| Pollution-free fruit production has been a trend in fruit tree industry all over the world. As an excellent soil management system, green cover in orchard has been developed to be a main technical system in developed countries. At present, conventional clean tillage is the main method in soil management in our country, and the area of clean tillage account for over 90% of the total area of orchard. Additionally, the green cover technology in orchard is still being in the test period and has been applied only in the small area in our country. Basically, studies on green cover are mainly productive experiment and contrast test, so no enough attention has been paid to the mechanism and systematic research. Furthermore, current studies are mostly held in orange , pear and longan orchard in south China , and less of them were taken in the Loess Plateau, In Weibei Plateau, this kind of study is even fewer. In this dissertation, apple orchards in Weibei area are taken as test area, field test integrated with laboratory analysis is adopt for the characteristics of microclimate, soil manure and soil moisture . Subsequently, the eco-environmental effect and its mechanism of green cover in apple orchard are analyzed including the effect of green cover pattern on apple tree growth, apple yield and quality. With the analysis about productive auxiliary energy flow characteristics of"fruit-forage grass-livestock-marsh gas pool-cellar", integrated technical system of"fruit-forage grass-livestock-marsh gas-cellar"is established. Meanwhile, according to existed problems of green cover in the apple orchard in Weibei arid area, the integrated technology system of green cover in apple orchard is constructed in Weibei arid area.The main results are as follows:1. The microclimate characteristics of apple orchard with green cover in Weibei area has been ascertained. The results show that green grass regulates the surface temperature, humidity, ralitive light intensity, wind speed as well as soil temperature. In different developmental stages, the regulation effects of forage grass are also different. Furthermore, the regulation effects are closely related to the types of grasses. The result of Grey Correlation Analysis shows that the micro-climate effect of the white clover is better than the ryegrass does.2. Revealed the effects of green cover on water, soil and fertilizer of apple orchard in Weibei. Subsequently the interactive features of grass with soil, water, fertilizer as well as their evolution mechanism are illustrated. (1) Green cover in apple orchard improves a series of the soil physical and chemical properties. For example, green cover reduces the soil bulk density, and increases the soil porosity, the soil organic matter content and water-stable aggregate content. With the progress of growing herbage years, the effects are more and more obvious, and the effects are observed within 40 cm soil layer. Green cover in apple orchard also has positive effects on available N, available P, and available K. With the progress of growing herbage years, the content of available Mn,available Fe,available Zn and water-soluble Ca, water-soluble Mg trend to increase. Green cover greatly increased the amount of bacteria, actinomycetes and fungi, also strengthened the soil enzyme activity. (2)The correlation analysis showed that: the accumulation of soil organic matter was the core of promoting the sustainable development of soil fertility in non-irrigation apple orchard. The results of principal component analysis and evaluation on soil synthetical fertility showed that: soil synthetical fertility was increased with the progress of growing herbage years. Long-term growing herbage was favorable for soil fertility. White clover had better effects than ryegrass. (3) Green grass increases soil water storage capacity and soil reservoir. With the progress of growing herbage years, soil water storage, retained water capacity and saturated water capacity trended to increase. White clover had better effects than ryegrass. Soil infiltration capability was significantly improved with green cover in apple orchard, and the soil water infiltration process of non-irrigated apple orchard in Weibei could be better reflected by the equation. But there was water competition between apple trees and herbages in non-irrigation orchard, it mainly occured in 0-40 cm soil layers, and mainly reflected at herbage tillering stage in spring and fall, it was especially obvious in the drought year. A binary optimized model of"Green cove in the inter-row orchard + mulching in the clear tillage belt"was advanced according to the characteristic of soil moisture.3. Clarified the growth of apple trees, the yield and quality of the fruits in orchards with green cover . According to the statistical analysis, it shows that:①green cover improved the leaf weight, the number of middle-short branches, abloom rate and fruit set percentage of apple trees. With the progress of growing herbage years, these characters increases accordingly and the white clover has more obvious effect.②green cover promotes the root development of apple trees when the root diameter classes is less than 2 mm. Also it promotes the root extend to a deep layer of soil, especially in the layer of 20-60 cm.③green cover improves the nutrition of the apple trees, and N, P, K, Ca, Mg, Fe, Mn, Zn content of leaves was increased separately. Meanwhile, along with the progress of growing herbage years, nutrient contents changed a liitle except for the N content of white clover leaf, the P content of ryegrass leaf.④green cover increases the chlorophyll content, improves the photosynthesis and leaf water use efficiency;⑤green cover improves the quality of the fruit, and with the progress of growing herbage years, fruit quality improves significantly. Different grass has different improvements.4. Quantitatively analyzed the yield and quality characteristics of apple trees during the epitaxial grass growth and development area, as well as the characteristics of support to the production flow in the"fruit-forage grass-livestock-marsh gas pool-cellar"apple orchard system. Revealed the operational mechanism of this kind of apple orchard system. All these theories can provide us a basis to increase the comprehensive benefits of green cover in orchards, and a methodology of the optimal adjustment to this model. Result shows that: epitaxial use of green cover in orchards system improves the growth of apple trees as well as the fruit yield and quality; the composition, distribution and flow of productive auxiliary energy change a lot. In apple subsystem organic energy increased considerably while industrial auxiliary energy decreased by 26.69 percent. Meanwhile, the input of chemical fertilizers and pesticides is reduced. Energy-flow-cycle index of epitaxial use of green cover in orchards is 2.46 times of the apple subsystem, while, economic output is 1.94 times of the green cover in orchard.5. Based on systematic investigation and study, according to existed problems of green cover in the apple orchard in Weibei arid area, the integrated technology system of green cover in apple orchard is constructed in Weibei arid area. The integrated green cover technology system of apple orchard in Weibei include: how to choose green cover area, grass species, and agronomic technical measures, etc... Based on the effect of deep soil reservoir, the suitable areas for green cover in non-irrigated apple orchard should be the areas with more than 550 mm annual precipitation according to a typical investigation. Overall, some new concepts, principles and methodology have been achieved and illustrated when the study of eco-environmental effect & integrated technical system of green cover in apple orchard is conducted. Due to the author's limited knowledge, deficiencies in the text are inevitable. Your correction and suggestion will be appreciated sincerely.
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