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Inherently poor soil fertility and non-adoption of fertilizer recommendations based on soil test and yield targets by farmers limit the productivity and profitability from monsoon rice in Bangladesh and much of South Asia. In the Level Barind Tract (LBT; AEZ-25) and the High Ganges River Floodplain (HGR; AEZ-11) agro-ecological zones (AEZs) of Bangladesh, monsoon (aman/kharif) season transplanted rainfed rice (known as T. aman rice) is grown in large areas after maize, wheat and/or mungbeans, with residues of each crop removed from the field after grain harvest. This results in lower grain yield and lower profits in these AEZs as compared with other AEZs. Nutrient management, based on soil test, yield targets, or integrated use of inorganics and organics for each AEZ together with retention of crop residue, has the potential to increase rice yield, reduce production cost and increase income. With this hypothesis, this study was conducted to determine the optimum nutrient management practices for achieving higher yield, maintaining apparent soil nutrient balance, and obtaining high profits from monsoon rice. Twelve nutrient management options were evaluated, of which the first six were: (i) 80-16-44-12-2 kg ha-1 of N, P, K, S, Zn respectively for a high yield goal (T1; ‘HYG’); (ii) 56-12-32-8- 1.5 kg ha-1 respectively for a medium yield goal (T2; ‘MYG’); (iii) 65-13-32-9-2 kg ha-1 respectively plus 5 t ha-1 cowdung as integrated plant nutrient management system (T3, ‘IPNS’); (iv) 67-14-41-9-2 kg ha-1 respectively as a soil test-based fertilizer management strategy (T4; ‘STB’); (v) 40-9-11-0-0 kg ha-1 respectively as per farmers’ practice (T5; ‘FP’) and (vi) 0-0-0-0-0 kg ha-1 as a control (T6; ‘CON’). The remaining six treatments were the same as above but each also included the crop residue incorporation (CRI), i.e., (vii) T7, ‘HYG+CRI’; (viii) T8, ‘MYG+CRI’; (ix) T9, ‘IPNS+CRI’; (x) T10, ‘STB+CRI’; (xi) T11 ‘FP’+CRI’; and (xii) T12, ‘CON+CRI’. In both AEZs, STB plus CRI resulted in the highest rice yield (p≤0.05) followed by ‘STB’ and ‘IPNS+CRI’. In comparison with ‘FP’ and ‘CON’, each without CRI, balances were positive (p≤0.05) for P, S, Zn and B but were negative for N and K in ‘HYG’, ‘MYG’, ‘IPNS’ and ‘STB’ with or without CRI. In both AEZS, STB nutrient management had the highest (p≤0.05) net returns (526 & 487 US$ ha-1, respectively), highest benefit cost ratio (BCR; 3.54 & 3.36) and highest marginal benefit cost ratio (MBCR; 10.47 & 10.19). These were followed by STB+CRI’ and ‘IPNS’, while they were lowest (p≤0.05) for CON and FP. We recommend that nutrient application, based on soil test with incorporation of mungbean residue, followed by IPNS, could be the best strategies for achieving high yield, improving soil fertility and for fetching a higher profit from monsoon rice in Bangladesh and similar soils and growing environments of South Asia.

It is important to identify and develop stable wheat varieties that can grow under heat stress. This important issue was addressed in Bangladesh using six wheat genotypes, including three existing elite cultivars (‘BARI Gom 26’, ‘BARI Gom 27’, ‘BARI Gom 28’) and three advanced lines (‘BAW 1130’, ‘BAW 1138’, ‘BAW 1140’). Six sowing dates, namely early sowing (ES) (10 November), optimum sowing (OS) (20 November), slightly late sowing (SLS) (30 November), late sowing (LS) (10 December), very late sowing (VLS) (20 December) and extremely late sowing (ELS) (30 December) were assessed over two years in four locations, representative of the diversity in Bangladesh’s agro-ecological zones. In a split plot design, sowing dates were allocated as main plots and genotypes as subplots. A GGE biplot analysis was applied to identify heat tolerance and to select and recommend genotypes for cultivation in heat-prone zones. All tested genotypes gave greatest grain yield (GY) after OS, followed by SLS, ES and LS, while VLS and ELS gave smallest GY. When GY and the correlations between GY and stress tolerance indices were considered, ‘BAW 1140’, ‘BARI Gom 28’ and ‘BARI Gom26’ performed best under heat stress, regardless of location or sowing date. In contrast, ‘BARI Gom 27’ and ‘BAW 1130’ were susceptible to heat stress in all locations in both years. Ranking of genotypes and environments using GGE biplot analysis for yield stability showed ‘BAW1140’ to be most stable, followed by ‘BARI Gom 28’ and ‘BARI Gom 26’. Wheat sown on November 20 resulted in highest GY but that sown on December 30 resulted in lowest GY in both years. In conclusion, ‘BAW 1140’, ‘BARI Gom 28’ and ‘BARI Gom 26’ are the recommended wheat genotypes for use under prevailing conditions in Bangladesh.

