Evaluation of Plant Residues on the Dynamics of Weed Populations and Corn (Zea mays L.) NS640 cultivar in two Types of Soil Textures

The use of cultivated plants in the consecutive of cropping systems is one of the most important alternative and sustainable methods to eliminate or reduce the use of herbicides. To investigate the effect of crop residues on weed control and corn yield of NS640 cultivar, an experiment was conducted in 2015-2016 and 2016-2017 cropping years. This experiment was performed in two years and two places in a randomized complete block design with four replications. Two farms with clay- loamy and sandy-loam soil as a place and cultivation of four pre-corn crops including bean-branch (Vicia faba L.), wheat-Chamran (Triticum aestivum L.), rapeseed-Hayula 401 (Brassica napus L.), cabbage - Steady hybrids (Brassica oleraceae L.) and fallow were the treatments. Combined analysis of the results showed that the comparison of weed density and dry weight in different treatments of pre-cultivated plants with fallow (without pre-cultivated plants) showed the potential of pre-cultivated plant residues in reducing and controlling weeds. The reduction in the number of weeds in clay-loam field in the residues of bean, wheat, rapeseed and cabbage pre-cultivation plants compared to fallow were 22, 9, 10 and 29%, respectively, and in sandy-loam field 40, 48, 42 and 46%, respectively. Weed dry weight was significantly affected by crop residues. Bean, wheat, canola and cabbage residues reduced weed dry weight by 54, 55, 43 and 65% compared to fallow, respectively. The use of bean residues as a growing crop in clay-loamy and sandy-loam soils increased corn seed yield by 40 and 55%, respectively. The use of crop residues by higher decomposition of crop residues in the second year and creating a state of soil damage and a negative effect on weed dynamics indices can play an effective role in improving corn growth and increasing the productivity of the cultivation system.