Corn yields with organic and inorganic amendments under changing climate

We evaluated the productivity and sustainability responses of corn (Zea mays L.) cultivated in brown soil (FAO: Haplic Luvisol) to long-term fertilization (1983–2011) and climate change in Shandong Province, eastern China. The experimental system comprised a crop rotation of winter wheat and summer corn, with a control (CK) and four fertilization treatments consisting of nitrogen (N), phosphorus (P), and potassium (K), and organic manure (M) in various combinations (N, NP, NPK, NPKM). The average corn grain yields in the four fertilization treatments were 1.3–2.3 times greater than that of the control (CK) (P < 0.001). The sustainable yield index (SYI) ranged from 0.5 to 0.8. The four treatments and CK were ranked, from highest SYI to lowest, as follows: NPKM > NPK > NP > CK > N. Corn grain yields in N, NP, and CK significantly increased over time (P < 0.05), but remained relatively high and stable over time in the NPK and NPKM treatments. Soil organic matter content increased over time, and was highest in the NPKM treatment. Soil pH did not change significantly over time (P > 0.05). Bivariate correlation analyses showed that the corn grain yields in CK and the four treatments were significantly positively correlated with mean temperature difference (max–min) during the growth season (P < 0.05). The correlation coefficients were higher for CK, N, and NP than for NPK and NPKM treatments. Corn productivity was more sensitive to climatic changes under long-term imbalanced nutrient application or no fertilizer application.