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Mitigation of greenhouse gases (GHGs), improving nutrient-use efficiency (NUE), and maximizing yield in rainfed lowland rice cultivation poses significant challenges. To address this, a two-year field experiment (2020 and 2021) was conducted in Assam, India, to examine the impact of different fertilizer-management practices on grain yield, NUE, and GHGs in wet direct-seeded rice (Wet-DSR) during the kharif season. The experiment included eight treatments: control; farmer's practice (30-18.4-36 kg N-P2O5-K2O ha−1); state recommended dose of fertilizer (RDF) @ 60-20-40 kg N-P2O5-K2O ha−1 with N applied in three splits @ 30-15-15 kg ha−1 as basal, at active tillering (AT), and panicle initiation (PI); best fertilizer management practices (BMPs): 60-20-40 kg N-P2O5-K2O ha−1 with N applied in three equal splits as basal, at AT, and PI; and fertilizer deep placement (FDP) of 120%, 100%, 80%, and 60% N combined with 100% PK of RDF. The experiment was arranged out in a randomized complete block design with three replications for each treatment. The highest grain yield (4933 kg ha−1) and straw yield (6520 kg ha−1) were achieved with the deep placement of 120% N + 100% PK of RDF. FDP with 80% N + 100% PK reduced 38% N2O emissions compared to AAU's RDF and BMPs, where fertilizer was broadcasted. This is mainly due to the lower dose of nitrogen fertilizer and the application of fertilizer in a reduced zone of soil. When considering both productivity and environmental impact, applying 80% N with 100% PK through FDP was identified as the most effective practice. [ABSTRACT FROM AUTHOR]

The neglected use of micronutrient greatly hampered the productivity of oilseed crop. Thus, to determine the optimal dose of S and B on toria under rice-fallow system, an experiment was carried out with five doses of S i.e. 0, 10, 20, 30 and 40 kg/ha and 3 doses of B i.e. 0, 1 and 2 kg/ha for two consecutive years (2018–19 and 2019–20). The plant growth parameters, i.e. plant height, dry matter accumulation, leaf area index and crop growth rate, and yield attributing parameters, i.e. siliqua/plant and seeds/siliqua, were greatly enhanced through application of S @ 30 kg/ha as well as B@ 2 kg/ha. The higher seed yield (10.11q/ha), stover yield (22.00q/ha) and oil yield (3.86 q/ha) were registered with the application of S @ 30 kg/ha + B @ 2 kg/ha, but it was at par with S@ 30 kg/ha + B @ 1 kg/ha. The combined application of S@ 30 kg/ha + B @ 2 kg/ha also noted higher plant nutrient uptake of N, P, K including S and B closely followed by S@ 30 kg/ha + B @ 1 kg/ha. But in terms of economics, conjugate application of S@ 30 kg/ha + B @1 kg/ha showed maximum monetary benefit with highest B:C (2.24). The pearson correlation indicated strong and positive correlation of seed yield with growth and yield parameters as well as nutrient uptake by plants. Regression analysis revealed that each one unit increase in plant dry matter accumulation showed an increase in seed yield by 4.56 unit and each one increase uptake in N, P, K, S and B showed an increase in seed yield by 0.19, 0.63,0.40,0.55 and 0.05, respectively. Henceforth, considering all the factors the combination of S@ 30 kg/ha and B@1 kg/ha may be recommended under the late sown toria in rice-fallow system. [ABSTRACT FROM AUTHOR]

Increased levels of the non-essential hazardous metalloid arsenic (As) in rice grains pose a threat to human health and the sustainability of the rice industry. In several counties, the average As contamination in polished rice has been detected to range from 0.002 to 0.39 mg/kg, which is above the safe limit of 1 mg/kg as recommended by the World Health Organisation. Beyond this limit, the digestive tract, circulatory system, skin, liver, kidney, nervous system and heart can be affected. Humans can develop cancer from consuming or inhaling As. In addition, long-term exposure to drinking water contaminated with arsenic has also been linked to a dose-response relationship with an increased risk of hypertension and diabetes mellitus. Rice has been shown to be an indirect source of arsenic accumulation in human bodies. Under flooded paddy soil, trivalent arsenate (AsIII) occupies 87-94% of the total As, while under non-flooded soil, pentavalent arsenate (AsV) predominates (73-96% of the total As). This review aims to provide a thorough and interdisciplinary understanding of the behaviour of As in the paddy soil and transportation to rice grain and further investigate efficient ways to limit arsenic contamination. Supplementation of soil with specific mineral nutrients such as iron (Fe), sulphur (S) and silicon (Si) can significantly decrease the arsenic accumulation in rice grain by minimising its uptake and translocation. The hydrogen bonding potentials of uronic acids, proteins and amino sugars on the extracellular surface of soil microorganisms facilitate the detoxification of arsenic species. Further, rice is absorbed less when exposed to aerobic water management practices than anaerobic ones since it reduces the build-up of As in rice, and the solution is immobilised as in the soil. [ABSTRACT FROM AUTHOR]