膜下滴灌条件下玉米开花期水流阻力分布规律

Research on the Distribution Law for Water Flow Resistance on SPAC to Corn Florescence of Drip Irrigation under Mulch

通过田间试验,以玉米开花期为例,分析了膜下滴灌条件下株高、单株叶面积、根系直径、根系重量等生长指标及土水势、叶水势、根水势与灌水量之间的关系。计算了玉米开花期不同界面的水分传输阻力,并分析了各阻力与灌水量之间的关系。结果表明,膜下滴灌条件下450、525、600 m3/hm2的灌水定额对玉米的株高影响不大,但单株叶面积随着灌水定额的增大而增大;玉米根系在0~40 cm土层所占的重量百分比分别为83.74%、92.94%、93.55%。玉米根水势为叶水势的5~6倍,相比膜孔灌,滴灌条件下叶—气水势差略有所减小,土根、根叶水势差均有所增大。玉米土根接触阻力、根系吸收阻力分别占土根总阻力的46.12%~57.15%、42.45%~53.37%。在各界面阻力中,叶气界面阻力占总阻力的98%左右,植物内部阻力占总阻力的1.11%~1.52%,土根接触阻力占总阻力的0.43%~0.46%,土壤阻力所占总阻力比重较小。

The field trials study the relationship between the corn growth Index （ height, leaf area, root diameter, root weight and so on） and soil water potential, leaf water potential, root water potential and irrigation amount under mulched drip irrigation. The study calculates corn flowering period different interfaces of the water transfer resistance and analyzes the relationship between each resistance and the irrigation a- mount. The results show that irrigation amount of 450, 525, 600 m3/hm2 has little effect on the corn plant height while leaf area increases with irrigation quota and corn roots in 0-40 cm soil of weight percentages were 83.74%, 92.94%, 93.55%. Corn root water potential is 5 to 6 times to the leaf water potential. Leaf - air water potential difference decreases slightly while soil - root, root - leaf waler potential difference both increased. The soil-root contract resistance, root absorption resistance are the total resistance of soil - root of 46.12% to 57.15% and 42.45% to 53.37%. The study also shows that leaf-atmosphere interface account for about 90% of the total resistance ,the resistance in plants and the soil-root contract resistance are the total resistance of 1.11% - 1.52% to 0.43%- 0.46% respectively, and simultaneously, soil resistance has a smaller proportion to the total resistance.