Effects of Postponing Nitrogen Topdressing on Water Use Characteristics of Maize-Pea Intercropping System

Abstract

In oasis irrigation agricultural region, water resources deficit is one of the most penetrating constraints for developing intercropping. However, these was neither sufficient academic basis for enhancing water utilization rate through optimizing chemical nitrogen application, nor available practices for increasing yield and water use efficiency (WUE) of crops in developing cereal/legume intercropping. Here, we carried out a field experiment in Hexi Corridor, a typical arid oasis irrigation area in 20122013, and the effect of postponing nitrogen topdressing on yield and water use characteristics of soleand intercropping maize, pea systems was investigated. The total nitrogen application level for the same cropping system was equal. On the basis of 10% basal N fertilizer plus 50% pre-tasseling N fertilizer, three N treatments were managed with different topdressing amounts postponed: N1, N postponing application with 30%; N2, N postponing application with 15%; and N3, traditional nitrogen application. The purpose of the study focused on providing academic and practical evidence for increasing yield and WUE through optimizing nitrogen fertilizer management. The results showed that, N postponing application had no significant influence on total water consumption (ET) of maize-pea intercropping in the whole growing stage, but the soil evaporation (E) and E/ET were significantly decreased. As compared with traditional nitrogen application treatment, evaporation and E/ET in 15% N postponing application maize-pea intercropping were reduced by 6% and 4%, respectively, while those in maize-pea intercropping with 30% N postponing application both by 2%. In maize-pea intercropping systems, average soil evaporation in pea strips was 329 mm, but 第 3期 滕园园等: 氮肥后移对玉米间作豌豆耗水特性的调控效应 447 that in maize strips was 232 mm, showing that invalid water consumption in pea strip is significantly higher than that in maize strips. Mixed grain yield of maize-pea intercropping under N postponing application with 15% was 6% higher than that of the traditional nitrogen application treatment. And WUE of pea-maize intercropping systems was also significantly higher than that of the traditional nitrogen by 5%. As well as mixed grain yield and WUE of pea-maize intercropping under N postponing application with 30% was 3% and 2% higher than that of the traditional nitrogen application treatment respectively. Consequently, the 15% N postponing application (topdressing fertilizer with 67.5 kg N ha at pea flower pod period/maize jointing period, topdressing fertilizer with 225 kg N ha at maize pre-tasseling period and topdressing fertilizer with 112.5 kg N ha at maize 15 days after flowering period) combined with maize-pea intercropping could be one of the effective strategies to promote grain yield and WUE of cereal-legume intercropping in Oasis irrigation region.