Revaluing the nutrition potential of reclaimed water for irrigation in southeastern Spain
2019
Maestre-Valero, J.F. | Gonzalez-Ortega, M.J. | Martinez-Alvarez, V. | Gallego-Elvira, B. | Conesa-Jodar, F.J. | Martin-Gorriz, B.
Reclaimed water (RW) can alleviate agricultural water scarcity all around the year with the quality factor, but its use is often questioned by farmers due to agronomic concerns. In this study, we selected three areas and five different representative crops (muskmelon, lettuce, lemon, peach and tomato) in the southeast of Spain to study the impact of the irrigation with RW on (i) the supply of essential nutrients, (ii) the effect of water salinity on the crop yield, (iii) the crop toxicity to Cl−, Na and B ions, (iv) the soil sodicity risk and (v) the economic inflow-outflow analysis.The results evidenced that RW could supply a large part of the crop nutrient requirements, particularly in the selected woody crops, although temporal mismatches between crop nutrient requirements and nutrients in the water supplies should be considered when preparing fertigation plan. The electrical conductivity (ECw) of the RWs could lead to yield reductions from 0% in muskmelon to 23.2% in peach. Despite this, only chlorosis risk in lemon and peach and toxicity effects of Na and B in lemon trees could be envisaged. In addition, soil sodicity risks were low for most of the RWs. The economic inflow-outflow balance justified the fertigation with RW in muskmelon, lettuce and lemon. However, for peach and tomato, despite the economic savings associated to the fertigation, the high yield reduction due to the ECw made less viable the irrigation with RW. Overall, the study shows that fertigation accounting for RW nutrients can substantially save fertilizers costs while agronomical risks, when present, can be controlled with irrigation management strategies for several crops in SE Spain.
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