Nutrient balances in calcareous soils after application of different rates of pig slurry

Changes in amounts of macro-(N, P, K) and micro-nutrients (Fe, Mn, Zn and Cu) were determined in two calcareous soils amended over an eight-month period with pig slurry applications ranging from 0 to 500 m3/ha, and planted in containers with green pepper (Capsicum annuum). Total N and exchangeable K increased after slurry applications of 300 m3/ha or more, and available P increased after the smallest application rate (100m3/ha). Maximum crop nutrient uptakes of 41, 40 and 91% for N, P and K occurred with the smallest dose of slurry. Large losses of N, ranging from 27 to 74% (mean 55%) of N added to soil, occurred with all slurry treatments. From 41 to 71% (mean 55%) of the total P added in pig slurry was fixed in non-assimilable forms. Most of the K from the pig slurry was available to the plants. Most of the micro-nutrients (Fe, Mn, Zn and Cu) from the slurry were immobilized in the soil, probably because of the high pH and the small amounts of organic matter in both the slurries and soils tested.Peer reviewe