Diagnose foliar, extração e exportação de nutrientes em variedades de cana-de-açúcar (Saccharum spp.) em argissolos, no estado de Alagoas

Abstract

Sugar-cane fertilization is a factor of high importance for the increase of productivity and represents 30% of its production costs. Despite the fact that Brazil is the biggest sugar-cane producer in the world, there are still various problems to be sorted out, especially those concerning fertilization management. The knowledge of the nutritional state of the culture, the nutrients accumulation and allocation data becomes a very important tool in the fertilizing management process allowing thus, the use of rational fertilization aiming at productivity increase and avoiding fertilizers waste. In this respect, two experiments were conducted in Cansanção de Sinimbú Mill, located in Jequiá da Praia-AL, in Fragipanic Adherent Hard Dystrophic Yellow Argisoil (PAdx1) and Fragipanic Adherent Hard Dystrophic Abrupt Yellow Argisoil (PAdx2) with ten sugar-cane varieties: RB92579, RB867515, SP81-3250, VAT90-212, VAT90-61, SP83-2847, RB863129, RB931011, RB931566 and RB855113, with four repetitions. The tests correspond to the summer planting season, when sugar-cane was harvested after 13 months of its planting. 550 kg ha-1 of the 10-17-00 formula was applied at the bottom of the furrow + quantity of wine, in the PAdx1. In the PAdx2, 30 t ha-1 of filter sugar cane organic matter was applied to the plating furrow. After 5 months leaves samples were collected and undergone to macro and micronutrients to determine the foliar content. After 12 months the aerial part of the varieties were collected and separated in culms, leaves and edges, to later determine the macronutrients, and after to obtain the absorption and exportation. At the end of the culture cycle, the agricultural and industrial yields were evaluated. The N and Cu foliar contents were not affected by the interaction soil versus variety, showing this way that the varieties behaved similarly in the two soils. The macronutrients extraction order per sugar-cane ton by the varieties concerning the studied soil was: K > N > P > S > Mg > Ca.