Use of agro-chemicals in forage crops is restricted due to the fear of direct toxicity to livestock and risk of pesticide residue accumulation in the food chain. Wheat and barley can be used as green fodder and silage, and herbicide residue estimation in green fodder and silage is important for ensuring the safety of dairy cattle. A field experiment was conducted for two years to study pendimethalin residues in the green fodder and silage of wheat and barley. In both cereal crops, pendimethalin (1.125 kg a.i./ha) was applied as pre-emergence along with an unsprayed control. Pendimethalin residues in fodder, silage, and soil were estimated using gas chromatography-tandem mass spectrometry (GC-MS/MS). At harvest, pendimethalin residues in fodder and silage of wheat and barley were below the limit of quantification (<0.01 mg/kg) during both crop seasons. Pendimethalin can be safely used for weed control in winter cereals grown for fodder and silage.
Herbicide application with Unmanned Aerial Vehicle (UAV) is among few breakthroughs due to drift risk and loading capacity limitations. This study explored a perspective of using UAVs to spray herbicides. Effects of different treatments (control, knapsack sprayer, knapsack sprayer with adjuvant, UAV sprayer, UAV sprayer with adjuvant) were observed in pre- and post-herbicide spray applications in wheat crop to compare droplet distribution pattern and Phalaris minor weed control efficacy of UAV sprayer with a knapsack sprayer, and its effect on yield of wheat (Triticum aestivum L.) crop. Uniformity Coefficient was found in the range of 1.80 - 2.25 using a UAV sprayer, and was similar (1.18 - 2.12) to that for the use of knapsack sprayer. However, volume median diameter (VMD) of UAV sprayer was in the range of 437.33 µm to 540.67 µm, while it was in the range of 670.33 µm to 768.33 µm in case of knapsack sprayer. The droplets of UAV sprayer with adjuvant and knapsack sprayer with adjuvant were bigger in size as compared to treatments without adjuvant. Least Phalaris minor weed density after 60-day crop was observed in the case of UAV sprayer with adjuvant treatment, but there was no significant difference between UAV sprayer and knapsack sprayer in weed control density. Higher yield was observed with UAV sprayer treatments as compared to knapsack sprayer and control treatments.
Weed management is a major constraint in low input organic production systems and necessitates integration of different non-chemical practices for satisfactory weed management. Present field study investigated combinations of cultural and mechanical practices for effective weed management in organic wheat in winter season of 2018–19 and 2019–20 at Ludhiana in north-west India. The integrated interventions viz; mechanical weeding, straw mulch and soil mulch enhanced wheat grain yield by 3448% than unweeded check. Manual weedings recorded the significantly highest wheat grain yield than all other treatments Among other weed management practices, sowing wheat on raised beds (broad bed; 4 rows/bed) integrated with two mechanical weedings (both on beds and in furrow) at 30 and 45 days after sowing, had the lowest weed density and dry biomass and it provided the highest wheat grain yield (3.54–3.73 t/ha) and highest economic returns. It was at statistically at par with wheat sown on beds (2 rows/bed) and mechanical weeding done on bed and in furrows at 30 and 45 days.
Vegetable and floricultural crops are major components of the horticultural industry in India. Weed management is an important aspect in the successful production of these crops. Weeds reduce crop yields, lower their quality and increase costs of production. They host pests and diseases thereby raising the need to control them as well. Weed management may involve non-chemical and or chemical methods. The decision of method to be used depends on the environmental conditions, available labour, weed population, the crop, desired management practices and the cost of controlling weeds. The major aim is to manage the weed population to a level below that will cause a reduction in economic return for the farmer. An integration of different control methods, therefore, needs to be addressed in future research. Furthermore, specific researches on weed management in horticultural crops in India need to be addressed. This article attempts to highlight important weed flora of vegetables and flower crops in India and some of the management strategies that could be used to manage these weeds.
Nutrient uptake by direct seeded rice and associated weeds was studied in a field experiment during kharif 2008. Twenty four treatment combinations viz. six sowing dates (direct seeding on 0 (June 5), 7, 14, 21 and 28 days after nursery sowing (DANS); transplanting 28 DANS); two varieties (short duration PR 115 and medium duration PAU 201) and two weed control treatments (3 hand weedings at 20, 40, 60 days and pendimethalin 0.75 kg ha -1 pre-emergence followed by bispyribacsodium 0.030 kg ha -1 as post emergence) were evaluated in a split plot design with three replications. Among sowing dates and establishment methods, rice grains in manual transplanting utilized significantly higher amount of nitrogen and phosphorus than all the direct seeding dates 0, 7, 14, 21 and 28 DANS; potassium uptake was at par to direct seeding on 0 DANS. The rice straw utilized the highest amount of potassium in transplanted treatment and was at par to direct seeding 0 DANS; nitrogen and phosphorous uptake did not show any specific trend. The nitrogen and potassium removal by the weeds was the lowest in transplanted check which was at par to direct seeding on 0-7 DANS and for phosphorous removal it was at par to 0-14 DANS. Nitrogen and potassium uptake by rice grain and straw did not vary among varieties, however, phosphorous uptake by grain and straw was significantly higher in case of PR 115 than PAU 201; weeds also removed significantly higher amount of potassium in PR 115 as compared to PAU 201. Among weed control treatments, rice grains in the three hand weeding treatment utilized significantly higher amount of nitrogen as compared to sequential application of herbicides; nitrogen uptake by straw was non-significant. The weeds in herbicidal plot removed significantly higher amount of nitrogen, phosphorous and potassium as compared to three hand weedings. The nutrient uptake by crop was directly related to crop dry matter accumulation and grain yield while nutrient removal by weeds was directly related to the weed dry matter accumulation under different treatments.
Morningglories are summer annual or perennial dicots, and are troublesome weeds in sugarcane cultivated in northern India. If not controlled, they may compete with sugarcane, interfere in the harvest operation, and reduce yields. Managing morningglories in sugarcane continues to be a serious challenge for sugarcane growers. Field experiments were conducted during the 3-yr period from 2007 to 2009 to evaluate herbicides applied PRE and POST for control of morningglories in sugarcane. The herbicides applied PRE included diuron, metribuzin, and atrazine at 1.6, 1.4, and 1.0 kg ai ha −1 , respectively, applied alone or followed by 2,4-D amine salt (0.58 or 1.16 kg ae ha −1 ) or 2,4-D sodium salt (0.8 or 1.6 kg ae ha −1 ) applied POST. Herbicides applied PRE controlled morningglories ≤ 87% at 15 d after treatment (DAT); however, control reduced to ≤ 56% at 90 DAT. Control improved when herbicides applied PRE were followed by POST application of 2,4-D amine or sodium salt. For example, diuron applied PRE followed by 2,4-D amine salt applied POST at any rate provided 100% control of morningglories at 15 and 30 DAT. At 90 d after POST application, control ranged from 68 to 82% with the PRE followed by POST herbicides, compared to 0% control when metribuzin or atrazine were applied PRE alone. The density and biomass of morningglories was also reduced to zero in treatments that included 2,4-D amine salt. The number of millable canes, cane height, and single cane weight was superior in PRE followed by POST herbicide treatments compared to herbicides applied PRE alone. Maximum cane yield was recorded for the treatments that included 2,4-D amine or sodium salt compared to only PRE treatments, and it was usually comparable with the nontreated weed-free control. It is concluded that a combination of PRE and POST herbicides were effective for control of morningglories; however, more research is required to evaluate other herbicides and their tank mix partners for control of morningglories in sugarcane.
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