Studies Of Soil Ecological Effects Under The Different Mulching Measures In Xinyang Maojian Tea Garden

The experiment was conducted to study the effects of different mulching measures on the soil temperature, soil moisture, relative moisture of air, light intensity, wind speed, physical and chemical properties of soil, dynamic changes of microbial biomass of soil, and yield, quality and harvest time of tea in tea experimental garden of Xinyang agricultural science research institute from 2005 to 2007. The main results were as follows:1. Two different mulching patterns significantly improved the soil temperature and moisture in the tested teagarden. Mulching measures, particularly the grass mulching, showed double effects on increasing and decreasing the soil temperature, particularly, in the top soil layer. The soil temperature increased during the low temperature season and decreased during the high temperature season after mulched, moreover, the frequency of high soil temperature effectively reduced, the effects of decreasing temperature of the grass mulching were better than the straw. The annual variation of soil temperature under mulching changed more smoothly than that of the control (CK), so the differences among the soil layers were small.Coverage measures increased not only the infiltration of rainfall but also decreased the evaporation of soil water during the drought season as a result of increasing of soil moisture. Compared with CK, the grass coverage, especially the straw coverage, increased the soil water content. The coverage measurements significantly improved the soil water supply to tea trees during the crucial period, and improved the utilization of the soil water as well.2. The coverage increased the air humidity in the teagarden, decreased the light intensity on the soil's surface, and had almost no influence on the wind speed in the teagarden.3. The mulching treatments effectively increased the total soil porosity of 0-60 cm soil layer, reduced the soil specific gravity, and increased the percentage of soil physical sand grain. The coverage improved the soil holding water and the water of soil pore, and finally increased the utilization efficiency of the soil water. The grass mulching was much better than that of the straw coverage.4. Compared to CK, the soil organic matter content under the straw and grass coverage increased 17.1% and 12.9% respectively, and as well as the total N, P, and K of the covered soil increased. The soil specific gravity decreased and the amount of soil round grain increased after the long-term coverage, as a result the coverage measurements improved the soil property and enhanced the soil fertility.5. The content of soil microbial biomass of C, P, and K after two years' mulching was higher than that of the control, and showed a dynamic changes and correlation to the seasons' temperature. The results indicated that the straw and grass mulching increased the number and activity of the soil microorganisms, which could enhance the cycle and conversion of soil C, N, P, and the utilization efficiency of soil minerals.6. The yield of the tea under the two mulching measures of straw and grass increased by 32.3% and 33.6% compared to CK. The content of amino acid and water extractions was higher than that of CK, but the content of tea polyphenols and aminophenols was relatively lower. It suggested that the mulching could improve tea quality and yield. The mulching also promoted the harvest time of tea probably due to its effect on improving the soil temperature in early spring and the promotion of early growth of tea trees.