Influence of climate variability and management on the productive performance of star grass (Cynodon nlemfuensis V.)

Abstract

In response to the growing demand for animal protein and concerns about the impact of climate change on food production and efficient land use, this study evaluated the productive performance of star grass (Cynodon nlemfuensis V.) in dairy farming systems in Valle del Cauca, Colombia, taking into account climate variability and management practices. Three farms located at different altitudes were selected, and the growth dynamics and chemical composition of the grass were analyzed at 14, 21, and 28 days during three grazing cycles in the dry and rainy seasons. Variables such as plant height, forage biomass, and chemical composition (dry matter, crude protein, neutral detergent fiber, acid detergent fiber, lignin, and dry matter digestibility) were measured using near-infrared spectroscopy (NIRS). The results revealed that, although forage biomass increases with maturation, maximum temperature and accumulated precipitation significantly influence yield. The farm located at a lower altitude showed the highest rate of biomass accumulation, but with lower protein levels and higher lignin content, indicating lower forage quality in warmer and wetter conditions.The differences in yield between farms were attributable to specific climatic conditions rather than intrinsic or fixed management characteristics. It is concluded that star grass in the low tropics is more vulnerable to abiotic stress, which affects its nutritional composition. Consequently, there is a recognized need to incorporate a greater number of variables to improve the accuracy of mathematical models aimed at predicting grass growth dynamics, taking into account their specific growth habits and the prevailing agroclimatic conditions in which they are established.