Glauber José de Castro Gava

Degradação da palhada de cana-de-açúcar

Avaliou-se a influencia da aplicacao de ureia e vinhaca na degradacao da lignocelulose e na liberacao dos nutrientes da palhada de cana-de-acucar. Os tratamentos foram: vinhaca (dose equivalente a 100 m3 ha-1) aplicada sobre a palhada, combinada com ureia (dose equivalente a 100 kg ha-1) aplicada sobre a palhada ou enterrada no solo; mistura de cloreto de potassio (dose equivalente a 120 kg ha-1 de K2O) com ureia (dose equivalente a 100 kg ha-1) aplicada sobre a palhada ou enterrada no solo. Durante o periodo experimental, janeiro a novembro de 1997, a palhada recebeu uma lâmina de agua de 1.839 mm, sendo 923 mm de precipitacoes e 916 mm de irrigacoes. As medias das temperaturas maximas e minimas foram 28,4 e 15,5°C, respectivamente. Nao houve efeito dos tratamentos na degradacao da lignocelulose da palhada e na liberacao de nutrientes, verificando-se diferencas estatisticamente significativas apenas entre os resultados da palhada da cana recem colhida e os das remanescentes. Ocorreu reducao de massa de aproximadamente 80% para a hemicelulose e para o conteudo celular, e de 30 e 50% para a lignina e celulose, respectivamente. A porcentagem media de liberacao dos nutrientes N, P, K, Ca, Mg e S, em relacao ao total contido na palhada da cana recem colhida, foi de 18, 67, 93, 57, 68 e 68%, respectivamente.

Produtividade de três cultivares de cana-de-açúcar sob manejos de sequeiro e irrigado por gotejamento

This study aimed to evaluate the effect of drip irrigation technology in different sugarcane varieties in two crop cycles (plant cane and ratoon). The experimental design was in completly randomized blocks, in split-plot with four replications, constituted by three sugarcane genotypes: RB867515; RB855536 and SP80-3280 and two crop management: drip irrigation system and rainfed system, totalizing six treatments. The first cycle lasted for 336 days, with rainfall of 1,480 mm. The volume of water provided by the system of drip irrigation was 400 mm, totaling 1,880 mm. The second cycle lasted for 365 days, the volume of water through rainfall was 1,394 mm, added to 320 mm provided by the system of irrigation, totaled 1,714 mm. Interaction between management and cultivars was found significant for the variables: productivity of stalks (TCH) and sugar yield (TPH), in which the largest difference was observed for cultivar SP80-3280. There was significant response to drip irrigation, on average the increase of production of stalks and sugar was 24 and 23%, respectively.

Urea and sugarcane straw nitrogen balance in a soil-sugarcane crop system

Os objetivos deste trabalho foram avaliar a utilizacao do nitrogenio por soqueira de cana-de-acucar de duas fontes, ureia e palha de cana-de-acucar, e a recuperacao do N de ambas as fontes no sistema solo-planta. Os tratamentos foram estabelecidos em blocos casualizados, com quatro repeticoes: T1, mistura de vinhaca e ureia (100 kg ha-1 de N), aplicada em area total sobre o solo coberto com palha de cana-de-acucar marcada com 15N; T2, mistura de vinhaca e ureia (ureia marcada com 15N - ureia-15N; 100 kg ha-1 de N) aplicada em area total sobre o solo coberto com palha de cana-de-acucar nao marcada; e T3, ureia-15N (100 kg ha-1 de N) enterrada em sulcos laterais as linhas de cana-de-acucar, com previa aplicacao de vinhaca sobre o solo sem palha. A vinhaca foi aplicada no volume de 100 m3 ha-1 em todos os tratamentos. O experimento foi realizado em um Podzolico Vermelho-Amarelo (Paleudalf), entre outubro de 1997 e agosto de 1998, em Piracicaba, SP. A eficiencia de uso de N da ureia pela soqueira de cana-de-acucar foi de 21% e a de N da palha de cana-de-acucar foi de 9%. A principal contribuicao do N da palha de cana-de-acucar e a manutencao ou aumento do N orgânico do solo. A tendencia de menor acumulacao, pela cana-de-acucar, do N da ureia no tratamento com palha, foi compensada pela acumulacao de N proveniente da mineralizacao da palha. O N da palha ficou disponivel na segunda metade do ciclo da cultura.

