Soil attributes and leaf nitrogen estimating sugar cane quality parameters: Brix, pol and fibre

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The area of sugar cane production in Brazil has substantially increased in the last few years due to the high demand for ethanol. It is estimated that the actual area, which is approximately 8 Mha, will increase to as much as 15 Mha in the next 10 years. In addition to enlarging the boundaries and installing new industrial units, sugar cane expansion demands better use of production areas and improvement of both yield and quality, combined with a reduction of production costs. Thus, models that can describe the behaviour of sugar cane quality parameters could be important in understanding the effects of soil and plant attributes on these parameters. The objective of this work was to fit mathematical models to the sugar cane Brix, pol and fibre parameters using physical soil attributes, chemical soil attributes and leaf nitrogen as predictors from the previous year. This work was carried out in an area of 10 ha located in Araras, SP, Brazil, from November 2008 until July 2011 in the first (plant cane), second (first ratoon) and third (second ratoon) cycles of the crop. The chemical soil attributes analysed were the macronutrients and micronutrients, and the soil physical attribute analysed was the soil texture. The variables used in the models were chosen using principal component analysis (PCA), and the fit of the models was made as the mean of multiple regressions. The results were compared using kriging to map the Brix, pol and fibre with the true and estimated values. The Brix, pol and fibre models presented R (2) values of 0.17, 0.06 and 0.18, respectively, for the first ratoon of the crop and 0.23, 0.19 and 0.52, respectively, for the second ratoon. These results allowed the estimation of Brix, pol and fibre with estimation errors less than 1 % for the first and second ratoons. The PCA approach identified soil organic matter, phosphorus and potassium as the soil attributes that had the higher variance of the dataset during the years studied.143270289Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FINEP (Brazilian Agency of Innovation)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Correlation Between Chemical Soil Attributes and Sugarcane Quality Parameters According to Soil Texture Zones

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Significant changes in the Brazilian sugarcane agricultural sector have been observed in recent years, with the rapid expansion of planted areas, mainly in the western part of the country. In addition to the enlargement of boundaries and the installation of new industrial units, sugarcane expansion demands the development of new technologies to facilitate better use of the production areas, increase the yield and quality of the sugarcane, and reduce production costs. For that, the adoption of precision agriculture may be an important tool in the management of sugarcane production, which is based on the understanding of the relationship between soil attributes and sugarcane quality. Therein, the objective of this work was to study the Pearson correlation between chemical soil attributes and sugarcane quality parameters based on soil physical zones and to verify the spatial-temporal variability of the quality attributes over time. The work was carried out in an area of 10 ha located in Araras, Sao Paulo, Brazil, from November 2008 to July 2011. Sugarcane quality (Brix, pol, and fiber) was measured in samples collected within a grid of 30 x 30 m (total of 117 sample points) just before harvesting. The soil samples were collected immediately after harvesting in the same grid points. The chemical soil attributes analyzed were macronutrients and micronutrients, and the soil physical attribute was soil texture. The correlations obtained between the sugarcane quality parameters and soil chemical attributes varied from weak (Zn0-0.2: -0.36; Ca0.2-0.5: -0.30 with fiber and soil organic matter (0-0.2): -0.36 with pol) in sandy loam zone at the first year to strong correlations (P0-0.2: 0.77; Ca0-0.2: 0.67 with fiber) in sand clay loam zones at the second year. They also revealed major negative soil property correlations (P, Ca, Mg, sum of base, cation exchange capacity, base saturation) with sugar concentration and positive correlations with fiber. There were no clear patterns of the temporal stability of the quality parameters, which suggests that studies that include more crop cycles are needed.1783147156Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FINEP (Brazilian Agency of Innovation)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Agronomic, economic, and environmental assessment of site-specific fertilizer management of Brazilian sugarcane fields

Precision agriculture (PA) is an essential tool for site-specific management of soil fertility in sugarcane fields. However, the complexity of the cropping system, limitations on data handling, availability of adequate equipment and the lack of appropriate decision support systems limit the adoption of PA by the sugarcane industry. The objective of this study was to verify the potential economic, environmental and yield gains provided by the site-specific management of soil fertility in the sugarcane industry. A field experiment was conducted over four years, using conventional soil analysis, yield monitor data and variable rate application of lime, nitrogen (N), potassium (K) and phosphorus (P). After two years of variable rate application of fertilizer, available phosphorus (P) content was better distributed, stable, and sufficient to meet crop needs. Maps of potassium (K) rates changed each year, and K content reduced over the years, demonstrating that plant uptake of K was higher than applied. Results showed that applying fertilizer according to the spatial variability of soil can produce better economic and environmental gains, despite the similar average yield (∼80 Mg ha¯¹ year¯¹) when compared with a field managed according to mill procedures. Maps of yield and soil fertility are a powerful tool for sugarcane management, providing useful information about nutritional requirements based on spatial variation of soil fertility. The economic-environmental assessment performed in this study showed that the site-specific management provides improved soil fertility and sustainability indicators, contributing to higher profitability and low environmental impacts

Assessment of sugarcane trash for agronomic and energy purposes in Brazil

Due to new possibilities for using sugarcane (Saccharum spp.) trash for electricity generation, and the production of 2nd generation ethanol and others chemicals, the interest for its recovery has increased. However, the question of how much trash can be removed from sugarcane field still needs to be clarified. This study evaluated the amount of dry matter, nutrients content, structural compounds and efficiency of the enzymatic hydrolysis of the hydrothermal pretreated materials for tops and dry leaves in samples from sugarcane varieties. Tops and dry leaves present differences in nutrients content and moisture. Therefore, the amount of trash to be collected should not be simply based on percentages, but also should take into account the different fractions of the crop residues. For instance, around 80 % of N, P and K were derived from tops. Therein, the environmental indicators of the entire chain of sugarcane could be benefited because more nutrients would be recycled and less mineral fertilizers might be used for sugarcane production if tops are left on the field. Further, the tops have seven times more moisture than dry leaves and higher amounts of extractives (organic compounds of low molecular weight). Moreover, as the result of yield obtained in the pretreatment steps for dry leaves were superior to the tops and the glucose yields obtained in the enzymatic hydrolysis step were similar, it can be predicted that for second generation ethanol production, it is more viable to recover parts of the dry leaves fraction, leaving the tops on the field.70530531

Environmental and economic assessment of sugarcane first generation biorefineries in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The majority of current sugarcane mills in Brazil are annexed plants, producing both ethanol and sugar; the other plants are dedicated only to ethanol production (autonomous distilleries). This study focuses on the technical, environmental, and economic impacts of these first generation sugarcane processing facilities in Brazil using an innovative framework, the so called Virtual Sugarcane Biorefinery. Results showed that optimization technologies presents potential for reducing environmental impacts and improve economic results in comparison to base scenarios for both annexed and autonomous plants. It was also observed that annexed plants that diverted more sugarcane juice for sugar production were more profitable, considering the average prices for the past 10 years in Brazil. In addition, results indicate that scenarios considering more flexibility in annexed plant are more profitable than the conventional annexed one (diverting 50% of the sugarcane juice to sugar and 50% to ethanol production) if increases in prices were to occur. This study shows quantitatively the benefits of optimization techniques and allows understanding the real benefits of the sugarcane plant flexibility in the Brazilian context.143399410Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP