Nutrient and Water use Efficiency, Nutrient Uptake and Rice Yield as Influenced by Fertigation Levels and Weed Management Practices

Abstract

A field experiment was carried out at AICRP on Weed Management Research Farm, Department of Agronomy, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola during kharif 2020-21. Fertigation is the technique of supplying dissolved fertilizers to crops through an irrigation system.The experiment was laid out in split plot design with three replications and twenty treatment combinations having four different fertigation levels and five weed management practices. The results revealed that, significantly maximum grain yield of rice (5103 kgha-1), straw yield (7268 kgha-1) and harvest index (41.25%) were found maximum at 125% RDNK level of fertigation in 5 splits than lower fertigation levels (75 and 100 per cent) and over conventional soil application of 100 per cent RDF. Nutrient use efficiency (NUE) was found better in lower drip fertigation level of75 per cent recommended dose of N and K per ha as compared to conventional soil application of fertilizers. Among the herbicides, directed spray of Pretilachlor + Pyrazosulfuron Ethyl @ 0.615 a.i. kgha-1 PE fb. Bispyribac sodium @ 0.025 a.i kgha-1 at 25 DAS resulted in maximum rice grain yield (5231 kgha-1) and also total nutrient uptake by crop and water use efficiency indicating the feasibility of using herbicides for effective weed management in rice and for enhancing NUE and WUE. The 125% RDNK through drip fertigation in 5 splits recorded maximum Gross Monetary returns (₹120353 ha-1), Net Monetary Returns (₹72924) and B:C ratio (2.54), nutrient use efficiency and water use efficiency.The herbicidal treatment of Pretilachlor + Pyrazosulfuron Ethyl0.615 kgha-1 PE fb. Bispyribac sodium 0.025 kgha-1 at 25 DAS registered maximum GMR (₹128755 ha-1), NMR (₹81412ha-1) and B:C ratio (2.72) among all herbicidal treatments, indicating the feasibility of using herbicides for effective weed management in rice.