Decision-making on the optimum timing for nitrogen fertilization on sugarcane ratoon

Low efficiency of nitrogen from fertilizers is a major concern worldwide, threatening the sustainability of sugarcane production. The N use efficiency (NUE) by sugarcane can be improved by adopting better fertilizing management practices, reducing environmental impacts. This work evaluated the effects of varying N rates and time of application on stalks and sugar yield in ratoon harvested early in the crop season. The experimental design was a randomized block in a 2 × 4 factorial design and a control (no N) with five replications, including two application times (45 or 90 DAH – days after harvest) and four N rates (50, 100, 150, or 200 kg N ha−1). The time of N fertilizer application promoted differences in stalk yield, as the cumulative yield of two harvests was increased by 8 % (15 Mg ha−1) at 45 DAH when compared to the application at 90 DAH. The application performed at 45 DAH augmented sugar yield by 10 % (2.8 Mg ha−1 of sugar) in relation to 90 DAH. The N rates that promoted the highest sugarcane yield were, respectively, 122 and 144 kg N ha−1 in the first and second crop cycles. The average economical rates obtained for the first and second agricultural cycles were, respectively, 104 and 127 kg N ha−1, demonstrating that the gains by applying high amounts of fertilizers (rates above 150 kg N ha−1) may not cover the investment.

Decision-making on the optimum timing for nitrogen fertilization on sugarcane ratoon

Low efficiency of nitrogen from fertilizers is a major concern worldwide, threatening the sustainability of sugarcane production. The N use efficiency (NUE) by sugarcane can be improved by adopting better fertilizing management practices, reducing environmental impacts. This work evaluated the effects of varying N rates and time of application on stalks and sugar yield in ratoon harvested early in the crop season. The experimental design was a randomized block in a 2 × 4 factorial design and a control (no N) with five replications, including two application times (45 or 90 DAH days after harvest) and four N rates (50, 100, 150, or 200 kg N ha−1). The time of N fertilizer application promoted differences in stalk yield, as the cumulative yield of two harvests was increased by 8 % (15 Mg ha−1) at 45 DAH when compared to the application at 90 DAH. The application performed at 45 DAH augmented sugar yield by 10 % (2.8 Mg ha−1 of sugar) in relation to 90 DAH. The N rates that promoted the highest sugarcane yield were, respectively, 122 and 144 kg N ha−1 in the first and second crop cycles. The average economical rates obtained for the first and second agricultural cycles were, respectively, 104 and 127 kg N ha−1, demonstrating that the gains by applying high amounts of fertilizers (rates above 150 kg N ha−1) may not cover the investment.(AU)

Agronomic performance of sugarcane cultivated under quantities of sugarcane straw on the soil surface / Desempenho agronômico da cana-de-açúcar cultivada sob diferentes quantidades de palhada da cultura na superfície do solo

Mechanized harvesting has become increasingly common in the sugarcane production system. The sugarcane straw removed by mechanical harvesting could be converted into ethanol or be used to generate electricity by burning the material. At the same time, it is important to determine the amount of biomass that could be removed from the soil surface without damage to the cane crop. The agronomic performance of sugarcane was evaluated by growing the variety RB92579 under different amounts of sugarcane straw on the soil surface, in the first and second years of cane crop growth. An experimental randomized block in a split-plot design was used with four replications. In the first year the plots received five amounts of straw (0.0, 4.5, 9.0, 13.5, and 18 Mg ha-1), and six assessments (60, 120, 180, 240, 300, and 360 days after planting) were made in the subplots. In the second year, the plots received the same amount of straw and four assessments (60, 120, 240, and 540 days after the regrowth) in the subplots. Biometric indexes, components of production, and crop yield were evaluated. The data were submitted to variance analysis and polynomial regression (p < 0.05). Increasing amounts of sugarcane straw deposited on the soil surface reduced the number and diameter of stalks at the beginning of crop establishment and the number of leaves for the first year. The maximum productivity of stalks was achieved by maintaining on the soil surface 9.6 Mg ha-1 of straw in the first year and 4.7 Mg ha-1 of straw in the second year of cane crop production.

