Changes in soil fertility parameters and the environmental effects in a rapidly developing region of China

An extensive knowledge of the temporal variability of soil fertility parameters and how this variation affects the environment is imperative to a wide range of disciplines within agricultural science for optimal crop production and ecosystem preservation. This paper examines the temporal variability of soil pH, organic matter (CM), cation exchange capacity (CEC), total nitrogen (TN), total phosphorus (TP), available phosphorus (P-AV), and available potassium (K-AV) on Cambosols (Entisols) (n = 179) and Anthrosols (Inceptisols) (n = 95) in Zhangjiagang County, China from 1980 to 2004. Nutrient input was monitored from 1983 to 2004. Annual N fertilizer rates were significantly different during three periods (1983-1989, 1989-1999, 1999-2004), where annual rates increased significantly after 1989 and then decreased after 1999. Annual P fertilizer rates were significantly different during two periods (19831993, 1993-2004) where annual rates increased after 1993. No change was found in K fertilizer rates. Soil pH marginally increased by 0.14 units in Cambosols, but significantly decreased by 1.02 units in Anthrosols. CM, CEC, and TN increased in both soil orders an average of 2.15 g kg(-1), 1.6 cmol kg(-1), and 0.21 g kg(-1), respectively. TP decreased in Anthrosols by 70 mg kg(-1), P-AV increased in Cambosols by 4.83 mg kg(-1), and K-AV decreased in Cambosols by 15 mg kg(-1). Fertilizer input rates are causing nutrient imbalances, contributing to acidification in Anthrosols, and decreasing C/N ratios. Nutrient loading of N and deficiency of K is also a potential problem in the area. Efforts should be made to readjust soil nutrient inputs to reach an optimal, sustainable level. (C) 2008 Elsevier B.V. All rights reserved.