Phenological behaviour of gobhi sarson (Brassica napus l.) and thermal indices as influenced by drip irrigation and fertigation schedules under semi-arid subtropical conditions of punjab

Abstract

A field experiment was conducted during rabi 2016-17 and 2017-18 at the Research Farm of Department of Agronomy, Punjab Agricultural University, Ludhiana, to study the phenological behaviour of gobhi sarson (Brassica napus L.) and thermal indices as influenced by drip irrigation (60, 80 and 100% of cumulative pan-evaporation, CPE) and fertigation schedules (60, 80 and 100% recommended dose of fertilizers, RDF) in comparison with conventional flood irrigation and manual application of fertilizers i.e. absolute control. The pooled data revealed that Brassica irrigated through drip at 100% of CPE took maximum number of days to attain 50% flowering, 50% siliqua formation and physiological maturity, followed by 80 and 60% of CPE. Higher fertigation levels also delayed the number of days taken to attain various phenological stages. Maximum seed yield was observed at 100% of CPE with 100% RDF which was statistically at par with 100% of CPE with 80% RDF and 80% of CPE with 80 or 100% RDF, but significantly higher than absolute control. Maximum accumulation of heat units along with heat use efficiency (1.49 kg grains ha-1 °C day hour-1 ) was also obtained at 100% of CPE with 100% RDF.