A colheita mecanizada está cada vez mais presente no sistema de produção de cana-de-açúcar. A palhada retirada durante a colheita pode ser convertida a etanol ou utilizada para geração de energia elétrica por meio da queima, sendo importante determinar a quantidade desta biomassa que pode ser removida, sem que haja prejuízos à cultura. Objetivou-se avaliar o desempenho agronômico da cana-de-açúcar, variedade RB92579, cultivada sob diferentes quantidades de palhada da cultura na superfície do solo, em cultivo de primeiro e segundo ciclo. Utilizou-se o delineamento experimental em blocos casualizados, com parcelas subdivididas no tempo, com quatro repetições. No primeiro ciclo as parcelas receberam cinco quantidades de palhada (0,0; 4,5; 9,0; 13,5 e 18 Mg ha-1) e seis épocas de avaliação (60, 120, 180, 240, 300, 360 dias após o plantio – DAP), dispostas nas subparcelas. No segundo ciclo, nas parcelas foram depositadas as mesmas quantidades de palhada e nas subparcelas foram dispostas as quatro épocas de avaliação (60, 120, 240 e 540 dias após a rebrota – DAR). Foram avaliadas as características fitométricas, os componentes de produção e a produtividade. Os dados foram submetidos à análise de variância e estudo de regressão polinomial (p < 0,05). O aumento das quantidades de palhada depositadas na superfície do solo reduz o número e o diâmetro do colmo no início do estabelecimento da cultura, e o número de folhas para a cana de primeiro ciclo. A produtividade máxima de colmos é obtida com a manutenção de 9,6 Mg ha-1 de palhada para o primeiro ciclo e 4,7 Mg ha-1 de palhada para o segundo ciclo.

Agronomic performance of sugarcane cultivated under quantities of sugarcane straw on the soil surface / Desempenho agronômico da cana-de-açúcar cultivada sob diferentes quantidades de palhada da cultura na superfície do solo

Mechanized harvesting has become increasingly common in the sugarcane production system. The sugarcane straw removed by mechanical harvesting could be converted into ethanol or be used to generate electricity by burning the material. At the same time, it is important to determine the amount of biomass that could be removed from the soil surface without damage to the cane crop. The agronomic performance of sugarcane was evaluated by growing the variety RB92579 under different amounts of sugarcane straw on the soil surface, in the first and second years of cane crop growth. An experimental randomized block in a split-plot design was used with four replications. In the first year the plots received five amounts of straw (0.0, 4.5, 9.0, 13.5, and 18 Mg ha-1), and six assessments (60, 120, 180, 240, 300, and 360 days after planting) were made in the subplots. In the second year, the plots received the same amount of straw and four assessments (60, 120, 240, and 540 days after the regrowth) in the subplots. Biometric indexes, components of production, and crop yield were evaluated. The data were submitted to variance analysis and polynomial regression (p < 0.05). Increasing amounts of sugarcane straw deposited on the soil surface reduced the number and diameter of stalks at the beginning of crop establishment and the number of leaves for the first year. The maximum productivity of stalks was achieved by maintaining on the soil surface 9.6 Mg ha-1 of straw in the first year and 4.7 Mg ha-1 of straw in the second year of cane crop production.(AU)

