Effect of Different Method of Rice Establishment and Weed Management Options on Yield and Economics of Paddy

A field experiment was conducted during rabi 2022 at Zonal Agricultural and Horticultural Research Station, Brahmavara, Udupi, Keladi Shivappa Nayaka University of Agricultural and Horticultural Sciences, Shivamogga, on sandy loam soil to study the effect of different method of rice establishment and weed management options on yield and economics of paddy. The experiment was laid out in Factorial Randomized Complete Block Design with broadcasting and drum seeder method of establishment and five treatment combinations, replicated thrice. The study revealed that, the weed free treatment maintained by hand weeding recorded highest growth parameters and rice grain yield. The sequential application of pre-emergence herbicide pendimethalin 38.7 % CS @ 750 g a.i. ha-1 at 0-3 DAS (fb) early post-emergence application of bispyribac sodium 10 % SC @ 25 g a.i ha-1 at 13-15 DAS, recorded lowest total weed density (36.92, 31.73 and 40.45 No. m-2) at 15, 30 and 45 DAS, respectively and lower weed index (7.23%) under drum seeder method of establishment . The yield and yield attributing parameters like number of tillers (291.33 m-2), panicle length (19 cm), filled grains (89.33 panicle-1), grain yield (4221 kg ha-1) and straw yield (5387 kg ha-1) were observed in sequential application of pre-emergence herbicide pendimethalin 38.7 % CS @ 750 g a.i. ha-1 at 0-3 DAS (fb) early post-emergence application of bispyribac sodium 10 % SC @ 25 g a.i ha-1 at 13-15 DAS under the drum seeder method of establishment. The highest net return (? 82586 ha-1) and B:C ratio (2.81) was also recorded in the same treatment.

Impact of Pre and Post-emergence Herbicide Mixtures in Direct Seeded Rice (Oryza sativa L.)

Rice (Oryza sativa L.) is a major source of food for more than half of the world population especially in South and Southeast Asia and Latin America. A field experiment was conducted at Krishi Vigyan Kendra, Yamunanagar district, Haryana during Kharif season of 2022 to study the effect of pre and post-emergence herbicides combinations herbicides in direct-seeded rice under irrigated condition. The experiment was laid out in a Randomized block design with three replications. The weed management treatments were T1: Pendimethalin + pyrazosulfuron T2:Pendimethalin + pyroxasulfone, T3:Pretilachlor + pyrazosulfuron, T4: Fenoxaprop-p-ethyl with safener + ethoxysulfuron,T5: Cyhalofop-butyl + penoxsulam and metsulfuron-methyl + chlorimuron-ethyl, T6.:Triafamone + ethoxysulfuron, T7: Pendimethalin + pyrazosulfuron fb bispyribac-sodium, T8: Pendimethalin + pyroxasulfone fb bispyribac-sodium, T9:Pretilachlor + pyrazosulfuron fb bispyribac-sodium, T10:Pendimethalin fb fenoxaprop-p-ethyl + ethoxysulfuron T11: Weed free, T12:Weedy check. Among herbicides, application T10 (pendimethalin fb fenoxaprop-p-ethyl + ethoxysulfuron) and T5 (cyhalofop-butyl+ penoxsulam and metsulfuron methyl + chlorimuron ethy (pre-mix) was superior over other treatment. Application of pendimethalin fenoxaprop-p-ethyl + ethoxysulfuron reduced 58.89% grassy weed and 50 % BLWs compared to weedy check plot at 60 DAS. Assessment at 60 DAS and at harvest showed that bispyribac-sodium was effective in controlling E. colona and E. crus-galli. However, bispyribac-sodium did not control D. aegyptium and L. chinensis. Fenoxaprop significantly reduced the densities of Dactyloctenium aegyptium, L. chinensis, and Digitaria sanguinalis. Fenoxaprop tank-mix with ethoxysulfuron appeared to be synergistic for the control of E. crusgalli and E. colona, and Cyperus sp. as this tank mixture. Integration of pendimethalin fb fenoxaprop-p-ethyl+ ethoxysulfuron provided control of all type of weeds with highest grain yield (6.1 t ha-1) among different treatments which was statistically at par with weed free (6.3 t ha-1). In economics points of views, the highest B-C ratio (3.03) was obtained in cyhalofop-butyl + penoxsulam + metsulfuron methyl + chlorimuron ethy followed by pendimethalin fb fenoxaprop-p-ethyl + ethoxysulfuron (2.98).

