Comparative and States of Soil Health as Supported By Nature-Based Solutions under Organic and Conventional Tea Lands in Upper Highlands, Sri Lanka

Thalawaththa D.M.R.U.D.B, Ayomi Witharana, Keerthi M Mohotti, Nirmalie Pallewaththa, Deepthi Amarasena, Mrs. jananey.B

Abstract

Conventional approach of tea cultivation using agrochemicals is negatively affecting soil natural fertility. Excessive and unbalanced use of agro-chemicals has led to increased production costs but decline in farm productivity. Organic sources may reduce the dependency on chemical fertilizers. An organic system uses compost, animal manure, green manuring, biofertilizer (liquid fertilizer), tree lopping, and leguminous plants. Organic tea fields use a mulching system using rice straw, weed barrier, and defoliate leaves. Also, use deep drains and rainwater harvesting systems to conserve soil moisture. The sustainable Agriculture network (SAN) promotes the social and environmental sustainability of agricultural activities. A certification body certifies farmers of group administrators that comply with SAN standards and policies. The present study was planned with an overall objective of comparing soil health including soil pH, soil moisture and soil microbial activity under organic, sustainable agriculture standards and conventional systems. The experiment was carried out at smallholder organic tea fields and conventional tea fields in the Upper highlands in Sri Lanka. Minimum and maximum temperatures are 18°C and 34°C respectively. Soil microbial activity is determined by analyzing the amount of CO2 released using Anderson method. Also soil pH was measured using pH meter. The data of biological and chemical parameters of tea soils exposed to organic and conventional practices of tea were analyzed by SAS package. A questionnaire was given to tea farmers in order to gain information on cost for tea cultivation, income status, yield, problems and social satisfaction. The presence and action of all fauna and flora in soils is exhibited as biological activity. Organic tea soil has a significant difference with Natural forests, Pinus, Eucalyptus and vegetable soils. The reason for the lower value of soil biological activity may be due to the reduction of soil organisms as a result of excessive fertilizer applications in conventional fields. Soil moisture retention capacity is influenced by texture, structure, organic matter and soil depth. According to Duncan's Multiple Range Test soil moisture of organic and conventional has a significant difference. Conventional practices in tea cause the lower soil moisture of organic practices and enhance that by ensuring soil health. Organic tea fields use a mulching system using rice straw, weed barrier and defoliate leaves. Also use deep drains and rain water harvesting systems to conserve soil moisture. Both the organic and conventional tea soils are within recommended pH range for tea growth (4.5-5.5). However, long term exposure to organic tea cultivation will result in increased pH which is considered a limitation. The organic lands in Upper highlands are yet in the preliminary stage and would later experience high pH levels. There is an enhancement of biological and chemical properties in organically maintained soils in upper highlands compared to those under conventional practices. Organic soils are in a good range caused by good biological, chemical, cultural, and traditional methods. Organic farmers use environmentally friendly manures and fertilizers to improve their yield.

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