Comparison of nitrogen loss in fertilizers applied to coffee plants using Gompertz model estimates

Abstract

The increase in coffee productivity is related to many factors, mainly the management of soil fertility. Nitrogen (N) is among the nutrients most demanded by the coffee and the conventional nitrogen fertilizer most used to suppress this demand is urea. However, urea has a large loss of N, mainly due to ammonia volatilization. With the aim of reducing the losses of conventional fertilizers and improving their use, researchers have developed innovations such as stabilized nitrogen fertilizers, resulting in the need to compare N losses in each one of them. The nonlinear Gompertz model is commonly used to describe the sigmoidal pattern, characteristic of the accumulated loss of N by ammonia volatilization. Thus, the objective of this study is to compare the accumulated loss of N from the nitrogen fertilizers urea, urea + NBPT and Ammonium Nitrate applied to coffee plants based on the parameters of the nonlinear Gompertz model. Comparison between treatments was performed using the method proposed by Carvalho et al. (2010), the Gompertz model was adjusted to each of the repetitions of the experiment, the analysis of variance was performed for each of the parameters, the F test was significant in all cases, so the Tukey test was applied. The analyzes were carried out in the R software at the 1% probability level. The conventional nitrogen fertilizer urea showed the highest accumulated loss of N in the coffee tree, whereas the stabilized nitrogen fertilizers urea + NBPT and ammonium nitrate did not show significant differences between them.