Study of Real -time nitrogen management and sustainable weed management practices on maize productivity

A field experiment was conducted during two consecutive kharif 2019 and 2020 on sandy loam soils of S.V. Agricultural College, Tirupati, Andhra Pradesh. The field experiment was laid out in a split-plot design with three replications. The treatments comprised of four nitrogen management practices viz., control (N1), recommended dose of fertilizer (N2), green seeker directed N application (N3) and soil test based fertilizer application (N4) assigned to main plots and nine weed management practices viz., unweeded check (W1), hand weeding twice at 15 and 30 DAS (W2), pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of topramezone 30 g ha-1 (W3), pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of tembotrione 120 g ha-1 (W4), application of parthenium water extract 15 l ha-1 twice at 15 and 30 DAS (W5), application of sunflower water extract 15 l ha-1 twice at 15 and 30 DAS (W6), pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of parthenium water extract 15 l ha-1 (W7), pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of sunflower water extract 15 l ha-1 (W8) and brown manuring (W9) allotted to subplots. Growth parameters of maize, yield attributes, and yield were higher with green seeker-directed N application (N3). Control (N1¬) recorded significantly lower values during both the years of study and in the pooled mean. With regard to weed management practices, significantly higher values were produced with hand weeding twice at 15 and 30 DAS (W2), which was however, in parity with pre-emergence application of atrazine 1.0 kg ha-1 fb post-emergence application of topramezone 30 g ha-1 (W3) and pre emergence application of atrazine 1.0 kg ha-1 fb post-emergence application of tembotrione 120 g ha-1 (W4). Lower values of growth parameters were recorded with an unweeded check (W1). Significant interaction between nitrogen and weed management practices was observed with dry matter production, cob length, kernel weight cob-1, kernel yield and stover yield. Higher and lower values were recorded with green seeker-directed N application along with hand weeding twice at 15 and 30 DAS (N3W2) and control coupled with an unweeded check (N1W1) respectively during both the years of study and in pooled mean.