Agro-food and agro-industrial systems in Latin America must anticipate future trends and ensure permanent adjustment ofresearch priorities to the evolving global needs. Innovations should follow the logic of productiv...Agro-food and agro-industrial systems in Latin America must anticipate future trends and ensure permanent adjustment ofresearch priorities to the evolving global needs. Innovations should follow the logic of productive chains, which are highly dependentupon knowledge and technology. Agribusiness sector needs to reinvent itself for efficiently providing new products based on stricterquality controls, traceability, and greater diversification. In the region, alfalfa has an enormous potential to be cultivated for multiplepurposes other than just animal products, going from pharmaceutical and cosmetic industry to human consumption. No singleorganization or isolated group of scientists hold alone the capacity to deal with increasingly complex and dynamic productionsystems in order to efficiently compete in a globalized market. These challenges require an interdisciplinary approach, not only to adomestic level but also to an international one. The present paper proposed the constitution of a virtual alfalfa network platform forarticulating and guiding alfalfa research efforts in Latin America. The network will focus on identifying the most important needs forLatin America, promoting an active interaction among educational and scientific institutions through collaborative research projects.The platform comprises four main research axes: (1) efficient production (agronomy);(2) animal production (diversified feeds);(3)quality and innocuousness applied (human feeding);(4) novel products (pharmaceutical and cosmetics). During the initial phase, theBrazilian Agricultural Research Corporation (EMBRAPA, Brazil) and National Institute of Agricultural Technology (INTA,Argentina) will jointly coordinate the network.展开更多
Information about the geographic distribution of agricultural pests is the basis for all pest-related agricultural and environmental protection policies. However, often the pest’s records are incomplete and uncertain...Information about the geographic distribution of agricultural pests is the basis for all pest-related agricultural and environmental protection policies. However, often the pest’s records are incomplete and uncertain. Even with limitations, the pest records are needed for any country to organize a system for agriculture protection and to mobilize surveillance efforts. The first point is to identify the imminence of biological invasions, which can be accomplished through the collection of data on pest distribution. The basic information to evaluate the predictability of an invasion is geographic distribution and the identification of pathway types associated with the potential invader. Thus, the level of the risk of introduction is assessed more objectively. In this article, cases of introduction of pests were analyzed from published reports in Brazil in terms of their geographic distribution at the time of their introduction. Taking into consideration the country’s extensive terrestrial borders, this study attempts to elucidate the role played by different pathways in each bioinvasion. This analysis recognized the limitations of the historical method and underlying uncertainties of each invasion event. Human-mediated pathways were the main source of agricultural pest invasions in Brazil and the country was more a disperser than a receptor of exotic agricultural pests and diseases in South America. A new geographical hotspot (Northern South America and Caribbean Region) for possible invasions was identified.展开更多
An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To se...An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To select soil quality indicator variables in sugarcane (Saccharum officinarum L.) production areas that fulfill the criteria of sensitivity to management practices and between-season consistency in the management discrimination, ten composite soil samples (0–10 cm) were collected in July 2005 (rainy season) and again in March 2006 (dry season) from areas under cultivation of organic sugarcane (OS), green sugarcane (GS), burned sugarcane (BS) and from an adjacent native forest (NF) area at Usina Triunfo, Boca da Mata, Alagoas, Brazil. Microbial biomass-C (MBC), total organic C (TOC), soil enzyme activity expressed as the rate of fluorescein diacetate (FDA) hydrolysis, mean weight diameter of water-stable soil aggregates (MWD), and percentage of water-stable macroaggregates (PWSA) were analyzed. Although MBC and TOC were higher in NF than in the cultivated areas, no differences were observed in these C pools between the three sugarcane systems. The response of FDA to the site management was dependent on the sampling time. In the rainy period, the activity followed the order: NF > OS > GS > BS, whereas in the dry season, only NF differed from the other treatments. Irrespective of the sampling time, MWD and PWSA decreased in the order NF > OS = GS > BS. The variables MWD and PWSA are quite sensitive for discriminating between site management histories regardless the sampling season.展开更多