In South Asia, including Bangladesh, most farmers sow wheat under residual soil moisture after rice is harvested, but the upper layer of soil dries quickly after soil has been prepared for wheat sowing. Crop seeds that are sown either deeply or shallowly can result in failed emergence, low dry matter accumulation, and reduced grain yield. Therefore, appropriate sowing depth is crucial for seedling emergence and successful crop establishment. Considering this, a two-year field experiment was conducted at the research field of the Agricultural Research Station of the Bangladesh Agricultural Research Institute at Dinajpur during the dry, rabi (winter) season of 2013-14 and 2014-15, at four sowing depths, i.e., 2, 4, 6 and 8 cm, to identify the most appropriate sowing depth for higher grain yield. Wheat seeds sown at a depth of 4 cm resulted in significantly highest number of seedlings and seminal roots, tallest plants as well as largest roots and plant biomass followed by sowing at a depth of 6, or 2 cm. Depth of sowing also significantly affected the yield and yield-related attributes, all performing best at a depth of 4 cm. The highest number of spikes m-2, grain yield, straw yield and harvest index were observed when seeds were sown at depths of 4 or 6 cm, relative to 2 or 8 cm. Therefore, a sowing depth of 4 to 6 cm is recommended for wheat cultivation in South Asia, including Northern Bangladesh.

Nepalese community forests are globally recognized for sustainable forest management and improving the livelihoods of forest-dependent communities, but their contribution to carbon sequestration in trees and soil is rarely studied. This study was performed to understand the effect of management practices on carbon stock of two community forests (CFs) - Taldanda (managed) and Dangdunge (unmanaged) - dominated by Sal (Shorea robusta) in the mid-hills of Nepal. Twenty-one concentric sample plots, each of 250 m2, were laid out in each forest to estimate different carbon pools and a stratified random sampling intensity of 0.5% used to collect data. Results showed significant (p<0.05) differences in above and below-ground biomass and carbon sequestration potential between the two CFs. The managed and unmanaged forests had total carbon stock of 269.3±27.4 and 150.0±22.7 ton/ha, respectively, demonstrating 1.79 times higher carbon stock in the former than the latter. The managed forest had significantly (p<0.05) greater mean soil organic carbon (SOC) stock than the unmanaged forest. The SOC was highest in the upper soil layer (0-10 cm), with a steady decrease as the soil depth increased. All other measured carbon pools values were higher in managed compared to unmanaged forest. The difference in carbon stock was due to the manipulation of different forest management activities, including thinning, timber extraction, fire control, grazing, and fuel wood/fodder extraction. The study suggests that the implementation of proper forest management would be necessary for enhancing carbon stock in forest trees and soils. [ABSTRACT FROM AUTHOR]

Effective broad-spectrum herbicides are needed to address the issues of herbicide resistance and weed shifts in common cropping systems. A field experiment was conducted in 2016 and 2017 in West Bengal, India to compare the performance of three post-emergence herbicides (bispyribac-sodium; fenoxaprop-p-ethyl; penoxsulam) in monsoon rice (Oryza sativa L.) and their residual effects on succeeding rapeseed (Brassica rapa L.). Rice yield loss due to competition with Echinochloa colona (L.) Link, Leersia hexandra Sw., Cyperus iria L., Ludwigia parviflora L., and Monochoria vaginalis (Burm f.) C. Presl. Ex Kunth was 64% compared with weed-free control. Bispyribac-sodium 10% SC applied at 30 g a.i. ha−1 20 days after transplanting reduced weed density over the weedy control, ranging from 37% (M. vaginalis) to 87% (L. hexandra). Fenoxaprop-p-ethyl and penoxsulam applied, respectively, at 86 and 20 g a.i. ha−1 were effective in controlling grasses, but less effective against sedges and broadleaves. Bispyribac-sodium application resulted in highest rice yield (5.45 t ha−1), net return (Indian Rupees 42,677 ha−1), and benefit cost ratio (1.72). Bispyribac-sodium had neither adverse effect on soil microbes nor phytotoxic effect on rice and subsequent rapeseed. We recommend bispyribac-sodium for weed control in transplanted rice under rice-rapeseed system in eastern India. [ABSTRACT FROM AUTHOR]