Impact of Oil Field Effluent on Some Physico-Chemical Properties of Soil, Quality and Growth of Tea in the Plantation of Small Growers of Dibrugarh, Assam

Aims: To study the impact of the oil field effluents discharged to the plantation on soil physicochemical, quality and growth of the tea crop.

Study Design: The experimental design was 4x2 Factorial Randomized Block Design with 3 replications.

Place and Duration of Study: It was conducted in Department of Tea Husbandry & Technology, Assam Agricultural University, Jorhat during September, 2019 and November, 2019.

Methodology: The total number of bushes per treatment are 35 each of +12 years age. The soil and plant samples were collected from four different levels of distance are D1: 0-21m; D2: 21-42m; D3: 42-63m and DC: beyond 63m (Control).

Results: The results showed that, disregarding the Flushing season the tea grown in the vicinity of the oil pit recorded the lowest value of caffeine content (1.58%), total chlorophyll (1.54 mg g-1) total polyphenol content (21.47%) which was significantly lower than the tea grown away from the oil pit. The plucking point density and number of primaries per plant recorded the lowest value in the vicinity of the effluent pit. In case of soil physical parameters, both porosity and hydraulic conductivity recorded lowest value of 45.64% and 0.25 cm min-1, respectively. The bulk density of soil near the oil effluent pit recorded the highest value (1.31 Mg m-3) and gradually decreases. Soil pH, organic carbon content and electrical conductivity recorded highest value in the vicinity of the effluent pit. Regardless of the flushing season the available nitrogen and potassium recorded the highest. Available phosphorous of the soil adjacent to the effluent pit recorded the lowest value. Both quality and growth parameters had significantly higher value in the rain flush than the autumn flush. The soil parameters did not record any significant variation among the seasons.

Conclusion: The vicinity area of the effluent pit found to be the most vulnerable.