Effect of fertigation on available soil micro-nutrient under Kinnow Mandarin
A field experiment was conducted at Division of Fruit and Horticultural Technology, Indian Agricultural Research Institute (IARI), on 5-year-old plants at Todapur Orchard, IARI, New Delhi, during 2010-2011, to study the effect of fertigation on nutrient distribution pattern under Kinnow mandarin. Standard dose of fertilizers were 600g of N, 300g of P, and 400g of K per tree per year, scheduled in three splits during the period of February (300g N, 75g P and 100g K), April (150g N, 112.5g P and 150g K) and August (150g N, 112.5g P and 150g K) respectively. The soil nutrient was measured at the start and end of the experiment in February 2010 and January 2011 at three depths, viz. 0-15, 15- 30 and 30- 60 cm corresponding to two radial distances (50 and 100 cm) for different experimental treatments. The highest amount of soil iron at the end of experiment was observed in T6 having 3.98 ppm, followed by 3.78 ppm and 3.72 ppm at three different depths viz: 0-15, 15-30 and 30- 60 cm respectively at 50 cm distance whereas 3.56 ppm followed by 3.49 ppm and 3.32 were found at 100 cm distance away from the tree. T6recorded the highest amount of available copper in soil having 2.76 ppm followed by 2.73 ppm and 2.67 ppm from 0-15, 15-30 and 30- 60 cm depths respectively at the distance of 50 cm while, 2.68 ppm, 2.65 ppm and 2.61 ppm from 0-15, 15-30 and 30- 60 cm depths respectively at 100 cm away from the tree. T8 recorded the highest amount of soil zinc at the end of experiment, 2.59 ppm, 2.50 ppm and 2.20 ppm from 0-15, 15-30 and 30- 60 cm depths respectively from the distance of 50 cm and 2.31 ppm, 2.20 ppm and 1.74 ppm from 0-15, 15-30 and 30- 60 cm depths respectively away from the tree. The highest amount of soil manganese was recorded in T8 at the end of experiment. From 0-15, 15-30 and 30- 60 cm depths respectively 28.38 ppm followed by 24.84 ppm and 21.09 ppm at a distance of 50 cm while 29.88 ppm, 22.40 ppm and 17.43 ppm were observed at 0-15, 15-30 and 30- 60 cm depths respectively away from the tree. Fertigation resulted in increase in concentrationsof micro- nutrients near the zone of active roots (0-15 and 15-30 cm depths), exhibiting a radial decrease with increasing horizontal distance from the point of application, i.e. higher at 50 cmand lower at 100 cm distance from the trunk. It was recommended that fertigation with 75 per cent N and 100 per cent P & K (450 g N, 300g P and 400 g K) can be recommended for application in three splits during February (225N:75P:100K), Apri1(112.5N: 112.5P: 150 K) and August (112.5N: 112.5P: 150 K) for young Kinnow orchards.
Keywords: Kinnow, fertigation, micronutrient, depth, distance