Fertirrigação nitrogenada de palma forrageira resistente à cochonilha do carmin.

Abstract

The agronomic performance of forage palm is directly influenced by irrigation management as well as fertilization. Thus, the objective of this study was the agronomic performance and nutrient extraction in three forage palm cultivars under nitrogen fertirrigation. The experiment was carried out under field conditions in Santa Luzia-PB, at the Poço Redondo farm. The statistical design adopted was a randomized block design in a 5 x 3 factorial scheme, the first factor being five levels of nitrogen fertilization applied via fertigation (0, 150, 300, 450 and 600 kg ha -1 of N), and the second factor three cultivars of forage palm species Opuntia fícus-indica (L.) Mill.cv. "Elephant Ear" and Nopalea cochenillifera (L.) "Miúda" and Baiana, with three replications, totaling 45 experimental plots. After 365 days after planting, the variables of growth, productivity, nutrient extraction in the plant tissue and nitrogen use efficiency were analyzed. The data were submitted to analysis of variance, F test, Tukey test and polynomial regression analysis, where the coefficients of the models will be tested based on the mean square of the residue. The agronomic characteristics of forage palm and nutrient extraction differed among cultivars studied. Nitrogen doses applied via fertigation positively influenced the number of cladodes, plant width and productivity. The highest productivity was obtained for the elephant ear cultivar when associated with a maximum dose of 284 kg ha-1 of nitrogen applied via fertigation. The nutrients extracted by forage palm plants presented the following order of magnitude of accumulation in cladodes of forage palm: macronutrients - potassium> nitrogen> sodium> sulfur. The efficiency in the use of nitrogen decreased linearly with the increase of the dose of nitrogen applied via fertigation.