Efecto del tipo de fertilizante sobre el ph, la producción y el contenido en potasio y fósforo en un sistema silvopastoral de Pinus pinaster aiton

Resumo

Nowadays, silvopastoral system implementation and the use of sewage sludge as fertilizerin agriculture are promoted by European Directives. One of the main advantages of the use ofsilvopastoral systems in forestlands of Galicia is the establishment of an herbaceous understory,which reduces fire risk. The herbaceous layer is promoted by fertilization practices performedin this kind of systems, which enhances herbaceous species competitiveness when comparedwith shrubby species. In the last years, the use of sewage sludge as fertilizer in Galicia is increasingdue to its acceptable nutrient content and the increase of inorganic fertilizer prices. The fertilizervalue of sewage sludge depends on the stabilisation process that takes place in the wastemanagement plant. This study aims at evaluating the effect of different stabilised types of sewagesludge (anaerobic, composting and pelletization) on the soil pH, pasture production and qualitycompared with two control treatments (lack of fertilization and mineral fertilization) in a silvopastoralsystem established in an abandoned agricultural land afforested with Pinus pinaster Aitonafter pasture sowing. Main results showed that composted sewage sludge increased soil pH butdid not modify pasture production due to the lack of precipitation happened during the evaluatedyears. However, composted sewage sludge inputs improved the levels of phosphorous andpotassium in the pasture, while pelletized sludge increased the potassium pasture compared withthe other treatments.