Kikuyu (Cenchrus clandestinus) is the predominant grass in the Colombian high tropics and is the main forage in specialized dairy systems; however, it must be subjected to high doses of nitrogen (N) and phosphorus (P) from chemical sources. The aim of this study was to evaluate the effect of the arbuscular mycorrhizal fungi - FMA (Rhizophagus intraradices and Rhizophagus manihotis) under three levels of fertilization with N (0 [0%], 200 [50%] and 400 kg N ha-1 year-1 [100%]) and P (0 [0%], 100 [50%] and 200 kg P ha-1 year-1 [100%]) in dry matter content (DM%), crude protein (PC%), gross energy (EB), calcium (Ca%) and P (P%) in kikuyo. This study was carried out with the plants sown in pots and under mesh house conditions. The results indicate that the use of HFMA in the fertilization program improved some bromatological variables of the kikuyo grass, like what was found with the applicat...

The aim of this study was to describe the texture of soils on farms with agricultural production systems in the subregions of the department of Antioquia, Colombia. In total, 1729 soil samples were taken in the nine subregions of the department, of which 415, 622, 376 and 316 belonged to cocoa, beef livestock, specialized dairy and dual-purpose livestock production systems, respectively. The variables of interest were the percentages of sand, silt, and clay, from which the textures of the soils were determined. The statistical analysis included generalized additive models with effects such as geographical position, altitude, tropical level, type of production system, municipality and region. The best models were selected based on the highest coefficient of determination and the highest deviance value. In the soils, the textural classes clay (Ar), loam (F), clay loam (F-Ar), sandy clay lo...

El objetivo del estudio fue ajustar las curvas de crecimiento de cuatro Urochloas mediante un modelo matemático que permita la comparación entre ellas. Se tuvieron en cuenta las variables de altura (cm), temperatura (°C), precipitación (mm) y edad del pasto (días). El crecimiento de cada especie se analizó en el software estadístico R-Project. Se ajustaron los datos de crecimiento de las especies con el uso del modelo cuadrático yt = β0 +β1 t -β3 t2, con coeficientes de determinación (>0.9) y un valor de p<0.001. Como resultado, Urochloa brizantha cv Piatá presentó un R² = 0.9859 y fue la especie más influenciada positivamente en su crecimiento por el efecto de la edad (días), seguido por U. decumbens, U. mutica y U. brizantha cv Toledo, esta última con el menor ajuste. La precipitación influyó en la tasa de crecimiento de la U. mutica mientras que la temperatur...