Tej Pratap

Different Weed Management Practices and Their Effect on Soil Micro Flora in Spring Season Sweet Corn (Zea mays L. saccharata) in Tarai Region of Uttarakhand

Maize is one of the potential cereal crops grown in India. Due to its versatility in use and huge production potential it is referred as the „Queen of Cereals‟. Sweet corn (Zea mays L. var. saccharata) is a special kind of maize having at least 16% sugar in its kernel. It is a crop grown for fresh green cobs for human consumption and also used as raw or processed material for the food industry throughout the world. It‟s taste and nutritional value have made it a valued crop in all countries and the scope of corn production is constantly increasing (Olabode and Sangodele, 2015). Among the several factors most critical for the low yield of maize appears to be the weeds, competing with the International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 09 (2018) Journal homepage: http://www.ijcmas.com

Efficacy of propanil for the mixed weed flora in direct-seeded rice

A field experiment was carried out at G.B. Pant University of Agriculture and Technology, Pantnagar, U.S. Nagar, Uttarakhand during rainy season of 2015 and 2016 to evaluate the efficacy of propanil 80% WG against mixed weed flora in direct-seeded rice. The most dominant weeds were: Echinochloa colona, Echinochloa crus-galli, Leptochloa chinensis, Eleusine indica and Digitaria sanguinalis among grassy weeds; Celosia argentea as broad-leaved weed and Cyperus spp. as sedge. Results revealed that propanil 4000 g/ha being on a par with 3000 g/ha was found most effective for controlling grassy as well as broadleaved weeds as compared to other herbicidal treatments. The lowest weed biomass (11.9 g/m2) and the highest weed control efficiency (73.6%) were also recorded with this treatment. Propanil 4000 g/ha being on a par with 3000 g/h recorded maximum grain yield (4.6 t/ha) which was superior to rest of the herbicidal treatments.

Chemical control of weeds in dry-seeded rice

Rice (Oryza sativa L.) is the principal crop of India cultivated in an area of 43.95 million hactares annually with a production of 106.65 million tonnes, with an average productivity of 2.4 t/ha (Ministry of Agriculture 2015). The conventional system of rice production i.e transplanting under puddled conditions is mainly followed by farmers. However, it is water, labour and energy intensive. Therefore, to assure sustainability of rice production, more resource efficient alternative methods of rice cultivation are needed. The dry seeded rice (DSR) technology being water, labour, energy efficient and having ecofriendly characteristics, received much attention as a potential alternative to transplanting under puddle conditions (Kumar and Ladha 2011). However, weed control is major limitation for the success of DSR as compared to transplanted rice (Chauhan and Yadav 2013). In DSR, weeds emerge simultaneously with crop seedlings and grow more quickly in moist soil than in puddled transplanted rice, resulting in severe competition for resources to the crop. Therefore, weeds present in the field are the main biological constraint to the success of DSR and failure to control weeds result in yield losses ranging from 50 to 90% (Chauhan and Opena 2012). Therefore, an experiment was conducted to study the sequential application of preand post-emergence herbicides and their combination along with hand weeding for weed control in dry seeded rice.

Rice productivity under different weed management and establishment methods

Field experiment was conducted to find out alternative tillage practices with appropriate weed management opportunities to increase the yield potential of rice crop. Major associated weeds were Echinochloa colona, E. crus-galli, Leptochloa chinensis among grasses, Caesulia axillaris, Alternanthera sessilis, Ammania baccifera among broad-leaved weeds and Cyperus rotundus, C. iria, C. difformis and Fimbristylis miliaceae among sedges at 60 DAS. Adoption of conventional transplanted rice (TPR) with Sesbania inclusion as green manure along with integrated approaches of weed management using bispyribac-sodium 20 g/ha supplemented with one hand weeding at 45 DAS was found effective and profitable alternative than conventional transplanted rice and hand weeding to attain higher productivity of rice crop. However, the benefit cost ratio was higher when the crop was grown under zero-till situation (ZTR) along with retention of crop (wheat) residues followed by Sesbania as brown manure due to less cost involved under zero-till situation.

Herbicides combination for control of complex weed flora in transplanted rice (Oryza sativa L.)

A field experiment was carried out at Norman E. Borlaug Crop Research Centre of G. B. P. U. A. & T., Pantnagar, U. S. Nagar, Uttarakhand during kharif seasons of 2014 and 2015 to evaluate the efficacy of different herbicides and their combinations to control the different weed flora in transplanted rice. The experimental site was silty clay loam in texture, medium in organic carbon (0.66%), available phosphorus (27.5 kg/ha) and potassium (243.5 kg/ha) with pH of 7.3. The experiment was laid out in randomized block design with 12 treatments replicated thrice. In the present study, Echinochloa colona, Echinochloa crus galli, Leptochloa chinensis, Ammania baccifera, Caesulia axillaris, Cyperus iria and Cyperus difformis were found as major weeds in experimental field during both the years. The results revealed that among the herbicidal treatments penoxsulam+cyahalofop-butyl @ 135 g/ha recorded lowest total weed density which was statistically similiar to pretilachlor @ 750 g/ha fb ethoxysulfuron @ 18.75 g/ha, bispyribac-sodium+ethoxysulfuron @ 25+18.75 g/ha, pretilachlor @ 750 g/ha fb readymix of chlorimuron-ethyl +metsulfuron-methyl @ 4 g/ha and pendimethalin @ 1000 g/ha fb bispyribac-sodium @ 25 g/ha. The total weed dry weight was significantly reduced with penoxsulam+cyahalofop-butyl @ 135 g/ha, pendimethalin @ 1000 g/ha fb bispyribac-sodium @ 25 g/ha and pretilachlor @ 750 g/ha fb ethoxysulfuron @ 18.75 g/ha over rest of the herbicidal treatments. The highest weed control efficiency (98.2%) was also recorded with readymix of penoxsulam+cyahalofop-butyl @ 135 g/ha followed by pendimethalin @1000 g/ha fb bispyribac-sodium 25 g/ha, pretilachlor 750 g/ha fb ethoxysulfuron 18.75 g/ha, bispyribac-sodium+ethoxysulfuron @ 25+18.75 g/ha. The maximum grain yield (6.8 t/ha) was recorded with penoxsulam+cyahalofop-butyl @ 135 g/ha which was statistically at par with pendimethalin @ 1000 g/ha fb bispyribacsodium @ 25 g/ha, twice hand weeding at 25 and 45 DAT, bispyribac-sodium+ethoxysulfuron @ 25+18.75 g/ha, pretilachlor @ 750 g/ha fb ethoxysulfuron @ 18.75 g/ha and readymix of triafamone+ethoxysulfuron @ 60 g/ha.