Produtividade da cana-de-açúcar relacionada à localização de adubos nitrogenados aplicados sobre os resíduos culturais em canavial sem queima

Knowledge about the proper management of not-burned sugar cane is still limited, particularly regarding nitrogen fertilization. A field experiment was carried out to evaluate sugar cane yield, the balance of 15N fertilizers in the soil-plant-residue system and ammonia loss by volatilization in sugarcane ratoon crop without straw burning prior to mechanical harvesting, comparing different locations of surface-applied nitrogen fertilizers. The sugar cane variety SP81-3250. Treatments were arranged in a complete randomized blocks, with four replicates. The treatments consisted of four N fertilizer sources: ammonium nitrate (AN), ammonium sulfate (AS), urea and Uran, applied over the residues in two ways: over the entire area or side dressed on both sides of the ratoon crop line, at a rate of 70 kg N ha-1. The plots treated with AS and urea were divided in microplots with 15N labeled fertilizers. The ammonia losses by volatilization were higher for urea and uran, which contain amidic nitrogen, especially when sidedressed in bands. Ammonia losses by volatilization caused a reduction in yield, whereas the location of the fertilizer-N had no influence on the sugar cane yield. Independent of the nitrogen source location, the recovery of 15N from AS in sugar cane was twice as high as from urea. The nitrogen recovered in the soil-plant-trash system was 74 and 55 % of the N applied as AS and urea, respectively.

Uso de reguladores de crescimento como potencializadores do perfilhamento e da produtividade em cana-soca

The use of plant growth regulators as ripeners in sugarcane has been an agronomic practice with well solidified results. However, the residual effect of these products over the next ratoon is still not very well studied. This research aimed to evaluate the residual effect of two plant growth regulators, applied before the harvest, in the stool regrowth and productivity of three sugarcane genotypes. The experiment was carried out near Jau (SP). The experimental design was a randomized complete block, in split-plot, with four repetitions, constituted by the genotypes IAC87-3396, IAC91-2195 and IAC91-5155, and by three crop management: 20 g ha-1 sulfomethuron-methyl; 480 g a.i. ha-1 ethephon and control. The growth regulators were applied 126 days before harvest. To quantify the action of growth regulators the following variables were evaluated: the number of tillers m-1 at 0, 90, 180, 270 and 360 days after the harvest; the final percentage of stalk number by meter in relation to the initial percentage; the mass of 10 stalks, the length and the diameter of stalks; the pol and the fiber% cane, the reducing and total recoverable sugars, and the productivity of stalks and sugar. It was concluded that there was stimulating effect on the emergency of tillering up to six months after the harvest. The ethephon promoted larger productivities of stalks and sugar. There were differences among genotypes in relation to growth regulators for stalk length. There was no effect on the technological quality over the subsequent ratoon crop.

Balanço do nitrogênio da uréia (15N) no sistema solo-planta na implantação da semeadura direta na cultura do milho

This work aimed to study possible alterations in the production and partitioning of the phytomass, in the accumulation of total nitrogen and nitrogen in the plant derived from the fertilizer, by using the 15N side-dressing fertilization at the establishment of no-till management. The experiment was carried out in a Nitosol at Agua Sumida Farm located near Barra Bonita, State of Sao Paulo. The experiment was arranged in completely randomized block design, with 4 replicates. The following treatments were studied: conventional tillage system (one ploughing and two harrowings) and no-tilllage, both fertilized with urea (15N) applied at the rate of 100 kg ha-1 nitrogen. All treatments were subjected to sowing fertilization, by applying 25 kg ha-1 N as urea, 80 kg ha-1 P2O5 as simple superphosphate and 60 kg ha-1 K2O as potassium chloride. At the end of the phenological cycle, the following comparisons among the treatments were performed: crop yeld; nitrogen accumulation in the aerial and underground parts; use of nitrogen from urea (15N) and residual nitrogen in the soil. The modifications of the soil caused by implantation of no-till neither restricted the availability of nitrogen to maize plants, nor the production of dry matter. The use efficiency of nitrogen fertilization of maize plants and the recovery of the soil nitrogen fertilizer were around 45% and 30%, respectively, for the urea-N side-dressing fertilization in both conventional and no-till systems. Nitrogen applied as side-dressing fertilization, and not recovered from urea (NNR) averaged 25%, independently of the sowing system.

