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Abstract To feed the world population while mitigating pressing nitrogen (N) pollution problems, tremendous efforts have been devoted to developing and implementing N‐efficient technologies in crop or livestock production, but limited progress has been made. The N management improvement on a farm does not necessarily translate to N pollution reduction on a broader scale due to complex responses of natural and human systems and lack of coordination among stakeholders. Consequently, it is imperative to develop an N management framework that encompasses the complex N dynamics across systems and spatial scales, yet simple enough to guide policies and actions of various stakeholders. Here, we propose a new framework, CAFE, that defines four N management systems (Cropping, Animal‐crop, Food, and Ecosystem) in a hierarchical manner, and apply it to 13 representative countries to partition N surpluses across systems in a simple and consistent manner, thereby facilitating the identification and prioritization of systems‐based intervention strategies. Surprisingly, the Cropping system contributes less than half of the total N surplus within its Ecosystem for most countries, highlighting the importance of N management beyond croplands. This framework reveals that the relevant priorities and key stakeholders for enhanced N management vary among countries, such as improving the Cropping‐system efficiencies in China, adjusting the animal‐crop portfolio in the Netherlands, reducing food wastage in the U.S., and lowering crop storage losses and increasing overall production capacities in African countries. As N surplus increases along the CAFE hierarchy, systems‐based intervention strategies are revealed: (a) coupling chemical fertilizers with other N sources by maintaining half of the N from manure and biological N fixation; (b) coupling animal‐crop production by reducing animal density to lower than 1.2 livestock units per hectare, and increasing self‐sufficiency of animal feed to above 50%; (c) coupling food trade with domestic demand and production; and (d) coupling population needs for economic opportunities with environmental capacity of the region. This novel framework can help unpack the “wicked” N management challenges across systems to provide new insights and tools for improving N management on and beyond farms.

The Neotropics harbor some of the most diversified woody species in the world, and to understand the nutrient dynamics in these ecosystems, it is crucial to understand the role of plant taxonomy. In addition, biological nitrogen (N) fixation (BNF) in the tropics is one of the key processes affecting the global N cycle. Our objective was to (i) investigate the role of taxonomy and sampling site as predictors of foliar carbon (C) and N concentration and its stable isotopes (i.e., δ13C and δ15N); (ii) assess differences in foliar N, C:N ratio, and δ15N among three functional groups: species of N2-fixers and non-fixers of the Fabaceae family, as well as non-Fabaceae species; and (iii) examine the effect of wood density on tree foliar properties. We hypothesized that Fabaceae specimens in symbiosis with N2-fixers would possess a higher foliar N than non-fixing plants, including those of the Fabaceae family, as well as high-density trees would have higher foliar C and C:N ratio relative to low-density trees, where the latter invest in nutrients instead of structural C. We used a data set composed of 3,668 specimens sampled in three main biomes of Brazil: Amazon, Atlantic Forest, and Cerrado. The partitioning of variance had a higher influence of taxonomy on leaf C, N, and C:N ratio. Conversely, foliar δ13C and δ15N were environmentally constrained. While family was the most important taxonomy level for C, N, and C:N ratio, species played a major role for δ13C and δ15N. Foliar N followed the pattern fixers > non-fixers > non-Fabaceae, while C:N ratio had an opposite trend. In addition, foliar C was correlated with wood density, where high-density > medium-density and low-density woods. The large variability of δ15N was observed among Fabaceae species, demonstrates the complexity of using δ15N as an indicator of BNF. The higher foliar N of Fabaceae non-fixers than non-Fabaceae specimens support the hypothesis that an N-demanding lifestyle is an inherent pattern in this family. Lastly, although observed in some studies, the prediction of foliar properties using wood density is challenging, and future research on this topic is needed.

Abstract Nitrogen is a critical component of the economy, food security, and planetary health. Many of the world's sustainability targets hinge on global nitrogen solutions, which, in turn, contribute lasting benefits for (i) world hunger; (ii) soil, air, and water quality; (iii) climate change mitigation; and (iv) biodiversity conservation. Balancing the projected rise in agricultural nitrogen demands while achieving these 21st century ideals will require policies to coordinate solutions among technologies, consumer choice, and socioeconomic transformation.