A colheita mecanizada está cada vez mais presente no sistema de produção de cana-de-açúcar. A palhada retirada durante a colheita pode ser convertida a etanol ou utilizada para geração de energia elétrica por meio da queima, sendo importante determinar a quantidade desta biomassa que pode ser removida, sem que haja prejuízos à cultura. Objetivou-se avaliar o desempenho agronômico da cana-de-açúcar, variedade RB92579, cultivada sob diferentes quantidades de palhada da cultura na superfície do solo, em cultivo de primeiro e segundo ciclo. Utilizou-se o delineamento experimental em blocos casualizados, com parcelas subdivididas no tempo, com quatro repetições. No primeiro ciclo as parcelas receberam cinco quantidades de palhada (0,0; 4,5; 9,0; 13,5 e 18 Mg ha-1) e seis épocas de avaliação (60, 120, 180, 240, 300, 360 dias após o plantio DAP), dispostas nas subparcelas. No segundo ciclo, nas parcelas foram depositadas as mesmas quantidades de palhada e nas subparcelas foram dispostas as quatro épocas de avaliação (60, 120, 240 e 540 dias após a rebrota DAR). Foram avaliadas as características fitométricas, os componentes de produção e a produtividade. Os dados foram submetidos à análise de variância e estudo de regressão polinomial (p < 0,05). O aumento das quantidades de palhada depositadas na superfície do solo reduz o número e o diâmetro do colmo no início do estabelecimento da cultura, e o número de folhas para a cana de primeiro ciclo. A produtividade máxima de colmos é obtida com a manutenção de 9,6 Mg ha-1 de palhada para o primeiro ciclo e 4,7 Mg ha-1 de palhada para o segundo ciclo.(AU)

Sugarcane trash levels in soil affects the fungi but not bacteria in a short-term field experiment

Abstract The sugarcane in Brazil is passing through a management transition that is leading to the abolition of pre-harvest burning. Without burning, large amounts of sugarcane trash is generated, and there is a discussion regarding the utilization of this biomass in the industry versus keeping it in the field to improve soil quality. To study the effects of the trash removal on soil quality, we established an experimental sugarcane plantation with different levels of trash over the soil (0%, 50% and 100% of the original trash deposition) and analyzed the structure of the bacterial and fungal community as the bioindicators of impacts. The soil DNA was extracted, and the microbial community was screened by denaturing gradient gel electrophoresis in two different seasons. Our results suggest that there are no effects from the different levels of trash on the soil chemistry and soil bacterial community. However, the fungal community was significantly impacted, and after twelve months, the community presented different structures among the treatments.

Sugarcane trash levels in soil affects the fungi but not bacteria in a short-term field experiment

The sugarcane in Brazil is passing through a management transition that is leading to the abolition of pre-harvest burning. Without burning, large amounts of sugarcane trash is generated, and there is a discussion regarding the utilization of this biomass in the industry versus keeping it in the field to improve soil quality. To study the effects of the trash removal on soil quality, we established an experimental sugarcane plantation with different levels of trash over the soil (0%, 50% and 100% of the original trash deposition) and analyzed the structure of the bacterial and fungal community as the bioindicators of impacts. The soil DNA was extracted, and the microbial community was screened by denaturing gradient gel electrophoresis in two different seasons. Our results suggest that there are no effects from the different levels of trash on the soil chemistry and soil bacterial community. However, the fungal community was significantly impacted, and after twelve months, the community presented different structures among the treatments.(AU)

Sugarcane trash levels in soil affects the fungi but not bacteria in a short-term field experiment.

The sugarcane in Brazil is passing through a management transition that is leading to the abolition of pre-harvest burning. Without burning, large amounts of sugarcane trash is generated, and there is a discussion regarding the utilization of this biomass in the industry versus keeping it in the field to improve soil quality. To study the effects of the trash removal on soil quality, we established an experimental sugarcane plantation with different levels of trash over the soil (0%, 50% and 100% of the original trash deposition) and analyzed the structure of the bacterial and fungal community as the bioindicators of impacts. The soil DNA was extracted, and the microbial community was screened by denaturing gradient gel electrophoresis in two different seasons. Our results suggest that there are no effects from the different levels of trash on the soil chemistry and soil bacterial community. However, the fungal community was significantly impacted, and after twelve months, the community presented different structures among the treatments.

