稻草覆盖对亚热带红壤旱坡地玉米旱期生长的生理调节作用及其产量效应

Effect of Straw Mulching on Physiological Adjustment and Output of Maize Growing on Subtropical Red Soil Slopeland in Dry Season

对不同稻草覆盖量处理下亚热带旱坡地红壤水分、温度变化和玉米不同生育期生理指标值的测定结果表明,在有旱无灾年份,稻草覆盖可以明显地缓解表层(0—10 cm)土壤含水量减少和调节土壤温度。稻草覆盖可减轻玉米旱害,其效果随着覆盖量的加大而越明显,但受干旱程度和生育期影响。拔节期遇旱,稻草覆盖可以维持玉米的生理活性,覆盖稻草15 t.hm-2处理与其他处理之间存在显著性差异;但随生育期的推移和后期降雨频度的增加,各处理间玉米生理指标值差异减小,灌浆期和成熟期差异不明显。稻草覆盖可以增加玉米生物量和籽粒产量,覆盖稻草15 t.hm-2处理(T3)生物量最大,覆盖稻草5 t.hm-2处理(T1)产量最高,其原因主要是受旱时期为拔节期,造成处理T3贪青生长,但对处理T1后期生理机制影响不大。

Results of determination of soil moisture, soil temperature, and physiological characteristics of maize growing in plots different in mulching treatment showed that straw mulching could minish the range of variation of soil moisture and temperature in the surface soil layer of 0 - 10 cm ; thus mitigating harm of drought on the crop. The thicker the straw mulching, the more significant the effect. But the effect was limited by soil aridness and growth stage of maize. For instance, at the elongation stage, straw mulching may maintain physiological activity of the crop and significant difference in this effect was observed between Treatment 33 （15 t · hm^-2） and other treatments. But along with growth of the crop and increasing frequency of rainfall the difference gradually narrowed. At the milking and maturing stages, the effect was insignificant. Mulching may increase the yield of biomass and grains of the crop. In the experiment, Treatment T1 （5 t · hm^-2 ） was the highest in grain yield whereas Treatment 33 in biomass production. The main reason for that was that the drought occurring at the elongation stage led to fast growth of the crop in Treatment 33, but didn＇t affect much the physiological mechanism of the crop in Treatment T1 in the late growing period.