Effects of straw management and nitrogen application on spring maize yield,dry matter and nitrogen accumulation and transfer

【Objectives】Nitrogen application and total straw incorporation affect spring maize yield, dry matter and nitrogen accumulation and transfer. The proper combination mode of N and straw returning was studied in this paper.【Methods】A two factors field experiment was conducted consecutively for two years in Tieling City, Liaoning Province. Two straw incorporation modes(rotary tillage and moldboard plow tillage) and five nitrogen application levels were designed. Spring maize yield, dry matter and nitrogen accumulation and transfer were analyzed.【Results】Compared with the moldboard plow tillage of straw incorporation, the dry matter, N accumulation were increased in the rotary tillage straw incorporation treatment, while there was no difference in the yield and grain nitrogen accumulation under the two straw incorporation treatments. The accumulation and contribution of dry matter and N to grain efficiency were increased in the rotary tillage straw incorporation treatment. The dry matter and N transfer, dry matter and N transfer efficiency were increased in the moldboard plow tillage straw incorporation treatment, and the contribution of dry matter and N transfer to grain efficiency pre-anthesis were 12.4% and 44.1%. With the increase of N application rate, the yield, grain nitrogen accumulation, dry matter and N accumulation were increased. No significant increase in yield and grain nitrogen accumulation was found when the nitrogen application rate was higher than 262.5 kg/hm~2. The highest dry matter and N transfer, dry matter and N transfer efficiency were obtained in the nitrogen application rate of 262.5 kg/hm~2,and the contribution of dry matter and N transfer to grain efficiency were 16.7% and 45.2%, respectively.【Conclusions】In this study, the two straw incorporation modes had similar yield and grain nitrogen accumulation, but the rotary tillage straw incorporation treatment could reduce the cost of soil tillage and greatly improve economic benefit, and the straw incorporation with nitrogen application rate of 262.5 kg/hm~2 was the optimal mode.