Changes in soil chemical reactions in response to straw sugar cane and vinasse / Alteração na reação química do solo influenciada pela palha de cana-de-açúcar e vinhaça

Sugarcane harvesting is predominantly mechanical because of environmental restrictions, reduced requirements for manpower, and the quest for improved efficiency. Therefore, large amounts of straw remain available in the soil. Vinasse, a liquid waste, is a main byproduct of the sugar and alcohol industry, in addition to sugarcane straw. Both accumulate in sugarcane fields; however, the effects of their interaction are unclear. In this study, the effects of applications of sugarcane straw and vinasse on the pH and the potassium (K), calcium (Ca), and magnesium (Mg) concentrations of a dystroferric Red Nitosol with a high base saturation were examined. The profiles of soil samples from sugarcane plantations collected at depths of 0-0.05, 0.06-0.10, 0.11-0.20, and 0.21-0.30 m were reproduced in 64 polyvinyl chloride (PVC) columns with dimensions of 0.036 × 0.30 m (diameter × height). The soils were treated with doses of 0, 125, 250, and 500 m3 ha-1 sugarcane vinasse and 0, 3, 6, and 9 t ha-1 sugarcane straw and incubated for 60 days. Following the analysis, by layer, the data were subjected to analysis of variance by partitioning the degrees of freedom into orthogonal polynomials. The pH and the Ca, Mg, and K concentrations increased throughout the soil profile upon vinasse application. An acid-base imbalance was observed in the topsoil layers in association with the high K...(AU)

Devido às restrições ambientais, falta de mão-de-obra e a busca por melhor eficiência, a colheita de cana-de-açúcar tende a ser mecanizada, fazendo com que grande quantidade de palhada esteja disponível no solo. Somada à palha, a vinhaça é o principal resíduo líquido da indústria sucroalcooleira. Ambos são depositados a campo; porém, o efeito da interação entre os mesmos, ainda não está esclarecido. Avaliou-se a influência da aplicação de palha de cana-de-açúcar e vinhaça no pH e nos teores de potássio (K), cálcio (Ca) e magnésio (Mg) em Nitossolo Vermelho distroférrico de alta saturação por bases. Em 64 colunas de PVC de 0,036 × 0,30 m (diâmetro × altura) foram reproduzidos perfis do solo coletados nas profundidades 0-0,05; 0,06-0,10; 0,10-0,20; 0,20-0,30 m, em área de cultivo. Os solos foram tratados com vinhaça, em doses equivalentes a 0, 125, 250 e 500 m3 ha-1 e 0, 3, 6 e 9 t ha-1 de palha de cana-de-açúcar e submetidos à incubação por 60 dias. Após as análises por camada, os dados foram submetidos à análise de variância com desdobramento dos graus de liberdade em polinômios ortogonais. Com a aplicação de vinhaça, houve elevação do pH e dos teores de Ca, Mg e K, com distribuição em todo o perfil. Observou-se desequilíbrio de bases nas camadas superficiais devido à alta saturação de K. A palha de cana-de-açúcar potencializou o efeito da vinhaça em todas as profundidades...(AU)

Changes in soil chemical reactions in response to straw sugar cane and vinasse / Alteração na reação química do solo influenciada pela palha de cana-de-açúcar e vinhaça

Sugarcane harvesting is predominantly mechanical because of environmental restrictions, reduced requirements for manpower, and the quest for improved efficiency. Therefore, large amounts of straw remain available in the soil. Vinasse, a liquid waste, is a main byproduct of the sugar and alcohol industry, in addition to sugarcane straw. Both accumulate in sugarcane fields; however, the effects of their interaction are unclear. In this study, the effects of applications of sugarcane straw and vinasse on the pH and the potassium (K), calcium (Ca), and magnesium (Mg) concentrations of a dystroferric Red Nitosol with a high base saturation were examined. The profiles of soil samples from sugarcane plantations collected at depths of 0-0.05, 0.06-0.10, 0.11-0.20, and 0.21-0.30 m were reproduced in 64 polyvinyl chloride (PVC) columns with dimensions of 0.036 × 0.30 m (diameter × height). The soils were treated with doses of 0, 125, 250, and 500 m3 ha-1 sugarcane vinasse and 0, 3, 6, and 9 t ha-1 sugarcane straw and incubated for 60 days. Following the analysis, by layer, the data were subjected to analysis of variance by partitioning the degrees of freedom into orthogonal polynomials. The pH and the Ca, Mg, and K concentrations increased throughout the soil profile upon vinasse application. An acid-base imbalance was observed in the topsoil layers in association with the high K...

