Total Weed Density Research Articles

Effect of Pre and Early Post Emergence Herbicidal Activity on Weed Flora and Yield of Irrigated Sesame (Sesamum indicum L.)

The experimental site was carried out at Agricultural College and Research Institute, TNAU, Coimbatore, during Rabi season of 2018-19 to evaluate the pre and post-emergence herbicides on weed control and yield of irrigated sesame (Sesamum indicum L.). The experiment was laid out in Randomized Complete Block Design with three replications. The results of the experiment concluded that application of pendimethalin at 750g ha-1 as pre-emergence followed by one-hand weeding at 30 days after sowing documented lower total weed density and higher weed control efficiency compared to other treatments and also found superior seed yield (843 kg ha-1). In addition, non-availability of pre-emergence herbicide at the appropriate time, application of early post- emergence of imazythapyr 35 a.e. + imazamox 35 a.e. @ 30 g a.i. ha-1 with hand weeding on 40 days after sowing was found to be better than hand weeding twice at 20 and 40 days after sowing.

Effect of tillage frequency, seed rate, and glyphosate application on teff and weeds in Tigray, Ethiopia

Summary Field experiments were conducted in 2015 and 2016 to study the effect of tillage frequency, seed rate, and glyphosate on teff and weeds. The experiments were arranged in a split plot design with three replications consisting of tillage frequency (conventional, minimum, and zero tillage) as the main plot and the combination of seed rate (5, 15, and 25 kg ha−1) and glyphosate (with and without) as subplots. Results showed that zero tillage reduced teff biomass yield by 15% compared to minimum tillage and by 26% compared to conventional tillage. Zero tillage and minimum tillage also diminished grain yield by 21% and 13%, respectively, compared to conventional tillage. Lowering the seed rate to 5 kg ha−1 reduced biomass yield by 22% and 26% compared to 15 and 25 kg ha−1, respectively. It also reduced the grain yield by around 21% compared to 15 and 25 kg ha−1 seed rates. Conventional tillage significantly diminished weed density, dry weight, and cover by 19%, 29%, and 33%, respectively, compared to zero tillage. The highest seed rate significantly reduced total weed density, dry weight, and cover by 18%, 19%, and 15%, respectively, compared to the lowest seed rate. Glyphosate did not affect weed density but reduced weed dry weight by 14% and cover by 15%. Generally, sowing teff using minimum tillage combined with glyphosate application and seed rate of 15 kg ha−1 enhanced its productivity and minimized weed effects.

Studies on weed management under transplanted rice condition

A field experiment was conducted during the kharif season of 2021 to evaluate the "Studies on weed management under transplanted rice condition" at Instructional-cum-Research Farm, Barrister Thakur Chhedilal College of Agriculture and Research Station, Bilaspur (C.G.). The experiment was laid out in a Randomized block design with seven treatments and three replication. The treatment consisted of T1: weed control, T2: one hand weeding at 20 DAT, T3: two hand weeding at 20 and 40 DAT, T4: Pyrazosulfuron- ethyl @ 20g a.i./ha as pre emergence, T5: bispyribac sodium@ 25 g a.i./ha as post emergence, T6: Pyrazosulfuron- ethyl@ 20 g a.i./ha as pre emergence at 0-5 DAT + bispyribac sodium@25g a.i./ha as post emergence and T7:weed free. The rice variety used in the experiment was Zinco rice MS. Among the different weed management practises at 30, 60 and 90 DAT weed free (T7) allowed the lowest total weed density (2.79 and 3.13 m⁻²), dry weight of weed (4.41 and 2.22, 4.97 and 2.47 g m-2), and highest weed control efficiency (75.05 and 80.97 percent) and was found to be very effective against weed flora in transplanted rice, followed by pyrazosulfuron ethyl @20g a.i./ha as PE at 0-5 DAT + bispyribac sodium @ 25g a.i./ha as a PoE at 20-25 DAT. According to the data, significant improvements in growth parameters, yield attributes, and grain yield (5066 kg ha-1) were obtained.

