Effect of different green manure application on soil fertility

There are many winter fallow fields in south of China, which can be used to plant green manure crops. Returning the green manure to farmland has been practiced for the agricultural sustainable development. This experiment was carried out to study the effect of turning over Common vetch (Vicia sativa L.), Chinese trumpet creeper (Vicia villosa Roth. Var.) and Lathyrus quinquenervius (Lathyrus palustris l. Var. Pilosus ledeb) on the dynamic of soil physical and chemical properties. The green manure was plowed over in the dry land, then the soil sample was collected periodically. The soil pH, organic carbon, total N, nitrate N, ammonium N, available P, available K were detected. The results showed that compared to control soil, the soil pH in the treatments with green manure in the first 25 days was higher than control soils while lower during other days; Organic carbon increased by 1.6%6.2%; Mineral N was increased significantly; Ammonium N was the dominate form between 020 days, but nitrate N became the dominate form between 3070 days. The available P content was also increased by 11.9%37.7%. The soil available K was increased 1.5 times with the application of green manure. The influence of these three kinds of green manures was not consistent on the soil, the organic carbon and mineral nitrogen content was highest in the soil treated with lathyrus quinquenervius, while the highest soil available potassium and available phosphorus were observed in the treatment with common vetch. Under this experiment condition, plowing down the three kinds of green manure application on soil could change soil pH, increase soil nitrate N and available K content, slightly increase organic carbon and available P content.