Fertilização nitrogenada do capim BRS Zuri, em gotejamento subsuperficial, com acionador simplificado para irrigação

Abstract

The hypothesis is that the supply of nitrogen via an automated subsurface irrigation system increases forage production. The objective of this work was to evaluate the productivity of the cultivar Megathyrsus (syn. Panicum) maximus cv. BRS Zuri, using fractionated nitrogen fertilization via an automated subsurface irrigation system. The experiment was carried out in a typical Orthotic Quartzene Neossolo, in the Agrostology Sector of the School of Veterinary Medicine and Zootechnics (EMVZ), Araguaína campus, of the Federal University of Tocantins (UFT), on the subsurface drip irrigation system, Netafim® Dripnet PCTM AS 16150, automated with simplified trigger for irrigation. To study the effect of nitrogen on forage, the treatments consisted of nitrogen (N) doses ranging from 0, 25, 50, 75 and 100 kg.ha-1 .cycle-1 of N, was used as a source of N urea, during the fixed cycle of 21 days. These quantities were divided into three applications via subsurface drip fertigation, on one day a week, randomly distributed in the four blocks of the design. On one day a week there was fertigation with N-P-K, whose sources: urea (46% N); mono ammonium phosphate - MAP Crystal (61% P2O5; 12% N); potassium chloride (60% K2O). A randomized block design with four blocks was used. The variables studied were: forage canopy height, tiller population density, leaf area index, leaf dry mass, stem, dead and total material, agronomic nitrogen efficiency, root mass. The polynomial regression equations provided the point of maximum production for each variable studied. Therefore, the split application of nitrogen, via fertigation in subsurface dripping with a simplified trigger for irrigation, is a strategy to overcome the period of water scarcity, ensuring supply of forage to the animals in the off-season period.