Herbicides for weed management in direct dry-seeded rice

A field experiment was conducted during Kharif seasons of 2010 and 2011 to evaluate the efficacy of different herbicides and their combinations in managing weeds of direct dry-seeded rice. The major weeds were Echinochloa colona, Echinochloa crus-galli, Leptochloa chinensis among grasses, Caesulia axillaris and Trianthema monogyna among broad-leaved weeds and Cyperus rotundus among sedge. The lowest total weed density was recorded with azimsulfuron 35 g/ha and cyhalofopbutyl + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha, which were at par with each other followed by fenoxaprop + ethoxysulfuron 60 + 15 g/ha and twice hand weeding at 20 and 40 days after seeding (DAS). The lowest weed biomass was recorded with combined application of fenoxaprop + ethoxysulfuron 60 + 15 g/ha and fenoxaprop + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha. The highest weed control efficiency was recorded with twice hand weeding at 20 and 40 DAS (89.9%) followed by fenoxaprop + ethoxysulfuron 60 + 15 g/ha, fenoxaprop + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha, bispyribac-sodium 25 g/ha and fenoxaprop 60 g/ha over the weedy check. The higher grain yield (3.50 t/ha) was recorded with twice hand weeding (20 and 40 DAS), which was at par with fenoxaprop + ethoxysulfuron 60 + 15 g/ha followed by bispyribac-sodium 25 g/ha alone and fenoxaprop + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha.

Azimsulfuron as an effective herbicides against sedges in transplanted rice

A field experiment was carried out at Pantnagar during Kharif seasons of 2013 and 2014 to know the bioefficacy of different doses of azimsulfuron 50 DF against sedges in transplanted rice. The soil of the experimental field was clay loam in texture, medium in organic carbon (0.67%), available phosphorus (29.6 kg/ha) and potassium (176.4 kg/ha) with pH 7.2. Major sedges were: Scirpus roylei, Cyperus iria, Cyperus difformis and Fimbristylis miliacea. Application of azimsulfuron 17.5, 26.25 and 35 g/ha with 0.2% surfactant and 35 g/ha without surfactant provided complete control of Scirpus roylei, Cyperus iria and Cyperus difformis. The lowest dry matter of weeds was recorded with azimsulfuron with 0.2% surfactant from 17.5 to 35 g/ha, which was found at par with azimsulfuron 35 g/ha without surfactant. Among herbicidal treatments, the highest grain yield (6.12 and 6.09 t/ha) was obtained in azimsulfuron + 0.2% surfactant at 26.25 and 35 g/ha, which was significantly similar to azimsulfuron + 0.2% surfactant 17.5 g/ha and azimsulfuron 35 g/ha without surfactant.

Effect of herbicides and their combinations on weed growth and yield of transplanted rice

A field experiment was carried out at Norman E. Borlaug Crop Research Centre of G.B.P.U.A.&T, Pantnagar U.S. Nagar, Uttarakhand during Kharif season of 2012 and 2013 to find out the efficacy of different herbicide combinations in transplanted rice. The experimental site was silty clay loam in texture, medium in organic carbon (0.66%), available phosphorus (27.5 kg/ha) and potassium (243.5 kg/ha) with PH 7.3. Echinochloa colona, Echinochloa crus-galli, Leptochloa chinensis, Alternanthera sessilis, Ammania baccifera, Caesulia axillaris and Cyperus iria were the major weeds in experimental field. Bispyribac–sodium + ethoxysulfuron 25 + 18.75 g/ha having statically similar with pretilachlor 750 g/ha fb ready mix of chlorimuron-ethyl + metsulfuron-methyl 4 g/ha and bispyribac-sodium + ready mix of chlorimuron-ethyl + metsulfuron-methyl 20 + 4 g/ha resulted in significantly lowest total weed density, dry matter accumulation and highest weed control efficiency, respectively. The maximum grain yield was recorded with twice hand weeding at 25 and 45 DAT, which was statistically at par with bispyribac– sodium + ethoxysulfuron 25 +18.75 g/ha, pretilachlor 750 g/ha fb ready mix of chlorimuron-ethyl + metsulfuron-methyl 4 g/ha, bispyribac–sodium + ready mix of chlorimuron-ethyl + metsulfuron-methyl 20 + 4 g/ha and pretilachlor 750 g/ha fb ethoxysulfuron 18.75 g/ha over the weedy check.