National Research Centre for Citrus, Amravati Road, Nagpur 440 010
Field studies were conducted in a eight year old mandarin orchard planted in deep black clay soil (Typic Chromustert). Five levels of nitrogen, viz., 0, 200, 400, 600 and 800 g N/plant/year with a constant dose of 200 g P2O5/tree/year was applied from 1990–93 and the K level was increased from 100 to 200 g K2O/tree in the year 1993, because leaf K content was low. Soil application of nitrogen effectively increased the vegetative growth and resulted in increased fruit bearing potential of trees. A maximum of 25.6 per cent increase in fruit yield from 85.01 kg in control to 103.39 kg fruits/tree with 600 g N treatment was observed. The above observation was further supported by optimum levels of leaf N and K. Higher K application in the third year, produced better combination of red to yellow colour, increased juice and reduced the acidity.