Agricultural systems are heterogeneous across temporal and spatial scales. Although much research has investigated farm size and economic output, the synergies and trade-offs across various agricultural and socioeconomic variables are unclear. This study applies a GIS-based approach to official Brazilian census data (Agricultural Censuses of 1995, 2006, and 2017) and surveys at the municipality level to (i) evaluate changes in the average soybean farm size across the country and (ii) compare agricultural and socioeconomic outcomes (i.e., soybean yield, agricultural production value, crop production diversity, and rural labor employment) relative to the average soybean farm size. Statistical tests (e.g., Kruskal–Wallis tests and Spearman’s correlation) were used to analyze variable outcomes in different classes of farm sizes and respective Agricultural Censuses. We found that agricultural and socioeconomic outcomes are spatially correlated with soybean farm size class. Therefore, based on the concepts of trade-offs and synergies, we show that municipalities with large soybean farm sizes had larger trade-offs (e.g., larger farm size was associated with lower crop diversity), while small and medium ones manifest greater synergies. These patterns are particularly strong for analysis using the Agricultural Census of 2017. Trade-off/synergy analysis across space and time is key for supporting long-term strategies aiming at alleviating unemployment and providing sustainable food production, essential to achieve the UN Sustainable Development Goals.

Several previous studies on targeted food items using carbon and nitrogen stable isotope ratios in Brazil have revealed that many of the items investigated are adulterated; mislabeled or even fraud. Here, we present the first Brazilian isotopic baseline assessment that can be used not only in future forensic cases involving food authenticity, but also in human forensic anthropology studies. The δ13C and δ15N were determined in 1245 food items and 374 beverages; most of them made in Brazil. The average δ13C and δ15N of C3 plants were −26.7 ± 1.5‱, and 3.9 ± 3.9‱, respectively, while the average δ13C and δ15N of C4 plants were −11.5 ± 0.8‱ and 4.6 ± 2.6‱, respectively. The δ13C and δ15N of plant-based processed foods were −21.8 ± 4.8‱ and 3.9 ± 2.7‱, respectively. The average δ13C and δ15N of meat, including beef, poultry, pork and lamb were -16.6 ± 4.7‱, and 5.2 ± 2.6‱, respectively, while the δ13C and δ15N of animal-based processed foods were −17.9 ± 3.3‱ and 3.3 ± 3.5‱, respectively. The average δ13C of beverages, including beer and wine was −22.5 ± 3.1‱. We verified that C-C4 constitutes a large proportion of fresh meat, dairy products, as well as animal and plant-based processed foods. The reasons behind this high proportion will be addressed in this study.

Streamwater is affected by several processes in the watershed including anthropogenic activities that result in changes in water quality as well as in the functioning of these stream ecosystems. Therefore, this work aims to evaluate the concentration of major ions (Ca2+, Mg2+, Na+, K+, NH4+, NO3-, NO2-, Cl-, SO4(2-), PO4(3-), HCO3-) in streams in the state of São Paulo (southeast Brazil). The sampling sites are located at undisturbed (ombrophilus dense forest, semideciduous forest and savanna - cerrado) and disturbed areas (pasture, urbanization and sugar cane crops). Streamwater chemistry varied according to land use change and, in general, was higher in disturbed sites. Streams located in undisturbed sites at Ribeira de Iguape/Alto Paranapanema watershed (streams 1, 2 and 3) seem to be regulated by soil characteristics, as the disturbed streams located at the same watershed covered by pasture (stream 7) showed high concentration for the most of the variables. Exception to streams located at Pontal do Paranapanema watershed where both disturbed (stream 8) and undisturbed streams (stream 4 and 5) presented similar patterns for almost all variables measured.A química da água é afetada por diversos processos que ocorrem no entorno da bacia de drenagem incluindo atividades antropogênicas que resultam em mudanças na qualidade da água bem como, no funcionamento desses ecossistemas. Portanto, o objetivo deste estudo foi avaliar a concentração dos íons dissolvidos (Ca2+, Mg2+, Na+, K+, NH4+, NO3-, NO2-, CL-, SO4(2-), PO4(3-), HCO3-) em riachos no Estado de São Paulo (sudeste brasileiro). Os pontos de amostragem estão localizados em bacias não alteradas (floresta ombrófila densa, floresta estacional semidecidual e cerrado) e alteradas (pastagem, urbanização e cana de açúcar). A química dos riachos variou de acordo com o uso da terra, sendo as maiores concentrações encontradas, em geral, nas bacias alteradas. Riachos localizados em áreas pouco alteradas na Bacia de Ribeira do Iguape/Alto Paranapanema (riachos 1, 2 e 3) são, provavelmente, regulados pelas propriedades do solo desde que os riachos alterados (riacho 7) localizados na mesma bacia sob pastagem apresentaram maiores concentrações para a maioria dos parâmetros avaliados. Exceção aos riachos localizados na Bacia do Pontal do Paranapanema onde ambos os riachos, alterados (riacho 8) e pouco alterados (riachos 4 e 5), apresentaram padrões similares para a maioria das variáveis avaliadas.

