Effects Of Fruit-crop Ecosystem On Soil Physical And Chemical Characteristics And Soil Enzyme Activities In Northern Anhui

As a sustainable land-use management, fruit-crop ecosystem could not only harvest the fruits and economic crops, which would bring economic benefits for orchard worker. The more important was that had a great promotion on soil quality improvement and sustainable forest management. In order to explore the influence of fruit-crop ecosystem on soil environmental quality and find sustainable fruit-crop compound mode, this research selected several typical fruiter-crop compound model in northern Anhui, which studied the characteristic of soil physical and chemical properties and soil enzyme activities in different model. Hopefully, the results of this research could prove theoretical direction for exploring efficient land utilization type and formulating scientific intercropping system. The main results were as follows:(1) The results showed that significant differences of four soil enzyme activities were appeared between fruiter-crop compound model and the control(p<0.05). The activities of invertase, urease, and protease decreased with the increase of soil layer. However, the activity of catalase increased. Also soil enzyme activities had a seasonal characteristic. The highest activities of sucrase, urease, and protease appeared in summer while catalase was in autumn.(2) The difference of soil physical properties between fruit-crop compound model and the control was significant(p<0.05). Fruit-crop ecosystem could significantly reduce the soil bulk density, improve soil porosity, enhance the formation of soil aggregate structure and promote effective water storage capacity. Compared with the control soil, the model of Malus-Atractylodes and Malus-Cochlearia had improved soil moisture content. The soil moisture of P*B was highest, which was 27.3% higher than CK. It would help reduce water infiltration and improve the utilization of soil moisture. However, since there was niche overlap in the roots among Ginkgo, Punica, Prunus and apple trees, which resulted in the competition for soil moisture, the soil moisture of the other fruit-crop compound model was decreased than the control.(3) Fruit-crop ecosystem had effects on soil nutrient content. The difference of soil nutrient content between the model of Malus-Ginkgo, Malus-Atractylodes, Malus-Cochlearia and the control was significant(p<0.05). The soil organic matter, total N, total organic C, total P, available P and available K decreased with the increase of soil layer. However, total K, total Ca, total Mg increased. Among six models, Malus-Ginkgo mode could effectively increase soil organic matter, total K, Mg, and available nutrients. Malus-Cochlearia mode was remarkable in keeping the balance between soil C and N. Malus-Atractylodes mode could improve the potential to supply P and Ca nutrients in soil. The other compound models were lower in soil nutrient content than CK in the same period. Because there was niche overlap between the roots of Ginkgo, Punica, Prunus and absorbing root of apple tree, resulting in the competition with apple tree for soil nutrient content so that the supply was less than demand. Soil nutrient content also had a seasonal characteristic. The highest soil nutrient content appeared in spring and the lowest was in winter. However, the lowest of soil organic matter and available P were in summer.(4) There was close relationship between the soil physical and chemical factors and soil enzyme activities in fruit-crop compound model. Organic matter, total organic C, total P and total Ca had the direct positive effect on the activity of invertase. So they were dominant factors to affect soil invertase activity in the region. There was a direct positive correlation between organic matter and soil urease activity, so organic matter was the main factor to affect urease activity. Soil total K, mainly through its own direct positive effect to influence the activity of catalase, was an important factor in determining the activity of catalase. Soil total organic C was dominant factor to affect protease activity in the region, which acted directly on the strongest impact of soil protease activity.(5) Principal components from a comprehensive ranking of view, different compound model of soil quality scores were sorted: P*L>P*Y>P*B>CK>P*T>P*S. Compared with the orchard soil of apple tree, the model of Malus-Cochlearia(P*L), Malus-Ginkgo(P*Y) and Malus-Atractylodes(P*B) could improve soil fertility and promote soil quality comprehensive upgrade significant effect. The overall score of Malus-Punica(P*S) and Malus-Prunus(P*T) was below than CK. Since Punica and Prunus competed in terms of soil nutrient with apple tree, which resulted in poor soil quality improvement.