Effects of nitrogen and phosphorus fertilization on fruit yield and quality of cactus pear Opuntia ficus-indica (L.) Mill

摘要

Introduction - In order to optimise the nitrogen (N) and phosphorus (P) fertilization of cactus pear in arid regions, we decided to determine its effects on the yield and fruit quality as well as on the plant phenology. Materials and methods - Five N-P dressings were compared on the spineless cv. Moussa in the Agadir area: 0-0, 0-80, 40-40, 60-0, and 60-80 (in kg N ha(-1) - kg P2O5 ha(-1)) over two consecutive growing seasons (2011 and 2012). Yield components and physico-chemical characteristics of the fruit were recorded at harvest. Results and discussion - Although in 2011 the applications of N and P had no effect on fruit yielding, in 2012 the dressings 60N or 80P alone increased the yield by +3.0 and 6.1 kg plant(-1), respectively, compared with the control. Combining both N and P at the same rate resulted in a maximum yield of 14.9 kg plant(-1). Fertilization had positive effects on flowering rates, fruit size and fruit number, and did not modify the content of pulp, the juice content, peel thickness, the juice dry matter, the pH, titratable acidity, total sugars and soluble solids. It also did not modify the dates of flowering and of ripening. Nitrogen dressings significantly increased the number of emitted buds and emitted shoots on one-year cladodes by four fold. Conclusion - Relevant N-P fertilization significantly improved fruit yield, the number of fruits per plant and fruit size in particular. Long term and postharvest effects shall be further studied.