FERTILITY DYNAMICS OF THREE TYPES OF TEA GARDEN SOILS IN WESTERN SICHUAN, CHINA

Understanding the seasonal dynamics of soil fertility is a key to providing decision support for rational use of fertilizers in tea gardens. in this study, seasonal variation in fertility parameters and the comprehensive fertility of 3 types of tea garden soils in western sichuan, china, were investigated using a field survey and laboratory analysis. the results showed that ph, available phosphorus (ap), and available potassium (ak) in yellow earth remained low regardless of season; the lowest levels (among all soils) of total organic carbon (toc) and total nitrogen (tn) occurred in yellow earth during spring and summer. higher toc, tn, and ap content occurred in spring due to basal fertilizer application; toc was lower in summer due to higher decomposition rates and extensive soil erosion; lower tn and ap contents in summer were attributed to absorption by tea plants and to soil erosion; higher toc and tn in autumn occurred as litter returned to the soil. seasonal variation in ak was less obvious than that of the other fertility parameters. the comprehensive fertility of tea garden soils, ranked in order from higher to lower by season and soil type, was as follows: spring > autumn > summer for bleached paddy soil and yellow earth; but spring > summer > autumn for acid purple soil. among the 3 tea garden soils, the fertility of acid purple soil was highest, and that of yellow earth was lowest in every season. fertility was highest in spring for all soils. these results can provide a theoretical basis for scientific management of tea plantations in western sichuan and similar regions.