Effect Of Weed Management Practices On Weed Dynamics, Yield And Economics Of Spring Maize At Dhading Besi, Nepal

Weeds have been a major constraint in maize cultivation resulting in huge economic loss to farmers. A field experiment was conducted at Dhading Besi, Nepal to evaluate the effect of different weed management practices on weed dynamics, yield and economics of spring maize in 2020. The experiment was laid out in Randomized Complete Block Design (RCBD) comprising of eight treatments with three replications. Rajkumar hybrid maize variety was used in the experiment. The treatments consisted of weedy check, weed free, atrazine as PE @1.0 kg a.i./ha, pendimethalin as PE @1.0 kg a.i./ha, atrazine @ 1.0 kg a.i./ha as PE followed by (fb) 2,4-D EE @0.5 kg a.i./ha as PoE, pendimethalin @ 1.0 kg a.i./ha as PE fb 2,4-D EE @ 0.5 kg a.i./ha as PoE, 2 hand weeding @ 20 and 40 DAS and Farmer’s practice. The experiment result revealed that sequential application of atrazine fb 2,4-D EE treatment resulted in highest grain yield (11.37 t/ha) which was statistically similar with weed free (11.24 t/ha) and followed by the treatment atrazine (10.36 t/ha). 16 weed species belonging to 6 different families were identified. The broad leaf weeds and grassy weeds were more prominent than sedges. The total density and dry weight of weeds were found significantly lower in sequential application of atrazine fb 2,4-D EE than other treatments. Similarly, application of atrazine fb 2,4-D EE resulted in maximum weed control efficiency of 87.59 %, 95.91 % and 92.17% at 30, 45 and 60 DAS respectively. The lowest weed index (-1.27%) was also obtained in the application of atrazine fb 2,4-D EE. Yield loss due to weed in the weedy check treatment was found to be 50.99% followed by farmer’s practice (43.17%). The benefit cost ratio and increment in benefit over weedy check were highest in atrazine fb 2,4-D EE followed by atrazine and significantly better than other weed management treatments. The sequential application of atrazine fb 2,4- D EE was found to be the most effective in controlling weeds, high yielding and economical among the different weed control treatments. The application of atrazine one time as PE was found to be next better option for weed control in spring maize.

Impacts of long-term composted manure and straw amendments on rice-associated weeds in a rice–wheat rotation system

AbstractAs part of a long-term experiment to determine the impacts of composted manure and straw amendments (replacing 50% of chemical fertilizer with composted pig manure, wheat straw return combined with chemical fertilizer, and setting no fertilizer and chemical fertilizer-only as controls) on rice-associated weeds in a rice (Oryza sativaL.)–wheat (Triticum aestivumL.) rotation system, species richness, abundance, density, and biomass of weeds were assessed during years 8 and 9. Fertilization decreased the species richness and total density of rice-associated weeds but increased their total biomass. The species richness and densities of broadleaf and sedge weeds decreased with fertilization, while species richness of grass weeds increased only with straw return and density was not significantly affected. The shoot biomass per square meter of grass and broadleaf weeds was significantly higher with fertilization treatments than with the no-fertilizer control, while that of sedge weeds declined with fertilizer application. With fertilization, the densities of monarch redstem (Ammannia bacciferaL.) and smallflower umbrella sedge (Cyperus difformisL.) decreased, that of Chinese sprangletop [Leptochloa chinensis(L.) Nees] increased, and those of barnyardgrass [Echinochloa crus-galli(L.) P. Beauv.] and monochoria [Monochoria vaginalis(Burm. f.) C. Presl ex Kunth] were not significantly affected.Ammannia bacciferawas the most abundant weed species in all treatments. Whereas composted pig manure plus fertilizer resulted in higher density ofA. bacciferaand lower shoot biomass per plant than chemical fertilizer only, wheat straw return plus chemical fertilizer caused lower density and shoot biomass ofA. baccifera. Therefore, it may be possible that fertilization strategies that suppress specific weeds could be used as improved weed management program components in rice production systems.

