EFFECTS OF THE SURFACE CRACKS CAUSED BY COAL MINING ON SOIL CHARACTERISTICS AND WHEAT GROWTH IN HUANG-HUAI-HAI PLAIN, CHINA.

Coal has provided a great proportion of energy supply for the country. However, coal mining has caused lots of ecological and environmental problems. In this study, a field investigation experiment was conducted in subsided area of Zhaogu coal mine of Jiaozuo Coal Group, Henan Province, China, to explore effect of surface cracks caused by coal mining on the soil characteristics and crop growth. The results showed that during the jointing stage of wheat, the ranges within which the larger crack (C-1) and smaller crack (C-2) caused the effects on both soil water content and soil respiration were 0-60 cm and 0-30 cm from the cracks, respectively. C-1 significantly reduced the activities of soil urease and invertase within 0-60 cm from the crack but C-2 did not cause significant inhibition on soil enzymes. During the flowing stage of wheat, C-1 and C-2 significantly reduced soil water content, available nitrogen content and soil respiration within 0-60 cm and 0-30 cm from the cracks, respectively. The range within which C- 1 caused inhibition on urease activity was 0-60 cm while such range for C-2 was 0-30 cm from the crack. The ranges within which both C-1 and C-2 caused significant inhibition on invertase activity were 0-60 cm from the cracks. C-1 and C-2 caused significant inhibition on photosynthesis of wheat within 0-60 cm and 0-30cm from the cracks, respectively. C-1 and C2 significantly reduced spike number and grain yield within 0-90 and 0-60 cm from the cracks, respectively. In conclusion, surface cracks resulted in loss of water and nutrients and reduction in crop yield, which is more serious with lager cracks. Therefore, further studies are needed to address this problem and to find effective measures to resolve it. [ABSTRACT FROM AUTHOR]