Soil fertility in tea plantations in different slope positions and elevation regions

The southern low mountain and hilly areas are the largest tea plantation regions in China. Soil fertility studies are therefore fundamental for improving soil nutrient status; implementation of safe, high and effective production; and sustainability of tea plantations. Hence soil fertility study on a representative tea plantation in western Sichuan was conducted through field investigation, transect sampling and experimental analysis. The principal component analysis (PCA) and multivariate statistical analysis were used to compare soil quality under different land-use types (QI, fertility index based on land-use type) and slope positions(PI, fertility index based on slope position). The study shows that in tea plantation soil, grit accounts for 39.13%, followed by clay and then silt. Average soil pH is lower than 4.5, which is the standard for soils in high quality tea plantations. The soils are rich in available N, but low in soil organic matter, total N and available P. There is insignificant change in available K. Soil particle content and available nutrient have no consistent changing pattern compared with those in waste lands and forestlands. Organic matter and total N in soils under tea plantations are lower than those under waste land and forestland, except for waste lands on low slopes. The quality of soil fertility in tea plantations changes drastically with slope position. PI is -13.64% for middle slope position, 0 for upper slope positions and 14.39% for lower slope positions (taking the zenith as datum).QI in tea plantations is lowest compared with waste lands and forestlands. For tea plantations, waste lands and forestlands QI is 0.56, 1.11 and 2.73 respectively.