The utility of submersible solar irrigation pumps in accessing deeper groundwater for sustaining dry season rice cultivation in off-grid Bangladeshi haor areas

Le résumé fourni par la source

In many countries, Solar (powered) Irrigation Pumps (SIP) are becoming a promising means to replace Diesel Irrigation Pumps (DIP) and facilitate irrigation in off-grid areas. In Bangladeshi off-grid haor areas, dry season Boro rice cultivation (January–April) faces immense challenges as traditional DIP-driven Shallow Tube Wells (STW) often run dry due to falling of groundwater level (GWL) below the practical suction limit (5–7 m). This study experimentally investigates the technical suitability of a submersible SIP (3.80 kW), designed and installed at a northeast rice-cultivated haor of Bangladesh. A questionnaire baseline survey of 115 farmers in the study area was conducted to get information about existing irrigation conditions. Real-time solar irradiance, GWL and hourly pump discharge were measured with a pyranometer, level logger and volumetric approach, respectively. Measured irradiance was very low (100–450 W m -2 ) in the early phase of growing season (January–mid February) due to foggy weather, then it increased with the highest values during noon–3:00 PM (700–900 W m -2 ) when the pump could yield its rated discharge (0.014 m 3 s -1 ). Measured drawdown was remarkably high (4.6–7.0 m) due to moderate geologic formation of the aquifer (medium sand). The SIP could potentially irrigate 3.45 ha of rice field without any risk of dry running throughout the growing season, a great implication for replacing DIPs having lower command area (≤ 2.5 ha). It has been demonstrated that SIP is more attractive compared to DIP technically, economically, and environmentally when its annual usage extends beyond a single crop season. • Submersible Solar Irrigation Pumps (SIP) are fit for groundwater rice irrigation. • SIPs are enough competitive to replace suction mode Diesel Irrigation Pumps (DIP). • Curvilinear irradiance-discharge relationship is more realistic than linear case. • SIPs are economically viable for areas with high cropping intensity and irrigation efficiency.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.