Eficiência da fertilização fosfatada e nitrogenada em cultivares de milheto

Abstract

In this study we aimed at evaluating the dry matter production(DMP), nitrogen content (NC) in plant tissues, above ground nitrogen conversion efficiency (ANCE) and above ground nitrogen recovery (ANR) by pearl millet cultivars submitted to different sources of phosphorus and nitrogen doses. The experiment was carried out in 2008 and a completely randomized block design was used in a 2 × 3 × 4 factorial arrangement with four replications. Treatments consisted of three pearl millet cultivars (ADR-7010; ADR-500 and BRS-1501), two sources of phosphorus (simple phosphate and thermo phosphate) at one dose (70 kg.ha-1) and four respectively, in the 40 kg.ha-1 dose. Nitrogen fertilization nitrogen (urea) doses (0; 40; 80 and 160 kg.ha-1). Statistical analysis revealed no significant interactions among variables. ADR-7010 presented (P<0.05) best dry matter production (1175.9 kg.ha-1) amongst cultivars; and simple phosphate showed better result than thermo phosphate. Increasing nitrogen doses led to increased production; harvest succession reduced DMP. There was difference (P<0.05) in NC. Linear NC increase was observed in function of N doses, with maximum value being 42.7 kg of extracted N. The ANCE and ANR decreased with nutrient input, maximum values being 10.7 kg.ha-1 and 33.4%, respectively, in the 40 kg.ha-1 dose. Nitrogen fertilization increased the pear millet cultivars dry matter production.