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In order to investigate the effects environmental factors on characteristics of tea garden soil carbon, nitrogen and phosphorus contents and their ecological stoichiometric, soil samples were collected from the 0 ~ 20 cm soil layers of main tea gardens different with altitudes and planting years in Jiangxi Province, which were used to determine soil SOC, TN and TP contents and calculate stoichiometric ratios. The results show these as follows. The average contents of soil SOC and TN in tea garden were 13. 84 g / kg and 1. 37 g / kg, respectively, which were higher than the average level of national soil and reached the fertility standard of grade-I tea garden. The average content of soil TP was 0. 47 g / kg, which was lower than the average level of national soil and reached the fertility standard of grade-II tea garden. The mean values of soil C∶N, C∶P and N∶P were 10. 97, 32. 61 and 3. 49, respectively, which were lower than the average level of national soil. It showed that soil phosphorus had high availability, while soil nitrogen was relatively deficient. With the increase of altitude, soil SOC content, C∶N, and C∶P showed a trend of first decreasing and then increasing, while soil TN content, TP content, and N∶P showed no obvious change. With the increase of planting years, soil SOC content, TN content and C ∶P all showed an increasing trend. Soil N∶P showed a trend of first increase and then decrease, and soil C∶N showed a trend of first decrease and then increase, while the of soil TP content was not obvious. These results can provide reference for judgment of nutrient-limited elements and scientific management of tea gardens in Jiangxi. It is suggested that nitrogen fertilizer should be appropriately applied to tea gardens to maintain the balance of nitrogen and phosphorus. [ABSTRACT FROM AUTHOR]

In order to explore a new mode of resource utilization of Pueraria root residue, a pilot vermicomposting indoor experiment was carried out using Eisenia fetida for bio-transformation of freshly decomposed Pueraria root residue and fresh Pueraria root residue mixed with cow dung at different ratios. The effect of decomposed Pueraria root residue and the effects of different ratios of Pueraria root residue and cow dung on the growth and reproduction index of earthworm were analyzed. The changes in fertilizing properties of the materials were analyzed before and after vermicomposting, and seed germination was evaluated to determine the effect of vermicomposting. The results showed that fresh Pueraria root residue and decomposed Pueraria root residue alone were not conducive to the growth and reproduction of earthworms. Earthworms were able to grow and reproduce normally in fresh Pueraria root residue mixed with cow dung, which a mixture of 10% fresh Pueraria root residue and 90% cow dung was the most favorable to earthworm reproduction. After earthworm composting, the total organic matter content decreased significantly, the total nutrient content increased significantly, and the seed germination index increased to a certain extent. The total nutrient content of a mixture composed of 70% fresh Pueraria root residue and 30% cow dung was 102.2 g·kg-1 and 57.7% higher than that of a mixture of 10% fresh Pueraria root residue and 90% cow dung. The earthworm bio-treatment technology can be applied to the production of fertilizer from Pueraria root residue. A mixture of 70% fresh Pueraria root residue and 30% cow dung delivers the optimal conditions for earthworm composting. [ABSTRACT FROM AUTHOR]

The degradation of cultivated-layer quality of sloping farmland shows the agro-ecological process of cultivated-layer profile damaged, soil nutrient depletion and the regulation ability of crops-ecological environment declined or even completed loss on the slope scale by the combining effects of nature and human factors. In order to analyze the characteristics of soil degradation and main factors affecting degradation of cultivated layer for slope farmland in southern red soil hilly area, taking the cultivated-layer soil (0-20cm) of red soil from a small watershed as research object, we analyzed the degradation characteristics of cultivated-layer quality by cultivated-layer degradation index (CLDI), identified the dominant factors and main driving factors of cultivated-layer degradation by principal component analysis and regression analysis, analyzed the variation characteristics of soil property parameters of different degradation degrees of cultivated-layer quality, and defined the main obstacle factors and obstacle amount of the cultivated-layer quality by the obstacle factor diagnostic model for red soil sloping farmland. The results showed that the distribution area of cultivated-layer quality was mainly medium and in a mildly degraded level (accounting for 70.4% of the total samples), severely degraded samples was 11.1%, and the samples of non-degraded cultivated-layer accounting for 18.5% in red soil small watershed. The main nature driving factors leading to cultivated-layer quality degradation were rainfall, slope and soil mother material, meanwhile, agricultural input per unit of sloping farmland, tillage measure, total mechanical power per unit of sloping farmland and amount of fertilizer applied per unit of sloping farmland were the main human-driving factors. In comparison with the no degraded soil, the cultivated-layer soil properties parameters in red soil sloping farmland showed characteristics in different degradation degree. The cultivated-layer thickness was gradually thinned. The pH value first decreased significantly and then tended to be stable, and the cultivated layer of degraded level was 9.8%, and lower than that of non-degraded cultivated layer. The thinning rate of severely degraded cultivated layer was 8.9%, compared with that of non-degradation cultivated layer, which was related to the water erosion and farmer’s improper tillage methods in daily farming. The soil clay content and soil shear strength increased gradually with the deterioration of cultivated layer soil. The main obstacles of the cultivated layer quality of red soil sloping farmland with highly soil clay content, lowly pH value, thinning cultivated layer and lowly soil shear strength, and their average obstacle amount were 0.15, 0.14, 0.13 and 0.10, respectively. However, the average obstacle amount of other soil property parameters was relatively low. The obstacle amount of soil clay content, pH value and cultivated layer thickness significantly increased with the degradation degree intensifying. However, the obstacle amount of soil shear strength decreased gradually, and other soil property parameters did not change significantly, which indicated that moderately sub-soiling about 30-48 cm and reasonable fertilization were effective measures to improve the cultivated layer quality of red soil sloping farmland. Our results could provide a theoretical basis and some parameter support to scientifically understand the degradation characteristics of cultivated layer quality, define the effective measures to improve the cultivated-layer quality and construct rational cultivated-layers for red soil sloping farmland. [ABSTRACT FROM AUTHOR]