تحلية المياه لأغراض الزراعة التحديات والفرص

Phosphorus (P) is one of the least available plant macronutrients due to its strong interaction with the soil solid phase (adsorption and precipitation). The dynamic processes involved on P bioavailability (desorption/ solubilisation and plant uptake) are greatly influenced by the soil microbial activity and its interplay root exudates in the rhizosphere of plants. Many authors have suggested a lower plant P uptake efficiency in salt affected soils, whilst conversely a higher P desorption is expected at higher ionic strengths. Little is known about the intrinsic microbial and chemical feedbacks to soil salinity, and how it affects P availability and fertility to crops. In this study we propose an integrated approach to assess the effect of soil salinity on the mobility of inorganic P from soil solid phase and its complex interplay with the microbial biomass P, microbial respiration and community structure. This study will consist of two phases: a) an exploratory characterization (P status, microbial biomass P, electrical conductivity, soil pH and other basic soil analysis) of 30 alluvial soil samples from representative Omani agriculture sites from the region of Al-Batinah; and b) a series of in vitro soil incubations with increasing NaCl concentrations using Diffusive gradient in thin films (DGT) as a plant root proxy together with the monitoring of soil chemical and microbial parameters. The potential outcome of is project is to build a new conceptual understanding for soil salinity effect on P cycling with an assessment of the salinity thresholds that trigger different soil biological/chemical responses. New insights will be obtained into the management of soil fertility of the Omani salt-affected soils and its delicate interplay with soil biological systems