[Effects of straw returning combined with nitrogen fertilizer on spring maize yield and soil physicochemical properties under drip irrigation condition in Yellow River pumping irrigation area, Ningxia, China].

Soil compaction and nutrient deficiency are common problems in Ningxia Yellow River pumping irrigation area, which adversely affect crop yield. A two-year (2017-2018) field experiment of straw returning combined with nitrogen fertilizer were designed. Four nitrogen application levels (pure N with 0, 150, 300 and 450 kg·hm) were set under the condition of full smashing of maize straw (12000 kg·hm) returning, with the conventional nitrogen application (pure N with 225 kg·hm) without straw returning as the control (CK) to investigate the effects of straw returning combined with different amounts of nitrogen fertilizer on soil physical and chemical properties and maize yield under drip irrigation condition.

[Effects of returning straw with nitrogen application on soil water and nutrient status, and yield of maize].

The study focused on the problems of lean soil and low fertility in arid area of central Ningxia. To explore the optimum rate of nitrogen (N) fertilizer application under straw returning, taking the treatment with straw return and no nitrogen fertilization as control, we investigated the effects of three N application levels (150, 300, 450 kg·hm) with return of total maize straw (9000 kg·hm) on soil water and nutrient status and maize yield. The results showed that the soil water storage (0-100 cm) at 300 and 450 kg N·hm in middle and late growing period of maize was significantly increased by 10.