Devido às restrições ambientais, falta de mão-de-obra e a busca por melhor eficiência, a colheita de cana-de-açúcar tende a ser mecanizada, fazendo com que grande quantidade de palhada esteja disponível no solo. Somada à palha, a vinhaça é o principal resíduo líquido da indústria sucroalcooleira. Ambos são depositados a campo; porém, o efeito da interação entre os mesmos, ainda não está esclarecido. Avaliou-se a influência da aplicação de palha de cana-de-açúcar e vinhaça no pH e nos teores de potássio (K), cálcio (Ca) e magnésio (Mg) em Nitossolo Vermelho distroférrico de alta saturação por bases. Em 64 colunas de PVC de 0,036 × 0,30 m (diâmetro × altura) foram reproduzidos perfis do solo coletados nas profundidades 0-0,05; 0,06-0,10; 0,10-0,20; 0,20-0,30 m, em área de cultivo. Os solos foram tratados com vinhaça, em doses equivalentes a 0, 125, 250 e 500 m3 ha-1 e 0, 3, 6 e 9 t ha-1 de palha de cana-de-açúcar e submetidos à incubação por 60 dias. Após as análises por camada, os dados foram submetidos à análise de variância com desdobramento dos graus de liberdade em polinômios ortogonais. Com a aplicação de vinhaça, houve elevação do pH e dos teores de Ca, Mg e K, com distribuição em todo o perfil. Observou-se desequilíbrio de bases nas camadas superficiais devido à alta saturação de K. A palha de cana-de-açúcar potencializou o efeito da vinhaça em todas as profundidades...

Impacts of harvesting methods of sugar cane on the soil macrofauna in production area in Espírito Santo Brazil / Impactos dos métodos de colheita da cana-de-açúcar sobre a macrofauna do solo em área de produção no Espírito Santo Brasil

The objective of this study was to evaluate the effects of harvesting methods on the macrofauna, a known indicator of soil quality that detects changes in the system and indicates management alternatives. The experimental design was randomized blocks with six replications, with each block consisting of four parcels that corresponded to treatments green cane (CC), burnt cane (CQ), green cane burnt cane (CC-Q) and burnt cane green cane (CQ-C). Samples were collected in February and July 2010. The animals were divided into major taxonomic groups and accounted. Were evaluated ecological indexes (Shannon, Pielou and richness) and average total density of individuals and groups. Data were analyzed by the nonparametric statistical tools by Friedman or Signal test at 5%. To check relationships between soil fauna and environmental variables, was used a multivariate conditional ordination method, the redundancy analysis (RDA). The index richness was more efficient than the total average density to evaluate the influence of cane harvesting systems, with the highest values related to areas harvested without burning. Further, the occurrence of key groups in the areas harvested without burning configures the establishment of a trophic web. There was dominance of the social group Formicidae in all treatments.

O objetivo deste trabalho foi avaliar os efeitos dos métodos de colheita sobre a macrofauna edáfica, um conhecido indicador da qualidade do solo que detecta as alterações ocorridas no sistema e indica alternativas de manejo. O delineamento experimental adotado foi blocos casualizados com seis repetições, sendo cada bloco composto por quatro parcelas que correspondiam aos tratamentos cana cru (CC), cana queimada (CQ), cana crua-queimada (CC-Q) e cana queimada-crua (CQ-C). As coletas foram realizadas nos meses de fevereiro e julho de 2010. Os animais foram classificados em grandes grupos taxonômicos e contabilizados. Avaliaram-se os índices ecológicos (Shannon, Pielou e riqueza) e a densidade média total de indivíduos e grupos. Os dados foram analisados por ferramentas de estatística não paramétrica através do teste de Friedman ou do Sinal a 5%. Para verificar relações entre fauna edáfica e variáveis ambientais utilizou-se um método de ordenação multivariada condicionada, a análise de redundância (RDA). O índice riqueza foi mais eficiente que a densidade média total na avaliação da influência dos sistemas de colheita da cana, estando seus maiores valores relacionados às áreas colhidas sem queima. Ainda, a ocorrência de grupos chave também nas áreas colhidas sem queima configura o estabelecimento de uma teia trófica. Houve dominância do grupo social Formicidae em todos os trat

