Maize yield and soil fertility with combined use of compost and inorganic fertilizers on a calcareous soil on the North China Plain.

Excessive N fertilization is a problem in the intensive cropping systems on the North China Plain. Proper N management is essential to maximize N efficiency and sustain agricultural production while minimizing negative impacts on the environment. The aim of the present study was to investigate N dynamics, maize yields and soil fertility in response to short term compost application and straw return vs. inorganic fertilization. A field experiment (2012–2014) was conducted for three years on a calcareous soil in Quzhou county, Heibei province, north China. There were four treatments: unfertilized control (T1), inorganic fertilizer (100% NPK, T2), compost (cattle wastes) + 70% NPK (T3), T3 + wheat straw (T4). No significant differences in biomass accumulation or N uptake among the fertilized treatments were observed across the maize growing season. Compost application for three years tended to increase grain yields particularly in the second and third years, and the average yield increase was approximately 7–15% over T2. Residual N min down the soil profile (1 m) in the compost treatments (T3 and T4) decreased by 50% deeper in the soil (60–100 cm depth) at the maize harvest in 2014. Compared to T2, the compost treatments significantly increased NUE and soil available P and K contents. Correlation analysis indicates that maize yield in 2014 was significantly correlated with soil available P and K and with soil organic carbon (SOC). Overall, straw return did not have a significant influence on any measured parameters in either soil or plant samples. Our results demonstrate that 30% replacement of N fertilizer by compost is an effective nutrient management strategy to maintain N uptake and yield of maize, reduce N loss and also increase soil fertility. A considerable increase in invertase activity in the compost treatments highlights that the critical importance of integrating the management of carbon and nitrogen for sustainable agricultural production in this region of highly intensive production. [ABSTRACT FROM AUTHOR]