Comparison of different phosphorus-fertiliser matrices to induce the recovery of phosphorus-deficient maize plants

BACKGROUND: Previous studies have demonstrated the capacity of a new type of mineral fertiliser, known as rhizosphere-controlled fertiliser (RCF), to supply adequate nutrition to plants while minimising nutrient losses. This fertiliser family is based on the presence a phosphoric matrix composed of metal-humic-phosphates, soluble not in water but in the rhizospheric acids released by plant roots as an expression of nutritional needs, principally citric acid. The aim of this study is to investigate the capacity of the RCF matrix and other phosphorus-containing products to induce the recovery of phosphorus-deficient maize plants. RESULTS: The results showed that RCF-based P fertilisers were able to facilitate plant recovery, measured by the dry root and shoot weights, to the same extent as a water-soluble P fertiliser (monopotassium phosphate). This fact was well correlated to both the variation pattern of citric and trans-aconitic acids in the shoot and roots during the treatment, and P shoot and root contents. Likewise the analysis of the variation of P concentration in the nutrient solution during the treatment indicates that plant recovery is associated with the capacity of the plant to mobilise P from the different fertiliser matrices studied. CONCLUSION: These results confirm the findings obtained in previous in vitro studies and indicate the suitability of RCF strategy for the preparation of mineral fertilisers with a nutrient release pattern more sensitive to plant nutritional needs. (c) 2009 Society of Chemical Industry