Document Type : Original Article
Authors
1
Plant Protection Department (Pesticides), Faculty of Agriculture, Zagazig University, Zagazig City - 44511, Egypt
2
Pedology Department, Water Resources and Desert soils Division, Desert Research Center, Cairo - 11753, Egypt
Abstract
An experiment under field conditions was carried out in the lowland at Wadi Al-Mollak, East Delta, Egypt during the 2019 season to control the rice weeds by clomazone herbicide concerning nutrient uptake as well as growth and yield of the transplanted rice. The experimental site soils were clay to clay loam in texture, medium in available nitrogen, and high in both available phosphorus and potassium. Seven treated plots with three replications of the experiment were conducted in different periods at twenty, forty, and sixty days after transplanting (DAT). Pre-emergence herbicide clomazone at different doses of 150, 200, 250, and 300 g/ha was compared with 0.75 kg/ha of pretilachlor, physical weed control (hand weeding twice), and untreated plot control. Six species of different weeds were identified throughout the growth stages of the rice crop. They are grasses (Echinochloa crus-galli and Echinochloa colonum), sledges (Cyperus difformis and Scirpus maritimus), and broad-leaved weeds (Eclipta alba, and Ammania baccifera). Grasses were the predominant weeds in the early stages, whereas in the latter stages clomazone @ 300 g/ha and broad-leaved weeds were predominant. The dose of 300 g/ha of clomazone resulted in lower values of macronutrients depletion by studied weeds and the highest uptake by rice crop. Further, these doses gave the highest values for plant height, crop dry matter production. The dose of clomazone @ 300 g/ha verified the highest grain yield of 5690 kg/ha with respect to 5613 kg/ha in T3 of clomazone @ 250 g/ha, 5665 kg/ha in T6-physical method by hand weeding twice, and 5611 kg/ha in pretilachlor. Among the clomazone treatments, the results may be concluded that the doses of clomazone @ 300 and 250 g/haare the optimal rates for effective management of weeds in the transplanted rice ecosystem. The research work recommended that the lower rates of herbicide treatment were not enough to curtail early weed competition, and therefore the dose of clomazone @ 250 g/ha incorporating hand-weeding are the safer and operative methods for controlling the tested weeds, enhancing nutrient uptake for optimum growth of rice plants, and obtaining the higher grain and straw yields of rice crop.
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