Potencial produtivo da cana-de-açúcar sob irrigação por gotejamento em função de variedades e ciclos

This study aimed to evaluate the yield potential of different varieties of sugarcane under drip irrigation in two growth cycles. A trial was set up in October 2006 at Jau region (Sao Paulo state, Brazil), in an experimental field with a eutrophic Ultisol. The experiment was conducted in randomized complete blocks with factorial treatment structure 8 x 2, constituted by eight sugarcane varieties and two crop cycles, with six replicates. Stalk productivity (TCH), sugar productivity (TPH), juice quality traits and water use efficiency in relation to stalk productivity were evaluated in each crop cycle. It was observed that varieties of sugarcane respond differently to full irrigation, and this response is influenced by climatic conditions of the agricultural year. In this study, only the first evaluation cycle (plant cane) was decisive to differentiate the performance among the varieties. The varieties IAC91-1099, IACSP96-3060, RB855536, RB867515 and SP85-1115 showed higher agro-industrial yield potential and less consumption of water and can be recommended for the management of production under drip irrigation.

Danos do complexo broca-podridão à produtividade e à qualidade da cana-de-açúcar fertirrigada com doses de nitrogênio

The objective of this work was to evaluate the effect of nitrogen-fertigation on the damage caused by the borer-rot complex to the productivity and quality of fertigated sugarcane. The experiment was carried out in field, using a randomized complete block design, with four replicates and five N doses (0, 50 100, 150, and 200 kg ha-1) applied through drip irrigation. The following variables were determined: number of holes caused by Diatraea saccharalis (Lepidoptera: Crambidae); number of internodes infected with red rot; incidence percentage of red rot; stalk productivity; and sugar content. In laboratory, the attractiveness and the consumption of culm fragments by fourth instar caterpillars, in trials with or without choice, were evaluated. Nitrogen fertigation increased the incidence of D. saccharalis and red rot. The number of holes produced by the larvae was correlated with the occurrence of red rot. Sugar percentage reduced with the increase in the number of red rot affected internodes. Nitrogen doses did not affect the attractiveness of sugarcane culm fragments; however, higher N doses increased the consumption of these fragments by D. saccharalis caterpillars. Despite the damages to quality, nitrogen fertilization expressively enhanced the productivity of stalks and sugar.

SOYA PROTEIN ISOLATED IN ALCOHOLIC FERMENTATION FOR THE PRODUCTION OF CACHAÇA

SOYA PROTEIN ISOLATED IN ALCOHOLIC FERMENTATION FOR THE PRODUCTION OF CACHACA The goal of this work was to evaluate the use of soya protein isolated as a proteic nitrogen organic source for sugar cane juice complementation and the effect in the yeast cell viability maintenance and cachaca quality. Batch fermentations of sugarcane juice with yeast recycling were performed, in scale pilot. The soya protein isolated influenced positively the cellular viability maintenance, and consequently resulted in a better recycled ferment and a reduction in time of fermentation. The proteic nitrogen addition in the juice didn’t affect the sensory acceptance of cachaca, and also didn’t result in different levels of volatile compounds. KEY-WORDS: Saccharomyces cerevisiae; CELULAR VIABILITY; VOLATILE COMPOUNDS; SENSORY ANALYSIS.

Interaction between N-fertilizer and water availability on borer-rot complex in sugarcane

This study aimed to evaluate the effects of nitrogen availability in fertigation and rainfed management, as well as their interactions with the incidence of and damage caused by D. saccharalis and red rot in sugarcane. The experiment consisted of four treatments (0 and 150 kg ha–1 of N-fertilizer with irrigation; 0 and 150 kg ha–1 of N-fertilizer in rainfed management) in a randomized complete block design with four replications. The evaluated parameters were the number of holes and internodes with red rot per meter of cultivation, stalk yield and sugar content. In the laboratory (T = 25 ± 2 °C; R.H. = 70 ± 10%: 12:12-L:D), we evaluated the attractiveness and consumption of fragments of stalks from the different treatments for fourth instar larvae through choice and no-choice tests in a randomized complete block design with ten replications. Nitrogen fertilization via irrigation has favorable effects on borer-rot complex and leads to higher gains in stalk and sugar yields when compared to rainfed management. The increments of stalk and sugar yields due to nitrogen fertilization compensates for the increase in borer-rot complex infestation. In laboratory tests, D. saccharalis larvae were similarly attracted to all treatments regardless of the doses of N-fertilizer or the water regimes evaluated. However, fragments of sugarcane stalks produced with nitrogen fertilization were consumed more by D. saccharalis in both water regimes.