Spraying of soybeans with nitrogenous fertilizers at earlier flowering stage: An ecofriendly fertilization management system to improve crop yield
2013
Mirshekari, Bahram
The experiment was conducted to study the effect of nitrogenous fertilizers on soybean leaf senescence and crop yield at Islamic Azad University of Tabriz, Iran. The experiment was carried out as a split-split plot based on randomized complete block design in three replications with three treatments viz., two soybean cultivars (L17 and Zan), nitrogen fertilizers (urea and ammonium nitrate) and rate of nitrogen (15, 25 and 35 kg ha−1). The stepwise regression analysis was carried out to test the significance of the independent variables affecting the seed yield as a dependent variable. Application of 15, 25 and 35 kg N ha−1 delayed nearly 2, 6 and 10 days in the leaf fall, respectively. With increasing of nitrogen rate, leaf chlorophyl content index increased significantly, compared to the check plots. Seed yield in cv. L17 treated with nitrate ammonium and cv. Zan treated with urea could be increased upto 6700 and 5100 kg ha−1, respectively. The multiple regression equation indicated that among the independent variables tested, the leaf senescence time and leaf chlorophyl content index showed a significant positive effect (P 0.05) on seed yield. Soybean farmers could improve seed yield of L17 and Zan cultivars by leaves spraying of 25 kg ha−1 ammonium nitrate or urea at earlier flowering stage, and consequently reduce nitrogen fertilizer amount, which could prove immensely useful in nutrition management in sustainable agricultural systems.
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