Soybean is the most important oilseed over the world. Different factors interfere in its development, among them, the interference of weeds. Thus, the objective was to analyze the performance of pre-emergence herbicides on the weed competition and agronomic components of soybean. For this, an experiment was carried out in commercial farming. The experimental design was in randomized blocks with three treatments and nine repetitions. The following treatments were tested: S-metolachlor (1,152 g a.i. ha-1); diclosulam (35 g a.i. ha-1; 42 g a.i. ha-1) + imazethapyr (164.8 g a.i. ha-1). Two phytosociological surveys were carried out at 21 and 32 days after sowing (DAS) for controlling the weed competition. At 14, 21, 32, and 37 DAS, stem height and diameter were analyzed, while at 115 DAS, the production components were estimated. The application of S-metolachlor (1,152 g a.i. ha-1) was efficient for pre-emergence weed control of weed competition in commercial soybean crops. Through this treatment, the conventional cultivar Ansc 89109 produced between 130,5 and 255,8 kg per hectare, this result is superior those obtained in plots treated with diclosulam (35 g a.i ha-1) + imazethapyr (164.8 g a.i. ha-1) and diclosulam (42 g a.i. ha-1) + imazethapyr (164.8 g a.i. ha-1). Thus, the application of higher-doses of diclosulam (42 g a.i. ha-1) in a mixture with imazethapyr (164.8 g a.i. ha-1) is not recommended since it presents eminent agronomic, environmental, and economic risks
The protection conferred via chemical treatment of seeds is indispensable to the normal development of crops, with a view to the best use of its productive potential. The objective of this study was to evaluate the soybean crop response, cultivate ‘FTS Paragominas RR’, to seed treatment. The study was conducted in an experimental area of the Center of Agrarian and Environmental Sciences of the Federal University of Maranhão, in Chapadinha (MA), from February to June 2018. A randomized complete block design was used, with split-plot in time. The plots consisted of five seed treatments: thiophanate-methyl + fluazinam fungicides, fludioxonil, carbendazim + thiram, the insecticide fipronil and the absence of the application. Throughout the crop cycle the agronomic characteristics were verified: plant height, stem diameter, and leaf area. And, at the time of harvesting, grain yield, the height of insertion of the first pod, the total number of pods and weight of 1000 grains. Seed treatments induced very variable responses on the growth and development of soybean ‘FTS Paragominas RR’. The best performances were obtained with the use of thiophanate-methyl + fluazinam fungicides (dose 198 mL) and fludioxonil (dose 200 mL). The application of carbendazim + thiram and fipronil, both at a dose of 200 mL, presented adverse effects throughout the vegetative and reproductive phases of soybean ‘FTS Paragominas RR’. None of the products provided significant increases in grain yield.
The soybean crop (Glycine max. (L.) Merril) shows strong participation in the Brazilian economy. Therefore, the aim of the present study was to quantify the losses in the cutting and feeding platform and in the trail system in mechanized soybean harvest by analyzing different speed and rotation adjustments of the trailing cylinder. The experiment was carried out in a commercial soybean plot on a farm located in the municipality of Brejo (MA), during the 2017/2018 harvest. The harvester evaluated was a Case IH 8120, with a maximum power of 34.2 kW, axial flow system, and 12.2-m platform equipped with a conveyor system (draper). The experiment was conducted in two different areas. Area 1 was planted with the Brasmax® Opus (BMX Opus) cultivar, while area 2 was cultivated with the BRS 9383 cultivar. The treatments consisted of three machine speeds (4 km h-¹, 6 km h-¹, and 7 km h-¹), associated with the rotation levels of 500 rpm and 800 rpm in the trail system. The experimental design used was randomized blocks in a 3 x 2 factorial arrangement, with four replications. For the BMX Opus cultivar, harvest losses did not influence the travel speeds and rotations evaluated in the experiment due to the marked instability within the treatments. The BRS 9383 cultivar showed satisfactory results at a speed of 4 km h-1 combined with a rotation of 800 rpm, which obtained acceptable numbers for the soybean harvest (54.09 kg ha-1).
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