Yerba mate(Ilex paraguariensis A.St.-Hil.)is a species of great economic,social and environmental importance for the southern regions of Brazil,Uruguay and Argentina.Currently the most diverse products are obtained fr...Yerba mate(Ilex paraguariensis A.St.-Hil.)is a species of great economic,social and environmental importance for the southern regions of Brazil,Uruguay and Argentina.Currently the most diverse products are obtained from mate leaves,including mate tea.The objective of this study was to establish shoot meristem cultures(meristematic dome and a few primordia)of elite clones and identify the endophytic bacteria present in the explants.We tested the effect of clones(F1,F2,A03 and A07),culture media(MS,1/2MS,1/4MS and WPM),cytokinins(kinetin,BA and 2iP),activated charcoal(1,2 and 3 g L^-1),and disinfecting agent(sodium hypochlorite and mercuric chloride)on in vitro establishment.F1 and F2 clones were the most responsive for shoot meristem in vitro culture.WPM medium supplemented with 8.8 lM 2iP,0.2 lM NAA and 3 g L^-1 activated charcoal was the most suitable for the in vitro establishment of the F1 clone.No phytotoxic effect of the disinfectant was observed and some meristems sprouted.The isolated endophytic bacterium was identified for the first time in yerba mate as Agrobacterium larrymoorei.To conclude,we were able to establish in vitro culture of yerba mate using meristems as explants but the tissues were not free of endophytic microorganisms which could interfere with explant response.展开更多
The diagnosis of nutritional state is an important tool to understand the nutritional requirement of plants and the influence of the nutritional balance on the yield. The proposed in this study was to apply the Diagno...The diagnosis of nutritional state is an important tool to understand the nutritional requirement of plants and the influence of the nutritional balance on the yield. The proposed in this study was to apply the Diagnosis and Recommendation Integrated System (DRIS) to assess the nutritional state of cotton crop through the order of nutrient requirement and nutritional balance. Yield data from plots (average acreage 100 ha) and foliar concentrations of macro and micronutrients of cotton (Gossypium hirsutum r. latifolium) plants were stored in a database. The criterion to define the reference population consisted of plots with above-average yields + 2/3 standard deviation (over 4785 kg·ha-1 seed cotton yield). The DRIS method was efficient to evaluate the nutrition state of cotton. It was feasible to identify the order of plant requirement and nutritional balance. It was feasible to observe that when minor the Nutritional Balance Index (NBI) it’s higher the yield. It means that to reach high yield it is necessary to show low NBI. The Sulphur, Boron and Zinc showed the higher frequency as the most required nutrients by plant. The Magnesium and Manganese were the less required by the cotton plant, this means that both of them were limiting the yield by excess in the tissue.展开更多
Fruit dehydration is a way of supplying the population with healthy and nutritious foods. The shelf life of dried fruit can be defined by the evaluation of changes occurred in chemical characteristics during storage. ...Fruit dehydration is a way of supplying the population with healthy and nutritious foods. The shelf life of dried fruit can be defined by the evaluation of changes occurred in chemical characteristics during storage. This study aims to evaluate the sensory quality and the stability of papaya cv. Tainung n° 1 dehydrated by convective drying. Fresh and dried papaya were evaluated for color, moisture, pH, acidity, water activity, soluble solids, vitamin C, carotenoids, total extractable polyphenols (TEP) and antioxidant activity (ABTS). The sensorial acceptance of the dried papaya was evaluated using a structured nine-point hedonic scale. For the stability study, the analysis of moisture, pH, titratable acidity, water activity, total carotenoids and vitamin C were carried out every 30 days of storage until 120 days. During storage, the moisture content of dried papaya remained constant, but there were undesirable changes in color, increase of acidity and reduction of soluble solids. The degradation of total carotenoids and vitamin C followed the first order reaction, and the half-life time was 346 days for carotenoids, whereas for vitamin C it was only 29 days. In the sensory analysis, the dried papaya received grades between 5.0 and 6.0 for all evaluated attributes. Dried papaya is recommended to be consumed up to 30 days, since within this period a product with higher total carotenoids content, vitamin C and with satisfactory physicochemical and sensorial characteristics were obtained.展开更多
The use of beneficial microorganisms in forage grasses is a potentially advantageous technique for a more sustainable pasture management by decreasing the need for chemical fertilization. Our aims were to determine th...The use of beneficial microorganisms in forage grasses is a potentially advantageous technique for a more sustainable pasture management by decreasing the need for chemical fertilization. Our aims were to determine the best method of microorganism inoculation on Brachiaria (Syn. Urochloa) brizantha cv. BRS Piata, compare the responses of inoculated plants of this forage grass with fertilized and unfertilized controls and examine its effect on some morphological, physiological and biochemical responses. On the first experiment, three inoculation methods were tested: in the seed, seed and soil, and soil, with Pseudomonas fluorescens (BRM-32111) and Burkholderia pyrrocinia (BRM-32113). In the second experiment, fertilized and unfertilized plants were either inoculated with BRM-32111, BRM-32113 and co-inoculated (BRM-32111 + BRM-32113). In a final experiment, B. brizantha was inoculated by soil drenching with BRM-32111, BRM-32113 and co-inoculated (BRM-32111 + BRM-32113), and compared to fertilized- and unfertilized-controls. The inoculation by soil drenching, at seedling stage, was more effective than inoculation only in the seed or both in the seed and by soil drenching. The fertilizer may have suppressed the beneficial bacterial effects on the growth of B. brizantha. P. fluorescens and B. pyrrocinia co-inoculated increased nitrate, protein, nitrogen concentration, Spad index (chlorophyll content), leaf area, number of tillers, net photosynthesis and total biomass production of B. brizantha plants. Our results point out to a potentially valuable source of practical information in the search of an eco-friendlier approach to increase pasture productivity.展开更多