Bio-Efficacy of Post Emergent Herbicides on Weeds in Direct Seeded Rice (Oryza sativa L.)

A field experiment was conducted to study the bio-efficacy of post emergent herbicides on weeds in direct seeded rice in medium black clay soil at Agricultural Research Station, Dhadesugur, University of Agricultural Sciences, Raichur, Karnataka during Kharif 2022. The experiment was laid out in Randomized complete block design with three replications. There were eight treatments consisting of five post emergent herbicides sprayed at 25 DAS, hand weeding at 20 and 40 DAS, weed free check and weedy check in direct seeded rice and the variety RNR 15048 was used in this trial. Application of cyhalofop butyl 5.1 % + penoxsulam 1.02 % OD @ 2000 ml ha-1 recorded significantly lower weed density, weed dry weight, weed index and higher weed control efficiency compared to all the other treatments. It also produced higher number of productive tillers (409.4 m-2), panicle weight (3.89 g), filled grains per panicle (243.1), lower number of unfilled grains per panicle (8.4), higher grain yield (6058 kg ha-1) and straw yield (6935 kg ha-1) in direct seeded rice. So it can be concluded that application of cyhalofop butyl 5.1 % + penoxsulam 1.02 % OD @ 2000 ml ha-1 at 25 DAS (weeds at 2-3 leaf stage) was most effective in managing the weeds with higher weed control efficiency. It also resulted in higher growth and yield components of direct seeded rice leading to higher grain yield.

Tillage and Crop Residue Management on Weed Dynamics and Productivity of Direct Seeded Rice

A field experiment was conducted during 2019 and 2020 to evaluate the effect of tillage and residue management on weed dynamics and productivity of direct seeded rice with four tillage systems; Conventional tillage in rice and wheat, Zero tillage in rice and wheat and two rotational tillage sequences that alternated between Conventional tillage and Zero tillage whereas four residue management practices; residue applied in both season, residue applied in kharif season only, residue applied in rabi season only and without residue in both season. The experiment was carried out at research farm of Birsa Agricultural University, Ranchi, Jharkhand. Results revealed that in direct seeded rice having highest grain yield (10%), straw yield (8%) and yield attributes (10-15%) as well as lesser weed density and weed dry matter found under Conventional tillage during both the seasons of experiment but performance of zero tillage was slightly better (3-4%) in second year as compared to all treatments. Whereas surface retention of residue @5 tonne/ha was significantly more effective in controlling different category of weeds, it decreased up to 60-75% weed population, resulting increment in grain yield up to 19% and 23% during first and second year, respectively, as compared to plot receiving no residue.

Intercomparison of Mechanical Transplanted Rice and Direct Seeded Rice in Climate Change Resilient for Improving Crop-Water Productivity and Soil Health in North West IGP: A Review

Climate change is a major issue facing humanity, and the most common method for growing rice is manual puddled transplanted rice (PTR). Direct-seeded rice (DSR) is becoming increasingly popular due to its reduced methane emissions and reduced labour costs. However, there are drawbacks to this transition, such as an increase in weeds, herbicide resistance, nitrous oxide emissions, nutritional disorders, and soil-borne diseases. To reduce these issues, appropriate weed, water, and fertilizer management practices should be applied. Chemical and biotechnological methods, such as herbicide-resistant and more competitive allelopathic variants, will be required for sustainable rice production. The development of site- and soil-specific integrated packages will increase the adoption of DSR and decrease the negative effects of PTR on the environment.

