Some considerations on nitrogen fertilization in pastures

Dear readers, pastures are crops of great relevance for the livestock sector, as we have mentioned in previous articles, these grass family plants or grass are the main natural food of ruminants for their valuable contributions in terms of fiber and protein, these nutrients are important for the metabolism of the animal. In that sense, the organ plant of the grass on which it feeds a greater percentage of the animals are the leaves, therefore, the producers have to put all their efforts for the plant to generate the largest amount of green biomass and of course quality; to increase the forage biomass a nutrient essential to it is the nitrogen, as it influences the growth of plants.

Generally, in livestock ecosystems they use the synthetic fertilizer urea that contains 46% nitrogen and is applied to forage surfaces by spreading them with the hands, this practice is not the most efficient because the element can be volatilized in the form of ammonia gas, but it decreases labor cost, ideally incorporating it into the soil. It is not a secret for farmers that fertilization is an important technique for any fodder crop that deserves care like any other plant; as for nitrogen fertilization on forage surfaces, it generates excellent responses from the point of view of growth and biomass production as long as there are no edaphoclimatic limitations that affect its physiological development, such as water stress.

On the other hand, the Fund European Agricultural guidance and Guarantee (2006), points out that all the grasses respond to nitrogen fertilization as long as the amount of fertilizer is adequate and its application to be made at the appropriate time, reiterate that it is convenient to make always a balance of nitrogen in soil at the time of fertilization and consider the inputs as mineralization of organic matter in the soil, the contribution of organic manures, crop residues, microbial fixation and the contribution of chemical fertilizers. It is also necessary to consider the outputs such as denitrifcation, volatilization, crop extraction and leaching of nitrates.

In addition Chacon Hernandez and The Eagle (2004), in a research conducted on the effect of nitrogen fertilization on the nutritive value of the grass past colorado (Panicum coloratum), observed that the foraging species responded positively to different levels of fertilization with an increase in the dry matter yield, but without modifications in the nutritional composition and digestibility.

Therefore, the use of nitrogen fertilizers is an interesting tool to be applied in the management of pastures, since the addition of nutrients that stimulate plant growth, would increase forage productivity and represents the key practice in the establishment and renewal of different species of pastures. In the case of guinea grass (Megathyrsus maximus), excellent results have been observed in terms of yield and quality when fertilized with doses between 80 and 150 kg / ha / year of nitrogen accompanied with the application of other nutrients such as phosphorus.

Dear readers, another ecological alternative that is used in some agro-agricultural ecosystems are the associations of grasses with forage legumes, since they are capable of recycling the nitrogen element to the soil through a symbiotic process and together with it improve the quality of biomass, we could corroborate this when we associated guinea grass (Megathyrsus maximus) with arachis pintoi and a higher growth and better quality of forage biomass was obtained.

On the other hand, organic fertilization also improves certain productive variables in pastures, therefore, in future publications we will share with you some results obtained in an experimental trial where a synthetic nitrogen fertilizer and an organic fertilizer were tested in the production of a kind of grass.