Irrigation and Nitrogen Management of Sal (Shorea robusta Gaertn. F.) Saplings in Red Soils of Chotanagpur (Bihar)

Experiments were carried out in pots to evaluate the effects of nitrogen levels, moisture regimes and soil texture on growth and nutrients uptake by Sal seedlings. Almost all the growth attributes such as height, girth, branching and dry weight of ischolar_mains and shoots of the seedlings of Sal (Shorea robusta) increased significantly under loam soil followed by sandy loam and clay loam soils. Increasing rates of nitrogen application was found beneficial for Sal seedlings. It is aparent from the results that during the first year of seedlings transplantation, 50 kg N/ha was more effective followed by 25 kg N/ha in the next year. Similarly, increasing availability of moisture was essential for the growth of Sal seedlings. To economise on water, however, irrigation in the heavier soils Chotanagpur be given after 50 to 75% depletion of soil moisture. In case of light soils, irrigation should be given after 25% to 50% depletion of available soil moisture for good growth of Sal seedlings. There was more uptake of N, P, K from loam soil as compared to sandy loam and clay loam soils. Increasing rates of nitrogen application was conducive to N, P, K uptake by the seedlings. Low or high frequency of irrigation was generally not beneficial in regard to N, P, K uptake by plants. Irrigation at 50% available soil moisture depletion was beneficial for the uptake of N, P, K by Sal seedlings. Two or three factor cotmbinations of these variables produced significant effect on uptake of N, P, K by Sal seedlings.