Impacts of harvesting methods of sugar cane on the soil macrofauna in production area in Espírito Santo Brazil / Impactos dos métodos de colheita da cana-de-açúcar sobre a macrofauna do solo em área de produção no Espírito Santo Brasil

 The objective of this study was to evaluate the effects of harvesting methods on the macrofauna, a known indicator of soil quality that detects changes in the system and indicates management alternatives. The experimental design was randomized blocks with six replications, with each block consisting of four parcels that corresponded to treatments green cane (CC), burnt cane (CQ), green cane burnt cane (CC-Q) and burnt cane green cane (CQ-C). Samples were collected in February and July 2010. The animals were divided into major taxonomic groups and accounted. Were evaluated ecological indexes (Shannon, Pielou and richness) and average total density of individuals and groups. Data were analyzed by the nonparametric statistical tools by Friedman or Signal test at 5%. To check relationships between soil fauna and environmental variables, was used a multivariate conditional ordination method, the redundancy analysis (RDA). The index richness was more efficient than the total average density to evaluate the influence of cane harvesting systems, with the highest values related to areas harvested without burning. Further, the occurrence of key groups in the areas harvested without burning configures the establishment of a trophic web. There was dominance of the social group Formicidae in all treatments.

O objetivo deste trabalho foi avaliar os efeitos dos métodos de colheita sobre a macrofauna edáfica, um conhecido indicador da qualidade do solo que detecta as alterações ocorridas no sistema e indica alternativas de manejo. O delineamento experimental adotado foi blocos casualizados com seis repetições, sendo cada bloco composto por quatro parcelas que correspondiam aos tratamentos cana cru (CC), cana queimada (CQ), cana crua-queimada (CC-Q) e cana queimada-crua (CQ-C). As coletas foram realizadas nos meses de fevereiro e julho de 2010. Os animais foram classificados em grandes grupos taxonômicos e contabilizados. Avaliaram-se os índices ecológicos (Shannon, Pielou e riqueza) e a densidade média total de indivíduos e grupos. Os dados foram analisados por ferramentas de estatística não paramétrica através do teste de Friedman ou do Sinal a 5%. Para verificar relações entre fauna edáfica e variáveis ambientais utilizou-se um método de ordenação multivariada condicionada, a análise de redundância (RDA). O índice riqueza foi mais eficiente que a densidade média total na avaliação da influência dos sistemas de colheita da cana, estando seus maiores valores relacionados às áreas colhidas sem queima. Ainda, a ocorrência de grupos chave também nas áreas colhidas sem queima configura o estabelecimento de uma teia trófica. Houve dominância do grupo social Formicidae em todos os trat

Avaliação técnico-econômica da colheita manual e mecanizada da cana-de-açúcar (saccharum spp) na região de Bandeirantes: Pr / Technical and economical evaluation of hand and mechanized harvest of sugar cane (saccharum spp) in Bandeirantes: Pr

A prática da queima antes da colheita da cana-de-açúcar vem sendo muito questionada, tanto pelo poder público quanto pela sociedade, preocupada com as questões ambientais. A colheita mecanizada da cana sem queima é apontada como um dos possíveis métodos para evitar a queima, e ainda não está sendo utilizada na região de Bandeirantes-PR. Neste trabalho avaliou-se a viabilidade técnica- econômica da utilização de colhedoras automotrizes de cana-de-açúcar sem queima em toletes, comparando com ocusto da colheita manual da cana queimada, de modo a fornecer subsídios que auxiliem no planejamento de investimentos agrícolas. As determinações de campo foram realizadas em área pertencente à Usina de Açúcar e Álcool Bandeirantes. As variedades de cana-de-açúcar, Saccharum spp, utilizadas foram: RB 72-454, SP 81-3250 e RB 85-5113, plantadas em espaçamento de 1,40 m em nitossolos com declividade inferior a 12%. Foram encontrados valores de 3,06 US$.t-1 para o custo da colheita mecanizada da cana sem queima e de 4,14 US$.t-1 para a colheita manual da cana queimada, observando-se uma redução de 32,74% em favor do custo da tonelada colhida mecanicamente. A capacidade operacional da máquina,estimada a 5,39 km.h-1 e com eficiência de campo de 60%, foi calculada em 0,45276 ha.h-1.(AU)