The aim of this study was to investigate the level of evolutionary divergence among five isofemale lineages of Metopolophium dirhodum Walker (Hemiptera: Aphididae) using sequences of the Internal Transcribed Spacer (I...The aim of this study was to investigate the level of evolutionary divergence among five isofemale lineages of Metopolophium dirhodum Walker (Hemiptera: Aphididae) using sequences of the Internal Transcribed Spacer (ITS) of ribosomal DNA (rDNA). These isofemalelineages were derived from parthenogenetic females, previously genetically characterized by having strong association of RAPD (Random Amplified Polymorphic DNA) molecular markers and host plant preference. Out of 25 sequences, only 17 containing ITS2 (the second spacer) were used for analysis due to their quality. Within 250 nucleotide sites originated by multiple alignments, 10.4% were variable, with the predominance of indels over substitutions. The average of nucleotide diversity (π) within isofemale lineages was similar to the diversity found among all isofemale lineages. The topology inferred by the Neighbor-Joining method showed that no evolutionary divergence inferred by ITS2 sequences among isofemale lineages typified by RAPD could be associated with host preference. The ITS2 sequence differences found within lineages and their causes are discussed.展开更多
Brazil is the largest consumer of pesticides worldwide. Public health studies in Brazil show that inadequate use of pesticides increases the incidence of accidents and contamination of poor rural communities. This stu...Brazil is the largest consumer of pesticides worldwide. Public health studies in Brazil show that inadequate use of pesticides increases the incidence of accidents and contamination of poor rural communities. This study sought to identify factors that determine the occurrence of problems with pesticides in a typical Brazilian land reform settlement. The study was carried out in Caiaponia, Goias state. In the empirical analysis, the econometric model pro bit was used. The dependent variable was the existence of health problems in the family setting that are caused by pesticides. The independent variables were the family size; the attendance to any church, whether Catholic or Protestant; if farmers received any technical assistance; the current health condition of the family, and if there are exacerbated erosion problems on the farm. Data from 28 farmers were collected through a structured questionnaire. Among the main findings, larger families have a higher probability of accidents involving pesticides. The current healthy conditions of family and the problems of soiled gradation in the farm imply are duction in the likelihood of contamination with pesticides. These two results indicate that rural households that have good health condition and have experienced environmental degradation on their farm have higher environmental awareness.展开更多
Advanced field methods of carbon (C) analysis should now be capable of providing repetitive, sequential measurements for the evaluation of spatial and temporal variation at a scale that was previously unfeasible. Some...Advanced field methods of carbon (C) analysis should now be capable of providing repetitive, sequential measurements for the evaluation of spatial and temporal variation at a scale that was previously unfeasible. Some spectroscopy techniques, such as laser-induced breakdown spectroscopy (LIBS), have portable features that may potentially lead to clean and rapid alternative approaches for this purpose. The goal of this study was to quantify the C content of soils with different textures and with high iron and aluminum concentrations using LIBS. LIBS emission spectra from soil pellets were captured, and the C content was estimated (emission line of C (I) at 193.03 nm) after spectral offset and aluminum spectral interference correction. This technique is highly portable and could be ideal for providing the soil C content in a heterogeneous experiment. Dry combustion was used as a reference method, and for calibration a conventional linear model was evaluated based on soil textural classes. The correlation between reference and LIBS values showed r = 0.86 for medium-textured soils and r = 0.93 for fine-textured soils. The data showed that better correlation and lower error (14%) values were found for the fine-textured LIBS model. The limit of detection (LOD) was found to be 0.32% for medium-textured soils and 0.13% for fine-textured soils. The results indicated that LIBS quantification can be affected by the texture and chemical composition of soil. Signal treatment was shown to be very important for mitigation of these interferences and to improve quantification.展开更多
Transformations of natural ecosystems in tropical regions, which are usually covered by high-biomass forests, contribute to increased atmospheric CO2. Much of the carbon in forest ecosystems is stored in the soil. Thi...Transformations of natural ecosystems in tropical regions, which are usually covered by high-biomass forests, contribute to increased atmospheric CO2. Much of the carbon in forest ecosystems is stored in the soil. This study estimates soil carbon stock in a dense forest in central Amazonia from sets of soil samples collected in three topographic positions (plateau, slope and valley bottom). Soil organic matter (SOM) was fractionated by density and particle size, thus obtaining the free light fraction (FLF), intra-aggregated light fraction (IALF), sand fraction (F-sand), clay fraction (F-clay) and silt fraction (F-silt). Soil organic carbon (SOC) stocks on the plateaus (Oxisol), slopes (Ultisol) and valley bottoms (Spodosol) were 98.4 ± 7.8 Mg·ha-1, 72.6 ± 5.4 Mg·ha-1 and 81.4 ± 8.9 Mg·ha-1, respectively. Distribution of carbon in soil fractions was: 112.6 ± 15 Mg·ha-1 (FLF), 2.5 ± 0 Mg·ha-1 (ILAF), 40.5 ± 1.5 Mg·ha-1 (F-silt), 68.5 ± 4.2 Mg·ha-1 (F-clay) and 28.3 ± 1.4 Mg·ha-1 (F-sand), totaling 252.4 ± 22.1 Mg·ha-1 of carbon. Carbon is largely in labile form and near the soil surface, making it liable to release from deforestation or from climate change. Spodosols are more susceptible to soil carbon losses, demonstrating the need to preserve forested areas close to Amazonian rivers and streams.展开更多