Urbanization has changed the livelihood diversity of rural communities worldwide. This study aimed to fit an indicator of the functional diversity of livelihood activities to assess the heterogeneity of socioeconomic conditions and their influence on agro-food changes in rural communities in Brazil. This study was conducted in three macro regions of Brazil, through semi-structured questionnaire interviews conducted in 1012 households to verify details about food patterns, self-consumption farms, and socioeconomic conditions. Data from questionnaires were analyzed using multivariate statistical models to appraise similarities among communities and determine the relative influence of socioeconomic factors on agro-food patterns. Specific socioeconomic status and use of natural resource data were analyzed while adjusting for Petchey and Gaston's indicator of functional diversity to evaluate the heterogeneity of local livelihood activities and socioeconomic conditions. This indicator summarizes the proportional livelihood richness in all sampled places, as better conditions for survival were found in specific localities of the central-west and eastern Amazon regions of Brazil. We also verified that the remote areas of the Goiás and Pará states were regions with the most significant maintenance of traditional food habits and use of natural resources. Although these results do not allow us to establish that all of these areas are undergoing an agro-food transition process, some localities are more likely than others to adjust their livelihood strategies to face global food changes. This interdisciplinary approach facilitated the identification of the most similar groups regarding their livelihoods and socioeconomic conditions that influenced the agro-food transition process in rural regions.

Studies were carried out to investigate the contamination of Piracicaba and Mogi-Guaçu River basins (São Paulo State, Southeastern, Brazil) for heavy metals (Cd and Pb), using the limnic bivalve Anodontites trapesialis as a biological monitor. The results showed that the concentrations of Pb were higher than the control group in both basins, showing the bioavailability of this non-essential element in the basins. The concentrations were higher in the Mogi-Guaçu than in the Piracicaba basin, and in the slightly contaminated sites in both basins. There was no correlation between the degree of human impact and Cd and Pb concentrations, it was not possible to infer about concentrations of these heavy metals in the bivalves based only in a broad evaluation of human impact.O principal objetivo deste estudo foi investigar a contaminação pelos metais pesados Cd e Pb nas bacias dos rios Piracicaba e Mogi-Guaçu (Estado de São Paulo, Brasil), utilizando o bivalve limnico Anodontites trapesialis como indicador biológico. As bacias estudadas apresentam diferentes graus de impacto, sendo a qualidade da água geralmente melhor na bacia do rio Mogi-Guaçu. Os teores de Pb detectados nos bivalves não podem ser considerados críticos, contudo, houve acúmulo em relação ao grupo de controle em ambas as bacias, especialmente na bacia do rio Mogi-Guaçu. As maiores concentrações dos elementos, especialmente Pb, foram observadas nos locais menos poluídos e na bacia menos degradada. Este fato sugere que estas concentrações não estão sendo afetadas apenas pelas atividades antrópicas nas bacias, mas deve-se considerar também fatores que afetem a biodisponibilidade ou fontes específicas e não pontuais.

