Effects of Burning Crop Residues on Soil Quality in Wenshui, Shanxi of China

Abstract

Large amount of crop residues are produced every year in China. Although crop residues are rich in organic matter, nitrogen, phosphorus, potassium, calcium and magnesium, local farmers tend to burn residues in the fields in order to simplify preparation for following cultivations and to enhance the development of economic conditions. Thus, attention has been paid to the effects of crop residues burning on soil environment. The objectives of this study are to observe changes in burning density and to evaluate changes in soil quality caused by burning practices in Wenshui, Shanxi of China. Burning density was analyzed based on the Fire Information for Resource Management System (FIRMS). In addition, onsite experiment on residue burning was conducted in Wenshui and soil samples were collected for evaluating the change of soil quality and soil fauna. It was observed that the burning density in Wenshui of Shanxi in 2009 was much larger at 0.0467 events/km²/year than that in 2001 at 0.00141 events/km²/year. Also, the results of onsite experiment on residue burning conducted in Wenshui indicated that soil surface temperature rose to 415 degrees Celsius resulting in the sudden decrease of microorganism population. In addition, values of electrical conductivity (EC) and pH increased to 219 mS/m and 9.04, respectively. However, there was a slight decrease in soil permeability. Burning crop residues on farmland may accelerate nitrogen loss. Besides, concentration of phosphorous in soil tended to increase with the burning process. Therefore, it was concluded that the burning of residues significantly affects soil ecosystem and its quality.