Previous research has explored the potential to integrate lidar and optical data in aboveground biomass(AGB)estimation,but how different data sources,vegetation types,and modeling algorithms influence AGB estimation i...Previous research has explored the potential to integrate lidar and optical data in aboveground biomass(AGB)estimation,but how different data sources,vegetation types,and modeling algorithms influence AGB estimation is poorly understood.This research conducts a comparative analysis of different data sources and modeling approaches in improving AGB estimation.RapidEye-based spectral responses and textures,lidar-derived metrics,and their combination were used to develop AGB estimation models.The results indicated that(1)overall,RapidEye data are not suitable for AGB estimation,but when AGB falls within 50–150 Mg/ha,support vector regression based on stratification of vegetation types provided good AGB estimation;(2)Lidar data provided stable and better estimations than RapidEye data;and stratification of vegetation types cannot improve estimation;(3)The combination of lidar and RapidEye data cannot provide better performance than lidar data alone;(4)AGB ranges affect the selection of the best AGB models,and a combination of different estimation results from the best model for each AGB range can improve AGB estimation;(5)This research implies that an optimal procedure for AGB estimation for a specific study exists,depending on the careful selection of data sources,modeling algorithms,forest types,and AGB ranges.展开更多
Water scarcity threatens global food security and agricultural systems are challenged to achieve high yields while optimizing water usage.Water deficit can be accentuated by soil physical degradation,which also trigge...Water scarcity threatens global food security and agricultural systems are challenged to achieve high yields while optimizing water usage.Water deficit can be accentuated by soil physical degradation,which also triggers water losses through runoff and consequently soil erosion.Although soil health in cropping systems within the Brazilian Cerrado biome have been surveyed throughout the years,information about soil erosion impacts and its mitigation are still not well understood;especially concerning the role of cropping system diversification and its effects on crop yield.Thus,the aim of this study was to assess whether ecological intensification of cropping systems-inclusion of a consorted perennial grass and crop rotation-could promote soil coverage and consequently decrease water erosion and soil,water,and nutrient losses.This work studied the effects of crop rotation and consorted Brachiaria,along with different levels of investment in fertilization on soil physical quality and on soil,water,and nutrient losses,and crop yields.Results proved that soybean monoculture(SS)is a system of low sustainability even under no-till in the Brazilian Cerrado conditions.It exhibited high susceptibility to soil,water,and nutrient losses,causing low crop yields.Our results showed that water losses in SS cropping system were approximately 10%of the total annual rainfall,and total K losses would require an additional 35%of K application.Conversely,ecological intensification of cropping systems resulted in enhanced soil environmental and agronomic functions,increased grain yield,and promoted soil and water conservation:high soil cover rate,and low soil,water and nutrient losses.Ecological intensification proved to be an adequate practice to boost crop resilience to water deficit in the Brazilian Cerrado.展开更多
Biochar application has the potential to improve soil fertility and increase soil carbon stock, especially in tropical regions. Information on the temperature sensitivity of carbon dioxide(CO2) evolution from biochar-...Biochar application has the potential to improve soil fertility and increase soil carbon stock, especially in tropical regions. Information on the temperature sensitivity of carbon dioxide(CO2) evolution from biochar-amended soils at very high temperatures, as observed for tropical surface soils, is limited but urgently needed for the development of region-specific biochar management targeted to optimize biochar effects on soil functions. Here, we investigated the temperature sensitivity of soil respiration to the addition of different rates of Miscanthus biochar(0, 6.25, 12.5, and 25 Mg ha-1) in two types of soils with contrasting textures. Biochar-amended soil treatments and their controls were incubated at constant temperatures of 20, 30, and 40℃. Overall, our results show that: i) considering data from all treatments and temperatures, the addition of biochar decreased soil CO2 emissions when compared to untreated soils;ii) CO2 emissions from biochar-amended soils had a higher temperature sensitivity than those from biochar-free soils;iii) the temperature sensitivity of soil respiration in sandy soils was higher than that in clay soils;and iv) for clay soils, relative increases in soil CO2 emissions from biochar-amended soils were higher when the temperature increased from 30 to 40℃, while for sandy soils, the highest temperature responses of soil respiration were observed when increasing the temperature from 20 to 30℃. Together, these findings suggest a significantly reduced potential to increase soil organic carbon stocks when Miscanthus biochar is applied to tropical soils at high surface temperatures, which could be counteracted by the soil-and weather-specific timing of biochar application.展开更多
