Effects Of Organic Fertilization on Biomass Production in Urochloa spp. Pastures and Soil Biological and Physical Properties in the Colombian Amazon Region

Abstract

The objective of this was to evaluate the effects of organic fertilization on biomass production in Urochloa spp. pastures, and the soil biological and physical properties in the Colombian Amazon region. Three pastures crops (Urochloa decumbens, Urochloa humidicola and Urochloa brizantha) with 5 years old were examined in a hill landscape. A randomized complete blocks design covering an area of 5005 m2, with 1 m separation between units to minimize edge effects. Highly significant differences in Urochloa spp. biomass production were observed before and after organic fertilization (i.e., initial time: 992.19±97.66 kg DM ha-1 vs. final time: 1920.94±155.44 kg DM ha-1 vs.), but not between different fertilization treatments. The interaction between the treatment and time was significant for total density (p=0.0300) and richness (p=0.0300) of soil macrofauna. Furthermore, the interaction between treatment and soil depth was significant for bulk density (p=0.0187). The linear mixed effects analysis showed that soil bulk density and penetration resistance were lower in 0 - 10 cm depth than that observed in 10 - 20 depth and 20 - 30 cm depth. Overall, the application of organic fertilizers had a significant and positive effect on Urochloa spp. forage biomass and on the physical and biological properties of soils that had historically been affected by extensive livestock farming in a deforested hill landscape in the Colombian Amazon region.