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The tillage method determines several soil physical parameters that affect the emergence of post-rice chickpea (Cicer arietinum L.) in the Indo-Gangetic Plain of South Asia. Mechanised row-sowing with minimum soil disturbance and crop residue retention in medium-to-heavy-textured soils will alter the seedbed when compared to that prepared after traditional full tillage and broadcast sowing. Whilst minimum soil disturbance and timely sowing may alleviate the soil water constraint to crop establishment, other soil physical properties such as soil strength, bulk density, and aggregate size may still inhibit seedling emergence and root elongation. This study's objective was to determine the limitations to chickpea crop establishment with increasing bulk density and soil strength, and different aggregate sizes below and above the seed. In two growth cabinet studies, chickpea seed was sown in clay soil with (i) a bulk density range of 1.3–1.9 Mg m−3 (Experiment 1) and (ii) the combination of bulk densities (1.3 and 1.8 Mg m−3) and aggregate sizes (<2 mm and >4 mm) above and below the seed (Experiment 2). Root length was significantly reduced with increasing bulk density (>1.4 Mg m−3), and soil strength impeded early root growth at >1 MPa. Where main root growth was impeded due to high bulk density and soil strength, a greater proportion of total root growth was associated with the elongation of lateral roots. The present study suggests that the soil above the seed needs to be loosely compacted (<1.3 Mg m−3) for seedling emergence to occur. Further research is needed to determine the size of the soil aggregates, which optimise germination and emergence. We conclude that soil strength values typical of field conditions in the Indo-Gangetic Plain at sowing will impede the root growth of chickpea seedlings. This effect can be minimised by changing tillage operations to produce seedbed conditions that are within the limiting thresholds of bulk density and soil strength. [ABSTRACT FROM AUTHOR]

The intensification of cropping systems in the salt-affected coastal zones of the Ganges Delta can boost food security in the region. The scarcity of fresh water, coupled with varying degrees of soil and water salinity are however limiting factors for the expansion of irrigated cropping in that area. In this study, we assessed the potential of growing sunflowers using combinations of low and medium saline water for irrigation. The experiments were conducted at two locations with six irrigation treatments in 2016–2017 and 2017–2018. The treatments were: T1—two irrigations at early vegetative (25–30 days after sowing; DAS) and flowering stages (60–65 DAS) with low salinity water (LSW, electric conductivity, ECw < 2 dS m−1); T2—two irrigations, one at the vegetative stage with LSW and one at the flowering stage with medium salinity water (MSW, 2 < ECw < 5dS m−1); T3—two irrigations, one at the vegetative stage with LSW and one at seed development stage (75–80 DAS) with MSW; T4—three irrigations at the vegetative, flowering and seed development stages with LSW; T5—three irrigations, at vegetative stage with LSW, and flowering and seed development stages with MSW; and T6—three irrigations, two at the vegetative and flowering stages with LSW and one at the seed development stage with MSW. Irrigation with LSW at early growth stages and MSW at later growth stages did not significantly (p < 0.05) affect the yield compared to the LSW irrigation at early and later growth stages. Crop water productivity and irrigation water productivity of sunflowers (p < 0.001) increased substantially with the decreasing amount of irrigation water with an average of 1.18 kg m−3 and 2.22 kg m−3 in 2017 and 0.92 kg m−3 and 1.29 kg m−3 in 2018, respectively. Grain yield was significantly correlated with root zone solute potential. The flowering and seed development stages of sunflowers in February–March were sensitive to both low and medium saline water irrigation for seed yield. Overall, the results show that irrigation with LSW (ECw < 2dS m−1) at early growth stages and MSW (2 < ECw < 5dS m−1) at later growth stages could be an option for dry-season sunflowers in the coastal zones of the Ganges Delta which would allow double cropping in this area. [ABSTRACT FROM AUTHOR]

