Efecto del tamaño de la caliza en las propiedades químicas de un suelo de Galicia y en la producción de pratenses

Resumo

Magnesium limestone of different particle sizes (2 - 4 mm, 2 - 0.5 mm, 0.5 - 0.25 mm and < 0.25 mm) was applied to an acid Galician soil. The fi nest limestone (< 0.25 mm) was applied either as a single dose or split in three annual applications. The coarser limestones were applied as a single dose at sowing. The effect of particle size and application scheduling on soil pH, cation exchange capacity, exchangeable cations and pasture yield was studied. The experimental design consisted of four replications for each treatment. The experimental plots received 3 t ha-1 lime. After liming, a grass/clover pasture was grown during two years and forage maize during the third year. The plots receiving the fi nest limestone (< 0.25 mm) in a single dose at sowing exhibited the highest values of pH, exchange Ca and Mg and effective cation exchange capacity, the lowest exchange Al concentration and Al saturation as well as the highest yield of sown species and sown/ volunteer species ratio. The same amount of lime split in three annual applications of 1 t ha-1 was less effective. During the three years of trial, the plots that received the coarsest limestone (2 to 4 mm) showed soil properties and pasture yield similar to control plots.