Antonio Alberto Costa

Adubação NK em três variedades de cana-de-açúcar em função de dois espaçamentos

Two factorial field experiments were carried out in the years of 1981 to 1984, in two soils (Dark-red Latosol - LE, and Dusky-red Latosol - LR) of the State of Sao Paulo, Brazil, with the objective of assessing the effect of N and K application on yield of three varieties of sugarcane grown in two row spacings. The fertilizer treatments for plant-cane consisted of the following combinations of N and K2O, in kg/ha: 0-210, 70-210, 140-210, 210-210, 140-0, 140-70, 140-140, and 140-210. All plots received equal amounts of P, at the rate of 120 kg P2O5/ha. The fertilizer treatments for 1st and 2nd ratoon were the same for all plots: 100, 30, and 120 kg/ha of N, P2O5, and K2O, respectively. Significant effects of row spacings, varieties, and NK application were observed on yields of cane and sucrose in both soils. Maximum calculated yields of cane were obtained with 165 kg N/ha and 148 kg K2O/ha in the LR soil, and 180 kg N/ha in the LE soil. The corresponding values for maximum sucrose yields were 153 kg N/ha and 104 kg K2O/ha in the LE soil and 128 kg K2O/ha in the LR soil. The highest rates of both N and K applied caused a decrease in the sucrose concentration of cane so that the rates of fertilizer application necessary for maximum sucrose yield were lower than those for maximum cane yield. The data for total cane and sucrose production (plant + ratoon) showed that the effects of N and K were similar to those obtained for plant-cane. The 1.2-meter row spacing produced higher yield of cane per unit area than that of the 1.5-meter spacing (increases of 14% in LR and 7% in LE, for plant + ratoon), and lower values per unit length of row (- 18% in LR and - 10% in LE). Varieties IAC58-480 and IAC64-257 showed greater sucrose yield than that of IAC52-150: 17% and 12% respectively in LR; in LE, both varieties produced 12% more than IAC52-150. Varieties also differed regarding sucrose content: IAC58-480 was 5% higher than IAC52-150 and the latter was 2% higher than IAC64-257.

CARACTERIZAÇÃO TECNOLÓGICA DE HÍBRIDOS DE AGAVE

Fiber production per plant and leaf dry matter content as well as leaf fiber and non-fibrous fraction levels have been scored in 152 Agave hybrids, and the results compared with those of Agave sisalana (common species). Those hybrids were derived from the backcross (A. amaniensis x A. angustifolia) x A. amaniensis. Fiber production (0.2 to 2.5 kg/plant), leaf dry matter content (142.3 to 216.0 g/kg), leaf fiber (189.9 to 361.9 g/kg) and leaf non-fibrous fraction (219.2 to 365.1 g/kg) varied sharply among the hybrids tested, as compared with the values obtained in Agave sisalana. Average fiber production (1.4 kg/plant) from the 58 highest yielding hybrids significantly outscored that of the common species (0.7 kg/plant).

Caracterização tecnológica de espécies liberianas para o estabelecimento de métodos de análise quantitativa de fibras

The technological characteristics of five bast plants were determined mainly to establish a new methodology for textile and cellulosic fibers determinations. The studied species (Crotalaria juncea, Hibiscus cannabinus, Corchorus capsularis, Urena lobatta and Boehmeria nivea) were collected in 1987, from experiments carried out at the Experiment Center of Campinas, and Experiment Station of Pariquera-Acu, Instituto Agronomico, State of Sao Paulo, Brazil. The results showed technological differences among species. The Crotalaria stalks with the lowest bast contents (19.65%), presented the highest value for the total cellulosic fibers (54.84%) obtained from the bast and woody fraction of the stalk. The bast content for other species varied from 30.74 to 41.13% and the total fibers from 39.46 to 48.38%. The methods of analysis utilized and described in this paper, represent a new methodology for the quantitative determination of textile and cellulosic fibers.Procedeu-se a caracterizacao tecnologica de cinco especies nao arboreas fornecedoras de fibras liberianas, visando, principalmente, ao estabelecimento de novo metodo de analise quantitativa de fibras texteis e celulosicas. Essas especies - Crotalaria juncea, Hibiscus cannabinus, Corchorus capsularis, Urena lobatta e Boehmeria nivea - foram coletadas em 1987, de experimentos desenvolvidos no Centro Experimental de Campinas e na Estacao Experimental de Pariquera-Acu do Instituto Agronomico (IAC). Os resultados mostraram variacoes tecnologicas significativas entre tais especies. A crotalaria, com o menor teor de liber (19,65%) apresentou o maior teor de fibras celulosicas totais (54,84%), provenientes das fracoes liberianas e lenhosas do caule. Para as demais especies, os teores de liber variaram de 30,74 a 41,13% e as fibras celulosicas de 39,46 a 48,38%. Os procedimentos de analise descritos representaram novo metodo para avaliar quantitativamente os teores de fibras texteis e celulosicas nos caules de especies nao arboreas.

