Produção de capim e feno de Tifton 85 sob doses de nitrogênio em diferentes dias de rebrotação

Abstract

The present research was carried out at the Janaúba Campus Experimental Farm of the State University of Montes Claros - UNIMONTES, Janaúba, MG-Brazil, with the objective of evaluating the production, structural characteristics and nutritional value of tifton 85 grass (Cynodon spp.) and the production and the nutritional value of hay of Tifton 85, both harvested at four re-growth ages (28, 35, 42, 49) and fertilized with two nitrogen doses (100 and 300 kg N. ha-1 ). The design used in the two experiments was a randomized block design, arranged in a 4 x 2 factorial scheme, with six replications. For chapter I, nitrogen fertilization influenced (P<0,05) the canopy height, the number of leaves, the final leaf length and the PMS of tifton 85 grass. The different days of regrowth influenced (P<0,05) in a positive way the height, the number of leaves, the final length of stem and leaves and the dry matter production, and in a negative way the number of tillers, the relation blade: stem, crude protein contents And digestibility. In Chapter II, fertilization nitrogenated positively influenced (P<0,05) the dry matter production and the dry matter digestible hay production, as well as lignin and crude protein contents. The age of regrowth promoted linear increase (P<0,05) in neutral detergent fiber corrected for ash and protein, acid detergent fiber, and lignin, and linear reduction in dry matter production, dry matter production, and crude protein content. For in situ digestibility of hay, a quadratic effect was observed, with a maximum value of 73.1% at 37 days of regrowth. Tifton 85 grass fertilized with 300 kg ha-1 of N presents higher yield, better structural characteristics and better nutritional quality. Until the age of 49 days of regrowth the tifton 85 grass maintained the fiber contents, however it is observed a fall in crude protein and dry matter digestibility. Tifton 85 hay fertilized with 300 kg ha-1 of N and harvested with up to 35 days of regrowth shows higher DM production and better nutritional value.