Conservation agriculture (CA) involves minimum soil disturbance, permanent soil cover through crop residues or cover crops, and crop rotations for achieving higher productivity. Even though the adoption of CA in India is still in an early stage, it has been successfully used in the irrigated rice-wheat cropping systems of the Indo Gangetic Plains (IGP) and recently been demonstrated in parts of central India. Increased weed problems during the ‘transition period’ tends to be the most common hurdle in adoption of CA by farmers. Research has shown that cover crops could play an important role in weed management in CA systems; however, their level of adoption at present is fairly low. Changes in patterns of tillage, planting systems, and other management strategies can alter the soil environment and lead to a major change in weed flora. Herbicide use has been an extremely important component of weed management in CA systems but greater effort is needed to integrate non-chemical weed control tactics with herbicides. Farmer-participatory model of research has proved highly effective in developing CA in rice-wheat system in the IGP. Efforts are required to increase the rate of adoption of direct seeded rice and zero-till wheat throughout the IGP. At present, residue retention on farmer fields tends to be low. Greater awareness of the benefits of residue retention for improved soil health is worthy of an extension campaign in particular and in India in general. Research effort needs to be enhanced to develop CA and promote its adoption in non-rice-wheat cropping systems in India.

Results of experiment conducted during Kharif season of 2010 and 2011 with ten different herbicides and combinations on yield of direct seeded rice revealed that crop resistance index and agronomic management index were maximum in hand weeding treatment followed by fenoxaprop + (chororimuron + metsulfuron) and cyhalofop butyl +(chlorimuron + metsulfuron). Weed persistence index was also maximum in Hand weeding treatment followed by cyhalofopbutyl and pyrazosulfuron. Hand weeding treatment has maximum phytotonic effect followed by fenoxaprop + (chororimuron + metsulfuron) and cyhalofop butyl + (chlorimuron + metsulfuron). Fenoxaprop + (chororimuron + metsulfuron) and cyhalofop butyl + (chlorimuron + metsulfuron) were best herbicides for direct seeded rice from economics and environmental point of view. Fenoxaprop + (chororimuron + metsulfuron) and cyhalofop butyl + (chlorimuron + metsulfuron) have recorded lower persistence of escaped weeds indicating broad spectrum effect in controlling the weeds

A field study was conducted at Chiplima and Sambalpur under West Central Table Land Zone of Odisha during the winter (Rabi) seasons of 2013 and 2014 to evaluate different integrated weed management practices under modified water regimes in rice grown under System of Rice Intensification. Application of 5 cm depth of  irrigation water before the day of weeding operation was effective in increasing  yield significantly (4.72 t/ha) over saturation moisture regime (3.48 t/ha) due to low weed density, weed dry weight and highest number of ear bearing tillers per plant (24) and filled grains/panicle (72). Out of four levels of different weed management systems tested, the application of pretilachlor 750 g/ha (pre-emergence) fb chlorimuron-ethyl + metsulfuron-methyl 4 g/ha (post-emergence) recorded minimum weed density and weed dry weight, higher weed control efficiency and significantly higher grain yield of 5.45 t/ha. The same treatment also recorded highest net return ( 41, 441/ha) and highest B: C ratio (2.17).

Field experiments were conducted during Kharif 2012 and 2013 sandy clay loam soil to study the effect of times of planting and weed management in direct-seeded aromatic rice in foot hills J&K Himalayas. Results revealed that direct-seeded basmati rice sown on 15th June and 10th July recorded non-significant results with respect to grain and straw yield. Among herbicidal weed management, post-emergence application of bispyribac at 30 g/ha recorded significantly higher grain and straw yield which was at par with post-emergence application of cyhalofop-butyl + 2, 4-D 90 g/ha + 500 g/ha and anilophos + ethoxysulfuron at 375 g/ha + 15 g/ha with B:C ratio of 2.98 and 3.95 during Kharif 2012 and 2013, respectivly. It was owing to higher number of panicles/m2, grains/panicle and 1000-grain weight along with lowest weed density, weed dry matter, higher weed control efficiency and lowest weed index.

