Crescimento e acúmulo de nutrientes em sete cultivares de cana-de-açúcar (Saccharum spp.) na região de Coruripe-AL

Abstract

The studying of analysis of sugarcane growth is considered a pattern method to measure the biological productivity of a vegetable species in certain environmental conditions. The awareness of the culture growth rate, the accumulation data and the nutrients allocation become a quiet important tool in the process of manuring hadling. To get the regular and high plants productivity it is necessary to work on water and manure hadling. The water and nutrients of plants supplement capacity are dependent of manuring, the phenological cultivation phase, the physical and chemistry properties of soil and the local atmosphere condition. In spite of Brazil being the world biggest sugarcane productor. There are yet many problems to work out, especially about the manuring management. The sugarcane necessity on nutrients is supplied by fertilizers providing. This way we can presume that in several conditions this fertilizer is sometimes underestimated or other times overestimated. This experiment was accomplished in Progresso farm which belongs to the Usina Coruripe-AL, under waste conditions, with the cultivators: SP79-1011, RB72454, RB855113, RB867515, RB92579, RB93509 and Co997. The spacing was the array simple system of 1,00 x 1,00 m. it was made a manuring, in the dose of 84 kg ha-1 of N, 60 kg ha-1 of P2O5 and 144 kg ha-1 of K2O. The readings were made every 30 days in the first two months for the height and stool plants count. In that same portion, every 60 days were made the diameter measures of the stem, the foliating area, the foliating index area and total phytomass (they were appraised 30 plants for sub-portions). With the study of the growth analysis of cultivators it was observed that happened difference in the studying variables in the respective times (30, 60, 120, 180, 240, 300 and 360 days of DAP planting). There were two important phases of growth: intense adopting until 120 DAP; and the second phase, the stem height, the IAF increase and the intense green mass accumulation, starting from 180 DAP. And, in relation to the nutrients accumulation in the same times mentioned above, the largest rates of nutrients accumulation X II were in the period of 240 DAP, which were coinciding with the high pluvial precipitation period, and the appropriate conditions for the whole development of the culture. The RB92579 cultivating in the end of the experimental period had accumulated 119,27 t ha-1 of green matter in the aerial part, and for the nutrients: N, P, K, Ca, Mg and S the accumulation was of 158,8; 23,3; 231 35,4; 30,7; 26,7 kg ha-1, respectively.