The energy consumption pattern and greenhouse gas (GHG) emission of any rice production system is important to know the sustainability of varied cultivation and establishment technique. This study was conducted to determine the energy use pattern, GHG emission and efficiency of rice farms in puddled transplanted (PTR, rainfed) and direct-seeded rice (DSR, irrigated) production systems in Karnataka, India. The energy indices and GHG emission of different input and output in a rice production system were assessed by using energy and carbon equivalence. The efficiency of PTR and DSR farms were identified using data envelopment analysis (DEA) and energy optimization was ascertained. The key finding was excessive use of non-renewable energy inputs was observed for the PTR (92.4%) compare to DSR (60.3%) methods. The higher energy use efficiency (7.3), energy productivity (0.3 kg MJ⁻¹) and energy profitability (6.3) were mainly attributed to the large decrease in energy inputs under DSR. The DEA showed efficiency for 26 PTR farms in comparison for 87 DSR farms. The mean technical efficiency value highlighted the scope for saving energy by 6% and 2% in PTR and DSR, respectively and showed an economic reduction of $405.5/ha with PTR versus $163.3/ha with the DSR method if these inefficient farms perform efficiently. The GHG emissions revealed that the total emissions for PTR versus DSR production caused by on-farm emissions were 86% and 65%, respectively. The DSR method also had a higher carbon efficiency ratio and carbon sustainability index (10.1 and 9.1, respectively). Thus, adoption of DSR method is imperative for reduction of energy consumption and GHG emissions to achieve the carbon sustainability.

An experiment was conducted at Agricultural Research Station, Dhadesugur, UAS, Raichur, Karnataka during 2015–16 and 2016–17 to study the effect of weed control practices on growth and yield of sugarcane and its associated weeds. Dominant weeds were Echinochloa spp. (E. crus-galli and E. colona), Dactyloctenium aegyptium, Eleusine indica, Brachiaria spp. (B. mutica and B. ramosa) and Digitaria sanguinalis among grasses, Eclipta alba, Chenopodium album, Physalis minima, Ageratum conyzoides, Parthenium hysterophorus and Portulaca oleracea as broad-leaf weeds and Cyperus spp. (C. rotundus and C. iria) as sedges. Among the herbicidal treatments, pyrazosulfuron-ethy + metribuzin + 2, 4-D sodium salt WDG (3000 g/ha) recorded significantly higher millable cane yield (119.5 t/ha) as compared to other treatments due to lower weed biomass (42.7 and 47.0 g/m2 at 45 and 75 DAP, respectively) and higher weed control efficiency at 45 and 75 DAP (86.4 and 85.5% at 45 and 75 DAP, respectively) during 2015–16. Similar trend was observed in 2016–17.

The work on enrichment of rock phosphate with vermi-compost and use of VAM is limited. Therefore, an ex- periment was conducted during 2008 and 2009 in sandy clay loam soil at Kathalagere, Karnataka to study the effect of phosphorus enriched vermin-compost on juice quality, ethanol yield and nutrients balance in soil after harvest of sweet sorghum [Sorghum bicolor (L) Moench]. Results revealed that, application of 125 kg N + 50 kg K + vermi-compost enriched (VCE) with rock phosphate (RP), phosphorus solubilizing bacteria (PSB) and vescular arbuscolor mycorrhiza (VAM) resulted significantly higher grain (178 and i .72 t'ha), millable stalk (30.7 and 29.6 t/ha), juice (10,472 and 9,934 1/'ha), ethanol yield (492.2 and 465.2 b'ha), net returns ( 23,844/ha and 22,461/ha) and ratio (259 and 2.5) during 2008 and 2009, respectively and which was on par with the appli- cation of 125 kg N + 50 kg K + VCE with RP and PSB, Whereas, application of 50 kg N + 20 kg K + VCE with RP, PSB, VAM and Azatobacter recorded significantly lower grain, millable stalk, juice, ethanol yield, net returns and B:C ratio. The uptake of nitrogen, phosphorus and potassium by crop was significantly higher with the applica- tion of 25 kg N + 50 kg K + VCE with RP, PSB and VAM during both the years of experimentation.

An experiment was conducted during Kharif 2016 and 2017 at Agricultural Research Station, Dhadesugur, University of Agricultural Sciences, Raichur, Karnataka, India, to study the bio-efficacy of weed control practices on weeds and grain yield of dry-seeded rice. The dominant grassy weeds in fields were Echinochloa sp. Panicum repens, Cynodon dactylon, Bracharia mutica, Digitarias sanguinalis, Commelina communis and Leptochloa chinensis. Broad-leaf weeds were Eclipta alba, and Ludwigia parviflora and Cyperus sp. as sedge. Results revealed that, pre-emergence application of pretilachlor + pyrazosulfuron-ethyl (600 + 15 g/ha) recorded significantly lower weed dry weight at 15, 30 and 45 DAS during Kharif 2016 and 2017, higher weed control efficiency at 15, 30 and 45 days after sowing (DAS) (82.6, 80.2 and 80.6% during Kharif 2016 and 82.1, 82.7 and 80.2%, respectively during Kharif 2017, respectively) and higher rice grain yield (4.92 and 4.98 t/ha during Kharif 2016 and 2017, respectively) and which was at a par with twice hand weeding at 20 and 40 DAS.

An experiment was conducted during Kharif 2012 and 2013 at Agricultural Research Station, Dhadesu-gur, University of Agricultural Sciences, Raichur, Karnataka, India, to evaluate the phytotoxicity and bio efficacy of pyrazosulfuron ethyl 10 % WP (wettable Powder) @ 5, 10, 15 and 20 g a.i./ha against the weeds in transplanted rice. Sprays of Saathi (Market Sample) @ 15 g a.i./ha (gram active ingredient/hectare), Pretilachlor 50% EC @ 500 ml a. i/ha, hand weeding at 15 and 40 days after planting (weed free check) and a weedy check (untreated check) were also maintained. The dominant weeds were Echinochloacolona, Panicum repens, Cynodondoctylon, Lud-wigiaparviflora, Leptochloachinensis and Cyperus sp. Application of pyrazosulfuron ethyl 10 % WP @ 20 g a.i./ha was recorded significantly higher grain yield (6266 kg/ha) by controlling the associated weeds in transplanted rice without any phytotoxic effect.

An experiment was conducted during Kharif 2014 and 2015 at Agricultural Research Station, Dhadesu-gur, University of Agricultural Sciences, Raichur, Karnataka, India, to know the herbicide sequence for weed man-agement in direct seeded rice. The dominant weeds in direct seeded rice were Echinochloa sp, Panicum repens, Cynodon doctylon, Leptochloa chinensis, Bracharia sp. Ludwigia parviflora, Commelena sp. and Cyperus sp. Pooled data revealed that, application of pyrazosulfuron ethyl 10 % WP at 20 g a.i./ha as pre-emergent herbicide followed by the application of Bispyribac sodium 10 % SC @ 250 ml/ha at 20 to 25 days after sowing as post-emergent herbi-cide in direct seeded rice was most effective in controlling of grasses, broad leaf weeds and sedges and increased the rice grain yield (5583 kg/ha) without any phytotoxic effect and which was onpar with the application of Pendime-thalin 30 EC @ 1 kg a.i. /ha as pre-emergent herbicide followed by one hand weeding at 30 days after sowing and weed free check .Therefore, the application of pre emergent herbicides followed by the post emergent herbicide application can reduce the weed problem in direct seeded rice.