Effect of Crop Cover and Stage of Crop Growth on Soil L-Glutaminase Activity

A pot culture experiment was conducted at glass house of Department of Soil Science and Agricultural Chemistry, College of Agriculture, Rajendranagar, Hyderabad. The aim of the present experiment was to study the influence of crop cover and stage of crop growth on soil L- glutaminase activity in an Alfisol and Vertisol. The experiment was under taken with six crops viz., two cereals (Rice, Maize), two legumes (Groundnut, Greengram), one oilseed (Sunflower) and one vegetable (Bhendi) crop. The experiment was conducted in Completely Randomized Block design with three replications along with the uncropped control. The results obtained with regard to the effect of these crops on soil L-glutaminase activity showed that there was an increase in enzyme activity with age of the crop upto 60 DAS and it varied with crops grown. The increased enzyme activity (μg of NH4+ released g-1 soil 4h-1) varied from 5.56 to 12.17 for groundnut, 5.58 to 11.25 for greengram, 5.43 to 10.87 for sunflower, 5.48 to 8.61 for rice, 5.39 to 8.23 maize and 5.31 to 7.92 for bhendi in Vertisol. In Alfisol the L-glutaminase activity (μg of NH4+ released g-1 soil 4h-1) under different crop cover found to vary from 6.72 to 13.59 (groundnut), 6.68 to 12.71 (greengram), 6.63 to 11.96 (sunflower), 6.61 to 10.25 (rice), 6.59 to 9.47 (maize), 6.62 to 9.26 (bhendi). A close perusal of the data indicates that the L-glutaminase activity followed the sequence groundnut > greengram > sunflower > rice > maize > bhendi, in both Alfisol and Vertisol.