The polders and islands in the salt-affected coastal zone of the Ganges Delta, home to approximately 15 million people in Bangladesh and 5 million in West Bengal, face challenges such as poverty, food insecurity, environmental vulnerability, and limited livelihood opportunities. Historically, agricultural production in these areas was mainly confined to the wet/Kharif season, with much of the land remaining fallow during the dry/Rabi season due to waterlogging, soil salinity, and perceived lack of irrigation water. Since 2015, researchers and NGOs from Australia, Bangladesh, and India collaborated on the project "Cropping system intensification in the salt-affected coastal zones of Bangladesh and West Bengal, India" to sustainably increase cropping intensity and productivity in this area. During 2015-2021, the project has made significant achievements and has demonstrated strategies that are likely to increase productivity, cropping intensity, and livelihoods of the people. However, to maintain these gains and address risks like climate change impacts, untimely rainfall, and market fluctuations, further research was deemed necessary. Thus, ACIAR funded Phase 2 of the project for 2021-2025 which aims to sustain and enhance the achievements. This special issue presents some research findings on projected climate change, agronomic experiments, irrigation and drainage management, and social and economic issues conducted under the project Phase 2 in Bangladesh and West Bengal, India. [ABSTRACT FROM AUTHOR]

Along with other Asian Mega Deltas, the Ganges Delta, and its coastal zone, are attracting increased attention due to the threats posed by climate change and the extent of rural poverty, juxtaposed against the potential for systems intensification and improved livelihoods. While it is a salt-affected zone, the constraints to systems intensification are many and they often interact (drought-salinity, waterlogging-salinity, heat stress). Moreover, the expression and intensity of these constraints can change throughout the year, particularly during the dry/Rabi season, from year to year, and from location to location. Improved rice varieties that mature 10 to 15 days earlier and increase yield by 0.5-1 t ha-1 are a foundational change that enables cropping systems intensification in the coastal zone in the dry season. Sowing Rabi season crops earlier (before mid-December) increases their yield potential and decreases the risk associated with many constraints which intensify towards the end of the dry season (low solute potential, waterlogging and salinity, heat stress, storms). However, early sowing of Rabi season crops increases the risk of early waterlogging and that needs to be managed by drainage. Scarcity of freshwater continues to be a major constraint to dry season cropping. Short duration crops (e.g., vegetables, watermelon), water-saving technologies (e.g. mulch, drip irrigation) and restricted planting of dry-season Boro rice (to areas with adequate fresh water) are needed for resilience of the cropping systems intensification. Community-based management of water resources for both drainage and equitable allocation of freshwater needs to be part of intensification plans. Within the coastal zone, there is considerable diversity of land type, fresh water resource availability, and farm type which need to be recognized in scale-out programs. Disaster preparedness needs to be embedded in any scale-out plans for systems intensification since the risk of land and water salinization from storm surges is real and enduring. [ABSTRACT FROM AUTHOR]

Rice-fallow and rice-rice are important cropping systems in India next to rice-wheat. Rice-fallow system faces critical resource shortages such as irrigation water and encounters salinity whereas, rice-rice system is heavily dependent on extensive non-renewable natural resources with poor resource use efficiency and unsustainability. Sustainable cropping intensification options through on-station and on-farm research have been developed under a multi-institutional project funded by the Australian Centre for International Agricultural Research (ACIAR) during 2015-2022 to address these challenges. The results showed that rice followed by zero tillage planting of potato with paddy straw mulching (ZTPSM), and the rice-potato ZTPSM-green gram cropping patterns are the most promising systems compared to conventional rice-rice rotation. System rice equivalent yield increased from 11.7 t ha-1 in rice-rice to 20.2 t ha-1 in rice-potato ZTPSM - green gram (R-PZTPSM-GG). The soil salinity (ECe) diminished to <3.6 dS m-1 due to ZTPSM from 5.29-6.36 dS m-1 under conventional practice. There is scope to sustainably intensify the rice-fallow lands to atleast 200% cropping intensity from the current 150% with additional net returns of ... 0.95 Lakhs ha-1. In addition, the R-PZTPSM-GG system has a lower environmental footprint due to lower irrigation water (0.31 m³ kg-1 rice-eq) requirement and lower carbon (10.1 t CO2-eq ha-1) emissions intensity than rice-rice system (1.19 m³ kg-1 rice and 30.5 t CO2-eq ha-1). [ABSTRACT FROM AUTHOR]