Effect of Crop Establishment Methods and Weed Management Practices on Weed Density and Productivity of Basmati Rice (Oryza sativa L.)

Aim: Present experiment was conducted to study the effect of crop establishment methods and weed management options on weed dynamics and performance of Basmati rice.
 Study Design: Split plot design.
 Place and Duration of Study: Iinvestigation was conducted during the kharif-season of 2019 and 2020 at Crop Research Center, S.V.P.University of Agriculture &Technology, Meerut (U.P.), India.
 Methodology: Mainfactors consist of the crop establishment methodsviz.(1) Conventional Puddled Transplanting, (2) Unpuddled Flat and (3) Furrow Irrigated Raised Beds, the sub factors consist of five weed management options viz., (1) Pretilachlor @ 0.75 Kg ha-1 PE fb Bispyribac sodium @ 20 g a.i. ha-1 POE at 20 DAT, (2) Almix 4 g a.i. ha-1 + Bispyribac sodium @ 20 g a.i. ha-1 POE at 20 DAT, (3) Bispyribac sodium @ 25 g a.i. ha-1 POE at 20 DAT, (4) Two hand weedings and (5) Weedy check.
 Results: Minimum total weed density was recorded under CPT (E1) followed by FIRB(E3) while itwas maximum under UPF(E2). Two hand-weedings effectively reduced total weed density. In herbicides, application of pretilachlor @ 0.75 Kg ha-1fb Bispyribac sodium @ 20 g a.i. ha-1 (W1) was found most effective in reducingtotal weed density.Higher yield and yield attributes were found under CPT which was significantly higher than the UPF and at par with FIRB. Amongweed management practices highest yield and yield attributes were obtained with pretilachlor @ 0.75 Kg ha-1fb Bispyribac sodium @ 20 g a.i. ha-1.Lowest yield and yield attributes were obtained in weedy check.
 Conclusion: Puddled transplantation in rice might be the best option to get higher yield and for weed control, application of Pretilachlor @ 0.75 Kg ha-1 PE fb Bispyribac sodium @ 20 g a.i. ha-1 POE at 20 DAT may be done to get higher yield.

Response of Cowpea [Vigna unguiculata (L.) Walp.] as Succeeding Crop to Residual Effect of Extreme Levels of Atrazine Administered in Preceding Maize (Zea mays L.)

Background: Globally, grain legumes are the paramount family of agricultural crops following cereals. Generally, sequence cropping has manifested effectual in increasing farm productivity and profitability. However, sometimes herbicides administered in previous crop may be associated with phytotoxic effects that can later cause damage to the succeeding crops. The present study aimed to understand the residual effect of extreme levels of atrazine on succeeding cowpea under maize-cowpea cropping system. Methods: Field experiments were conducted during Kharif and rabi season of 2019-20 and 2020-21 in a randomized block design with eleven treatments, replicated thrice. Result: Residual effect of pre-emergence atrazine at 0.50 kg a.i. ha-1 followed by tembotrione at 120g a.i. ha-1 as post-emergence at 25 DAS recorded the lowest total weed density (4.41), total weed dry weight (9.81 g m-2) and highest weed control efficiency (39.25%) during rabi 2019-20 while during rabi 2020-21 lowest total weed density (5.03), total weed dry weight (10.68 g m-2) and highest weed control efficiency (39.65%) were noticed in pre-emergence atrazine 50% WP at 2.00 kg a.i. ha-1. Highest seed yield (788.67 and 842.33 kg ha-1) was obtained in weed free treatment.

