Desenvolvimento morfofisiológico da cana-de-açúcar em regime irrigado e sequeiro na zona da mata paraibana.

Abstract

Na experiment was carried in filed conditions of the capim I I farm, district of Capim /Pbwith the objective of avaluating the effect of two different systems of cultivation (rainy conditions and irrigation) on the development of sugar cane 'SP 79 1011' (Sacharum spp.). The statiscal design was of radomized blocksin a factorial scheme (2x6), with six replication,where the studied factors was the cultivation systems and phenological periods of the samplings. the statistical design was of radomized blocks in a factorial scheme (2x6), with six replications, where the studied factores was the cultivations nad phenological periods of the samplings. The tilling was evaluated, number of leaves, the leave area, the dry weigth accumulations accumulation evaporates; the growth of the culture was evaluated through the growth variables: rate of growth absolute and relative and of the rate of liquid assimilation. A study was accomplished on the root system and certain the maximum depth of the same in different stadiums. They were still determined the médium height of the plants, weight of fresh matter and you varied technological (Pol, Brix, Fiber, Purity and PCC) as well as the final revenue of the culture. the tiling of culture was of 40% smaller in area under raine conditions (12 pl/m) than in the irrigated area (20 pl/m) falling the difference for 35% in the end of the first year of cultivation. The médium number of leaves the end of the cycle, went larger in to irrigated culture that in the rainy conditions culture. The leav area index maximum for the irrigated culture it went of 6,48 at 171 DAP and 6,33 to 98 DAP to the rainy culture. The growth of the culture, in relation to dry the dry phytomass accumulation, it was divided in four phases: I) slow growth; II) fast growth; III) stabilization of the growth and IV) decrese in the phytomass accumulation. The rate of absolute growth reached the maximum values of 145,1 and 128,3 g.m"2dia"' to the 246 and 171 DAP for the irrigated culture and of rayne culture, respectively. The TAL reached values of 0,4481 and 0,2241 g.cm"2.dia"1 for the irrigated cane and of raine respectively. The root system at the end of the cycle, 76% of its mass in the first 45 cm of soil and about 80% in the first ones 60cm. Thetilling of the culture went of fundamental importance to the final revenue that reached 43,83 and 29,26 t/ha for the irrigated cane and of raine, respectively.