Coastal areas of the Ganges delta require optimization of agronomic practices to reduce the salinity effect on the crop production that can support the "Bangladesh Delta plan 2100". The present study was conducted in the Rabi seasons of 2018-19 and 2019-20 to determine the optimum sowing method and plant spacing of sunflower (variety Hysun 33) in the saline area of Bangladesh. Two sowing methods: flatbed sowing and ridge and furrow sowing and; three plant spacings: 40 cm x 25 cm, 50 cm x 25 cm and 60 cm x 25 cm were laid out in a randomized complete block design with three replications on a farmer's field at Dacope, Khulna. Results showed that although method of sowing had no significant effect on the yield of sunflower the ridge and furrow sowing method reduced the soil bulk density and soil salinity and increased the soil water holding capacity and solute potential significantly. Plant spacing and planting system (interaction of sowing method x plant spacing) had significant effects on growth and yield of sunflower. Plant spacing 50 cm x 25 cm produced the highest sunflower seed (2233 kg ha-1) by achieving optimum plant population to utilize the resource. Planting sytem: ridge and furrow sowing at 50 cm x 25 cm spacing had the lowest soil salinity (4.01 dS m-1) and soil bulk density (0.90 Mg m-3) which leads to highest solute potential (-380 KPa) and highest soil water holding capacity (21%,w/w) at 85 days after sowing of sunflower. This planting system had the highest crop growth rate (24.4 g m-2 day-1) that ultimately produced the highest grain weight per head (36 g) and seed yield (2274 kg ha-1) of sunflower. Ridge and furrow sowing at 50 cm x 25 cm can be effective for achieving maximum yield of sunflower in the Ganges tidal floodplain of Bangladesh. [ABSTRACT FROM AUTHOR]

Boro rice (irrigated rice) cultivation in the saline area of the coastal region of Bangladesh is limited because of increased soil and water salinity, lack of freshwater for irrigation and proper agronomic practices. An on-farm field trial was conducted in the farmer's field at Dacope upazila in Khulna district of Bangladesh during the dry season (Boro) in 2022-23 to evaluate the growth and yield of Boro rice with different establishment methods and soil salinity dynamics with each type of establishment. The tested establishment methods were: (i) conventional tillage wet direct seeding (CTWDS), (ii) no-tillage wet direct seeding (NTWDS), (iii) conventional tillage transplanting rice (CTTP) and (iv) conventional tillage dry direct seeding (CTDDS). Grain yield was significantly higher (13-63%) in CTTP treatment than the other treatments. The direct seeding methods saved irrigation water but had a lower panicle-bearing tiller and grain per panicle which was related to lower yield. The direct seeding methods had also higher soil salinity. In conclusion, Boro rice cultivation with conventional transplanting (CTTP) method in the saline area maintained a higher yield and lower soil salinity than the direct seeding method. [ABSTRACT FROM AUTHOR]

The productivity of rice-based cropping systems in the coastal zones of eastern India and Bangladesh is low, and we hypothesized that optimizing nutrient management could increase the system productivity as well as farm income. Therefore, we conducted an on-farm study in Barguna district, the coastal zone of Bangladesh, from 2019 to 2021 to optimize nutrient management for two intensifiedrice-based new cropping patterns (CP1: T. Aus rice-T. Aman rice-Sunflower and CP2: T. Aus rice-T. Aman rice-Sweet gourd) for increasing crop productivity. The study considered five nutrient management packages namely, soil test-based (STB) fertilizer dose, STB fertilizer dose plus 25% NK, fertilizer dose as per the Fertilizer Recommendation Guide-2018, soil testing kit-based fertilizer dose, and farmers' applied fertilizer dose for both the cropping patterns. Higher profitability was obtained from the T. Aus rice-T. Aman rice-Sweet gourd pattern than the T. Aus rice-T. Aman rice-Sunflower pattern. The highest system productivity was achieved by the application of STB fertilizer dose plus 25% NK which increased the system productivity of CP1 by 21% and 31% compared to the STB fertilizer dose and farmers' applied dose, respectively. The productivity of CP2 with STB fertilizer dose plus 25% NK was increased by 31% over both the STB fertilizer and farmers' applied doses. The findings of the study indicate that intensified cropping patterns such as T. Aus rice-T. Aman rice-Sweet gourd with optimized nutrient supply (i.e., STB fertilizer dose plus 25% NK) can be highly profitable for the coastal farmers. [ABSTRACT FROM AUTHOR]