| A field experiment was conducted to study the effects of straw mulching and interplanting on soil temperature, water, physical and chemical properties, microbe quantity and growth of Camellia Oleifera young forest, it indicated as below:Covering has significant regulation on soil temperature. Covering straw has temperature-increasing effect in low temperature season, the average soil temperature is 0.1-1.01℃higher than no covering in 10 cm soil layer; Covering straw has temperature-decreasing effect in high temperature season, the average soil temperature is 0.26-4.12℃lower than no covering in 10 cm soil layer; interplanting peanut and sweet potato is decreased by 17.60% and 12.44% in comparison with no interplanting in high temperature season.Covering straw could increase the soil water content of Camellia Oleifera forest land especially during the drought and less rain period from July to September in south, and had very significant moisture conservation effect. The soil water content of D treatment (7500kg/hm2 straw cover amount) is 17.59%,126.4% of control. However, the effect of interplanting was quite the contrary, as a lot of water was depleted in the growth of peanut and sweet potato, and soil agglomerate structure was destroied by fruit growth, and soil erosion was accelerated. So the water content of each soil layer from 0 to 40cm with interplanting were all lower than control.Covering has some influence on the soil physical and chemical properties of Camellia Oleifera forest land. The soil nutrient content is significant high than control when the straw cover amount reaches some values. The nutrient contents of D treatment's (7500kg/hm2 straw cover amount) each index are highest; the content of soil organic matter, total nitrogen and P, available nitrogen, P and K in the 0-40cm soil layer increases respectively by 62.99%,67.23%,39.56%,66.07mg/kg, 4.34mg/kg and 33.35mg/kg in comparison with control.With interplanting sweet potato the content of soil organic matter, total nitrogen and P, available nitrogen, P and K in the 0-40cm soil layer increases respectively by 88.88%,185.43%,20.05%, 138.60%,458.56% and 41.02% in comparison with control. After covering straw the soil physical and chemical properties were improved, and the soil bulk density decreased, and the soil porosity increased. But interplanting destroyed the soil agglomerate structure and increased the soil bulk density; with interplanting sweet potato the soil bulk density in the 0-10cm and 10-20cm soil layer increased respectively by 0.02g/cm3 and 0.04g/cm3.Covering provides ample energy and carbon source for soil microorganism activity and propagation, and it increases the microorganism number, and enhances the microorganism activity. In comparison with control, the mumber of bacteria, fungi and actinomycetes of D treatment increased 402.82%,119.53% and 144.52% respectively in the 0-20cm soil layer, and 1102.08%,80.18%and 38.39% respectively of interplanting peanut, and 748.80%,1.90% and 26.50% of interplanting sweet potato.Covering has improved the growth of young forest. After one year's tracing observation, straw could improve the fresh treetop and tree height, and it's effects was more obvious with the increase of straw cover amount, and the effects comparison of all treatments was D>C>B>A>E>CK1. The length of spring, summer and autumn shoots of D treatment was 12.63cm,28.52cm and 22.38cm respectively,130.6%,144.8% and 125.7% of control;and tree height reached 1.71m, whose increasing range was 44.25%. Interplanting could not only improve the fresh treetop and tree height, it could also fully reasonable utilizate the land resources, to improve the land utilization ratio, and gain extra benefits. The length of spring, summer and autumn shoots and tree height respectively increased 34.02%,15.18%, 17.29%and 30.50% with interplanting peanut, and the length of summer and autumn shoots and tree height respectively increased 27.51%,6.84% and 32.93% with interplanting sweet potato. The net income of interplanting peanut and sweet potato respectively increased 706.1 yuan/667m2 and 686.5 yuan/667m2.The content of soil water, soil organic matter, total nitrogen and P, available nitrogen, P and K, the mumber of bacteria, the length of fresh treetop, and tree height net growth were selected as determination standard respectively, and the comprehensive scores of neight treatments in the 0-20cm soil layer were obtained through principal component analysis.The result is as below:covering straw and interplanting could both improve the soil physical and chemical properties of forest land and the growth of young forest;the D treatment (7500kg/hm2 straw cover amount) have the best effect in covering straw experiment, and interplanting sweet potato have the best effect in interplanting experiment; by comparing the D treatment and interplanting sweet potato,the latter is the best Mulching Methods on Camellia Oleifera forest land.
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