滴灌模式和水分调控对夏玉米干物质和氮素积累与分配及水分利用的影响

采用裂区试验设计探究了地下滴灌和地表滴灌(drip underground, DU; drip surface, DS)模式下土壤水分调控(分别为田间持水量的40%～50%、60%～70%和80%～90%,记为W40、W60和W80)对夏玉米干物质和氮素积累与分配及水分利用效率的影响。结果表明,DU处理的吐丝后氮素积累量及水分利用效率分别较DS显著提高了6.18%和4.85%～8.61%。夏玉米的干物质、氮素指标及产量对滴灌模式的响应依赖于土壤水分调控水平,在W40和W60处理条件下,DU处理显著增加夏玉米的净光合速率,提高了吐丝后干物质和氮素的积累量及向籽粒的转运,最终DU处理的干物质积累量、籽粒氮素积累量、产量及氮肥偏生产力分别提高了3.29%～19.94%、?1.10%～20.65%、3.29%～19.94%和3.31%～23.64%。而在W80处理条件下, DS处理的干物质积累量、吐丝后氮素积累量、产量及蒸散量比DU处理分别提高了6.80%～12.24%、5.93%、8.39%～14.91%和9.73%～14.57%。综上所述,在限水灌溉条件下,地下滴灌能够增加吐丝后干物质积累量、氮素积累量及其对籽粒氮素的贡献率,最终增加产量。在充分供水条件下,地表滴灌更有利于干物质及氮素的积累,但由于消耗过多的水分,因此水分利用效率未显著增加。

Effects of drip irrigation pattern and water regulation on the accumulation and allocation of dry matter and nitrogen,and water use efficiency in summer maize

A split-plot experiment was conducted to explore the dry matter and nitrogen accumulation and allocation characteristics, and water use efficiency of maize in response to different drip irrigation regimes. Drip underground (DU) and drip surface (DS) were applied with three levels of water treatment [W40, W60, and W80 referring to 40%-50% field water capacity (FWC), 60%-70% FWC, and 80%-90% FWC, respectively]. The nitrogen accumulation and water use efficiency of DU treatment has been significantly increased by 6.18% and 4.85%-8.61% respectively compared with DS treatment. The response of dry matter and nitrogen characteristics to drip irrigation patterns was depended on soil water regulation levels. Under W40 and W60 conditions, DU significantly increased the net photosynthetic rate of summer maize, improved dry matter and nitrogen accumulation after silking and their contribution to grains. At last, DU increased the dry matter accumulation, nitrogen accumulation in grains, yield and nitrogen partial factor productivity by 3.29% to 19.94%, -1.10% to 20.65%, 3.29% to 19.94%, and 3.31% to 23.64% respectively. While under W80 condition, dry matter and nitrogen accumulations, yield and crop evapotranspiration were 6.80% to 12.24%, 5.93%, 8.39% to 14.91%, and 9.73% to 14.57% respectively higher in DS than in DU. In conclusion, drip underground could improve dry matter and nitrogen translocated to grain, and increase yield under limited irrigated condition (W40 and W60), while under adequate water supply (W80), drip surface could enhance the dry matter and nitrogen accumulation with lower water use efficiency due to excessive water consumption.