The use of burning before the sugar cane harvest has suffered a lot of controversy for both the public organization and the society, worried about the environmental damages. The mechanized harvest of sugar cane has been discussed as one of the possible methods to avoid burning, and in the area around Bandeirantes this method has not been used yet. In this work it has been considered the technicaleconomical viability of using self motive power reaper of sugar cane in rolls comparing to hand harvest cost of burning sugar cane so as provide subsidies that can help agriculture investments plans. The areas where the field decision has been performed were properties of Usina de Açucar e AlcoolBandeirantes, and the varieties of sugar cane used were: RB 72-454, SP 81-3250 and RB 85-5113, planted in a 1.40 m distance in a nitosoil arranged in down grade lower than 12%. The cost of mechanical harvest of sugar cane was 3.06 US$.t-1 and the cost of burnt sugar cane hand harvest was 4.14 U$.t-1. This was a 32.74% reduction in the price per each ton harvested. The operational capacity of the machine, estimated at 5.39 km.h-1 and efficiency of 60% in the field, was calculated in 0.45276 ha.h-1.(AU)

Avaliação técnico-econômica da colheita manual e mecanizada da cana-de-açúcar (saccharum spp) na região de Bandeirantes: Pr / Technical and economical evaluation of hand and mechanized harvest of sugar cane (saccharum spp) in Bandeirantes: Pr

A prática da queima antes da colheita da cana-de-açúcar vem sendo muito questionada, tanto pelo poder público quanto pela sociedade, preocupada com as questões ambientais. A colheita mecanizada da cana sem queima é apontada como um dos possíveis métodos para evitar a queima, e ainda não está sendo utilizada na região de Bandeirantes-PR. Neste trabalho avaliou-se a viabilidade técnica- econômica da utilização de colhedoras automotrizes de cana-de-açúcar sem queima em toletes, comparando com ocusto da colheita manual da cana queimada, de modo a fornecer subsídios que auxiliem no planejamento de investimentos agrícolas. As determinações de campo foram realizadas em área pertencente à Usina de Açúcar e Álcool Bandeirantes. As variedades de cana-de-açúcar, Saccharum spp, utilizadas foram: RB 72-454, SP 81-3250 e RB 85-5113, plantadas em espaçamento de 1,40 m em nitossolos com declividade inferior a 12%. Foram encontrados valores de 3,06 US$.t-1 para o custo da colheita mecanizada da cana sem queima e de 4,14 US$.t-1 para a colheita manual da cana queimada, observando-se uma redução de 32,74% em favor do custo da tonelada colhida mecanicamente. A capacidade operacional da máquina,estimada a 5,39 km.h-1 e com eficiência de campo de 60%, foi calculada em 0,45276 ha.h-1.

The use of burning before the sugar cane harvest has suffered a lot of controversy for both the public organization and the society, worried about the environmental damages. The mechanized harvest of sugar cane has been discussed as one of the possible methods to avoid burning, and in the area around Bandeirantes this method has not been used yet. In this work it has been considered the technicaleconomical viability of using self motive power reaper of sugar cane in rolls comparing to hand harvest cost of burning sugar cane so as provide subsidies that can help agriculture investments plans. The areas where the field decision has been performed were properties of Usina de Açucar e AlcoolBandeirantes, and the varieties of sugar cane used were: RB 72-454, SP 81-3250 and RB 85-5113, planted in a 1.40 m distance in a nitosoil arranged in down grade lower than 12%. The cost of mechanical harvest of sugar cane was 3.06 US$.t-1 and the cost of burnt sugar cane hand harvest was 4.14 U$.t-1. This was a 32.74% reduction in the price per each ton harvested. The operational capacity of the machine, estimated at 5.39 km.h-1 and efficiency of 60% in the field, was calculated in 0.45276 ha.h-1.