Modelling the impact of different irrigation regimes and mulching on strawberry crop growth and water use in the arsenic-contaminated Bengal basin.

Replacement of water-intensive winter rice with strawberry (Fragaria × ananassa Duch.) may restrict groundwater extraction and improve water productivity and sustainability of agricultural production in the arsenic-contaminated Bengal basin. The potential of strawberry cultivation in terms of yield obtained and water use efficiency need to be evaluated under predominant soil types with mulch applications. Water-driven model AquaCrop was used to predict the canopy cover, soil water storage and above-ground biomass of strawberry in an arsenic-contaminated area in the Bengal basin. After successful calibration and validation over three seasons, AquaCrop was used over a range of management scenarios (nine drip-irrigation × three soil types × four mulch materials) to identify the best irrigation options for a drip-irrigated strawberry crop. The most appropriate irrigation of 176 mm for clay loam soil in lowland and 189 mm for sandy clay loam in medium land rice areas and the use of organic mulch from locally available jute agrotextile improved 1.4 times higher yield and 1.7 times higher water productivity than that of without mulch. Strawberry can be introduced as an alternative crop replacing rice in non-traditional upland and medium land areas of the arsenic-contaminated Bengal basin with 88% lower groundwater extraction load and better economic return to farmers.

Seed priming with selenium and zinc nanoparticles modifies germination, growth, and yield of direct-seeded rice (Oryza sativa L.).

Direct-seeded rice (DSR) seeds are often exposed to multiple environmental stresses in the field, leading to poor emergence, growth and productivity. Appropriate seed priming agents may help to overcome these challenges by ensuring uniform seed germination, and better seedling stand establishment. To examine the effectiveness of sodium selenite (Na-selenite), sodium selenate (Na-selenate), zinc oxide nanoparticles (ZnO-NPs), and their combinations as priming agents for DSR seeds, a controlled pot experiment followed by a field experiment over two consecutive years was conducted on a sandy clay loam soil (Inceptisol) in West Bengal, India. Priming with combinations of all priming agents had advantages over the hydro-priming treatment (control). All the combinations of the three priming agents resulted in the early emergence of seedlings with improved vigour. In the field experiment, all the combinations increased the plant chlorophyll, phenol and protein contents, leaf area index and duration, crop growth rate, uptake of nutrients (N, P, K, B, Zn and Si), and yield of DSR over the control. Our findings suggest that seed priming with the combination of ZnO-NPs, Na-selenite, and Na-selenate could be a viable option for the risk mitigation in DSR.

Replacing winter rice in non-traditional areas by strawberry reduces arsenic bioaccumulation, and improves water productivity and profitability.

Use of huge amount (1450-1650 mm) of arsenic contaminated (14.0-24.5 mg l-1) ground water to irrigate winter rice resulted in high deposition of arsenic (As) in the topsoil and in rice grains, posing a serious threat to soil and human health of the Bengal basin. Strawberry (Fragaria × ananassa Duch.) requires 250 mm irrigation and fetches 3.5 times more net return over the winter rice, and can be grown as an alternate crop in place of winter rice to save the environment. In comparison to rice As load in edible parts of strawberry reduced from 865 to 39 µg kg-1. Deficit irrigation (0.8 and 0.6 crop evapotranspiration, ETc) to strawberry further reduced total as well as different As species load in fruits. Jute and straw mulches recorded lower As in fruits over other mulches. Drip irrigation to recharge full or 80% of ETc loss and use of jute agrotextile surface mulch maximized root growth and yield in strawberry, benefit:cost ratio, and energy efficiency and productivity. Results demonstrate that strawberry cultivation in non-traditional winter rice growing areas of Bengal basin can potentially benefit millions of people by reducing As load in food chains, ensuring higher returns, and aid in reviving the local jute agrotextile industry.