Vol. 10, Issue 11 (2021)

Author(s):
B Raghavendra Goud, G Prabhakara Reddy, V Chandrika, MVS Naidu, P Sudhakar, K Madhusudhana Reddy, GV Venkataravana Nayaka, G Suresh, G Adilakshmi and G Karuna Sagar

Abstract:
A field study was conducted during two consecutive rabi seasons of 2019-20 and 2020-21 to study the influence of irrigation regimes and nitrogen levels on weed growth in aerobic rice under drip irrigation. The major weed flora observed in the field were Cyperus rotundus, Celosia argentea, Dactyloctenium aegyptium, Digitaria sanguinalis, Euphorbia hirta and Lantana camara. Weed density was significantly influenced by nitrogen levels at all the stages of crop, but by irrigation regimes at 60 DAS during both years of study and at 90 DAS during second year. Significantly higher weed density was observed with the nitrogen dose of 180 kg N ha^-1 (N₄) and the lower value was recorded with 90 kg N ha^-1 (N₁). Irrigation regime of 2.0 Epan (I₄) recorded significantly higher weed density over lowest irrigation regime of 1.25 Epan, but was comparable with 1.75 Epan and 1.5 Epan, at different stages wherever significant variation due to irrigation regimes was observed. Weed dry weight was non-significant with respect to irrigation regimes at 30 and 90 DAS, but was significantly influenced at 60 DAS during first year of study and in the pooled mean where drip irrigation regime of 1.5 Epan recorded significantly higher weed dry weight over lowest irrigation regime of 1.25 Epan, but was at par with remaining irrigation regimes. Nitrogen doses significantly influenced weed dry weight at all the stages of crop with higher weed dry weight values at 180 kg N ha^-1 (N₄) and the lowest at 90 kg N ha^-1.