Hamilton Medeiros de Azevedo

Índices de crescimento da cana-de-açúcar irrigada e de sequeiro no Estado da Paraíba

The experiment was conducted in the Capim II Farm, in the Capim municipality of Paraiba, with the objective of evaluating the growth indices of the aerial parts and the root system of variety SP 79 1011 of sugar cane (Saccharum officinarum L.) under irrigated and non-irrigated conditions. The statistical design adapted was a randomized blocks, in a 2 x 6 factorial scheme, with three replications, being six plants samplings made and the components of aerial part and root system analyzed. The dry mass accumulation maximum rate was 0.7169 g d-1 for irrigated sugar cane and 0.6974 g d-1 for sugar cane without irrigation. The maximum Leaf Area Index (LAI) was 6.82, observed around 152 days after planting (DAP) under irrigation; the LAI maximum without irrigation was 6.80 at 157 DAP. More than 90 and of 80% of root dry mass concentrated in the first 60 cm of depth, respectively, under irrigated and non-irrigated conditions. Around 76% of root dry mass was found in the first 45 cm of depth. The irrigation system can be designed taking as a base the depth of 60 cm.

Resposta da cana-de-açúcar, primeira soca, a níveis de irrigação e adubação de cobertura

This research was accomplished in the Capim Farm of the Distillery Miriri located in the municipality of Capim city in Paraiba state, Brazil, with the objective of identifying the behavior of sugarcane crop, second leaf, for different irrigation water depths and levels of topdressing manuring with a mixture containing N and K2O in 1:0.94 proportion. With this purpose, an experiment was conducted using the variety SP79-1011, in completely randomized blocks in a factorial scheme of 4 x 2 (four irrigation depths and two levels of topdressing manuring), with three replications. The total water applied in the respective treatments was 807, 986, 1164 and 1343 mm and the levels of topdressing manuring were 85 and 305 kg ha-1. The growth, quality and yield parameters of sugarcane were analyzed. The irrigations prevailed in the initial growth phase of the second leaf and at the beginning of maximum development. The manuring dose influenced more the analyzed parameters than the water depth. The water depth influenced significantly, according to a positive linear behavior, the parameters of growth; while the sucrose (POL) of the cane showed a quadratic behavior.

Doses de adubação nitrogenada e potássica em cobertura na cultura da cana-de-açúcar, primeira soca, com e sem irrigação

O presente trabalho teve como objetivo avaliar os efeitos de diferentes doses de N e K2O, aplicados em cobertura, no desenvolvimento e rendimento de colmos, acucar e alcool da cana-soca (Saccharum spp, cultivar SP79 1011) cultivada com e sem irrigacao, em area da Destilaria Miriri, municipio de Capim, PB. O arranjo experimental foi um fatorial 2 x 4 (com e sem irrigacao, e quatro doses de adubacao de cobertura de N e K2O) com tres repeticoes. A lâmina de irrigacao usada, 27,5 mm, foi aplicada em intervalos de irrigacao de 12 dias. As adubacoes de cobertura foram compostas dos elementos N e K2 O aplicando-se respectivamente: AC1 = 44 e 41, AC2 = 86 e 81, AC3 = 157 e 148; e AC4 = 236 e 222 kg ha-1. As interacoes estudadas regime de irrigacao x doses de adubacao de cobertura foram nao-significativas. Quando submetida a irrigacao, a cultura apresentou melhores rendimentos em todas as variaveis avaliadas, exceto peso medio do colmo, quando comparada a nao irrigada. Nas parcelas irrigadas, a dose de adubacao influenciou significativamente, segundo um comportamento linear positivo, os rendimentos de colmos, acucar e alcool, enquanto que nas parcelas nao irrigadas esse efeito so foi evidenciado no rendimento dos colmos. A maxima dose de adubacao de cobertura utilizada no presente trabalho nao foi suficiente para se atingir picos maximos de rendimentos, seja no regime irrigado ou nao.

RESPONSE OF SUGARCANE TO IRRIGATION LEVELS IN COASTAL TABLE LANDS OF PARAÍBA STATE – BRAZIL

This research had the purpose of studying the response of sugarcane crop (Saccharum officinarum L., variety SP-79 1011) to different irrigation water depths. An experiment was conducted in the Capim Farm at the Miriri distillery, in the municipality of Capim, Paraiba State, Brazil, which consisted of a scheme with completely casualized plots and with three replications, where the irrigation water depths studied were W0=0, W1=152, W2=303, W3=308, W4=344 and W5=397 mm. The water application was made by a mobile Center Pivot irrigation system. The water amount applied was equal to the Class A pan evaporation tank subtracting the effective precipitation. The mean production of the gross sugar was 12.3 t ha-1, and the lowest and the highest values were, respectively, equal to 6.7 t ha-1 (W0=0 mm) and 6.3 t ha-1 (W2=303 mm). The irrigation water depths of 397 and 308 mm promoted, respectively, the maximum yield (11,609.00 L ha-1) and the maximum net income (R

RENDIMENTO E QUALIDADE DA CANA-DE-AÇÚCAR IRRIGADA SOB ADUBAÇÕES DE NITROGÊNIO E POTÁSSIO EM COBERTURA

1,439.00 ha-1). The maximum net income was 2.6, 1.1, and 1.2 times higher than the incomes generated, respectively, by the irrigation water depths of 0, 344 and 397 mm. It was verified that the state mean production of alcohol gross yield, estimated in 3,451.00 L ha-1, represents 34% and 32%, respectively, of the alcohol gross yield and of the net income obtained by water irrigation depth equal to 308 mm, that promotes the maximum net income.