Manual cono weeding in rice is a tedious job requiring more labour and energy. An effort was made to develop prototype of a self propelled cono-weeder under the AICRP on Weed Management at the College of Horticulture, Kerala Agricultural University, Vellanikkara, Thrissur with an objective to reduce drudgery involved in manual cono-weeding in rice. Main components of the newly developed self propelled cono-weeder are the main frame, a prime mover, front and rear floats and a rotor. Field experiment was conducted at Pattambi in Palakkad district to study the performance of the prototype in comparison with manual cono weeding and conventional weeding methods in rice. The weed density, weed dry weight and the grain and straw yields of rice at various treatments were observed. It was found that self propelled cono-weeder had a field capacity of 0.1 ha/h at an operating speed of 2.0-3.0 km/h. The weeding efficiency of the unit in rice was at par with that of the manual cono-weeder operated twice at 15 and 30 days after transplanting.

Biological properties of the soil have often been proposed as early and sensitive indicators of soil ecological stress or other environmental changes. In the present investigation, the soil samples were collected from weeds associated with rice- wheat cropping system from open- top chambers to assess the effect of elevated CO2 and temperature on soil enzymes. In Rabi season, higher activity of FDA hydrolysis rate was noticed in wild oat with 26.5 (µg fluorescein/g/h) at elevated CO2 + ambient temperature levels. Dehydrogenase activity was higher at enrichment of CO2 for P. minor with 35.9 (µg TPF/g soil/24 h). Urease significantly was higher in enrichment of CO2+ elevated temperature with wild oat 34.6 (µg NH4/g soil/24 h) followed by wheat (31.5µg NH4/g soil/24 h) with elevated CO2 + ambient temperature. In Kharif season, enrichment of CO2 concentration in rhizosphere of Echinochloa crusgalli recorded with higher FDA hydrolysis rate (19.8 µg fluorescein/g/h), dehydrogenase activity (39.8 µg TPF/g soil/24 h) and urease  activity (45.6 µg NH4/g soil/24 h) respectively. We found the carbon dioxide enrichment significantly increased the soil enzymes like dehydrogenase, fluorescein diacetate (FDA) hydrolysis and urease activity in weeds rhizosphere than the crops

The weed species emerged in wheat and cauliflower were screened for heavy metal accumulation ability under sewage water contaminated sites in Jabalpur and adjoining areas. It was observed that nearly 2-10 times higher accumulation of DTPA extractable heavy metals, viz. 0.42-6.30 µg/g cadmium, 2.43-24.1       µg/g lead, 3.06-89.43 µg/g copper, 88.9-226 µg/g manganese and 30-200 µg/g iron were recorded in sewage water soils than the tube well irrigated soils containing 0.69 µg/g Cd, 2.85 µg/g Pb, 62.8 µg/g Mn, 7.36 µg/g Cu, and 37.7 µg/g Fe. Relatively crops accumulated metals to lower extent than the weed species. Among weed species, Avena ludoviciana removed higher 69.6-122.3 µg/g manganese and 48.9-104 µg/g copper, Parthenium hysterophorus extracted 1065-2507 µg/g iron whereas Sonchus arvensis extracted 3.07 µg/g cadmium which were higher than the metal hyperaccumulating Brassica juncea (43.5 µg/g Mn, 19.0 µg/g Cu, 1352 µg/g Fe, 1.40 µg/g Cd). Thus, information on the build up of heavy metal concentration in soil and their removal by seasonal weed species grown on sites receiving sewage water indicate risk of metal entry in animal food chain as these weed species except Parthenium are used as a feed for animals. Besides this these weed species can be exploited for phyto-extraction of heavy metals under abiotic stress situation of metalliferrous sites.

A field experiment to study the efficacy of imidazolinone herbicides in greengram was conducted during Kharif seasons of 2012 and 2013. Ten weed control treatments viz. imazethapyr at 50 and 70 g, premix of imazethapyr + imazamox at 60 and 70 g/ha, both applied as post-emergence at 20 days after sowing; pendimethalin 1000 g and premix of pendimethalin + imazethapyr at 800, 900, 1000 g/ha, both applied as pre-emergence, along with two hand weedings and weedy check were evaluated. Imazethapyr alone and its premixes with pendimethalin and imazamox recorded effective control of mixed weed flora and produced significantly higher greengram seed yield than weedy check. Pendimethalin alone did not control Commelina benghalensis and recorded lower seed yield. All the herbicides were safe to crop.