文摘Agro-food and agro-industrial systems in Latin America must anticipate future trends and ensure permanent adjustment ofresearch priorities to the evolving global needs. Innovations should follow the logic of productive chains, which are highly dependentupon knowledge and technology. Agribusiness sector needs to reinvent itself for efficiently providing new products based on stricterquality controls, traceability, and greater diversification. In the region, alfalfa has an enormous potential to be cultivated for multiplepurposes other than just animal products, going from pharmaceutical and cosmetic industry to human consumption. No singleorganization or isolated group of scientists hold alone the capacity to deal with increasingly complex and dynamic productionsystems in order to efficiently compete in a globalized market. These challenges require an interdisciplinary approach, not only to adomestic level but also to an international one. The present paper proposed the constitution of a virtual alfalfa network platform forarticulating and guiding alfalfa research efforts in Latin America. The network will focus on identifying the most important needs forLatin America, promoting an active interaction among educational and scientific institutions through collaborative research projects.The platform comprises four main research axes: (1) efficient production (agronomy);(2) animal production (diversified feeds);(3)quality and innocuousness applied (human feeding);(4) novel products (pharmaceutical and cosmetics). During the initial phase, theBrazilian Agricultural Research Corporation (EMBRAPA, Brazil) and National Institute of Agricultural Technology (INTA,Argentina) will jointly coordinate the network.
文摘Information about the geographic distribution of agricultural pests is the basis for all pest-related agricultural and environmental protection policies. However, often the pest’s records are incomplete and uncertain. Even with limitations, the pest records are needed for any country to organize a system for agriculture protection and to mobilize surveillance efforts. The first point is to identify the imminence of biological invasions, which can be accomplished through the collection of data on pest distribution. The basic information to evaluate the predictability of an invasion is geographic distribution and the identification of pathway types associated with the potential invader. Thus, the level of the risk of introduction is assessed more objectively. In this article, cases of introduction of pests were analyzed from published reports in Brazil in terms of their geographic distribution at the time of their introduction. Taking into consideration the country’s extensive terrestrial borders, this study attempts to elucidate the role played by different pathways in each bioinvasion. This analysis recognized the limitations of the historical method and underlying uncertainties of each invasion event. Human-mediated pathways were the main source of agricultural pest invasions in Brazil and the country was more a disperser than a receptor of exotic agricultural pests and diseases in South America. A new geographical hotspot (Northern South America and Caribbean Region) for possible invasions was identified.
基金Project supported by the Brazilian Corporation for Agricultural Research (No.02.03.01.01.04) the Usina Triunfo(Alagoas State), Brazil.
文摘An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To select soil quality indicator variables in sugarcane (Saccharum officinarum L.) production areas that fulfill the criteria of sensitivity to management practices and between-season consistency in the management discrimination, ten composite soil samples (0–10 cm) were collected in July 2005 (rainy season) and again in March 2006 (dry season) from areas under cultivation of organic sugarcane (OS), green sugarcane (GS), burned sugarcane (BS) and from an adjacent native forest (NF) area at Usina Triunfo, Boca da Mata, Alagoas, Brazil. Microbial biomass-C (MBC), total organic C (TOC), soil enzyme activity expressed as the rate of fluorescein diacetate (FDA) hydrolysis, mean weight diameter of water-stable soil aggregates (MWD), and percentage of water-stable macroaggregates (PWSA) were analyzed. Although MBC and TOC were higher in NF than in the cultivated areas, no differences were observed in these C pools between the three sugarcane systems. The response of FDA to the site management was dependent on the sampling time. In the rainy period, the activity followed the order: NF > OS > GS > BS, whereas in the dry season, only NF differed from the other treatments. Irrespective of the sampling time, MWD and PWSA decreased in the order NF > OS = GS > BS. The variables MWD and PWSA are quite sensitive for discriminating between site management histories regardless the sampling season.
基金Brazilian Agricultural Research Corporation(EMBRAPA)Forestry
文摘Yerba mate(Ilex paraguariensis A.St.-Hil.)is a species of great economic,social and environmental importance for the southern regions of Brazil,Uruguay and Argentina.Currently the most diverse products are obtained from mate leaves,including mate tea.The objective of this study was to establish shoot meristem cultures(meristematic dome and a few primordia)of elite clones and identify the endophytic bacteria present in the explants.We tested the effect of clones(F1,F2,A03 and A07),culture media(MS,1/2MS,1/4MS and WPM),cytokinins(kinetin,BA and 2iP),activated charcoal(1,2 and 3 g L^-1),and disinfecting agent(sodium hypochlorite and mercuric chloride)on in vitro establishment.F1 and F2 clones were the most responsive for shoot meristem in vitro culture.WPM medium supplemented with 8.8 lM 2iP,0.2 lM NAA and 3 g L^-1 activated charcoal was the most suitable for the in vitro establishment of the F1 clone.No phytotoxic effect of the disinfectant was observed and some meristems sprouted.The isolated endophytic bacterium was identified for the first time in yerba mate as Agrobacterium larrymoorei.To conclude,we were able to establish in vitro culture of yerba mate using meristems as explants but the tissues were not free of endophytic microorganisms which could interfere with explant response.