Densidade básica do colmo e sua correlação com os valores de brix e pol em cana-de-açúcar

The correlation between the refractometric (Brix) and polarimetric (Pol) determinations and the culm basic density was determined. The objective was to establish a fast and semiquantitative method for sugarcane analysis, regarding sucrose determination in the culm. The results showed a significant correlation (p > 0.99) between the basic density and each of the values of Brix and Pol, mainly for the median portion of the culm. It was concluded that the culm basic density can be utilized as a speedy method to estimate the sucrose concentration of sugarcane culms.

Technological characterization of some bast plants for the establishment of a new method of fiber determination

The technological characteristics of five bast plants were determined mainly to establish a new methodology for textile and cellulosic fibers determinations. The studied species (Crotalaria juncea, Hibiscus cannabinus, Corchorus capsularis, Urena lobatta and Boehmeria nivea) were collected in 1987, from experiments carried out at the Experiment Center of Campinas, and Experiment Station of Pariquera-Acu, Instituto Agronomico, State of Sao Paulo, Brazil. The results showed technological differences among species. The Crotalaria stalks with the lowest bast contents (19.65%), presented the highest value for the total cellulosic fibers (54.84%) obtained from the bast and woody fraction of the stalk. The bast content for other species varied from 30.74 to 41.13% and the total fibers from 39.46 to 48.38%. The methods of analysis utilized and described in this paper, represent a new methodology for the quantitative determination of textile and cellulosic fibers.Procedeu-se a caracterizacao tecnologica de cinco especies nao arboreas fornecedoras de fibras liberianas, visando, principalmente, ao estabelecimento de novo metodo de analise quantitativa de fibras texteis e celulosicas. Essas especies - Crotalaria juncea, Hibiscus cannabinus, Corchorus capsularis, Urena lobatta e Boehmeria nivea - foram coletadas em 1987, de experimentos desenvolvidos no Centro Experimental de Campinas e na Estacao Experimental de Pariquera-Acu do Instituto Agronomico (IAC). Os resultados mostraram variacoes tecnologicas significativas entre tais especies. A crotalaria, com o menor teor de liber (19,65%) apresentou o maior teor de fibras celulosicas totais (54,84%), provenientes das fracoes liberianas e lenhosas do caule. Para as demais especies, os teores de liber variaram de 30,74 a 41,13% e as fibras celulosicas de 39,46 a 48,38%. Os procedimentos de analise descritos representaram novo metodo para avaliar quantitativamente os teores de fibras texteis e celulosicas nos caules de especies nao arboreas.

Palmito de cana-de-açúcar: nova opção alimentar

No presente estudo, realizado no Centro Experimental de Campinas (IAC), em 1991, procedeu-se a extracao e a caracterizacao do palmito de cana como alimento humano, determinando-se algumas de suas propriedades quimicas. O material genetico utilizado foi o clone IAC 70-32, proveniente da Estacao Experimental de Piracicaba (SP), do Instituto Agronomico (IAC). O palmito de cana e um subproduto da cultura da cana, com teor de proteina (2,10%) semelhante ao do palmito (Euterpe edulis) (2,18%), podendo ser utilizado como alimento humano. Considerando seu peso medio (8,29 g) e o numero de colmos de cana por hectare (60.000), pode-se obter uma producao de palmito de cana da ordem de 483 kg/ha.