Influence of weed management practices in maize (Zea mays) based intercropping system

A field experiment was conducted at University of Agricultural Sciences, Bengaluru during kharif 2016 and 2017 on red sandy loam soil and the experiment was laid out in Randomized Complete Block Design with factorial concept and replicated thrice. There were 15 treatment combinations involving three intercrops and five weed management practices. The results of the experiment revealed that intercropping of maize (Zea mays L.) with cowpea [Vigna unguiculata (L.) Walp.] has recorded significantly lower total weed density (5.92 No./m2), weed dry weight (6.21 g/ m2), higher WCE (66.97 %), lower WI (17.67 %), higher grain yield (5842 kg/ha) and stover yield (7035 kg/ha) but the higher MEY (8224 kg/ha) was recorded in maize + pole bean intercropping system. Among the different weed management practices, pre-emergence application of pendimethalin 30 % EC @ 1.50 kg/ha recorded significantly lower weed population (5.12 No./m2), weed dry weight (5.05 g/m2), higher WCE (81.81 %), lower WI (7.24 %), higher grain (6589 kg/ha), stover yield (8033 kg/ha) and MEY (8860 kg/ha) compared to other weed management practices.

Topramezone: A selective post-emergence herbicide in chickpea for higher weed control efficiency and crop productivity

Chickpea (Cicer arietinum L.) is a dominant pulse crop in the world for its climate resilience and nutritional values. Weed infestation causes a significant yield loss in chickpea and jeopardize in realizing the potential yield across regions. Pendimethalin as pre-emergence (PRE) is the ruling herbicide, however, post-emergence (POST) herbicides are limited in this crop particularly for managing broad-leaved weeds and higher yield gain. We assessed the impact of POST herbicides available in different crops on weed phytotoxicity, crop selectivity and yield performance in chickpea on sandy-loam soil of Kanpur, India. The experiment was undertaken for two consecutive years (2016-17 and 2017-18) comprising nine herbicides, besides unweeded control (UWC) and weed-free check (WFC). Among the herbicides tested, halosulfuron-methyl 70 g a.i. ha−1 and tembotrione 100 g a.i. ha−1 showed the maximum phytotoxicity scale of 5-10 on chickpea. Clodinafop-propargyl + sodium-acifluorfen 122.5 g a.i. ha−1 and imazethapyr + imazamox 70 g a.i. ha−1 had a recoverable phytotoxicity (scale 3–5) on chickpea. Topramezone 20.6 g a.i. ha−1 at 25 days after sowing (DAS) resulted in higher phytotoxicity on weeds (toxicity scale of 7–10) without any phytotoxicity on chickpea. It significantly controlled the dominant broad-leaved weeds: Chenopodium album L., Lepidium didymum L., Spergula arvensis L., Medicago polymorpha L. and Fumaria parviflora Lam. compared to the remaining herbicides. Topramezone reduced total weed density by 68-70% and 48–51% (P ≤ 0.05) at 45 and 95 DAS compared with UWC, respectively. Therefore, this herbicide had higher (P ≤ 0.05) weed control efficiency in both years (89.8% in 2016-17 and 76.5% in 2017-18) than remaining treatments. Topramezone increased 15.3-19.6% chickpea seed yield than the recommended herbicide pendimethalin 1000 g a.i. ha−1 - quizalofop-p-ethyl 100 g a.i. ha−1 without affecting the nodulation and fluorescein diacetate activity. The UWC resulted in 64% (mean of two years) yield loss compared to the WFC in chickpea. Importantly, topramezone gave comparable yield with WFC. Hence, topramezone can be safely used in chickpea for managing broad-leaved weeds and realizing higher productivity.

