The present investigation was taken up with an aim to optimize the phosphorus fertigation requirement and to determine correct fertigation schedule of phosphorus source through fertigation so as to maximize cane yield and juice quality in sugarcane crop. The phosphate source of fertilizers viz., Mono ammonium phosphate and 19-19-19 and phosphoric acid under sub surface drip irrigation were standardized at seven levels in randomized block design. The plant crop of sugarcane crop cv CoC (SC) 24 was planted on 23.7.2013 and subsequently ratooned on 12.9.2014 The fertigation was given at fortnight intervals up to 210 days after planting. The tiller and millable cane population was maximum with 217670/ha and 89440/ha in plant crop and 210750 /ha and 89950/ha in ratoon crop with 125 % recommended NPK (300:100:200 kg /ha.) through urea, 19-19-19 and KCl through subsurface drip systems. Application of 125 % recommended NPK as urea, 19-19-19 and KCl (T₆) were significantly superior in increasing the cane yield to 175.48 t/ha and on par with T₅(164.87 t/ha),T₄ (164.44 t/ha) and T₇ (162.46t/ha). In ratoon crop, application of 125 % recommended NPK as urea, 19-19-19 and KCl (T₆) were significantly superior in increasing the cane yield of 180.44t/ha and on par with T_4.The treatments did not affect the commercial cane sugar significantly in both plant and ratoon crop. The sugar yield followed the same trend as cane yield. The available nitrogen content was found to be maximum at 20 cm depth of soil both plant and ratoon crop. The available phosphorus content was accumulated at 40 cm depth of soil and available potassium content was observed to be higher at 20 cm depth of soil and decreased with increasing depth. Application of 125 % recommended NPK as urea, 19-19-19 and KCl (T₆) were significantly superior in increasing nitrogen, phosphorus and potassium content and uptake of 259.87, 103.19, 415.15 kg/ha respectively._. The benefit cost ratio was observed to be maximum in the treatment receiving 100 % recommended NPK as urea, 19-19-19 and KCl (T₄) both in plant and ratoon crops. So application of 100 % recommended NPK as urea and KCl along with 19-19-19 phosphate sources of fertilizers apply as fortnightly intervals upto 210 days after planting under sub surface drip fertigation improved the yield, economics and soil nutrient status.

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