Effect of burial depth on decomposition characteristics of sheared tea tree parts

【Objective】To explore the effect of burial depth on the decomposition and nutrient release of the sheared tea tree parts, so as to provide scientific basis for turning the sheared tea tree parts tofertilizer.【Method】Three burial depths were set, including:surface cover(T1), burial 10 cm(T2) and burial 20 cm(T3). By using nylon mesh bags method in the basin, a decomposing test was conducted to evaluate different buried depth on the decomposing rate of the sheared tea tree parts and nutrient return characteristics annually.【Result】When buried at 20 cm, stem rot the fastest, and the annual rot rate was 45.99%. When buried at 10 cm, leaf and stem decomposed the fastest, and the annual decomposition rates were 58.79% and 51.89%, respectively. After the annual decomposition, the nutrient enrichment coefficient of stem and leaf was significantly different, and the nutrient enrichment coefficient of leaf mixed with stem and leaf showed the same trend of change. Under surface cover treatment, the enrichment coefficient of nitrogen and phosphorus in stem increased to 1.46 and 1.36, respectively, and the enrichment coefficient of potassium in leaf decreased to 0.64. When buried at 10 cm, the enrichment coefficient of potassiumin stem decreased to 0.23, that of phosphorusin leaf increased to 1.41, that of carbon and nitrogen decreased to 0.81 and 0.80, and that of kalium was only 0.22. When buried at 20 cm burial, the enrichment coefficient of nitrogen in stem increased to 1.30, potassium decreased to 0.27, and the enrichment coefficient of carbon, nitrogen and potassium in leaves decreased to 0.77, 0.88 and 0.24, respectively. In terms of nutrient release rates, the carbon and nitrogen release rates of leaves were 66.7% and 67.1%, respectively, significantly higher than those of stems when buried at 10 cm(P<0.05, the same below). When buried at 20 cm, the phosphorus release rate of stem was 50.7%, which was higher than that of leaf(48.6%). The nutrient release rate of potassium was greatly affected by the returning method. The potassium release rate of leaves buried 10 cm was 90.6%, which was significantly higher than 62.5% under surface mulching.【Conclusion】Deep burial can promote the decomposition of prunedstems and leaves of tea tree, and the decomposition rate of leaves is higher. Deeper burial could increase the release of carbon, nitrogen, phosphorus and potassium, among which there lease of potassium was the fastest and the release of nitrogen and phosphorus was slow. In the process of production, prunedstems and leaves of tea tree can be mixed and buried as deep as 10-20 cm for improving the soil quality of tea garden.