| In the mosaic pattern of complex ecosystem system planted, the changes of soil chemical and physical properties have a direct impact on the growth and yield of forage grown on the patches embedded in the forests. So determining the appropriate area of grass patches and taking a scientific management method provide theoretical guidance and technical references for promoting the Grain for Green Project, and stable developmen.Besides, it has a very important significance to promote regional sustainable development. The research was about the measure of 4 different sizes H.compressa patch in the multiple cropping of Hemarthria compressa under 3 different periods. we discussed the physical properties, nutrient content and the treads of H. compressa growth of different size soil from the beginning of forest edge to the center in the compound planting mode of forestry and grass. And this study analyzed economically H.compressa, and the results showed as follows:1 In the same patch, soil nutrients (total N,hydrolysis N,total P,available P,organic matter) content from the forest edge to the center of the grassland patch did not change significantly. From the forest edge to the center, soil total K and available K content had the basic downward trend.By measuring in 3 different periods, in soil nutrients the hydrolysis N,total P,available P,organic matter changed significantly with the seasonal variations.2 In the same patch, from the forest edge to the center, grassland soil bulk was density, and non-capillary porosity had more significant differences. Within the same patch, soil moisture content was the upward trend from 0 to 1.5m from the forest edge to the center, and soil water content increased slightly more than 1.5m away from the forest edge. With fine weather continuing, in the grass patches soil moisture content decreased, but there were differences with the different distance from the forest edge into grassland that it dropped a litter between 0 and 1.5m and decreased greatly more than 1.5m from the forest margin.3 In the 4 different area of patches from the forest edge to the center. There were significantly differences between soil nutrients that soil total N, hydrolysable N, total P, organic matter content appeared in patch 8 (80m2)> patch 4 (150m2)> patch 1 (110m2)> patch 2 (120m2). The main reason for this law is that number 8 patch is small and in the shape of lines, and effected greatly by the distribution pattern around the Pleioblastus, for the other three square patches the larger the size, the higher nutrients content from the forest edge to the center was,but number 2 patches were affected by human activities, the overall nutrient content of soil is lower than other area of patch. Patches of different sizes of soil total K and available K change was not significant. Different soil physical nature had certain changes, but no significant variation.4 In the same patch, physiological characteristics of H. compressa indicated that the net photosynthetic rates of H. compressa showed significant differences in the different distances from the forest edge. According to analyzing that the light response curve of H. compressa show the size of quantum rate, we can get the conclusion that the quantum rate at the forest edge was maximum, indicating that H. compressa was sensitive to low light intensity.5 Patches of different sizes from the forest edge to the center had different net photosynthetic rate. H. compressa of patch 2 and patch 4 reaches the light saturation point in 4m away from the forest edge. According to the test data, in the required multiple cropping of bamboo+ grass patches, from the edge of patch to the center, the minimum distance for the normal growth of H. compressa growth should be at 4m from the forest edge, and in the patch 2 the best minimum distance of H. compressa growth should be at 5m. Meanwhile, with the grass patch size increasing, the bullwhip grass growth height and biomass per unit area have shown an increasing trend.6 In the same patches, H. compressa growth height had significantly correlation, with hydrolytic N content and soil bulk density, had significantly negatively correlation with available K and non-capillary porosity. Among compressa unit area biomass, available K, and non-capillary porosity were tested highly significant negative correlation and showed a significant positive correlation with soil bulk density.7 According to the analysis of H. compressa input and output in different patches at different distances from the forest edge. It is 2.42m for the 2 patches to keep grass growth where the input and output balance, is 1.61m for patch 4, and is 4.15m for patch 8. The minimum suitable for the growth of H. compressa is 23.43 m2 in patch 2,10.37 m2 in patch 4, 68.89 m2 in patch 8. According to the actual value of different patches and the linear regression equation produced from the distance from the forest edge, it could be established that the most suitable areas of plaque growth and maximize economic benefits were 140 m2 of 2 plaque and 144 m2 of patch 4 in the corresponding area.The theoretical area to make the No.8 appropriate was 324 m2, but the actual area of patch 8 was 80 m2.Patch 8 was like the line, and was surrounded by many higher bitter bamboos as well as multi-birch forest, which caused a serious shortage of light in number 8 plague. Therefore number 8 plague was not suitable to continue to grow H. compressa.8 According to the analysis of soil nutrient characteristics in the same patches and plaques of different areas, it was suggested that we shouldn't cut the grass from June to August, but should make grass organic fertilizer by nutrient analysis before spring in order to prevent reduction of soil nutrients, improve nutrient using efficiency and increase forest productivity,... |
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