Desempenho agronômico e relações hídricas da cana-de-açúcar irrigada em sistemas de cultivo com e sem manutenção da palhada no semiárido brasileiro

Abstract

Sugarcane is one of the most important crops for the Brazilian economy, with a high production capacity of biomass and derivatives, which is linked to the consumer market and is always focused on technological advances. The straw brings benefits to the system of production of sugarcane, but can affect the agronomic performance of the crop. Therefore, in the present study, the objective was to evaluate the productive performance and the efficiency of irrigated sugarcane water use in the Central Brazilian Sertão. The experiment was conducted from August 21, 2015 to July 28, 2016, in a commercial area of sugarcane (AGROVALE) with VAT 90-212 variety, in the city of Juazeiro, BA, in two experimental plots , With each plot being approximately 5.0 hectares, with two levels of straw above the ground (without and with 27.2 Mg ha-1 of the cultural residue). The straw decomposition rate and biometric measurements of the crop were evaluated over time and at the time of harvest, yield and quality data of sugarcane, and the mineral composition of plants and straw. It was observed that the straw decomposition rate was 0.0049 Mg ha-1 day-1, with release of 5.6 kg ha-1 of N and 0.98 Mg ha-1 of C, and dry mass Remaining 27%. The straw in the field reduced the stature of the stems by 0.38 m and by 248 ° C day in the development of sugarcane, but until the first 100 days after cutting. Most of the productivity and industrial indicators were not affected by the presence of the residue in the field. The efficiency of water and nutrient use was significantly increased by the above-ground straw (> 26%).