Characterization of soil enzyme activities and physicochemical characteristics of tea soil under waterlogging

Abstract

Understanding of soil properties to maintain the soil health and crop productivity in agricultural ecosystem is vital. As a consequence, soil type and its related chemical and biological characters are being evaluated to determine the quality of soil. In this study, soil properties in tea monocropping areas were evaluated for 21 tea gardens under waterlogged condition from North Bank (NB), South Bank (SB) of the Assam and Dooars region of West Bengal (WB). A total of 260 samples from 21 tea gardens were collected for three season including pre-rainy (January-May), rainy (June-September) and post-rainy (October-December) and evaluated for different chemical and biological activities. It was found that the NB soil type was sandy to silty loam with an average age of 43 to 80 years while the SB soil type was loam to silty loam with an average age of 50 to 70 years. The soil underlying tea gardens in WB was sandy loam to heavy soil with sandy patches and the age of cultivation was above 70 years. The soils of all the tea gardens were riiildly acidic (pH values from 3.6 to 5.9). The moisture content, soil respiration and temperature of the soils in each of the gardens showed significant variation. A mixed clustering was obtained for the tea gardens with much variation during pre-and post rainy based on studied soil parameters. It was also found that there was a significant correlation during the post-rainy seasons for enzyme activities including urease, phosphatase and dehydrogenase (P less than 0.05), respectively. During pre-rainy, six principal factors influence the soil characteristics with a variance level of 49.26%. During rainy, principal factors urease and phosphatase showed negative effects over the other soil factors whereas in post-rainy pH was the significant principal factor followed by urease, moisture and temperature at the variance level of 25.97%. From the observation it could be concluded that the variations in soil physical, chemical and biological properties were observed among soils from tea gardens of Assam and WB. These variations in soil characteristics under waterlogged conditions were due to variation in the soil texture, management practice. The present finding will help in improvement of tea production by establishing correlation with soil characters.