Response of maize and associated weeds to weed management and nitrogen rates

Abstract

Two field experiments were conducted at the Research and Experimental Station Farm, Faculty of Agriculture, Ain Shams University at Shalakan, Kalubia Governorate, Egypt, during 2009 and 2010 growing seasons. These experiments aimed to study the response of maize (yield, yield components, grain chemical composition) and associated weeds to eleven weed management treatments: pendimethalin, acetochlor, metribuzin, pendimethalin+metribuzin, acetochlor+metribuzin, pendimethalin+hoeing once, acetochlor+hoeing once, metribuzin+hoeing once, hoeing once, hoeing twice and unweeded, as well as two N rates (90 and 120 kg N/fad. Results showed that acetochlor+hoeing once was the most effective treatment against grassy, broadleaf and total weeds in both growing seasons. Such potent treatment was statistically at par for diminishing total weeds with those of hoeing twice in 2009 and metribuzin+hoeing once in 2010. Maize plots treated with 120 kg N/fad gave the highest value of dry weight of all weed groups. Grain yield, oil yield, protein % and protein yield possessed the highest values due to the application of acetochlor+hoeing once or hoeing twice.Also, plant height, ear length, weight of 100 grains, ear yield and grain yield, oil % oil yield, protein % and protein yield recorded the highest increases due to fertilizing maize plant by mineral N at 120 kg/fad over those of 90 kg/fad. Moreover, the highest grain yield and its components and grain chemical composition were obtained from weeded treatments under the higher N rate.