基金The authors are indebted to the Brazilian Federal Agency for Support and Evaluation of Graduate Education-CAPES for the doctoral fellowship of the first author at Universidade Federal da Grande Dourados(UFGD).
文摘The diagnosis of nutritional state is an important tool to understand the nutritional requirement of plants and the influence of the nutritional balance on the yield. The proposed in this study was to apply the Diagnosis and Recommendation Integrated System (DRIS) to assess the nutritional state of cotton crop through the order of nutrient requirement and nutritional balance. Yield data from plots (average acreage 100 ha) and foliar concentrations of macro and micronutrients of cotton (Gossypium hirsutum r. latifolium) plants were stored in a database. The criterion to define the reference population consisted of plots with above-average yields + 2/3 standard deviation (over 4785 kg·ha-1 seed cotton yield). The DRIS method was efficient to evaluate the nutrition state of cotton. It was feasible to identify the order of plant requirement and nutritional balance. It was feasible to observe that when minor the Nutritional Balance Index (NBI) it’s higher the yield. It means that to reach high yield it is necessary to show low NBI. The Sulphur, Boron and Zinc showed the higher frequency as the most required nutrients by plant. The Magnesium and Manganese were the less required by the cotton plant, this means that both of them were limiting the yield by excess in the tissue.
文摘Fruit dehydration is a way of supplying the population with healthy and nutritious foods. The shelf life of dried fruit can be defined by the evaluation of changes occurred in chemical characteristics during storage. This study aims to evaluate the sensory quality and the stability of papaya cv. Tainung n° 1 dehydrated by convective drying. Fresh and dried papaya were evaluated for color, moisture, pH, acidity, water activity, soluble solids, vitamin C, carotenoids, total extractable polyphenols (TEP) and antioxidant activity (ABTS). The sensorial acceptance of the dried papaya was evaluated using a structured nine-point hedonic scale. For the stability study, the analysis of moisture, pH, titratable acidity, water activity, total carotenoids and vitamin C were carried out every 30 days of storage until 120 days. During storage, the moisture content of dried papaya remained constant, but there were undesirable changes in color, increase of acidity and reduction of soluble solids. The degradation of total carotenoids and vitamin C followed the first order reaction, and the half-life time was 346 days for carotenoids, whereas for vitamin C it was only 29 days. In the sensory analysis, the dried papaya received grades between 5.0 and 6.0 for all evaluated attributes. Dried papaya is recommended to be consumed up to 30 days, since within this period a product with higher total carotenoids content, vitamin C and with satisfactory physicochemical and sensorial characteristics were obtained.
文摘The use of beneficial microorganisms in forage grasses is a potentially advantageous technique for a more sustainable pasture management by decreasing the need for chemical fertilization. Our aims were to determine the best method of microorganism inoculation on Brachiaria (Syn. Urochloa) brizantha cv. BRS Piata, compare the responses of inoculated plants of this forage grass with fertilized and unfertilized controls and examine its effect on some morphological, physiological and biochemical responses. On the first experiment, three inoculation methods were tested: in the seed, seed and soil, and soil, with Pseudomonas fluorescens (BRM-32111) and Burkholderia pyrrocinia (BRM-32113). In the second experiment, fertilized and unfertilized plants were either inoculated with BRM-32111, BRM-32113 and co-inoculated (BRM-32111 + BRM-32113). In a final experiment, B. brizantha was inoculated by soil drenching with BRM-32111, BRM-32113 and co-inoculated (BRM-32111 + BRM-32113), and compared to fertilized- and unfertilized-controls. The inoculation by soil drenching, at seedling stage, was more effective than inoculation only in the seed or both in the seed and by soil drenching. The fertilizer may have suppressed the beneficial bacterial effects on the growth of B. brizantha. P. fluorescens and B. pyrrocinia co-inoculated increased nitrate, protein, nitrogen concentration, Spad index (chlorophyll content), leaf area, number of tillers, net photosynthesis and total biomass production of B. brizantha plants. Our results point out to a potentially valuable source of practical information in the search of an eco-friendlier approach to increase pasture productivity.
