Most of the pig manure generated in the swine production in southern Brazil is handled and stored as liquid manure, but there is a growing interest in adopting the deep-litter production system and using the resulting organic material as fertilizer. A field experiment was carried out on a typic Hapludalf in an experimental area of the Universidade Federal de Santa Maria, Santa Maria, state of Rio Grande do Sul, from October 2002 to March 2003, to evaluate the soil N dynamics and nitrogen fertilization potential of deep-litter and pig slurry for corn production. The treatments consisted of the application or non-application of pig slurry and deep-litter manure on oat straw, with and without incorporation into the soil. One additional treatment was evaluated, in which mineral fertilizer (NPK) was applied without incorporation. The doses of deep-litter (13,2 Mg ha-1) and pig slurry (63,6 m³ ha-1) was equivalent to the application of 140 kg ha-1 N. In the soil, mineral N (N-NH4+ and N-NO2- + N-NO3-) was evaluated in six dates for the layers 0-10, 10-30, 30-60, and 60-90 cm. Corn grain yield and dry matter (DM) production and total N uptake were evaluated. The soil mineral N availability in the treatments with pig slurry application was higher than in the deep-litter treatments, indicating a low mineralization rate of organic N in deep-litter. Deep-litter manure and pig slurry promoted higher corn N uptake and DM production and corn grain yield as compared to the treatment without application of organic residues. The corn grain yield increments were 54 and 253 % with the application of deep-litter manure and pig slurry, respectively. The apparent N recovery by corn of N applied via deep-litter manure and pig slurry was 10.9 and 22.1 %, respectively. Although the application of deep-litter increased N supply and corn grain yield in comparison to the treatment without fertilizer application, results indicated that the immediate supply of N for corn by pig slurry or urea application is higher.
mineralization; mineral nitrogen; minimum tillage; nitrate leaching; no-tillage; swine manure
