无显著差异(P0.05)。各处理冠气温差与秸秆覆盖量、土壤贮水量均呈显著负相关(P0.05)。研究认为,冠气温差可合理反映不同覆盖量条件下作物水分亏缺程度和土壤水分变化状况,且渭北旱塬适宜的秸秆覆盖量以9 000 kg/hm2为宜。

Effects of Different Straw Mulch Amounts on Diurnal Variation of Difference between Canopy Temperature and Air Temperature and Leaves Water Potential of Spring Maize

Aiming at effects of different straw mulch amounts on daily changing of temperature difference between canopy temperature and air temperature and leaves water potential of spring maize on Weibei Highland,Shaanxi.The experiment was conducted to measure the Daily Changing of Temperature Difference between Canopy Temperature and Air Temperature(CATD) in spring maize booting stage,with 3 treatments of different straw mulch amounts(4 500、9 000 and 13 500 kg/hm2 respectively),as well as its effects on Leaves Water Potential of spring maize.Results indicated CATD of 4 500～13 500 kg/hm2 straw mulch amount treatments were decreased and increased Leaves Water Potential of spring maize than that of the contro1 treatment(CK),which showed a significant difference(P<0.05),especially the variance was the most obvious at 13:00～15:00.The treatment of 9 000 kg/hm2 was the best of all treatments,its CATD of daily mean and at 14:00 reached 0.79、-0.20 ℃,decreased by 75.8%、111.4% respectively than that of CK,which showed a significant difference(P<0.05),and its Leaves Water Potential of spring maize at 15:00 reached-1.58 MPa,inecreased by 7.06%,which showed a significant difference(P<0.05).The treatment of 13 500 kg/hm2 was in the second place.The treatment of 4 500 kg/hm2 was in the third place,which showed no significant difference(P>0.05).It showed a significant negative correlation between CATD and straw mulch amounts and soil water storage(P<0.05).The CATD can be an indicator used for evaluating the change of soil moisture and the degree of crop water defieieney,and the treatment of 9 000 kg/hm2 should be a more suitable straw mulch amount on Weibei Highland.