Journal of Research in Weed Science

Abstract Application of crop residues can be a good option for organic and sustainable weed management in rice. Consequently, the use of crop residues can suppress weed emergence and weed biomass. A study was conducted in two consecutive seasons firstly to optimize the mixture ratio to soil (v/v) of different crop residues on inhibition of common weed species and secondly to evaluate their performance on rice growth and yield. Among the crop residues used in this study sorghum was the most effective followed by mustard, barley, soybean, rice, wheat, triticale, maize, lentil and grasspea. The 50:50 (crop: soil, v/v) treatments incorporation rate of all crop residues suppressed the growth of all weed species in maximum level. The result revealed that broadleaf weed species were more susceptible to crop residues than grass weed species. In this respect, the highest growth inhibition (54.49%) was observed in controlling Monochoria vaginalis. Variety and rate of sorghum residues application significantly influenced weed growth and inhibition. A maximum increment in terms of plant height, dry weight and yield was observed due to sorghum 2.0 t ha^-1 residue applications. Considering yield and yield contributing characters, highest grain and straw yield was obtained from BRRI dhan29. All together, the result depicted that crop residues can effectively control weed along with enhancing growth and yield of rice and it can be successfully used in weed management program in rice.

Abstract Weeds are among the most harmful factors limiting sorghum production under Sudanian conditions of southern Senegal. Despite, the taxonomic structure of the flora is relatively well known, few studies have focused on crop-weed competition. Field experiment was carried out to determine the critical time for weed competition in grain sorghum. Ten treatments, weedy for initial 15, 30, 45 and 60 DAS and then weed-free, and weed-free for initial 15, 30, 45 and 60 DAS and then weedy, weed-free and weedy up to harvest were assigned in a randomized block design with four replications. The beginning and the end of critical period of weed competition were determined respectively under fertilized and unfertilized conditions. The results showed that more the weeds competition is longer, more sorghum parameters of growth and yield are reduced. Sorghum yield were significantly influenced by many factors such as year, nitrogenous fertilization and weeding periods. The highest plant height, dry matter, and yield were recorded in weed free treatment followed by weed free up to 60 DAS and weedy up to 15 DAS. Plant height, dry matter and yield decreased significantly with each increase in competition period. Therefore, the lowest growth parameters and yield were noticed in weedy check treatment followed by weedy up to 60 DAS and weed free up to 15 DAS. Moreover, our findings showed that sorghum height, dry matter and grain yield increased significantly under fertilized conditions compared to unfertilized conditions, which is widely used in traditional cropping system. The maximum competition between crop and weed was between 15-45 and 15-55 DAS under unfertilized conditions (F0) and 10-55 and 15-55 DAS under fertilized conditions (F1), which can be considered as critical period of crop-weed competition. The weeding practice should be adopted during these periods for getting optimum sorghum production under Sudanian conditions of Senegal.

Abstract The experiment was conducted in farmer field with farmer managed in Randomized Complete Block Design (RCBD) with three treatments and seven replications. The treatments were weed management practices including (i) Farmer’s Practice (FP) (ii) Two manual weeding (iii) First manual weeding and 2nd weeding by post emergence herbicides (Temboterine and Atrazine) application in Inner-terai, Dang, Nepal. Results showed that first manual weeding and 2nd weeding by herbicides significantly reduced weed infestation and gave higher maize grain yield. The yield attributes were cob length, total number of grain, number of grain per row, cob weight with husk and cob weight without husk. Thus, herbicides used after 1^st manual weeding is successful for high maize yield.

Abstract A field study was carried out to evaluate the efficacy of Prioxofop-Propanyl 15% WP (Markclodina) herbicide for wider weeds range in wheat crop during Rabi 2015-16. Six treatments including four herbicides treatments viz. Pendimethalin at 1.0 kg/ha, Clodinafop at 0.060 kg/ha, Markclodina at 0.060 kg/ha, Isoproturon + 2, 4-D at 1.0+0.5 kg/ha along with hand weeding twice (30 and 60 DAS) and one weedy check were used. Avena ludoviciana (34.30 %) and Phlaris minor (25.26 %) were the most dominatinggrassy weeds. New test herbicide Markclodino had better efficacy in controlling Phalaris minor, Avena fatua and Lolium temulentumas evidencedfrom significantly less number of weeds at all the stages of observations. The highest weed control efficiency (80.5 %) was recorded with post emergence application of Markclodina 0.060 kg/ha at 90 DAS. The application of markclodina at 0.06 kg/ha remaining at par with clodinofop propargyl (market sample) at 0.06 kg/ha, isoproturon + 2,4-D at 1.0 + 0.5 kg/ha produced significantly higher grain yield. The magnitude of increase in yield due to Markclodina over weedy check was 68.9 %. Field demonstrations on the performance of Markclodina under various locations showd that there was maximum 19.7 % increase in grain yield over control at distt. Hamirpur (Himachal Pradesh).

Abstract Sustainable agriculture requires the use of environmentally friendly management practices. Mulching is one of the most effective methods that can play a positive role in weed management, improving soil properties as well as increasing crop production. A field experiment was conducted at the research farm of National Maize Research Program (NMRP), Rampur, Chitwan, Nepal during winter season, 2016. The experiment was carried out in single factor randomized completely block design comprising of nine weed management methods with four replications. Data regarding the weed population, weed dry weight, yield attributes and yield were recorded during the study. Different weed management practices showed significant differences on weed dynamics and weed control efficiencies. Black polythene mulch and silver black mulch was found more effective to reduce total weed density and dry weight during whole crop season and remain comparable with other polythene mulch too. The effect of weed management practices observed on weed density and dry weight were reflected on grain yield. The highest grain yield was recorded in silver black plastic mulch (4537.50 kg ha^-1) followed by black plastic mulch (4068.20 kg ha^-1), clear plastic mulch (4065.22 kg ha^-1), green plastic mulch (3834.84 kg ha^-1) and weed free (3222.74 kg ha^-1) which were comparable to each other. At tasseling-silking stage among plastic mulch treatment, the higher moisture conservation observed on the black plastic mulch followed by clear plastic mulch, green plastic mulch and silver black plastic mulch. While comparing of plastic mulch with dead mulch, moisture on dead mulch remain higher than plastic mulch after 90 DAS. Thus, in humid subtropical region of western Chitwan, Rampur, the maize can be successfully cultivated by using different color of polythene mulch.