Use of conventional and innovative organic materials as alternatives to black plastic mulch to suppress weeds in tomato production

ABSTRACT Controversial issues have been raised regarding the use of plastic mulches, as they can have a destructive effect on agricultural production systems and because of the reliance on fossil fuels for the manufacturing. Investigating the use of organic materials as alternatives to black plastic mulch is thus crucial to enhance both the productivity and the sustainability of agricultural systems. A field experiment was carried out in three years, assessing the efficacy of several organic mulch materials, in comparison with black plastic mulch, for suppressing weeds in tomato production. The results showed that, mulching with shredded date leaves + sawdust, had the highest inhibiting impact in reducing the total weed density by approximately up to 31.3 weeds m-2 at 70 days after transplanting in all three years. The highest marketable yield of the tomatoes was obtained for plants grown with shredded date leaves + sawdust mulch in 2015, 2016 and 2017. Additionally, mulching with coco fibre, sawdust, wheat straw + sawdust, corn residue + sawdust and wood chips + sawdust resulted in similar values for marketable yield as the black plastic. The results revealed that shredded date leaves + sawdust could be a practical alternative to the use of black plastic in the production of processing tomatoes. The use of wheat straw + sawdust, barley straw + sawdust, rice straw + sawdust, corn residue + sawdust, coco fibre + sawdust, sawdust and especially coco fibre, as replacements for black plastic, would be rational options when there is no access to shredded date leaves + sawdust.

Effects of band steaming on weed control, weed community diversity and composition and yield in organic carrot at three Mediterranean sites

AbstractBand steaming is a non‐chemical weed control method of increasing interest for highly remunerative, low competitive crops. This study aimed to test the field application of a new prototype of band‐steaming machine in three organic fields under contrasting Mediterranean environmental conditions. Trials were conducted in carrot under real‐field conditions to investigate the effects of three steaming doses and one control (no steaming) on weed vegetation and crop yield. Soil temperature at steaming application, weed density at species level during carrot crop growth, and weed and carrot biomass at harvest were sampled at each site. Band steaming significantly affected total weed density: when comparing the untreated control with the highest steam dose, weed density reduction ranged from 62% (−492 plants m−2) at site II to 94% (−146 plants m−2) at site III. Generally, diversity of weed communities decreased with increasing steaming dose, indicating a progressive species filtering effect: Fumaria officinalis L. and Sonchus oleraceus L. were filtered by steaming application at site I, while Polygonum lapathifolium L. and Portulaca oleracea L. were filtered at sites II and III. Weed community composition was affected by steaming dose at two sites out of three. Small seeded species (seed mass <1.5 mg) were less tolerant of steaming than species with large seeds. Through reduction in weed density, steam application gave carrot a competitive advantage, increasing fresh yield from 47% at site III (+3,646 g m‐2) to 92% at site II (+1,866 g m‐2), compared with yields at non‐steamed plots.

Climate-smart agriculture practices influence weed density and diversity in cereal-based agri-food systems of western Indo-Gangetic plains

Climate-smart agriculture (CSA)-based management practices are getting popular across South-Asia as an alternative to the conventional system for particular weed suppression, resources conservation and environmental quality. An 8-year study (2012–2013 to 2019–2020) was conducted to understand the shift in weed density and diversity under different CSA-based management practices called scenarios (Sc). These Sc involved: Sc1, conventional tillage (CT)-based rice–wheat system with flood irrigation (farmers’ practice); Sc2, CT-rice, zero tillage (ZT)-wheat–mungbean with flood irrigation (partial CA-based); Sc3, ZT rice–wheat–mungbean with flood irrigation (partial CSA-based rice); Sc4, ZT maize–wheat–mungbean with flood irrigation (partial CSA-based maize); Sc5, ZT rice–wheat–mungbean with subsurface drip irrigation (full CSA-based rice); and Sc6, ZT maize–wheat–mungbean with subsurface drip irrigation (full CSA-based maize). The most abundant weed species were P. minor > A. arvensis > M. indicus > C. album and were favored by farmers’ practice. However, CSA-based management practices suppressed these species and favored S. nigrum and R. dentatus and the effect of CSAPs was more evident in the long-term. Maximum total weed density was observed for Sc1, while minimum value was recorded under full CSA-based maize systems, where seven weed-species vanished, and P. minor density declined to 0.33 instead of 25.93 plant m−2 after 8-years of continuous cultivation. Full CSA-based maize–wheat system could be a promising alternative for the conveniently managed rice–wheat system in weed suppression in north-west India.

