Doses de nitrogênio e molibdênio e seus efeitos na fisiologia e produção da cana-de-açúcar irrigada.

Abstract

The cane sugar is the culture of higher economic growth and responsible for much of the generation of employment and income in the state of Paraíba. The production of cane sugar in the crop 20013/2014, Paraiba was 5.2831 billion tonnes. According to the National Supply Company (Conab), there was a drop in production of 1.30% over the previous harvest which closed in 5.3549 billion tonnes. The production of ethanol closed the crop at 288,665.20 m³, amount 5.55% lower than in the previous harvest and for sugar production was 211.2 million tons in the 2013/2014 harvest and the current crop was 1.2549 billion tons of the product generating an increase of 3.6% of total production. All production takes place in an area of 122.35 million hectares of sugar cane plantation and involves 26 cities in Paraíba. Within this context, Usina Monte Alegre in the harvest 2013/2014, ground 777,439.060 tons whose agricultural yield was 64.3 t ha, totaling 78,693.18 tons of sugar and 18,014 m3 alcohol. In cane sugar, the most important micronutrients are boron, copper and zinc, and the absence or deficiency of these elements in the environment can cause major damage to sugarcane production. It adds that molybdenum (MoO42-) is an anionic micronutrients as any anion and suffers from the effects of higher leaching, since they are not easily adsorbed on soil colloids. This study was conducted under field conditions in the experimental area of the Plant Monte Alegre S / A, Fazenda Monte Alegre II, stand 81-064, Rio Tinto municipality - Paraiba - Brazil, which has in its geographic coordinates of latitude 6º54'49 , 37520 "S and longitude 35º05'35,91896" O. In view of the above, this study aims to evaluate the influence of nitrogen and molybdenum in the range 93-509 RB in the aspects of agricultural productivity - height plant, stem diameter, leaf area, leaf area index, weight of the fresh weight, the dry weight, productivity, and SPAD index for the two crop cycles. The experimental design was a complete randomized block design, in which we evaluated five doses of nitrogen (0, 36, 48, 60 and 72 kg ha-1) of the commercial formulation 12-18-24 and 5 doses of Molybdenum (0; 98; 96, 294 and 392 g ha-1) plus the absolute control totaling 78 experimental plots. Data were subjected to analysis of variance, and means were compared by Tukey test at 5% probability, using the statistical program SISVAR (FERREIRA, 2008) and ASSISTAT.