Analysis on basic soil productivity change of winter wheat in fluvo-aquic soil under long-term fertilization

Abstract: Fluvo-aquic soil areas are important grain production areas in China. With the population increasing and the economy developing, China is facing the big challenge to increase grain yield and ensure food security. Because the use of fertilizer has reached a high level, increasing fertilizer application is no longer an effective way to increase production. The results of many long-term soil fertility experiments show that the basic soil productivity (BSP) change was important to reduce fertilizer application rates and increase crop yield. Thus, studying the change characteristics of BSP in fluvo-aquic soil areas has theoretical and practical significance to guide the proper oriented soil fertility cultivation to meet the national demand for the grain increase.This paper analyzed the trends and influencing factors of BSP in winter wheat seasons under different long-term fertilization processes based on National Soil Fertility and Fertilizer Effects Long-term Monitoring Experiments, in order to provide a scientific basis to strengthen the oriented soil fertility cultivation in fluvo-aquic soil areas of China. The research was based on an 18-year field experiment on fluvo-aquic soil in Zhengzhou City, Henan Province. Five fertilization treatments were set up in the experiment, including CK (no fertilizer), NPK (single inorganic fertilizer), NPKM (organic fertilizer and inorganic fertilizer), 1.5 NPKM (organic fertilizer and inorganic fertilizer, the count was 1.5 times of NPKM), and NPKS (straw and inorganic fertilizer). The yields based on BSP were simulated by using the DSSAT (decision support system for agro-technology transfer) model. First, we input the parameters of soil, weather and field management into the DSSAT model, then modified and calibrated the crop variety parameters based on the measured yield; after that, we set up the fertilization opinion in the model to get the BSP yield. The contribution percentage of BSP to yield was calculated by the BSP yield and measured yield. The influencing factor was identified by analyzing the relationship between the contribution of BSP to yield and soil nutrient contents. The yields based on BSP of NPK, NPKM, 1.5NPKM, and NPKS treatments increased gradually with time. The yields based on BSP increased by 721, 1033, 2108 and 1306 kg.hm-2 after the 18-year fertilization management, respectively, with increasing rates of 29.6%, 42.4%, 86.6% and 53.7%, and average annual increasing rates of 1.6%, 2.4%, 4.8% and 3.0%, respectively. The average yields based on BSP were 2711.7, 3186.3, 3704.7 and 3053.6kg.hm-2, respectively. The treatment of 1.5 NPKM achieved the highest yield based on BSP, suggesting that it was the most effective measure to increase the BSP of winter wheat. The contribution percentage of BSP to yield ranged from 36.5% to 70.9% during 1991-2008, and the average contribution percentage of BSP to yield was 42.5%, 59.9%, 58.9% and 52.5% , respectively, following the order of NPKM > 1.5 NPKM > NPKS > NPK. This indicated that compared with the application of single chemical fertilizer, organic fertilizer or straw residue combined with inorganic fertilizers can increase the yield and more effectively increase the contribution percentage of BSP to yield of winter wheat in fluvo-aquic soil. The contribution percentage of BSP to yield was significantly correlated with soil organic carbon, total nitrogen, available nitrogen, available phosphorus and available potassium contents. However, the correlation between the contribution percentage of BSP to yield and the contents of soil total potassium and total phosphorus did not reach a significant level. Soil organic carbon and total nitrogen contents were the main controls of BSP in the fluvo-aquic soil area.