Comparative efficacy of pre- and post-emergence herbicides in greengram and their residual effect on succeeding crops was studied during Kharif season of the year 2011-2013. Inter-culturing and hand weeding carried out at 20 and 40 DAS produced the lowest weed dry weight with higher weed control efficiency. Among herbicidal treatments, pre-emergence application of pendimethalin at 500 g/ha or imazethapyr 75 g/ha followed by interculturing and hand weeding at 30 DAS proved to be efficient in reducing weed dry weight with more than 70% of weed control efficiency and recorded higher seed and haulm yield of greengram. Further, it was observed that none of the herbicides applied at tested rates had adverse effect on succeeding wheat, chickpea and mustard crops.

A field experiment was conducted to study the weed dynamics, productivity and economics of pigeonpea [Cajanus cajan (L.) Millsp.] under intercropping and weed management practices under rainfed. Among intercropping systems, greengram and blackgram were planted in paired row (2:2) system at 30/90 cm row spacing in main plots and six weed management treatments include pre-emergence herbicides (pendimethalin and oxiflourfen), post-emergence herbicide (imazethapyr) and their combinations in sub plots. Both the intercropping systems (pigeonpea + greengram or pigeonpea + blackgram) recorded higher Crop Equivalent Yield (CEY) (1.23 to 1.36 t/ha), Land Equivalent Ratio (LER) (1.6) and B: C ratio (2.5 - 2.7) than sole pigeonpea. Among herbicide treatments significantly higher weed controlling efficiency was recorded in pendimethalin + imazethapyr and oxyflourfen + imazethapyr (90.6 - 91.5%) as compared to pendimethalin or oxiflourfen or imazethapyr (72.1 - 84.6%).

A field experiment was carried out with twelve weed control treatments during the winter season of 2012-13 and 2013-14 on a silty clay loam soil to evolve an effective herbicide combination to control the complex weed flora in garden pea. Phalaris minor (28.8%), Alopecurus myosuroides (21.3%), Avena ludoviciana (15.8%), Lolium temulentum (12.1%) and Vicia sativa (16.7%) were found major weeds in experimental area. Pendimethalin 1000 g/ha supplemented with one HW at 45 DAS being statically at par to the application of pendimethalin 1000 g/ha (pre) fb imazethapyr + imazamox 60 g/ha (post) significantly reduced the density of major weeds. In general, the efficacy of the formulated mixtures whether as double knock or as a sole application was found better than the sole application of herbicides. Pendimethalin 1000 g/ha fb one HW and pendimethalin 1000 g/ha fb imazethapyr + imazamox 60 g/ha being statistically alike with weed free resulted in significantly higher number of nodules, green pod yield and straw yield.

Present study was carried out to explore the antibacterial potential of three weeds Mazus japonicus, Fumaria indica and Vicia sativa grown widely in Pakistan. Different extracts (aqueous, methanolic and petroleum ether) of the respective weeds were prepared and tested against nine bacterial strains using agar well diffusion assay. Bacterial strains included both gram positive (Staphylococcus aureus, Bacillus sp, Bacillus megaterium, Enterococcus faecium, Enterrococcus faecalis and Enteroccocus sp) and gram negative (Pseudomonas putida, Escherichia coli and Escherichia coli top10) bacteria. Ten different concentrations of each extracts were used. Enterococcus faecalis JH22 and Bacillus megaterium MB141 were the most resistant bacteria while Escherichia coli top10 was found highly susceptible and inhibited by all three extracts of M. japonicas and F. indica. Vicia sativa was effective only against Staphylococcus aureus and Pseudomonas putida at limited crude extract concentration while all other strains showed resistance against different extracts of the respective plant. Amongst the plant extracts screened for antibacterial activity, methanolic extracts showed best antibacterial activity whereas aqueous and petroleum ether were found least active. This study significantly supports the usage of these widespread weeds as traditional medicines for various bacterial infections.

