Características morfogênicas e estruturais do capim-andropogon sob irrigação e adubação

Abstract

It was evaluated the effects of different irrigation and nitrogen (N) doses on morphogenesis and structural Andropogon grass (Andropogon gayanus cv. Planaltina). The study was conducted in period from August to December, 2007 in experimental area of EMBRAPA Meio-Norte, located in city of Parnaíba, Piauí, Brazil. The treatments consisted of two irrigation levels (equivalent to replacement of 50% and 80% of the Class A pan evaporation - ECA) and four doses of nitrogen (equivalent to 200, 400, 600 and 800 kg N/ha/year) in a randomized block design in factorial 2 x 4 with three replications. The nitrogen in the form of urea was applied according to the amounts specified in the treatments (16.7, 33.3, 50.0 and 66.7 kg N/cut). The reduction in water depth provided decreases in leaf elongation rate, leaf appearance, final leaf length and number of life leaves, while the rate of senescence increases. Fertilization increased the leaf elongation rate and leaf appearance. However, tended to reduce the number of life of leaves and expand the level senescence.