EFFECT OF IRRIGATION AND NITROGEN MANAGEMENT PRACTICES OF RICE ON NUTRIENT UPTAKE AND AVAILABILITY OF NUTRIENT STATUS IN THE SOIL UNDER DIFFERENT ESTABLISHMENT METHODSI. Thirupathi, G.E.CH. Vidya sagar, R. Mahender Kumar, K. Surekha, J.V.N.S. Prasad and S. Narender Reddy
A field experiment was conducted on a clay loam soil at Indian Institute of Rice Research (IIRR) formerly Directorate of Rice Research (DRR), Rajendranagar, Hyderabad, Telangana during the kharif seasons of 2015 and 2016 to study the âAssessment of production potential of rice with irrigation regimes and nitrogen management practices under different establishment methodsâ. The treatments consisted of three establishment methods Normal transplanting (NTP), Mechanized System of Rice Intensification (MSRI) and Drum seeding (DS) as main plot treatments, two irrigation regimes continuous flooding, Alternate wetting and drying at 5cm depletion as sub plot treatments and two nitrogen management practices (RDN - 100 % through inorganic and RDN - 75 % inorganic and 25 % organic) as sub-sub plot treatments summing upto 12 treatment combinations laid out in split-split plot design with three replications. At harvest significantly higher uptake of N, P and K were noticed in MSRI but on par with NTP. N uptake was not found to be significantly different between irrigation regimes at 40, 70 and 100 DAS. The grain and straw uptake of N, P and K was higher with continuous flooding but it was on par with AWD with 5cmdepletion. Among nitrogen management practices significantly higher N uptake at all the crop growth stages were recorded with organic and inorganic combinations of nitrogen. At harvest uptakes of N, P and K were higher with RDN (75 % inorganic and 25 % organic) in grain and straw than RDN through inorganic source. Higher partial factor productivity of nitrogen, phosphorus and potassium was observed with MSRI than DS but it was comparable with NTP method. Between irrigation regimes, flooding recorded significantly higher partial factor productivity of N, P and K which was comparable with irrigation at 5 cm depletion. Soil available N, P and K was not influenced by establishment methods and irrigation regimes but nitrogen management shows the significant variation in available nutrient status of soil during both years of study.