S13 - Session O2 - Struvite as a reliable and more environmental friendly alternative of nutrients for vegetable crops

Authors: José Salvador Rubio-Asensio *, José Luis Ruiz-García, Margarita Parra, Rosa María Martínez-Meroño, Diego Intrigliolo

Finding alternative sources of nutrients for agriculture is becoming increasingly necessary. Struvite provides phosphorus, nitrogen and magnesium, and can be obtained from sewage treatment plant waste in the form of salt. In this experiment carried out in 3 L pots and using a silty clay soil without phosphorus in its composition, 5 treatments were compared. These were based on the supply of a two different salt sources [Struvite vs. monoammonium phosphate (MAP)] and two doses of phosphorus (20 vs 50 ppm). Treatments were; i) without supply of solid fertilizer, ii) 20 ppm of MAP, iii) 20 ppm of Struvite, iv) 50 ppm of MAP, and v) 50 ppm of Struvite. Except P and N, the rest of nutrients were applied by fertigation, and all plants received the same dose of them. The effects of the treatments were observed on the growth of endive and melon plants, and the leaching of nutrients. The results prove that biomass production of both crops increases as fertilizer dose increase, regardless of the nutrient source, and that Struvite, without yielding the same plant growth as MAP, provides results very close to this salt and therefore makes it an effective alternative nutrient source. In addition, the low solubility of Struvite reduces the loss of nutrients by leaching, which would provide an advantage in terms of reducing environmental problems caused by nutrient loss outside the agricultural system.