不同灌溉方式氢、氧同位素分布与夏玉米水分利用特征

Hydrogen and Oxygen Isotope Distribution and Water Use Characteristics of Summer Maize Under Different Irrigation Modes

利用氢氧稳定同位素示踪法,研究了人工控水条件下小白龙常规灌溉(X)与滴灌(D)不同灌水量(X1、D1:15 mm;X2、D2:30 mm;X3、D3:45 mm)夏玉米土壤水稳定同位素分布特征,以及土壤耗水量、光合作用及水分利用特征。结果表明:随生育期的推进,根系吸水逐渐加深。在拔节期,均以0~20 cm土层的水分贡献率最大,达60%以上。在D1和D2条件下,60~80 cm和20~40 cm土层的贡献率分别占21.4%和23.8%。到灌浆期,与常规灌溉相比,滴灌条件下更利于促进根系对40 cm以下土层水分的利用,从而减少水分的无效蒸发。随生育期的推进与灌水量的增加,玉米的日耗水量明显增加,滴灌低于传统灌溉。与常规灌溉相比,滴灌D2处理更利于提高玉米光合速率、蒸腾速率、气孔导度及叶片水分利用效率。此外,滴灌处理明显提高了收获期玉米的生物量。最终,与常规灌溉相比,滴灌降低了玉米总的耗水量,产量提高了5.3%~21.7%和水分利用效率提高了9.2%~26.8%,均以D2处理最高。相关分析表明:玉米拔节期20~40 cm和灌浆期60~80 cm土层水分更利于促进玉米产量的提高,而拔节期60~80 cm和80~100 cm土层的水分更利于促进玉米水分利用效率的提高。

Based on hydrogen-oxygen stable isotope tracing method,the characteristics of stable isotope distribution of soil water,and soil water consumption,photosynthesis and water use in summer maize under conventional irrigation(X)and drip irrigation(D)(X1,D1:15 mm;X2,D2:30 mm;X3 and D3:45 mm),were studied.The results showed that the absorption of water deepened with the advancement of wheat growth period.Soil moisture at 0~20 cm depth was mainly consumed by maize in the jointing stage under different treatments,reaching to over 60%.D1 and D2 treatments mainly used soil moisture at 60~80 cm and 20~40 cm depth,accounting for 21.4% and 23.8%,respectively.By the filling stage,compared with the conventional irrigation,the drip irrigation condition is more conducive to promote the utilization of water below 40cm soil layer,thus reducing the ineffective evaporation of water.With the advancement of growth stage of maize and the increase of irrigation water,the daily water consumption of maize increased significantly,and the water quantity of drip irrigation was lower than that of conventional irrigation.Compared with conventional irrigation,D2 treatment was more conducive to improve the photosynthetic rate,transpiration rate,stomatal conductivity and leaf water utilization efficiency of maize.In addition,drip irrigation treatment significantly increased the maize biomass during the harvest period.Finally,drip irrigation reduced the total water consumption of corn,increasing the yield by 5.3%~21.7% and water use efficiency by 9.2%~26.8% compared with conventional irrigation,the D2 treatment resulted in the highest among different treatments.Related analysis shows that,the water contribution rate of soil water at 20~40 cm depth in the jointing stage and soil water at 60~80 cm depth in the filling state were more conducive to the improvement of the yield of maize,and soil water at 60~80 cm and 80~100 cm depth in the jointing stage was more conducive to improving the water use efficiency maize.