文摘The aim of this study was to investigate the level of evolutionary divergence among five isofemale lineages of Metopolophium dirhodum Walker (Hemiptera: Aphididae) using sequences of the Internal Transcribed Spacer (ITS) of ribosomal DNA (rDNA). These isofemalelineages were derived from parthenogenetic females, previously genetically characterized by having strong association of RAPD (Random Amplified Polymorphic DNA) molecular markers and host plant preference. Out of 25 sequences, only 17 containing ITS2 (the second spacer) were used for analysis due to their quality. Within 250 nucleotide sites originated by multiple alignments, 10.4% were variable, with the predominance of indels over substitutions. The average of nucleotide diversity (π) within isofemale lineages was similar to the diversity found among all isofemale lineages. The topology inferred by the Neighbor-Joining method showed that no evolutionary divergence inferred by ITS2 sequences among isofemale lineages typified by RAPD could be associated with host preference. The ITS2 sequence differences found within lineages and their causes are discussed.
文摘Brazil is the largest consumer of pesticides worldwide. Public health studies in Brazil show that inadequate use of pesticides increases the incidence of accidents and contamination of poor rural communities. This study sought to identify factors that determine the occurrence of problems with pesticides in a typical Brazilian land reform settlement. The study was carried out in Caiaponia, Goias state. In the empirical analysis, the econometric model pro bit was used. The dependent variable was the existence of health problems in the family setting that are caused by pesticides. The independent variables were the family size; the attendance to any church, whether Catholic or Protestant; if farmers received any technical assistance; the current health condition of the family, and if there are exacerbated erosion problems on the farm. Data from 28 farmers were collected through a structured questionnaire. Among the main findings, larger families have a higher probability of accidents involving pesticides. The current healthy conditions of family and the problems of soiled gradation in the farm imply are duction in the likelihood of contamination with pesticides. These two results indicate that rural households that have good health condition and have experienced environmental degradation on their farm have higher environmental awareness.
基金The authors express their gratitude for the grant from FAPESP(2010/09211-6),CNPq(560292/2010-4)CAPES,Embrapa and Pecus Research Network.
文摘Advanced field methods of carbon (C) analysis should now be capable of providing repetitive, sequential measurements for the evaluation of spatial and temporal variation at a scale that was previously unfeasible. Some spectroscopy techniques, such as laser-induced breakdown spectroscopy (LIBS), have portable features that may potentially lead to clean and rapid alternative approaches for this purpose. The goal of this study was to quantify the C content of soils with different textures and with high iron and aluminum concentrations using LIBS. LIBS emission spectra from soil pellets were captured, and the C content was estimated (emission line of C (I) at 193.03 nm) after spectral offset and aluminum spectral interference correction. This technique is highly portable and could be ideal for providing the soil C content in a heterogeneous experiment. Dry combustion was used as a reference method, and for calibration a conventional linear model was evaluated based on soil textural classes. The correlation between reference and LIBS values showed r = 0.86 for medium-textured soils and r = 0.93 for fine-textured soils. The data showed that better correlation and lower error (14%) values were found for the fine-textured LIBS model. The limit of detection (LOD) was found to be 0.32% for medium-textured soils and 0.13% for fine-textured soils. The results indicated that LIBS quantification can be affected by the texture and chemical composition of soil. Signal treatment was shown to be very important for mitigation of these interferences and to improve quantification.
基金the Large-Scale Atmosphere-Biosphere Experiment in Amazonia(LBA),Instituto Nacional de Pesquisas da Amazonia(INPA),Empresa Brasileira de Pesquisa Agropecuaria(EMBRAPA),Conselho Nacional do Desenvolvimento Cientifico e Tecnologico(CNPq:Proc.610042/2009-2,573810/2008-7,610042/2009-2)Fundacao de Amparo a Pesquisa do Estado do Amazonas(FAPEAM Proc.708565)for financial and logistical support.
文摘Transformations of natural ecosystems in tropical regions, which are usually covered by high-biomass forests, contribute to increased atmospheric CO2. Much of the carbon in forest ecosystems is stored in the soil. This study estimates soil carbon stock in a dense forest in central Amazonia from sets of soil samples collected in three topographic positions (plateau, slope and valley bottom). Soil organic matter (SOM) was fractionated by density and particle size, thus obtaining the free light fraction (FLF), intra-aggregated light fraction (IALF), sand fraction (F-sand), clay fraction (F-clay) and silt fraction (F-silt). Soil organic carbon (SOC) stocks on the plateaus (Oxisol), slopes (Ultisol) and valley bottoms (Spodosol) were 98.4 ± 7.8 Mg·ha-1, 72.6 ± 5.4 Mg·ha-1 and 81.4 ± 8.9 Mg·ha-1, respectively. Distribution of carbon in soil fractions was: 112.6 ± 15 Mg·ha-1 (FLF), 2.5 ± 0 Mg·ha-1 (ILAF), 40.5 ± 1.5 Mg·ha-1 (F-silt), 68.5 ± 4.2 Mg·ha-1 (F-clay) and 28.3 ± 1.4 Mg·ha-1 (F-sand), totaling 252.4 ± 22.1 Mg·ha-1 of carbon. Carbon is largely in labile form and near the soil surface, making it liable to release from deforestation or from climate change. Spodosols are more susceptible to soil carbon losses, demonstrating the need to preserve forested areas close to Amazonian rivers and streams.
