title: Response of water deficit regime and soil amelioration on evapotranspiration loss and water use efficiency of maize (Zea mays l.) in subtropical northeastern Himalayas.
abstract: Rainfed maize production in the hilly ecosystem of Northeastern Himalayas often suffers from moisture and soil acidity induced abiotic stresses. The present study measured evapotranspiration loss (ETc) of maize crop under controlled condition (pot experiment) of water deficit (W25-25 % and W50-50 % of field capacity soil moistures) and well watered (W100= 100 % of field capacity (FC)) regimes in strong acid soils (pH = 4.3) of the Northeastern Himalayan Region of India. The response of soil ameliorants (lime) and phosphorus (P) nutrition under differential water regimes on ETclosses and water use efficiency was also studied. The measured seasonal ETcloss varied from 124.3 to 270.9 mm across treatment combinations. Imposition of water deficit stress resulted in significant (p < 0.05) reduction (by 33-50 %) of seasonal ETclosses but was at the cost of delay in tasseling to silking, 47-65 % reduction in dry matter accumulation (DMA), 12-22 days shortening of grain formation period, and complete kernel abortion. Liming @ 4 t ha-1significantly (p < 0.05) increased ETclosses and DMA across water regimes but the magnitude of increase was higher in severely water deficit (W25) regime. Unlike lime, P nutrition improved DMA only in well-watered regimes (W100) while seasonal ETcloss was unaffected. Vegetative stage (tillering to tasseling) contributed the maximum ETclosses while weekly crop ETcloss was estimated highest during 11th-14th week after sowing (coincided with blistering stage) and then declined. Water use efficiency estimated from dry matter produced per unit ETclosses and irrigation water used varied from 4.33 to 9.43 g dry matter kg-1water and 4.21 to 8.56 g dry matter kg-1, respectively. Among the input factors (water, P, and lime), water regime most strongly influenced the ETcloss, growth duration, grain formation, and water use efficiency of maize.
authors: ICAR Research Complex for NEH Region, Umroi Road, Umiam, Meghalaya, 793103, India.
authors: M A
authors: MA
authors: Marwein
authors: ICAR Research Complex for NEH Region, Umroi Road, Umiam, Meghalaya, 793103, India. burhan3i@yahoo.com.
authors: B U
authors: BU
authors: Choudhury
authors: ICAR Research Complex for NEH Region, Umroi Road, Umiam, Meghalaya, 793103, India.
authors: D
authors: D
authors: Chakraborty
authors: ICAR Research Complex for NEH Region, Umroi Road, Umiam, Meghalaya, 793103, India.
authors: M
authors: M
authors: Kumar
authors: ICAR Research Complex for NEH Region, Umroi Road, Umiam, Meghalaya, 793103, India.
authors: A
authors: A
authors: Das
authors: ICAR Research Complex for NEH Region, Umroi Road, Umiam, Meghalaya, 793103, India.
authors: D J
authors: DJ
authors: Rajkhowa
mesh_terms: D017610:Calcium Compounds / Q000494:pharmacology; D002980:Climate; D003681:Dehydration / Q000503:physiopathology*; D005308:Fertilizers; D007194:India; D009584:Nitrogen / Q000494:pharmacology; D010087:Oxides / Q000494:pharmacology; D010758:Phosphorus / Q000494:pharmacology; D018526:Plant Transpiration; D011188:Potassium / Q000494:pharmacology; D012987:Soil / Q000737:chemistry; D014867:Water / Q000494:pharmacology; D003313:Zea mays / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*
chemical_list: D017610:Calcium Compounds; D005308:Fertilizers; D010087:Oxides; D012987:Soil; D014867:Water; D010758:Phosphorus; C016538:lime; D009584:Nitrogen; D011188:Potassium
keywords: Crop evapotranspiration; Deficit irrigation; Maize; Northeast India; Water use efficiency