Abstract
Wheat is one of the most important food security crops which is cultivated from small to large scale farms in Ethiopia. However, its productivity has been limited due to various abiotic and biotic factors including weeds. The aim of the study was to investigate the effects of seed rates and post emergence herbicides application on weed management and productivity of wheat. Factorial combinations of three levels of seed rates (100,150 and 200 kg ha -1 )and four types of herbicides (Agro 2,4-D 720 g/L 1lt ha -1 ,Pallas 45 OD 0.5lt ha -1 , Derby 175 SC 100ml ha -1 and Lancolet 450 WG 33 gm ha -1 )along with control (a weedy check) were laid out in RCBD with three replications. The field was infested with thee grass weeds and nine broad leaved weed species. Weeds species included Phalais paradoxa L.,Setaria pumila L. and Arthraxon prinodes L. were categorized as grass weed while Polygonum nepalense L., Raphanus raphanistrum L., Plantago lanceoleta L., Corrigiola capensis Wild., Spergula arvensis L., Galinsoga pulviflora Cav., Guizotia scabra (Vis)Chiov, Cyanotis barbata D.Don and Oxalis corniculata HBK. The relative weed density indicated that from the total of identified 12 weed species identified 86 % broad leaf weeds and 14 % grass weeds.Results also revealed that significant effects of seed rate by herbicide interaction for all the traits studied. It was observed that the application of 150 kg ha -1 seed rate with Pallas 45 OD resulted in minimum weed densities of all weed species after application while the maximum weed densities were recorded at weedy checks.The minimum weed densities (4.52 m -2 ) at 25 days after planting (DAP).Longer duration of days to heading was recorded at weedy checks but there is no much significant variation due to other interactions. The maximum plant height was recorded from application of 100 kg ha -1 seed rate at weedy check.The highest number of grain yield (4516.42 kg ha -1 ) was recorded from the combination of 150 kg ha -1 seed rate with Pallas 45 OD while the lowest values were observed from the weedy check . It was also observed that, the combined use of seed rate 150 kg ha -1 with Pallas 45 OD effectively managed weeds, economical and gave maximum yields, which could be recommended for the test environment. Since the experiment was conducted in one location and for a single season, it should be repeated over seasons or multi locations for best recommendation. Keywords: combination, density, maximum, Pallas 45 OD , significant DOI: 10.7176/JEES/10-3-04 Publication date: March 31 st 2020
Highlights
Bread wheat (Triticum aestivum L.) is the most important cereal among the food grain crops in the world( Dalga,2016).It is produced in a wide range of climatic environments and geographic regions (Dixon et al, 2009).Wheat occupies about 17% of the world’s cropped land and contributes 35% of the staple foods, so its increased production is essential for food security (Shamsi, et al, 2006)
Weeds are one of the major constraints in wheat production as they reduce productivity due to competition, allelopathy and by providing habitats for pathogens as well as serving as alternate host for various insects, fungi and increase harvest cost (Abbas et al.,2009).Studies indicated that crop losses due to weed competition throughout the world as a whole are greater than those resulting from combined effect of insect pests and diseases.It causes yield reduction in wheat from 10- 65% (Genene and Habtamu, 2001).The losses caused by weed infestations vary depending up on the weed species, their density and environmental factors
Treatments and experimental design The experimental materials used in the experiment were popular bread wheat variety Dendea and four types of broad leaf herbicides that were registered in Ethiopia for the control of annual leaf weeds .The treatments included factorial combinations of three levels of seeding rates (100,150 and 200 kg ha-1) and four types post emergence herbicides
Summary
Bread wheat (Triticum aestivum L.) is the most important cereal among the food grain crops in the world( Dalga,2016).It is produced in a wide range of climatic environments and geographic regions (Dixon et al, 2009).Wheat occupies about 17% of the world’s cropped land and contributes 35% of the staple foods, so its increased production is essential for food security (Shamsi, et al, 2006). Percent viability and germination of seeds usually determine crop density and normally higher the density of a crop, lower is weed competition and vice-verse.The crop density cannot be increased arbitrarily and infinitely since every crop has an optimum population beyond which intraspecific competition among crop plants may begin. Recommended seed rates are optimized for the row distance normally used. A common assumption is that seed rate should be reduced when row distance is increased the optimal magnitude of the reduction is poorly www.iiste.org known. Better arrangement of crops with optimum seed rates to agro-ecological condition can be a feasible option in improving the wheat productivity
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