Assessment of water quantity and quality through soil column under ordinary and neem coated urea application rates
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Date
2022-09
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G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145
Abstract
Nitrogen one of the most important nutrient for agriculture production is usually supplied via application of ordinary and neem coated urea because of its high-water solubility and susceptibility to nitrogen loss through leaching. Its application at the soil surface may affect the infiltration, percolation through soil profile and leaching of nutrients in the soil profile may also deteriorate the ground water quality. Therefore, in the present study an attempt has been made to investigate the effect of application of two application rates i.e. 22 and 44 g/m2 of ordinary and neem coated urea on the infiltration and percolation behavior of soil and percolated water quality through a soil column after 24-hour, 48-hour, and 72-hour of saturation in the laboratory conditions on an experimental set up consisting of cylinder of 60 cm depth and 30 cm diameter with a 15 cm tall conical bottom with 2 cm hole. In total 54 experimental sets were performed having 3 replications of each of 18 treatment combinations of 2 factors time after saturation and applications rates of urea. Percolated water sample was collected after every 15 min to estimate percolated water quantity and quality was determined. The infiltration rates were found to 31.60 cm/h, 29.84 cm/h and 29.40 cm/h for the soil without urea application while the infiltration rate was found 29.26 cm/h, 26.64 cm/h and 21.76 cm/h for soil with application of 22 g/m2 of ordinary urea and 26.80 cm/h, 23.70 cm/h and 18.22 cm/h for soil with application of 22 g/m2 of neem coated urea respectively for 24, 48 and 72 h. The Percent volume reduction in percolation in case of ordinary and neem coated urea with application rate of 22 g/m2 as compared to soil without application of any urea was found 21.36 %, 25.03 % for 24 h after saturation 30.53 %, 34.21 % for 48 h after saturation and 44.44 %, 50.00% for 72h after saturation respectively. Maximum nutrient lost along with percolated water through after 24, 48 and 72h saturated soil column, under 22 g/m2 of ordinary and neem coated urea applications were found as 44.80, 42.56, 40.32 and 41.44, 39.20, 36.96 ppm respectively in case of nitrogen, 3.81, 3.77, 3.75 and 3.67, 3.61, 3.57 ppm respectively in case of phosphorous and for potassium as 7.10, 7.00, 6.70 and 6.40, 6.20, 5.90 ppm. The infiltration rates were determined to be 30.00 cm/h, 29.62 cm/h and 28.84 cm/h for the soil without application of urea while the infiltration rate was found 28.80 cm/h, 26.40 cm/h and 20.28 cm/h for soil with application of 44 g/m2 ordinary urea and 24.90 cm/h, 19.50 cm/h and 17.40 cm/h for soil with application of 44 g/m2 neem coated urea respectively for 24, 48 and 72 h. Application of ordinary and neem coated urea with application rate of 44 g/m2 as compared to soil without application of any urea were resulted in the percent volume reduction in percolation were found to be 28.33 %, 36.11 % for 24 h after saturation, 52.78 %, 61.11 % for 48 h after saturation and 54.29 %, 57.14 % for 72h after saturation respectively. Maximum nutrient lost along with percolated water through after 24, 48 and 72 h saturated soil column, under 44 g/m2 of ordinary and neem coated urea applications were found as 86.24, 81.76, 78.40 and 71.68, 68.32, 64.96 ppm respectively in case of nitrogen, 3.88, 3.85, 3.83 and 3.79, 3.71, 3.69 ppm respectively in case of phosphorous and for potassium as 7.60, 7.50, 7.30 and 6.90, 6.70, 6.50 ppm. The results shows that neem coated urea decrease all three-infiltration rate, percolation and the percent volume reduction more as compared to ordinary urea as well as in least nutrient losses through percolation. Infiltration rate, percolation and percent volume reduction decreases with increment in time after saturation. Rate of increase of cumulative infiltration is steady initially for a certain period of time and later on soil with neem coated urea resulted in the lowest value of cumulative infiltration and the rate while soil without urea in the highest value. Nutrient losses through percolation decreases with decrease in time duration after saturation.