A field experiment was conducted during 2012-13, to study the effect of herbicides applied in mixture and sequence for managing complex weed flora in transplanted rice. Among the herbicides applied, bispyribac-Na applied in combination with almix as tank mixture recorded the least weed count, weed dry matter and highest WCE. Significantly higher yield attributes, viz. number of grains/panicle and grain yield were also recorded when bispyribac-Na and metsulfuron-methyl + chlorimuron-ethyl were applied as tank mixture. Pre-emergence application of pretilachlor fb post-emergence application of metsulfuron-methyl + chlorimuron-ethyl and hand weeding twice at 25 and 45 DAT were also equally effective. Application of pre- and post-emergence herbicide alone were found to be less effective in reducing weed density and weed dry matter.

A field experiment was carried out at the Agricultural Research Farm, Rajendra Agricultural University, Pusa, Samastipur, Bihar (India), during Kharif season of 2012. The experiment involved 14 weed management treatments laid out in randomized block design with three replication. The highest grain yield (3.95 t/ha) was recorded with hand weeding twice at 20 and 40 DAS and lowest under weedy check (1.73 t/ha). Similar trend was observed in straw yield. Among different combination of herbicides, application of pretilachlor at 750 g/ha at 1 DAS fb azimsulfuron at 35 g/ha at 20 DAS was the best combination and comparable with hand weeding. Maximum weed control efficiency and weed control index were recorded under treatment hand weeding twice at 20 and 40 DAS and minimum under weedy check. However, weed density and weed dry weight were found maximum under weedy check and minimum with hand weeding twice at 20 and 40 DAS.

A field experiment was conducted on sandy loam soil of Birsa Agricultural University, Ranchi during rainy season of 2014 to evaluate the performance of weed-control methods on weed dynamics and productivity of maize. The experiment was laid out in randomized block design with 12 treatment in three replication.  Application of atrazine + pendimethalin 0.50 + 0.50 kg/ha as pre-emergence similar to two hand weeding at 20 and 40 DAS recorded reduced weed density dry matter accumulation compared to weedy check at 30 and 60 days after sowing. These resulted significantly increase in plant height, number of grains per cob, 100-seed weight as well as 65.6% significantly higher grain yield (3.80 t/ha) as compared to weedy check (1.309 t/ha), consequently maximum net return (  53492/ha) and benefit: cost ratio (3.57) than rest of the treatments.

Bio-efficacy and phytotoxicity of pre-emergence tank mix application of atrazine + pendimethalin, pendimethalin + imazethapyr, ready mix application of pendimethalin+ imazethapyr (Velore), imazethpyr + imazamox (Odessey), penoxsulam, and post-emergence application of penoxsulam, atrazine, imazethapyr  and  imazethpyr + imazamox along with standard pre-emergence herbicide atrazine were evaluated at ICAR-Indian Institute of Millet Research, Hyderabad during rainy season of 2014. The field was dominated with broad-leaved weeds (65.8%) followed by grasses (26.3%) and sedges (7.9%). Infestation of weeds throughout the cropping season caused 37 % reduction in grain yield. Post-emergence (15 DAS) application of imazethapyr and  velore herbicides was highly phytotoxic and caused complete mortality of both sorghum plants and weeds at 2 weeks after herbicide application. Tank mix application of atrazine + pendimethalin (500 + 750 g/ha) as pre-emergence was safe and most effective in sorghum. Atrazine as post-emergence was less effective than its pre-emergence application. New herbicide molecules viz., penoxsulam, velore and odessey, though effectively controlled the weeds but reduced the grain yield due to reduction in number of grains/panicle.

A field experiment was conducted during rainy season of 2014 at Experimental Farm, Hawalbagh, Almora, to know the effect of weed management practices on weed index and grain yield of rainfed finger millet. All the weed control measures significantly reduced total weed dry weight and weed index as compared to that of weedy check. Manual weeding at 20 and 40 DAS (5.6 g/m2) significantly lowered the total weed dry weight followed by manual weeding at 20 DAS (7.4 g/m2). Weed dry matter recorded in weed wiper treated plots were at par with pre-emergence pendimethalin at 1 kg/ha and post-emergence 2,4-D at 1 kg/ha. Apart from weed free check highest weed index was found in manual weeding at 20 and 40 DAS (82.0%) followed by manual weeding at 20 DAS (68.5%). Grain yield was significantly higher in hand weeding twice (2200 kg/ha) followed by weeding once (2.02 t/ha). The highest B:C ratio was in manual weeding at 20 DAS (1.39).

