Abstract:

Evaluating the regional differences of basic soil fertility and clarifying the impact of soil fertility on crop yield are of great importance to improving farmland soil fertility and optimizing nutrient management. In this study, 967 groups of ‘3414’ summer maize field trials, which were conducted in the piedmont and low plains of central and southern Hebei Province from 2005 to 2013, were used to analyze the impact of the difference in basic soil fertility on summer maize yield. The results showed that the soil organic matter, total nitrogen and available phosphorus in the piedmont plain of central and southern Hebei were higher than those in the low plain, and the available potassium content was slightly lower. The basic maize yield for piedmont and low plains were 6133 kg/hm² and 5815 kg/hm², respectively, and the soil fertility contribution rates were 71.2% and 69.0%, respectively. The minimum values of soil organic matter, total nitrogen, available phosphorus and available potassium that could support high yield in the piedmont plain without fertilization were 14.9 g/kg, 1.07 g/kg, 19.1 mg/kg and 127 mg/kg, respectively, and those in low plain were 16.0 g/kg, 0.76 g/kg, 18.8 mg/kg and 106 mg/kg, respectively. The main fertility factors affecting the basic maize yield in the piedmont plain were the soil available potassium content and available phosphorus content, with the influence degree of 38.6% and 24.8%, respectively; the main factors affecting the basic maize yield in the low plain were the soil organic matter content and available phosphorus content, with the influence degree of 45.0% and 32.2%, respectively. The study suggests that the soil fertility improvement in piedmont plain should focus on stabilizing and increasing soil available potassium and available phosphorus contents, while low plain areas should focus on increasing soil organic matter and available phosphorus contents.

Key words: soil basic fertility, soil fertility improvement, boundary line analysis, central and southern Hebei Plain, summer maize