Using Ficus retusa L. leaf residue for weed control in field grown green beans

ABSTRACT Given the need to minimise the environmental impact of synthetic agrochemicals in agroecosystems and to increase the sustainability of production systems, it is necessary to identify alternative methods for weed management and crop protection. Regular pruning of evergreen trees, including Ficus retusa L., can provide large quantities of leaf litter and this study aimed to evaluate the use of this leaf residue in a horticultural production system. The effects of using the residue as an organic soil amendment were assessed, including the potential of the residue to control weeds in green beans (Phaseolus vulgaris) crop. Three application rates of F. retusa leaf residue (250, 500 and 1000 g m−2) were applied to the soil at two locations. At both sites, the treatments significantly reduced the density and the biomass of several weed species in a dose- and weed species-dependent manner. The total weed density and weed biomass were also substantially reduced, but there were no effects on the growth or the yield of the P. vulgaris in the treated plots. The application of the leaf residue increased soil organic carbon and some macronutrients, including available nitrogen and potassium. High-performance liquid chromatographic (HPLC) analysis revealed the presence of phenolic and flavonoid compounds in the F. retusa leaves and the reduction of weeds may be attributed to the release of phytotoxins from the residue. Overall, the results suggested that F. retusa leaf residue can be used as part of the weed management strategy to control weeds in P. vulgaris crops.

Varying tillage promotes weed diversity, while a perennial alfalfa–grass mixture promotes weed control in an organic tillage system experiment in Germany

AbstractIn organic farming the control of perennial weed species, in particular Cirsium arvense, can be a major concern for farmers, especially if there is no regulation through perennial forage production. To test whether the stubble cleaner (SC), an enhanced skim plow (PL), is as effective in the control of C. arvense and other weeds as conventional ploughing and perennial forage production, an organic field experiment was established. Three different tillage/crop rotation systems were compared: an SC system and a PL system, both in a cereal-based crop rotation and an additional PL system in a crop rotation that included a perennial alfalfa–grass mixture (PLALF). In the SC system, tillage was carried out solely with the SC, while in the PL and PLALF systems, ploughing was alternated with chiseling. In the fifth year, each main plot was divided into subplots, and seven different cover crop treatments were integrated into each of the three systems. The effects of the three systems and the cover crop treatments on weed cover and density, weed biomass, and weed diversity in the sixth and seventh year of the experiment are the subjects of this paper. The choice of cover crop species was of minor importance for weed control. The PLALF system was generally more effective in controlling C. arvense than the PL and SC systems. No significant differences between the PL and SC systems regarding the control of C. arvense could be identified in four of five assessments. The SC system had significantly higher total weed density than the PLALF and PL systems in both years. However, the differences in weed emergence between the PL and SC systems diminished until the assessment of weed cover and biomass in the main crops, when no significant differences between these two systems (2012) or no differences at all (2013) could be identified. Species richness was not significantly influenced by the tillage/crop rotation system in both years. Evenness and Shannon–Wiener index were significantly higher in the PLALF and PL systems than in the SC system on most assessment dates in 2012. In 2013 there was no clear trend regarding evenness and Shannon-Wiener index probably due to a hoeing operation.. In conclusion, for weed control, the choice of crop rotation was more important than the choice of tillage method, while for the diversity of the weed community, the choice of tillage method was more important than the crop rotation.

