Nitrogen Mineralization and Released Nutrients in a Volcanic Soil Amended with Poultry Litter

Juan Hirzel1*, Pablo Undurraga1, and Ingrid Walter2

Optimum application rates of poultry litter (PL) spread out on the farmer´s field is a valuable source of available plant nutrients. The aim of this study was to compare the effect of two rates of PL and conventional fertilization (CF) on N mineralization and P, K, Zn, and Cu availability in an Andisol from Southern Chile under controlled conditions. Aerobic incubation was carried out for a 16-wk period. N mineralization rates were higher (61.5%) with the two PL treatments than with conventional fertilizer (23%). CF was associated with high N availability prior to the start of incubation and slight immobilization during the first week, perhaps due to a more rapid conversion of urea into NH4 which was then temporarily immobilized by the microbial biomass. At the start and end of the incubation period, Olsen-extractable P content was generally higher in CF. Due to the high fixation capacity of the soil studied, extractable P values were slightly increased suggesting that PL mineralization is only associated with a low risk of P contamination in volcanic soil. In PL, K, Zn, and Cu availability were higher than in CF. However, values obtained for Cu and Zn were average in relation to referential values used in agricultural soil. The results indicated that PL could be an alternative to conventional fertilizer under the conditions of the present study.

Keywords: aerobic incubation, poultry litter, nitrogen mineralization, nutrient availability, volcanic soil.
1Instituto de Investigaciones Agropecuarias INIA, Av. Vicente Méndez 515, Chillán, Chile. *Corresponding author (jhirzel@inia.cl). 2Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Apdo. Correos 8111, 28080 Madrid, Spain.