Reclamation and salt leaching efficiency for tile drained salineâsodic soil using marginal quality water for irrigating rice and wheat crops
2012
Ghafoor, A. | Murtaza, G. | Rehman, M. Z. | Saifullah, | Sabir, M.
Due to increased population and urbanization, freshwater demand for domestic purposes has increased resulting in a smaller proportion for irrigation of crops. We carried out a 3âyear field experiment in the Indus Plains of Pakistan on saltâaffected soil (ECe 15·67–23·96âdSâm−1, pHs 8·35–8·93, SAR 70–120, infiltration rate 0·72–0·78âcmâh−1, Ï b 1·70–1·80âMgâm−3) having tile drainage in place. The 3âyear cropping sequence consisted of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) crops in rotation. These crops were irrigated with groundwater having electrical conductivity (EC) 2·7âdSâm−1, sodium adsorption ratio (SAR) 8·0 (mmolâL−1)1/2 and residual sodium carbonate (RSC) 1·3âmmolcâL−1. Treatments were: (1) irrigation with brackish water without amendment (control); (2) Sesbania (Sesbania aculeata) green manure each year before rice (SM); (3) applied gypsum at 100 per cent soil gypsum requirement (SGR) and (4) applied gypsum as in treatment 3 plus sesbania green manure each year (GSM). A decrease in soil salinity and sodicity and favourable infiltration rate and bulk density over preâexperiment levels are recorded. GSM resulted in the largest decrease in soil salinity and sodicity. There was a positive relationship between crop yield and economic benefits and improvement in soil physical and chemical properties. On the basis of six crops, the greatest net benefit was obtained from GSM. Based on this longâterm study, combined use of gypsum at 100 per cent soil gypsum requirement along with sesbania each year is recommended for soil amelioration and crop production.
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