Effect of the three densities of plant residues of sunflower Helianthus annuus L. and deferent spraying rates of Chevalier herbicide on weeds control in Wheat Triticum aestivum L.

Abstract

Field study applied during the 2019-2002 season in the fields of the college of Agriculture, University of Tikrit, in order to study the combined effect of residues of plants sunflower Helianthus annuus L. cultivated in different plant densities with using different spraying rates of chevaller herbicide in developing efficient weeds with wheat crop Triticum aestivum L. as well as in the growth of the crop and yield.Field experiment was applied according to randomized complete block design RCBD in split plot. Plant densities of sunflower were but in main plots by three densities (53000,66000 and 88000 plants. ha-¹) with treatment without the cultivation of the plants. These treatments have been growing during the summer season of 2019 in order to obtain the residues of sun flower plants during the cultivation of wheat. While spraying rates applied of herbicide were four rates (without herbicide, 50% 75% 100%) of the recommended rates of chevaller herbicide spraying, (300 ml/ha-¹) in the sub plots. Characters studies of wheat crop and weeds which grow with developing wheat crop were (weed control %, dry weight of weeds, wheat plants height, total number of tillers, number of spikes, number of grains spike, 1000-grain weight, grain yield). The results that have been obtained from this research are as following:-Chevalere herbicide spraying under recommended amount (300 gm-h-¹) gave the highest weeds control percentage by (91.2%) comparing with the treatment without herbicide (22.0%).-High plant density of sunflower plant (88000 plant. ha-¹) gave the highest percentage of weeds control compared to other densities (53000 and 66000 plant).-The best weed control it was given by using a high density with spraying rate 75 % of recommended of herbicide-Dry weight of weeds were decreased significantly by using high density of sunflower residues, as well as with increase rate spraying of herbicide while the treatment which used a high density of plants with the 75% of the rate of spraying of the herbicide has achieved clear results in reducing the number of the weeds.- Some growth characters of wheat have been affected by the factors applied in the experiment significantly by decreasing the characters with increase the density of residues like (plant height, number of tillers total number of spikes, number of grains spike, grain yield), while others characters influenced positively with increase rates of spraying herbicide like the (the total number of tillers m-², number of spikes m-², 1000 grain weight and, grain yield).