RESUMO Objetivou-se, neste estudo, avaliar a produtividade da água em biomassa e açúcar de 23 variedades de cana-de-açúcar (segunda soqueira) irrigada por gotejamento sob dois níveis de irrigação. Dois experimentos foram instalados e conduzidos em casa de vegetação. Experimento 1: nove variedades em um solo argiloso e Experimento 2: 14 variedades em um solo franco-arenoso. Dois tratamentos de irrigação foram adotados: T100 - plenamente irrigado com reposição de 100% da evapotranspiração de cada variedade, mantendo a umidade do solo próximo à capacidade de campo; e T70 - irrigação com 70% da lâmina aplicada no tratamento T100. Avaliaram-se a produtividade da água em biomassa fresca de colmo (PABFC) e a produtividade da água em açúcar (PARBA). Houve variação na PABFC de 11,45 a 18,45 kg m-3. Observaram-se os maiores valores nas variedades CTC14, CTC6, RB867515 e SP81-3250 (T100) e nas variedades CTC6 e CTC14 (T70). A PARBA variou de 1,68 a 2,22 kg m-3, destaque para as variedades CTC6, RB967515, SP81-3250 e RB925211 em T100 e CTC6, CTC14 e SP81-3250 em T70.

ABSTRACT The aim of this study was to evaluate the water productivity into biomass and into sugar for 23 sugarcane varieties (second ratoon crop) under two levels of drip irrigation. Two experiments were conducted in a greenhouse. Experiment 1 comprised nine sugarcane varieties grown in a clay soil and Experiment 2 was composed of 14 varieties in a sandy-loam soil. Moreover, two irrigation treatments were adopted: T100 - full irrigation with 100% crop evapotranspiration replacement, maintaining soil moisture near field capacity for each variety; and T70 - irrigation with 70% T100 water depth. Water productivity was evaluated in terms of stem fresh biomass (WPFB) and sugar (WPGSY). The results showed that WPFB ranged from 11.45 to 18.45 kg m-3. The highest values were observed for varieties CTC14, CTC6, RB867515, and SP81-3250 (in T100) and for the varieties CTC6 and CTC14 (in T70). The WPGSY values ranged from 1.68 to 2.22 kg m-3, with emphasis placed on CTC6, RB9675-15, SP81-3250, and RB925211 (in T100) and on CTC6, CTC14, and SP81-3250 (in T70).

ABSTRACT This study aimed to quantify water deficit levels that compromise sugarcane initial growth exposed to different availability soil depths. The experiment was conducted in a greenhouse by using 100-liter capacity asbestos-cement boxes filled with different soil layers simulating depths of 10, 20, 30, and 40 cm. Water deficit levels were represented by accumulated reference evapotranspiration of 0, 40, 80, 120, 160, 200, 240, and 280 mm, which was considered from planting to irrigation return. Soil moisture at field capacity at planting time was sufficient to promote sprouting and emergence regardless the water deficit level that was subsequently exposed. For soil depths of 10 and 20 cm, a 160-mm water deficit level caused total plant death. On the other hand, for soil depths of 30 and 40 cm, a 200-mm water deficit level promoted plant death. A water deficit level from 40 mm significantly reduced plant growth regardless soil depth.

Os térmitas são bem conhecidos por sua capacidade de danificar madeira e vários tipos de produtos derivados. O estudo foi realizado no município de Seropédica, RJ, com o objetivo de avaliar a susceptibilidade da madeira de cinco essências florestais à ação do cupim subterrâneo asiático, Coptotermes gestroi. Como corpos-de-prova foram utilizados estacas de madeiras das seguintes essências florestais: pinho (Pinus sp.) (Pinaceae), castanheira (Bertholletia excelsa) (Lecythidaceae), angelim (Andira inermis) (Leguminosae-Papilionoideae), maçaranduba (Manilkara huberi) (Sapotaceae) e ipê (Tabebuia avellanedae) (Bignoniaceae). As estacas, com dimensões de 02 cm x 02 cm x 16 cm, foram submetidas à ação de C. gestroi, no período de 02 de setembro de 2006 a 02 de junho de 2007. O delineamento do experimento foi em blocos ao acaso com quatro repetições em arranjo fatorial 11x5x3, composto por 11 locais, cada um incluindo as cinco espécies florestais, totalizando 660 estacas e as avaliações efetuadas aos 90, 180 e 270 dias após a instalação das estacas. Os resultados indicaram que as estacas de pinho, castanheira e angelim são mais susceptíveis ao ataque de C. gestroi, enquanto que as estacas de ipê e maçaranduba não sofreram danos significativos por esse térmita. Houve correlação significativa e negativa entre as taxas de consumo de madeira e a densidade da madeira das essências estudadas. As madeiras mais susceptíveis ao ataque de C. gestroi apresentaram densidades moderadas a leves, portanto, menos densas e menos resistentes, como o pinho e a castanheira.

Termites are well known for their ability to damage wood and various types of wood-derived products. This study was performed in the municipality of Seropédica, Rio de Janeiro state, Brazil, with the objective of evaluating the susceptibility of the wood of five different forest species to the activity of the Asian subterranean termite, Coptotermes gestroi. Wood stakes from the following forest species were used as specimens: pine (Pinus sp., Pinaceae), Brazil nut (Bertholletia excelsa, Lecythidaceae), cabbage angelin (Andira inermis, Leguminosae-Papilionoideae), maçaranduba (Manilkara huberi, Sapotaceae) and pink ipê (Tabebuia avellanedae, Bignoniaceae). The stakes, with dimensions of 2 cm x 2 cm x 16 cm, were subjected to the activity of C. gestroi from September 2, 2006 to June 2, 2007. The experimental design consisted of randomized blocks with four replications in an 11 x 5 x 3 factorial arrangement. Twelve stakes of each of the five forest species were installed at each of eleven sites, totaling 660 stakes. Three evaluations were performed, at 90, 180 and 270 days after stake installation. The results indicated that the pine, Brazil nut and cabbage angelin stakes were more susceptible to C. gestroi attack, while the pink ipê and maçaranduba stakes suffered no significant damage from this termite. There was a significant negative correlation between the wood consumption rate and the wood density of the species studied. The woods most susceptible to C. gestroi attack presented moderate to low densities and therefore less resistance, as in the case of pine and cabbage angelin.