Direct Seeded Rice as Resource Efficient Technology

In Asia, seedlings are typically transplanted into puddled soil to cultivate rice (Oryza sativa L.). Due of the manpower, water, and energy requirements of this manufacturing system, it is becoming less lucrative as these resources become more scarce. Additionally, it impairs the soil's physical qualities, negatively impacts the performance of succeeding upland crops, and increases methane emissions. Different issues, such as a declining water table, a manpower shortage during peak seasons, and worsening soil quality, need the use of alternate establishment techniques to maintain both natural resource and rice yield. Due to its low input requirement, ability to reduce greenhouse gas emissions, and ability to adjust to climatic hazards, the direct seeded rice (DSR) technique has gained a lot of attention and popularity in recent years. Dry seed must be sown into a ready seedbed, while pre-germinated seed must be sown into standing water and puddles of soil. Many farmers have switched from transplanted to DSR culture as a result of the introduction of early maturing cultivars, the application of effective fertiliser management techniques, and increased adoption of integrated weed management strategies. In certain industrialised nations, such the USA, Australia, Japan, China, and Korea, DSR technology is heavily mechanised. By switching from conventional rice to DSR, crop water requirements, soil organic matter turnover, improved nutrient management, carbon sequestration, weed management, greenhouse gas emissions, and crop intensification will all be significantly reduced. The transition from PTR to DSR is hampered by a number of factors, including a high weed infestation, the development of weedy rice, an increase in soil-borne diseases (nematodes), nutritional disorders, poor crop establishment, lodging, the prevalence of blast, brown leaf spot, etc. By addressing these limitations, DSR may show to be a very viable, economically and technically viable substitute for PTR.

Adaptation Approaches for Direct Seeded Rice to Reduce Greenhouse Gas Emission in the Perspective of Climate Change

A field experiment was conducted at research farm, Bihar Agricultural University, Sabour, India during 2017 and 2018 to gain insight crop phonology mediated greenhouse gas emission under different tillage and nitrogen management practices in direct seeded rice (DSR). The experiment was conducted in split plot design with two tillage viz. zero tillage (ZT) and conventional tillage (CT) as main plot and four nitrogen management practices viz. 100% nitrogen through neem coated urea (S1), SPAD based nitrogen management (S2), 75% through neem coated urea + 25% nitrogen through vermicompost, (S3) and ¼ nitrogen as basal and rest in equal three splits at 20, 40, 60 DAS (S4) as sub plot, in three replication. The highest yield (4.69 t ha-1), net return (Rs 46440 ha-1) and B:C ratio (1.44) were recorded from zero tilled DSR. Further, highest yield (4.82 t ha-1), net return (Rs 44880 ha-1) and B:C ratio (1.36) was obtained under split application of nitrogenous fertilizers among other subplot treatments. The range of methane (0.57- 1.47 mg m-2 hr-1) carbon dioxide (0.32- 0.61 mg m-2 hr-1) and nitrous oxide (19.58- 38.79 µg m-2 hr-1) emission was recorded lowest in zero tilled plots and split application of nitrogenous fertilizer also emitted lowest values of 1.59 mg m-2 hr-1 methane, 0.86 mg m-2 hr-1 carbon dioxide and 46.76 µg m-2 hr-1 nitrous oxide at maximum tillering stage of crop growth. Moreover, methane and nitrous oxide emission was gradually decreased from maximum tillering to harvesting stage. Zero tilled DSR with split nitrogen fertilizer application ascribed lowest greenhouse gas intensity among the other crop establishment and nitrogen management options. Thus, zero tilled method of crop establishment with split application of nitrogenous fertilizer could be a remunerative and environmentally stable method for direct seeded rice cultivation.