Irrigation Timing as a Practice of Effective Weed Management in Established Alfalfa (Medicago sativa L.) Crop

Irrigation is an agronomic practice of major importance in alfalfa (Medicago sativa L), especially in the semiarid environments of Southern Europe. Field experimentation was conducted in Western Greece (2016–2018) to evaluate the effects of irrigation timing on weed presence, alfalfa yield performance, and forage quality. In a randomized complete block design (four replications), two cultivars (“Ypati 84” and “Hyliki”) were the main plots, while three irrigation timings were the subplots (split-plot). The irrigation timings were IT-1, IT-2, and IT-3, denoting irrigation 1 week before harvest, 1 week after harvest, and 2 weeks after harvest, respectively. IT-1 reduced Solanum nigrum L. density by 54% and 79% as compared to IT-3 and IT-2, respectively. Chenopodium album L. density was the highest under IT-2. IT-3 resulted in 41% lower Amaranthus retroflexus L. density in comparison to IT-2, while the lowest values were observed under IT-1. Stand density and stems·plant−1 varied between years (p ≤ 0.05). Mass·stem−1 and alfalfa forage yield were affected by the irrigation timings (p ≤ 0.001). Total weed density and forage yield were negatively correlated in both the second (R2 = 87.013%) and the fourth (R2 = 82.691%) harvests. IT-1 and IT-3 increased forage yield, leaf per stem ratio, and crude protein as compared to IT-2. Further research is required to utilize the use of cultural practices for weed management in perennial forages under different soil and climatic conditions.

Conservational Tillage and Weed Management Practices Enhance Farmers Income and System Productivity of Rice–Wheat Cropping System in Central India

An increasing cost of production, declining factor productivity and sustainability in rice–wheat cropping system are forcing the Indian farmers to shift from conventional tillage (CT) practice to conservational tillage (CA) practice for crop cultivation. With all the numerous advantage of CA practice, weed is a major concern restricting the farm productivity and profitability. To evaluate various tillage and weed management practices in rice–wheat cropping system of Central India, a study was carried out at farmers field. An integrated approach of weed management with Sesbania co-culture with rice followed by tank-mix application of bispyribac-Na + 2,4-d effectively reduced the total weed density and dry biomass accumulation and simultaneously increased the rice grain yield and farmers income, whereas, in case of wheat, as compared to CT practice, CA gave ~ 11% higher grain yield by restricting the growth of weeds. The weed density and dry weight were effectively diminished with pre-mix application of mesosulfuron + idosulfuron in wheat, and this pre-mix combination has also significantly increased the wheat grain yield over farmers practice. As compared to sole application, tank-mix or pre-mix application of different herbicides with varied target group of weeds controlled various weed species in a single application. The total system yield of rice–wheat cropping system with CA practice (6.27 t/ha) was higher as compared to CT practice (5.97 t/ha). The sustainable yield index, farmers profit and B:C ratio of the rice–wheat cropping system were in upper side by adopting the CA practice as compared to existing farmers (CT) practice.

Effect of different fertiliser levels and herbicide treatments on weeds and wheat

A field experiment was conducted during (winter) Rabi seasons of 2018–19 and 2019–20 at College of Agriculture, Jodhpur, Rajasthan with an objective to assess the effect of three fertiliser levels and seven weed management treatments on weeds and wheat to maximise productivity and profitability of wheat (Triticum aestivum L.) by effective and economical weed management. The total weed density was not influenced by increase in fertiliser rate. Significantly minimum weed biomass was recorded with the application of 75% of recommended dose of fertilisers (RDF) (90–30 kg N-P/ha). The 100% RDF (120-40 kg N-P/ha) application recorded significantly higher weed biomass, wheat growth indices (wheat growth rate, leaf area index net assimilation rate), grain, straw and biological yield than75% RDF and was at par with 125% RDF (150-50 kg N-P/ha). The post-emergence application (PoE) of clodinafop-propargyl 15% + metsulfuron-methyl 1% (ready-mix) 64 g/ha and sulfosulfuron 75% + metsulfuron-methyl 5% (ready-mix) 32 g/ha resulted in higher weed control efficiency, lower weed index with higher value of crop resistance index (CRI) and herbicide efficiency index (HEI). The use of 100% RDF with clodinafop-propargyl + metsulfuron-ethyl (ready-mix) 64 g/ha PoE recorded higher net returns and maximum B:C ratio.

