Evaluation of agricultural soil nutrient balance for Yutian County and Lingxian Experimental Area in Huang-Huai-Hai Plain

Nutrient balance of agricultural soil in Yutian County and Lingxian experimental regions of Huang Huai Hai Plain were studied and evaluated The results showed that nitrogen (N) surplus for grain crop regions in Yutian and Lingxian were 202.1 and 189.3 kghm-2a-1, respectively, and its real surplus rates were 64.4% and 71.8%, 69.2 and 94.9 percentage point higher than nitrogen permissible deficit rates Nitrogen permissible deficit rates were -4.8% and -23.1% for Yutian and Lingxian, respectively Nitrogen surpluses in two experimental sites greatly exceeded their rational range, and that will possibly lead to nitrogen loss to environment Phosphorus (P2O5) surplus in Yutian and Lingxian were 58.4 and 88.4 kghm-2a-1, respectively, and its real surplus rates were 57.2% and 84.6%, 46.1 and 146.9 percentage point higher than phosphorus permissible surplus and deficit rate Phosphorus permissible surplus rate in Yutian was 11.1%, while phosphorus permissible deficit rate in Lingxian was -62.3% Therefore, application of phosphate fertilizer in Yutian was basically rational, but in Lingxian phosphate fertilizer was not efficiently used Potassium (K2O) deficit in Yutian and Lingxian were relatively high, and differed greatly, were -50.9 and -115.3 kghm-2a-1,respectively Potassium real deficit rates in two experimental regions were lower than its permissible deficit rate The soil potassium in two experimental sites, especially in Lingxian was deficient for long term, soil potassium supplying power will decrease significantly