Effective levels of compost for improvement of green leaf production of tea in mid country wet zone

Abstract

Higher productivity and profitability of Sri Lankan tea industry can only come from a combination of strategies; conservation of soil from degradation and restoration of soil fertility are some of the major strategies practiced in order to increase the tea production. Application of compost with the chemical fertilizer helps to improve the chemical, physical and biological properties of soil. This investigation was undertaken to study the effective levels of compost for improvement of green leaf production of tea in Mid Country Wet Zone.

Compost produced from the Inclined Step Grade (lSG) system developed by the University of Peradeniya was used in eight treatment combinations. Three sites at the JEDB Estate, Hantana, were selected as three blocks, with two replicates. Treatment combinations were viz Tl-recomended chemical fertilizer only (I), T2-compost 2 t/ha + I, T3-compost 4 t/ha + I, T4-compost 6 t/ha + I, T5-compost Stlha + I, T6-compost 10 t/ha + I, T7-compost 12 t/ha + I, T8-compost only (70 t/ha). Supplementary nutrients were provided based on the recommendation except in T8. Green leaf yield was taken at weekly intervals and soil samplings were done at 3ʳᵈ 4ᵗʰ 6ᵗʰ and 8ᵗʰ weeks after compost application. Soil samples were analyzed for organic matter, total N, pH, available P, exchangeable K, Ca, Mg and biomass N.

Results showed that, increment of rates of compost increased soil organic matter, total N, available P, exchangeable K, Ca and biomass N. Treatment effect on yield was not significantly different Yield response was not clearly showed as data was collected only for two months. At the end of two months T7 treatment-having 12 t/ha + I had higher amount of exchangeable K, Ca, Mg, biomass N than other treatments, except compost only treatment. From the results, use of 12t compost + chemical fertilizers appeared to be beneficial as an effective combination for tea in Mid Country Wet Zone. For better understanding of yield response, experiments should be carried out in long-term.