不同土壤水分含量对水稻水分利用特征的影响

Effects of Soil Moisture on Water Utilization Characteristics of Rice(Oryza sativa)

采用控制土壤水分含量的盆栽实验,研究了土壤水分含量对水稻水分利用特性的影响。结果表明,常规水作累积耗水量显著高于覆膜未淹水处理,但稍低于覆膜淹水处理;覆膜轻度水分胁迫或无胁迫处理不仅能够维持和提高产量,水分利用效率也有所提高。随着土壤水分含量的降低,全生育期水稻累积耗水量、各生育期耗水量及耗水强度逐渐降低,且田间持水量与全生育期累积耗水量呈极显著二次曲线相关。无水分胁迫覆膜处理下拔节孕穗期耗水量及模比系数高于其他生育期,其他处理耗水量和模比系数在乳熟期最高。随着土壤水分含量降低,抽穗开花期前各生育期水稻耗水模比系数有降低趋势,其后则有升高趋势;耗水强度下降;有效穗数和实粒数减少,产量逐渐降低,水分生产率先上升后下降。水稻产量与水分利用率具有显著二次曲线相关性。

A pot experiment was conducted to study the effect of soil moisture on water utilization characteristics of rice. Results showed that the cumulative water consumption of rice during the whole growth period under conventional flooding cultivation was significantly more than that under non-flooding cuitivation with plastic film mulching, but slightly less than that under flooding cultivation with plastic film mulching. Compared to conventional flooding cultivation, the rice grain yield was not decreased or even increased with the increased water productivity under light and no water stress treatments with plastic film mulching. The cumulative water consumption of rice, the water consumption at each growth stage and its consumption intensity were decreased gradually with the decreasing soil moisture. And a significantly quadratic correlation was found between the field water-holding capacity and the cumulative water consumption of rice. The highest water consumption at each stage and the highest periodic consumption ratio were found at the elongation and booting stages under no water- stress treatments with plastic film mulching, and at the milky ripeness stage under the other treatments. With the decreasing soil water content, the periodic consumption ratio gradually reduced before heading and flowering, whereas increased after heading and flowering, in addition, the consumption intensity decreased. The number of effective panicles and the number of grains per panicle decreased with reducing water moisture, resulting in the declined rice yield. However, the water productivity increased gradually first and then decreased with the decreasing soil moisture. Quadratic correlation was also observed between the yield and the water productivity of rice.