Field experiments were carried out in order to investigate if brown manuring (BM) using Sesbania plants can be used to control weeds in maize, especially Cyperus rotundus (Experiment I), and further to optimize the BM technology through appropriate Sesbania seed rate (S), 2,4-D application time (T) and dose (D) (Experiment II). Each BM treatment received a pre-emergence application of pendimethalin 1.0 kg a.i./ha. Experiment I showed that the BM practice using 15 kg/ha Sesbania seed and 2,4-D 0.50 kg a.i./ha applied at 25 DAS led to better control of weeds, especially C. rotundus and higher maize grain yield. Further optimization studies (Experiment II) indicated that among the factors S, T and D, the BM combination S~25 kg/ha, D~0.50 kg a.i./ha and T~25 DAS (i.e. S25T25D0.50) resulted in lowest weed density (3.1/m2) and dry weight (3.8 g/m2) and highest weed control index (89.2%) at 60 days after sowing (DAS) which was at par with another BM practice S15T25D0.50. However, the later BM combination led to significantly higher maize productivity (5.25 t/ha) and profitability (net returns (NR) $878/ha), which were 103 and 280% higher, respectively, than the weedy check (WC). The Sesbania seed rate S~15 kg/ha gave 7% higher maize grain yield and 12% higher NR than its corresponding level S~25 kg/ha. Therefore, Sesbania BM with 15 kg seeds/ha and 2,4-D at 0.50 kg a.i/ha applied at 25 DAS can be recommended for effective and eco-friendly weed management in maize, which would provide higher maize grain yield and enhance farmers' profitability.

中文翻译：

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玉米褐肥优化：对杂草、作物生产力和盈利能力的影响

进行了田间试验，以研究是否使用褐肥（BM）田菁植物可用于控制玉米中的杂草，尤其是香附（实验一），进一步优化BM技术，通过适当的田菁播种率 (S)、2,4-D 施用时间 (T) 和剂量 (D)（实验 II）。每个 BM 处理在芽前施用 1.0 kg ai/ha 的二甲戊灵。实验 I 表明，BM 实践使用 15 kg/ha田菁种子和 2,4-D 0.50 kg ai/ha 施用 25 DAS 可以更好地控制杂草，尤其是C. rotundus和更高的玉米产量。进一步优化研究（实验 II）表明，在因子 S、T 和 D 中，BM 组合 S~25 kg/ha、D~0.50 kg ai/ha 和 T~25 DAS（即 S25吨25D0.50) 导致杂草密度最低 (3.1/m2) 和干重 (3.8 g/m2) 和播种后 60 天 (DAS) 时的最高杂草控制指数 (89.2%) 与另一种 BM 实践 S 相当15吨25D0.50. 然而，后来的 BM 组合显着提高了玉米生产力（5.25 吨/公顷）和盈利能力（净收益 (NR) 878 美元/公顷），分别比杂草检查 (WC) 高 103% 和 280%。这田菁播种量 S~15 kg/ha 使玉米产量比相应水平 S~25 kg/ha 提高 7%，NR 提高 12%。所以，田菁推荐在 25 DAS 施用 15 kg 种子/ha 和 0.50 kg ai/ha 2,4-D 的 BM 用于玉米中有效和环保的杂草管理，这将提供更高的玉米产量并提高农民的盈利能力。