RESUMO
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-2) were set under the condition of full smashing of maize straw (12000 kg·hm-2) returning, with the conventional nitrogen application (pure N with 225 kg·hm-2) 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. The results showed that, compared with no-straw returning treatment, the treatments of straw returning combined nitrogen fertilizer with 300 and 450 kg·hm-2 reduced soil bulk density (0-20 cm) by 3.3% and 5.4%, but increased soil porosity by 3.7% and 7.1%, respectively. Straw returning combined with nitrogen with 300 kg·hm-2 and 450 kg·hm-2 was the best treatment which increased soil organic matter content, available K, P, alkaline N and total N in 0-40 cm soil layer. Compared with the non-returning treatment, straw returning combined with nitrogen fertilizer 300 kg·hm-2 significantly increased soil water storage by 13.6% and 22.1%, increased maize yield by 31.1% and 46.0 % in 2017 and 2018, respectively. The analysis of yield components showed that the high maize yield was achieved mainly by increasing grain number and the100-grain weight. Curve fitting showed that the optimum amount of nitrogen fertilizer was 260 kg·hm-2. Our results provide important basis for soil fertility improvement and sustainable production.
Assuntos
Fertilizantes , Solo , Agricultura , China , Nitrogênio , Rios , Zea maysRESUMO
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-2) with return of total maize straw (9000 kg·hm-2) 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-2 in middle and late growing period of maize was significantly increased by 10.1% and 9.0%. The enhancement of soil fertility was highest at 300 kg N·hm-2, with significant increases of the contents of soil organic matter, total N, alkali-hydrolyzable-N, available P, and available K by 12.8%, 31.6%, 11.6%, 20.6% and 74.2%, respectively. The enhancement of maize grain yield was highest at 300 and 450 kg N·hm-2, with the value being 32.1% and 23.7%, respectively. The net income at 300 and 450 kg·hm-2 N was significantly increased by 31.8% and 16.8%, respectively. Our results showed that straw returning plus proper quantity of N fertilizer could improve soil water and fertilizer status and enhance maize yield and net income in arid area of central Ningxia. The treatment of straw returning with 300 kg·hm-2 N was the best one.
