REVIEW ARTICLE - THE USE OF SLOW-RELEASE FERTILIZERS IN CITRUS

In the last decades, an important change has taken place in agricultur al practices to increase production and thus the economic yield of cit rus. This increase has been supported mainly by new irrigable areas an d the wider use of fertilizers, especially nitrogenous ones. The effic iency of nitrogenous fertilization is highly variable. A great part of the nitrogen applied to the soil is lost by leaching, causing problem s in the environment due to water pollution by nitrates. Slow-release fertilizers can be alternatives to increase efficiency and can reduce the polluting action of the fertilizers, especially in intensive agric ultural areas. In this work, all publications found up to date dealing with the utilization of slow-release fertilizers in citrus seedlings and in young and mature trees are reviewed. Attention is paid to the s tudied responses (growth of the tree, content of nutrients in leaves a nd soils and the production and quality of the crop), as a function of the type of fertilizer employed in each experiment.