Experiment was conducted in the Research cum Instructional Farm, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh during Kharif season 2009. The treatment comprised of 14 weed management practices and blackgram variety “TU 94-2”. The results revealed that higher plant population, plant height, number of leaves, number of branches, dry matter accumulation, number of nodules, dry weight of nodules, crop growth rate, seed yield, weed growth rate, weed control efficiency and harvest index were obtained under hand weeding twice (20 and 40 DAS), followed by imazethapyr at 25 g/ha pre-emergence and minimum was obtained under unweeded check.

A field experiment was conducted during Rabi season of 2013-14 at Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.) to find out efficient herbicide combinations for weed management in chickpea. Further, significantly higher growth characters viz. plant height, number of branches, dry matter accumulation as well as yield attributes, seed yield, stover yield and harvest index were recorded under hand weeding twice at 25 and 45 DAS, which was at par with tank mix PE application of oxyfluorfen + metribuzin at 125 + 350 g/ha and registered an yield increase of 74.36 and 73.1%, respectively, over control. Metribuzin at 250 g/ha applied at 20 DAS and oxyfluorfen at 125 g/ha applied at 12 DAS showed phytotoxic effects on chickpea plants and recorded reduction in yield of 62.26 and 53.2%, respectively, over hand weeding twice at 25 and 45 DAS. Economics in terms of net return and B:C ratio recorded maximum under oxyfluorfen + metribuzin at 125 + 350 g/ha as PE. Dehydrogenase enzyme activity of experimental field was significantly maximum under control plot, followed by hand weeding twice at 25 and 45 DAS.

A field experiment was carried out on the silty clay soil at Mahatma Phule Krishi Vidyapith, Rahuri (Maharastra) during Kharif 2013-2014. One hoeing at 15 DAS and two hand weeding at 25 and 45 DAS best treatment in respect of growth attributing character and yield attributing characters. The weed dry matter and intensity was also lowest in one hoeing at 15 DAS and two hand weeding at 25 and 45 DAS, which was followed by pre-emergence application of  metribuzin at 2 DAS at 525 g/ha + 1 HW at 30 DAS, PE application of treatment pendimethalin at 20 DAS cs at 677.25 g/ha + 1 HW at 30 DAS, metribuzin at 525 g/ha  fb imazethapyr + propaquizafop-ethyl as post-aplication at 20 DAS at 80 + 60 g/ha. Metribuzin at 525 g/ha + 1 HW at 30 DAS was economic viable due to high B: C ratio and net return.

The field was infested with monocot weeds like Echinochloa colona, Cyperus iria whereas dicot weeds Alternanthera philoxiroides, Eclipta alba, Commelina benghalensis and Phyllanthus niruri were less dominant in soybean. The application of Chlorimuron-ethyl 24 g/ha as early post-emergence along with mechanical weeding was most effective in paralyzing the weed growth to that of chlorimuron-ethyl (12, 24, 36, 48 and 72 g/ha) and mechanical weeding at 20 DAS. The application of chlorimuron-ethyl herbicide at 24 g/ha as early post-emergence along with mechanical weeding was significant superior for growth parameters, yield attributes and seed yield (1.61 t/ha) of soybean than rest of the treatments without any phytotoxicity on soybean plants and was found more remunerative in terms of NMR (Rs  20023.8) and B-C ratio (2.06) than application of chlorimuron-ethyl herbicide at 12 g/ha to 72 g/ha, as early post-emergence. Two hand weedings (20 and 40 DAS) proved to be the best in terms of yield (1.69 t/ha grain, 3.49 t/ha stover); however, NMR (Rs 20011.7/ha) was almost at par to chlorimuron 24 g along with mechanical weeding (Rs 20023.8/ha).

A field experiment was carried out at research farm of Rajasthan College of Agriculture, Udaipur during Kharif 2014 in randomized block design (RBD) with 14 treatments pre-emergence application of pendimethalin 0.75 kg/ha + hand weeding 30 DAS resulted broad spectrum of weed control besides gives higher grain yield. This weed management method found to be promising to control weeds of soybean crop and would play an important role in areas where labour is too expensive and time is a constraint.

