Physiological and Biochemical Basis of Variation in Yield of Rice (Oryza sativa L.) under CA-based Crop Establishment Methods and Nutrient Management in R-W Cropping System

Background: Crop establishment methods and nutrient management practices treatments were continuously practiced in the same plots since 2011-12 as a part of long-term experiment. A field study was conducted during 2019-2020 and 2020-2021 i.e. during 9th and 10th year of study to investigate the effects of CE methods and nutrient management on growth, physiological, biochemical, yield attributes and yield of rice crop. Methods: Field experiments were carried out at the Agricultural Research Farm, Banaras Hindu University, Varanasi, laid out in split plot design replicated thrice with four crop establishment (CE) methods viz., CT (puddled transplanted) rice-CT wheat (CE1),CTDSR rice-CT wheat (CE2), CTDSR- ZT wheat (rice residue retention) (CE3), ZT rice-ZT wheat (residue retention in rice and wheat) (CE4) in main plots and three nutrient management (NM) practices viz., FP (164 kg N, 50 kg P2O5, 32 kg K2O and 4 kg Zn ha-1) (N1), RFD (150 kg N, 60 kg P2O5, 60 kg K2O and 5 kg Zn ha-1) (N2) and SSNM- RWCM recommendation (N3). The rice variety used was ‘Sarju-52’ in the present study. Result: The recorded data revealed that ZT rice–ZT wheat (CE4) recorded significantly higher plant height, tillers hill-1, leaf area, RWC, total chlorophyll content and protein content as compared to other CE methods. Among NM practices, SSNM-RWCM (N3) recorded significantly higher plant height, tillers hill-1, leaf area and protein content, whereas, RWC and total chlorophyll content did not differ significantly over farmer’s practice and recommended fertilizer dose. Improved growth and physio-chemical attributes in ZT rice-ZT wheat (CE4) and SSNM-RWCM (N3) resulted in significantly higher panicles hill-1, fertility percentage and number of filled grains panicle-1 over other CE methods and NM practices. Panicle length, spikelets panicle-1 and test weight showed non-significant differences. Grain yield, straw yield and biological yield were significantly higher in ZT rice-ZT wheat (CE4) among CE methods and SSNM-RWCM (N3) among NM practices. The harvest index showed non-significant differences for CE methods and NM practices both.