Efficacy of herbicides in managing Alternanthera sessilis (L.) R.Br. ex DC. and other weeds for improving the growth and yield of dry direct-seeded rice

A field study was carried out during (rainy) Kharif seasons of 2019 and 2020 at Raipur, Chhattisgarh to study the efficacy of eight herbicide treatments in managing weed community dominated by Alternanthera sessilis (L.) R.Br. ex DC. and improving the growth and yield of dry direct-seeded rice. The most dominant weed species was Alternanthera sessilis accounting for 70% of the total weed density in weedy check. Other associated weeds were Echinochloa colona (L.) Link, Brachiaria ramosa (L.) Stapf and Sporobolus diander (Retz.) P. Beauv. among grasses and the sedge Cyperus iria L. The post-emergence of penoxsulam + cyhalofop-butyl 135 g/ha very effectively controlled the A. sessilis and other weeds, produced highest of 5.04 and 4.63 t/ha grain yield and net return of ^ 71409 and 65563/ha and maximum weed control efficiency among the herbicide-based treatments during 2019 and 2020, respectively. Penoxsulam 22.5 g/ha post-emergence and bispyribac-sodium 25 g/ha post-emergence were also found to be equally effective to it with regards to rice grain yield.

Eco-friendly weed management in dry direct-seeded rice under organic production system

A field experiment was conducted at Agricultural Research Station, Dhadesugur, University of Agricultural Sciences, Raichur, Karnataka, India during rainy (Kharif) seasons of 2017 and 2018 to identify the eco-friendly weed management practice in dry direct-seeded rice under organic production system. The experiment was laid out on fixed site in two consecutive years in a split plot design with two main plot treatments and five sub plots. Along with main and sub-plot treatments, recommended weed management practice as outside uneven control was kept for comparison. The 25% higher rice population with the seed rate of 25 kg/ha along with rice bran at 2 t/ha followed by (fb) hand weeding (HW) recorded significantly lower total weed density (36.60, 46.72 and 42.94 g/m2) and biomass (28.28, 66.95 and 49.40 g/m2); higher weed control efficiency (62.82, 63.73 and 74.17% at 20, 30 and 50 DAS) and higher grain yield (4.81 t/ha) of dry direct-seeded rice under organic production system and it was at par with 25% higher rice population with the rice seed rate of 25 kg/ha along with one inter-cultivation (IC) and hand weeding.

Weed management with pre- and post-emergence herbicides in maize under maize-greengram cropping system

An experiment was conducted during the two consecutive years of winter, 201718, 2018–19 and summer, 2018 and 2019 at wetland farm of S.V. Agricultural College, Tirupati, Andhra Pradesh, in a randomized block design with ten weed management treatments and three replications. The lowest weed density and biomass, highest weed control efficiency and maize growth parameters, yield attributes, kernel and straw yields were recorded with hand weeding (HW) twice at 15 and 30 days after seeding (DAS), which was statistically at par with atrazine 1.0 kg/ha as pre-emergence application (PE) followed by (fb) topramezone 30 g/ha or tembotrione 120 g/ha as post-emergence application (PoE) or one HW at 30 DAS. Higher greengram seed yield, haulm yield, and lower total weed density and biomass in succeeding greengram were noticed with HW twice at 15 and 30 DAS, which was comparable with atrazine 1.0 kg/ha as PE fb one HW at 30 DAS or topramezone 30 g/ha or tembotrione 120 g/ha or halosulfuron methyl 67.5 g/ha as PoE applied in maize. Based on this study it was concluded that atrazine 1.0 kg/ha as PE fb topramezone 30 g/ha or tembotrione 120 g/ha as PoE can be used for the most effective weed management to increase the productivity in winter maize followed by summer greengram cropping system.