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

The transformation of forests into degraded pastures in the Amazon region has caused alterations in the soil components. Likewise, the use of organic fertilizers as an alternative to enhance soil quality and plant biomass accumulation have been poorly studied. The objective of this study was to evaluate the effects of organic fertilization on biomass production using three specific forage grasses ( Urochloa decumbens , Urochloa humidicola , and Urochloa brizantha ) aged 3 years in a hilly landscape. For each crop, an area of 5005 m² was delimited with a randomized complete block design consisting of four treatments and three replications. Biomass production of Urochloa spp. and the physical and biological soil properties were assessed under the influence of different fertilization treatments. The results revealed significant differences ( p < 0.0001) in the biomass production of Urochloa spp., with 1920.94 ± 155.44 kg of dry matter per hectare (kg DM ha −1 ) of forage at the end of the study, compared to 992.19 ± 97.66 kg DM ha −1 of forage at the beginning of the organic fertilizations. 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.