Abstract Piaractus mesopotamicus, is a fish usually farmed in semi-intensive systems with access to natural food and supplementary feed. This study evaluates effects of feed allowance on the productive performance, carbon turnover and proportions of nutrient (carbon) contribution of feed and natural food for the growth of pacu. Juvenile fish were stocked in fiberglass tanks and fed to 100, 75, 50, 25, 0% apparent satiety (ApS), with a practical, extruded (C4 photosynthetic pathway) feed in a randomized design trial (n=3); plankton production for simulated semi-intensive farming system condition was induced by chemical fertilization. A control treatment was set up in tanks devoid of natural food. Data on muscle stable carbon isotope ratios were used to study carbon turnover using a relative growth-based model. Low variation of the δ13C impaired fitting a turnover model curve for the 0 and 25 % ApS treatments. Fish of the 100% and 75% ApS treatments reached circa 95% and 82.85% of the carbon turnover, respectively. Extruded feed was the main nutrient source for the growth of pacu in the semi-intensive, simulated farming condition. The current study contributes to the knowledge of the relationship between feeding rates and carbon turnover rates in the pacu muscle.

The structure of food webs is a fundamental attribute of ecosystems, and their characterization provides an intrinsic knowledge of the trophic interactions among organisms and of nutrient and energy transfer within ecosystems. Over the last few decades, several chemical and biogeochemical approaches have been proposed to explore different aspects of food webs. In this sense, this study reviews the application of stable isotopes and mercury as main auxiliary tools to the characterization and modeling of aquatic food webs, including analytical and modeling advances, strengths and limitations. The metanalysis performed showed that the most used tools for trophic ecology studies are stable isotopes, and that they can provide better results when combined with mercury and specific chemical molecules such as amino and fatty acids. In addition, the statistical methods applied in the interpretation of results, such as isotope mixing models, have witnessed significant advances in the last two decades. All approaches have premises and limitations when applied to aquatic ecosystems, which must be well understood prior to results interpretation. The use of multiple tracers in trophic studies provides complementary information and in many cases is an appropriate alternative to overcome some limitations, allowing to expand the knowledge of the food webs.

Interactions between distant places are increasingly widespread and influential, often leading to unexpected outcomes with profound implications for sustainability. Numerous sustainability studies have been conducted within a particular place with little attention to the impacts of distant interactions on sustainability in multiple places. Although distant forces have been studied, they are usually treated as exogenous variables and feedbacks have rarely been considered. To understand and integrate various distant interactions better, we propose an integrated framework based on telecoupling, an umbrella concept that refers to socioeconomic and environmental interactions over distances. The concept of telecoupling is a logical extension of research on coupled human and natural systems, in which interactions occur within particular geographic locations. The telecoupling framework contains five major interrelated components, i.e., coupled human and natural systems, flows, agents, causes, and effects. We illustrate the framework using two examples of distant interactions associated with trade of agricultural commodities and invasive species, highlight the implications of the framework, and discuss research needs and approaches to move research on telecouplings forward. The framework can help to analyze system components and their interrelationships, identify research gaps, detect hidden costs and untapped benefits, provide a useful means to incorporate feedbacks as well as trade-offs and synergies across multiple systems (sending, receiving, and spillover systems), and improve the understanding of distant interactions and the effectiveness of policies for socioeconomic and environmental sustainability from local to global levels.

In forest nurseries, irrigation management becomes more complex as different seedlings of tropical species, with different architectures, are grown close to each other. In this context, there are gaps in knowledge about the physiological responses of species with different mean leaf angles when subjected to different irrigation depths. Thus, this work aimed to analyze whether mean leaf angles affect irrigation efficiency and, consequently, physiological responses of tree seedlings. Six species with different mean leaf angles were submitted to three irrigation depths (6, 9, and 12 mm) applied daily by micro-sprinklers in a completely randomized design in a split plot scheme. The following variables were evaluated: leaf water potential, stomatal conductance, relative water content in the leaf, daily transpiration, leaching fraction, and total dry mass. In tree species seedlings with positive mean leaf angles, smaller irrigation depths are already able to increase leaf water potential, stomatal conductance, leaf relative water content, and transpiration efficiency. In contrast, when the mean leaf angles are negative, it is necessary to apply larger irrigation depths so that seedling physiological responses do not reduce the production of total dry mass. [ABSTRACT FROM AUTHOR]