基金supported by the National Natural Science Foundation of China(No#41571411)the Zhejiang A&F University’s Research and Development Fund for the talent startup project(No#2013FR052)+1 种基金Keller,dos-Santos,Bolfe,and Batistella acknowledge the support from the Brazilian National Council for Scientific and Tech-nological Development–CNPq(No#457927/2013-5)Data were acquired by the Sustainable Landscapes Brazil project supported by the Brazilian Agricultural Research Corporation(EMBRAPA),the US Forest Service,the USAID,and the US Department of State.
文摘Previous research has explored the potential to integrate lidar and optical data in aboveground biomass(AGB)estimation,but how different data sources,vegetation types,and modeling algorithms influence AGB estimation is poorly understood.This research conducts a comparative analysis of different data sources and modeling approaches in improving AGB estimation.RapidEye-based spectral responses and textures,lidar-derived metrics,and their combination were used to develop AGB estimation models.The results indicated that(1)overall,RapidEye data are not suitable for AGB estimation,but when AGB falls within 50–150 Mg/ha,support vector regression based on stratification of vegetation types provided good AGB estimation;(2)Lidar data provided stable and better estimations than RapidEye data;and stratification of vegetation types cannot improve estimation;(3)The combination of lidar and RapidEye data cannot provide better performance than lidar data alone;(4)AGB ranges affect the selection of the best AGB models,and a combination of different estimation results from the best model for each AGB range can improve AGB estimation;(5)This research implies that an optimal procedure for AGB estimation for a specific study exists,depending on the careful selection of data sources,modeling algorithms,forest types,and AGB ranges.
文摘Water scarcity threatens global food security and agricultural systems are challenged to achieve high yields while optimizing water usage.Water deficit can be accentuated by soil physical degradation,which also triggers water losses through runoff and consequently soil erosion.Although soil health in cropping systems within the Brazilian Cerrado biome have been surveyed throughout the years,information about soil erosion impacts and its mitigation are still not well understood;especially concerning the role of cropping system diversification and its effects on crop yield.Thus,the aim of this study was to assess whether ecological intensification of cropping systems-inclusion of a consorted perennial grass and crop rotation-could promote soil coverage and consequently decrease water erosion and soil,water,and nutrient losses.This work studied the effects of crop rotation and consorted Brachiaria,along with different levels of investment in fertilization on soil physical quality and on soil,water,and nutrient losses,and crop yields.Results proved that soybean monoculture(SS)is a system of low sustainability even under no-till in the Brazilian Cerrado conditions.It exhibited high susceptibility to soil,water,and nutrient losses,causing low crop yields.Our results showed that water losses in SS cropping system were approximately 10%of the total annual rainfall,and total K losses would require an additional 35%of K application.Conversely,ecological intensification of cropping systems resulted in enhanced soil environmental and agronomic functions,increased grain yield,and promoted soil and water conservation:high soil cover rate,and low soil,water and nutrient losses.Ecological intensification proved to be an adequate practice to boost crop resilience to water deficit in the Brazilian Cerrado.
基金We acknowledge the National Council for Scientific and Technological Development(CNPq)of Brazil(No.404150/2013-6)for financing this research.T.F.Rittl is grateful to the São Paulo Research Foundation(FAPESP)of Brazil for supporting her postdoctoral scholarship(No.2015/10108-9)and L.Canisares thanks to CNPq for her undergraduate scientific scholarship.
文摘Biochar application has the potential to improve soil fertility and increase soil carbon stock, especially in tropical regions. Information on the temperature sensitivity of carbon dioxide(CO2) evolution from biochar-amended soils at very high temperatures, as observed for tropical surface soils, is limited but urgently needed for the development of region-specific biochar management targeted to optimize biochar effects on soil functions. Here, we investigated the temperature sensitivity of soil respiration to the addition of different rates of Miscanthus biochar(0, 6.25, 12.5, and 25 Mg ha-1) in two types of soils with contrasting textures. Biochar-amended soil treatments and their controls were incubated at constant temperatures of 20, 30, and 40℃. Overall, our results show that: i) considering data from all treatments and temperatures, the addition of biochar decreased soil CO2 emissions when compared to untreated soils;ii) CO2 emissions from biochar-amended soils had a higher temperature sensitivity than those from biochar-free soils;iii) the temperature sensitivity of soil respiration in sandy soils was higher than that in clay soils;and iv) for clay soils, relative increases in soil CO2 emissions from biochar-amended soils were higher when the temperature increased from 30 to 40℃, while for sandy soils, the highest temperature responses of soil respiration were observed when increasing the temperature from 20 to 30℃. Together, these findings suggest a significantly reduced potential to increase soil organic carbon stocks when Miscanthus biochar is applied to tropical soils at high surface temperatures, which could be counteracted by the soil-and weather-specific timing of biochar application.
