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A field experiment was conducted in 2014 and 2015 to find out the effect of herbicides on weed dynamics and productivity of wheat under Jharkhand situation. Two hand weeding performed in wheat crop at 30 and 60 DAS recorded significantly reduced weed density and weed dry matter of broad-leaf, grassy, sedges and total weeds at 30 and 60 DAS with WCE of 94.3 and 94.2%, respectively and was similar to post-emergence application of clodinafop 0.06 kg/ha and pre-emergence application of pendimethalin + metribuzin 1.0 kg/ha + 0.175 kg/ha. This resulted in maximum total and effective tillers, grain (3.08 t/ha) and straw (5.37 t/ha) yield and net return (` 32,019.00 and B:C ratio (1.33) compared to other herbicides application.

A weed management study on onion (Allium cepa L.) was conducted at Birsa Agricultural University, Jharkhand, India during winter season of 2016-17 and 2017-18 in a randomized block design comprised of nine weed control treatments consisting plastic mulch, available weeds mulch, straw mulch, cover crops (Fenugreek), oxyfluorfen 0.5 kg/ha pre-emergent (PE), pendimethalin 1.0 kg/ha PE, mechanical weeding by Dutch hoe, hand weeding at 20, 40, 60 days after transplanting (DAT) and weedy check. Hand weeding at 20, 40 and 60 DAT was most effective in reducing weed dry matter however it was similar to plastic mulch at all the growth stages of crop during 2016-17, 2017-18 as well as in pooled except at 60 DAT in 2016-17. Hand weeding reduced weed dry matter to the extent of 75.83 and 84.83 percent during 2016-17, 100 and 89.21 percent during 2017-18, 98.64 and 88.62 percent under pooled data at 30 and 60 DAT respectively and the corresponding reduction in weed dry matter due to application of plastic mulch was 70.73 and 40.32 percent during 2016-17, 100 and 93.64 percent during 2017-18, 98.37 and 86.52 percent under pooled data at 30 and 60 DAT respectively, compared to weedy check. Application of plastic mulch recorded 300 and 38 percent higher onion yield during 2016-17, 1959 and 117 percent during 2017-18, 576 and 70 percent higher under pooled data compared to weedy check and hand weeding respectively. Plastic mulch also recorded maximum net return 364136, 380185 and 372160 /ha during 2016-17, 2017-18 and under pooled data similar to net return with application of oxyfluorfen 0.25 kg/ha PE, pendimethalin 1 kg/ha PE and hand weeding during 2016-17 while under pooled data maximum B:C ratio was with plastic mulch and was similar to oxyfluorfen 0.25 kg/ha PE, pendimethalin 1 kg/ha PE and hand weeding.

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An experiment was conducted to find out the effect of tillage and weed control methods on weed dynamics and productivity of maize (Zea mays L.)-wheat (Triticum aestivum L.) cropping system. The treatments comprised of combinations of tillage sequences in main plots and weed control methods in sub plots. The results revealed that zero tillage in rainy and winter season is as good as conventional tillage method in reducing weed dry matter and producing maize and system yield, while, conventional tillage in rainy and winter seasons (CT-CT) and conventional tillage in rainy and zero tillage in winter (CT-ZT) reduced weed density as well as weed dry weight in wheat crop consequently, higher wheat grain yield was recorded compared to rest of the tillage sequences. Integrated weed management performed in maize and wheat (IWM-IWM) sequence recorded 51.78% and 61.96% higher maize grain yield and net return of maize, 18.40% and 17.23% higher wheat grain yield and net return of wheat, 31.78% and 34.96% higher system yield and net return respectively, compared to weedy check. Zero tillage with or without residue recorded improved soil pH, organic carbon, CO 2 and dehydrogenase activity. IWM in both the crops recorded higher yields, while significantly higher B:C ratio was under recommended herbicide i.e. atrazine 1.0 kg ha-1 pre emergence in maize and 2,4-D 0.5 kg ha-1 post emergence in wheat (RH-RH). IWM-IWM improved soil CO 2 and dehydrogenase activity than RH-RH sequences from their initial values.