Analysis of nutrient and microbial Biolog function diversity in teasoils with different planting years in Fujian Anxi

Premature aging and degradation of tea gardens have been critical issues limiting the economic development of tea industry. Nutrient and microbial diversity in tea garden soils with different planting years were studied. The study was based on pH and fertility indexes of tea producing environmental conditions (NY/T8 53-2004). Soil pH of 1-year-old tea was 4.73, which was at grade Ⅱ level. Also soil pH of 6-year-old tea was 4.41, close to grade Ⅱ. Both these grades conformed to acid-base indicators for high quality tea garden soils. The soil pH of 20-year-old tea was 4.15 (less than 4.5 but close to 4.0) and therefore identified as acidic. Organic matter, available N (nitrogen) and available P (phosphorus) in the 6-year-old tea soil were respectively at fertility gradeⅠlevel. That of available K (potassium) was at grade Ⅲ level. Available P was abundant in the 1-year-old tea soil, which was at gradeⅠlevel. While available N was at grade Ⅱ, organic matter and available K were at grade Ⅲ level. In the 20-year-old tea soil, organic matter reached grade Ⅱ and available N, P and K reached grade Ⅲ. While the 6-year-old tea soil fertility was the best, 1-year-old tea soil fertility was medium and then the 20-year-old tea soil fertility was the worst. Biolog analysis showed that the ability of microbial flora to use six kinds of carbon sources was highest in the 6-year-old tea soil. It was lowest in the 20-year-old tea soil. Microbial utilization of six kinds of carbon sources in the 1-year-old tea soil was moderate. Community diversity indexes analysis showed that the Shannon index, Brillouin index, homogeneity index and richness index of the 6-year-old tea soil were the highest. These indexes were worst in the 20-year-old tea soil. Compared with the 6- and 1-year-old tea soils, the 20-year-old tea soil presented the strongest acidification. Organic matter in the 20-year-old tea soil was 47.81% less than that in the 6-year-old tea soil. Physiological activity of the 20-year-old tea soil microbes was the lowest, which limited physical diversity functions.