We analysed carbon, nitrogen and δ13C values in sediment sampled in the Amazon floodplains. The surface sediment samples were collected along inland transects divided according to their vegetation cover: (a) forest, where the dominant vegetation was inundation forests; (b) grass, where the dominant vegetation was grasses, mainly from Echnochloa polystachya; (c) mixed, where the vegetation changed from grasses near the river bank to forest inland. The average sediment carbon and nitrogen concentrations were significantly higher in forest samples (C = 0·99%, N = 0·12%) than in grass samples (C = 0·84%, N = 0·10%). The average sediment δ13C was significantly heavier in grass (−26·7‰ ) than in forest samples (−28·6‰ ), reflecting the isotopically heavier C4 grasses carbon. In the forest and mixed transects inland, increases in the carbon and nitrogen concentrations were observed. At approximately 50 to 60 m from the riverbank, the concentration of carbon and nitrogen became similar to the river particulate organic carbon (POC) concentration, which is the primary floodplain sediment source. We hypothesized that this trend is caused by the deposition of carbon- and nitrogen-depleted sand-size particles in the first few metres of the floodplain, whereas the more enriched silt–clay particles are preferentially deposited far inland. In contrast to inland trends, no significant downriver trend was observed in the carbon and nitrogen concentrations. However, a downriver δ13C increase was observed for sediment in grass-covered areas. Based on δ13C values in different várzea environments, we estimated the relative contribution of riverine POC and vegetation material present in the várzea sediments under different vegetation covers. For forest sediment samples we estimated that 60% of the carbon was derived from the riverine POC and the forests provided the remaining 40%. For open areas covered with grasses we estimated that only 10% was derived from these plants, and 90% was derived from riverine POC. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Living trees constitute one of the major stocks of carbon in tropical forests. A better understanding of variations in the dynamics and structure of tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon, and for understanding how they recover from disturbance. Amazonian tropical forests occur over a vast area that encompasses differences in topography, climate, and geologic substrate. We observed large differences in forest structure, biomass, and tree growth rates in permanent plots situated in the eastern (near Santarém, Pará), central (near Manaus, Amazonas) and southwestern (near Rio Branco, Acre) Amazon, which differed in dry season length, as well as other factors. Forests at the two sites experiencing longer dry seasons, near Rio Branco and Santarém, had lower stem frequencies (460 and 466 ha -1 respectively), less biodiversity (Shannon?Wiener diversity index), and smaller aboveground C stocks (140.6 and 122.1 Mg C ha -1) than the Manaus site (626 trees ha -1, 180.1 Mg C ha -1), which had less seasonal variation in rainfall. The forests experiencing longer dry seasons also stored a greater proportion of the total biomass in trees with >50 cm diameter (41?45 vs 30% in Manaus). Rates of annual addition of C to living trees calculated from monthly dendrometer band measurements were 1.9 (Manaus), 2.8 (Santarém), and 2.6 (Rio Branco) Mg C ha -1 year -1. At all sites, trees in the 10?30 cm diameter class accounted for the highest proportion of annual growth (38, 55 and 56% in Manaus, Rio Branco and Santarém, respectively). Growth showed marked seasonality, with largest stem diameter increment in the wet season and smallest in the dry season, though this may be confounded by seasonal variation in wood water content. Year-to-year variations in C allocated to stem growth ranged from nearly zero in Rio Branco, to 0.8 Mg C ha -1 year -1 in Manaus (40% of annual mean) and 0.9 Mg C ha -1 year -1 (33% of annual mean) in Santarém, though this variability showed no significant relation with precipitation among years. Initial estimates of the C balance of live wood including recruitment and mortality as well as growth suggests that live wood biomass is at near steady-state in Manaus, but accumulating at about 1.5 Mg C ha -1 at the other two sites. The causes of C imbalance in living wood pools in Santarém and Rio Branco sites are unknown, but may be related to previous disturbance at these sites. Based on size distribution and growth rate differences in the three sites, we predict that trees in the Manaus forest have greater mean age (~240 years) than those of the other two forests (~140 years). [ABSTRACT FROM AUTHOR]

