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 those changes affect the environment is imperative to a wide range of disciplines within agricultural science for optimal crop production and ecosystem preservation. This paper examines the spatial and temporal variability of soil pH, organic matter (OM), 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 dramatically after 1989 and then decrease after 1999. Annual P fertilizer rates were significantly different during two periods (1983-1993, 1993-2004) where annual rates increased after 1993. No change was found in K fertilizer rates. Soil pH marginally increased in Cambosols, but dramatically decreased in Anthrosols. OM, CEC, and TN increased in both soil orders. TP decreased in Anthrosols, P_Av increased in Cambosols, and K_Av decreased in Cambosols. 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.