Sumit Chaturvedi

Biomass production and carbon sequestration in different tree-based systems of Central Himalayan Tarai region

Biomass, carbon storage and carbon dioxide mitigation potential of plantations of Populus deltoides, Eucalyptus tereticornis, Dalbergia sissoo, Mangifera indica, Litchi chinensis and Prunus salicina were assessed. Being economically viable, such tree plantations are grown by farmers on a large scale in north India. The maximum total biomass (94.8 Mg ha− 1) was observed in a 10-year-old D. sissoo monoculture plantation, followed by an 8-year-old P. deltoides block plantation (63.0 Mg ha− 1). Carbon stocks ranged from 4.51 Mg ha− 1 in an 8-year-old P. deltoides boundary plantation to 43.39 Mg ha− 1 in D. sissoo plantation. The carbon sequestration rate for P. deltoides block and boundary plantations was estimated to be 2.75 and 0.43 Mg C ha− 1 year− 1, respectively. Eucalyptus boundary plantation sequestered 0.84 Mg C ha− 1 year− 1 while D. sissoo plantation sequestered 2.73 Mg C ha− 1 year− 1. Among fruit trees, the highest sequestration rate was recorded in M. indica (mango) plantation, with 1.43 Mg C ha− 1 year− 1.

Management of complex weeds in sugarcane by ametryn + trifloxysulfuron

Field experiment was conducted to evaluate the bio-efficacy of ametryn 73.15% + trifloxysulfuron 1.85% W.G for the management of grasses, sedge and broad-leaf weeds in sugarcane. The experiment consisted of nine treatments laid out in randomized block design with three replications. Cyperus rotundus, Ipomoea spp, Brachiaria reptans, Echinochloa colona, Digitaria sanguinalis and Dactyloctenium aegyptium were observed as major weeds. Among herbicide treatments, the lowest density of total weeds was observed with ametryn + trifloxysulfuron at 1500 g/ha though the differences were nonsignificant when compared with its lower dose i.e. 1250 g/ha at 15 and 45 days after application (DAA). Application of ametryn + trifloxysulfuron 1250 and 1500 g/ha recorded significantly lower weed dry weight over any other herbicidal treatment at 15 and 45 days. Highest weed control efficiency of total weeds at both 15 and 45 DAA were recorded with the application of ametryn + trifloxysulfuron 1500 g/ha which was closely followed by 1250 g/ha. The highest cane yields (9.04 t/ha and 10.51 t/ha) were recorded from weed free plot being at par with hand weeding thrice at 30, 60 and 90 DAP.

Herbicidal Combinat ion for Effect ive Management of Complex Weed Flora in Transplanted Rice (Oryza sat iva L.)

Long term continuous use of similar herbicide is major culprit for weed shift and herbicide resistance. Therefore, a field experiment was conducted at Norman E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar during kharif 2012 to evaluate the performance of new broad spectrum herbicide molecules. Pre-emergence application of Pretilachlor 750 g ha−1 with no irrigation during initial one week along with post-emergence application of Bispyribac-Na 20 g ha−1 provided broad spectrum control of complex weed flora at 30 and 60 days after transplanting (DAT) resulted in significantly lower weed density and dry matter than rest of the weed control treatments. This treatment thus, provided higher weed control efficiency (98.7%) and yield (5729 kg ha−1), than test treatment i.e. pre-emergence application of Pretilachlor alone. However, one conoweeding (15 DAT)+one hand weeding (45 DAT) recorded higher weed density and dry matter at both the stages. Alone post-emergence application of Bispyribac-Na and twice hand weedings produced at par yield with Pretilachlor 750 g ha−1 with no irrigation during initial one week along with application of Bispyribac-Na 20 g ha−1. Among different doses of Penoxsulam, the increase in dose of Penoxsulam caused significant reduction in weed density and dry matter thus registered higher grain yield. Post-emergence application of Penoxsulam at 22.5 and 25 g ha−1 produced comparable yield with Bispyribac-Na. Conoweeding + one hand weeding was found least effective compared to rest of the treatments.