Field experiment was conducted at Research farm, College of Agriculture, JNKVV, Tikamgarh during Kharif 2013-14 to study the effect of herbicides for controlling weeds in linseed. There was prevalence of dicot weeds in experimental field as these weeds constituted the higher relative density (67.8%) at harvest as compared to monocot weeds which had only 18.04% relative density. On the basis of results, it can be concluded that hand weeding twice at 20 and 40 DAS recorded significantly the lowest weed density as well as weed dry weight followed by pre-emergence application of pendimethalin at 1.0 kg + imazethapyr at 1.0 kg/ha. The seed and straw yields of linseed was significantly higher under twice hand weeding at 20 and 40 DAS followed by pre-emergence application of pendimethalin at 1 kg/ha + imazethapyr at 1 kg/ha, pendimethalin at 0.75 kg/ha + imazethapyr at 1.0 kg/ha and post-emergence application of imazethapyr at 100 g/ha. The highest net monetary return obtained with twice hand weeding whereas the B:C ratio was the highest with the application of imazethapyr at 100 g/ha followed by imazethapyr at 75 g/ha.

A field experiment was conducted to study the effect of early post-emergence herbicide namely chlorimuron-ethyl and quizalofop-ethyl on weeds in castor and also to evaluate its weed control efficiency over hand weeding and power operated weeding. It was revealed that pre-emergence application of pendimethalin at 1.0 kg/ha followed by mechanical weeding twice at 20 and 40 DAS has recorded lower weed density with higher weed control efficiency. Mechanical weeding twice, pre-emergence application of pendimethalin followed by chlorimuron-ethyl at 0.01 kg/ha or mechnical weeding twice on 20 and 40 DAS have recorded higher yield and economics. Mechanical weeding twice (2.58 kg/ha), pre emergence application of pendimethalin at 1.0 kg/ha followed by mechanical weeding twice at 20 and 40 DAS (2.57 kg/ha) or post-emergence application of chlorimuron-ethyl at 0.01 kg/ha (2.47 kg/ha) have recorded numerically higher yield and B:C ratio.

On the basis of above findings, it may be concluded that treatment Two hand weeding at 20 and 40 DAS, followed by treatment Propaquizafop 10% EC (PoE) 50 g/ha are most effective and remunerative weed control practices for controlling the weeds in sesame under sandy clay loam soils of Northern M.P.. The higher grain yield and net return were obtained from treatment two hand weeding at 20 and 40 DAS.

The objective of energy usage and benefit-cost analysis of Bt cotton was to determine the energy efficiency indices under different weed management practices in Bt cotton. The field experiment was carried out at college farm, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad during Kharif, 2014 with ten weed management practices. The inputs in the calculation of energy usage in agro-ecosystems embraced labour, machinery, electricity, diesel oil, fertilizers, herbicides, pesticides, seeds, while seed cotton was included in the output. The results depicted that total input and output energy under different weed management practices were about 16051 to 18550 and 2360 to 16838 MJ/ha, respectively. Out of all the treatments tested the highest energy use efficiency (0.9), energy intensiveness (0.7 MJ/), specific energy (12.9 MJ /kg), energy productivity (0.9 kg/MJ), net energy       (-1712 MJ/ha) of Bt cotton production system were reported in mechanical weeding thrice at 20, 40 and 60 DAS. However the lowest energy intensiveness of 0.5 MJ per rupee was reported in pre emergence application of pendimethalin at 1000 fb 2 HW at 20 and 50 DAS treatment.

A field experiment was conducted during 2013-14 at Research Farm, College of Horticulture, Mandsaur (Madhya Pradesh) to study the weed management practices in cumin. Twelve weed management treatments were laid in randomized block design with three replications. Weed free treatment recorded significant maximum growth and yield attributes of cumin followed by oxadiargyl at 0.06 kg/ ha (PE) fb two hand weeding at 40 and 60 DAS. Similarly, significant maximum seed yield (595 kg/ha), straw yield (900 kg/ha) and harvest index (39.7%) was observed with oxadiargyl at 0.06 kg/ha as pre-emergence fb two hand weeding at 40 and 60 DAS. Maximum weed population was measured in case of weedy check, which was followed by hand weeding (40 DAS) at all the growth stages of cumin. It may be concluded that application of oxadiargyl at 0.06 kg/ha as pre-emergence fb two hand weeding at 40 and 60 DAS may be use for higher yield of cumin.