ABSTRACT Brazilian soil scientists have increased the use of the term “soil quality” in their scientific publications in the last decade. However, it remains unclear if those publications only mention “soil quality” in a broad context, or the studies are focused on soil quality assessments, integrating soil chemical, physical and biological indicators. The objective of this systematic review was to carry out a critical analysis of the conception in using the term “soil quality” in recent publications derived from studies performed in Brazil. For this purpose, the terms [(“soil health” or “soil quality” or “qualidade do solo”) and (“Brazil*” or “Brasil*”)] were searched in databases of Web of Science, Scopus, and Scielo from 2014 to 2021. Initially, 1,284 peer-reviewed papers were found, subsequently selected according to the criteria established in two filters: (i) First filter - studies carried out in Brazil, which mentioned at least one of the terms of interest (“soil health” or “soil quality” or “qualidade do solo”) and that evaluated soil biological, physical or chemical indicators, assessing at least one of them; (ii) Second filter - studies in which all three groups of soil indicators were assessed and integrated, and presented a specific discussion about soil quality. According to the results, 36 % of the papers met the first criteria (n = 464), and only 2 % (n = 30) attended the second filter. The terms “soil health” or “soil quality” or “qualidade do solo” were mentioned 7 and 37 times per paper for those papers selected in the first and second filter, respectively. We evidenced in our study that the term soil quality in agricultural science papers has been predominantly used in a broad context, mostly to refer to the suitable soil conditions for plant growth. Thus, we concluded that even if the use of soil quality term is increasing in Brazilian literature, there are still very few researchers working specifically with soil quality assessments, in its full conception (i.e., integrating chemical, physical and biological indicators). Therefore, there is a promising research field to be explored to promote scientific advances in the soil quality area (e.g., new concepts, assessment frameworks, on-farm monitoring protocols), as well as disseminate the soil quality assessment among the Brazilian farmers, environmentalists, and other stakeholders.

There have been a number of studies dealing with soil hydraulic properties. Yet, there is a poor discussion on the number of samples necessary to represent such variables that usually vary orders of magnitude in space. In the present paper, we examine the adequate number of samples for two soil saturated hydraulic conductivity (Ksat) data sets: (1) normal distribution (a 40 year-old pasture) and (2) non-normal distribution (primary forest). To assess the adequate number of samples in each case, we used for normal distribution, an statistical criterion of standard deviation lower than 5% compared to a high sampling effort (n = 25) as an indicative of a proper representation of Ksat variability. In the case of non-normal distribution, we used the same criterion but using median absolute deviation (a non-parametric statistics). Both data sets were available in Salemi et al. (2013) and were Ksat measured at 0.15 m soil depth for medium-textured inceptisols in São Paulo State, Brazil. For each data set, we simulated 10 ‘new’ samplings in which we calculated mean and standard deviation from sample 1 to 25 (for normal data) and median and median absolute deviation (for non-normal data). We found that, on average, at least 17 to 22 samples had to be collected to meet the adopted criterion for normal data whereas 20 to 25 had to be collected for non-normal data. Such numbers of samples exceed those used in a number of papers. Additional examples of this method with a light modification are given to establish number of samples in new study areas as well as to estimate number of samples when comparing two (or more) land-uses. Simple and practical procedures like those presented here could estimate the number of samples that adequately represents soil hydraulic properties variability.

Abstract Phosphorus (P) use in global food and bioenergy production needs to become more efficient and sustainable to reduce environmental impacts and conserve a finite and critical resource (Carpenter & Bennett, Environmental Research Letters, 2011, 6, 014009; Springmann et al., Nature, 2018, 562, 519). Sugarcane is one crop with a large P footprint because production is centered on P‐fixing soils with low P availability (Roy et al., Nature Plants, 2016, 2, 16043; Withers et al., Scientific Reports, 2018, 8, 2537). As global demand for processed sugar and bioethanol continues to increase, we advocate that improving P efficiency could become a key sustainability goal for the sugarcane industry. Here, we applied the 5R global P stewardship framework (Withers et al., Ambio, 2015, 44, 193) to identify more sustainable options to manage P in Brazilian sugarcane production. We show that current inputs of P fertilizer to the current crop area could be reduced by over 305 Gg, or 63%, over the next three decades by reducing unnecessary P fertilizer use, better utilization of recyclable bioresources and redesigning recommendation systems. Adoption of these 5R options would save the sugarcane industry in Brazil 528 US$ million and help safeguard global food and energy security.

In forest nurseries, irrigation management becomes more complex as different seedlings of tropical species, with different architectures, are grown close to each other. In this context, there are gaps in knowledge about the physiological responses of species with different mean leaf angles when subjected to different irrigation depths. Thus, this work aimed to analyze whether mean leaf angles affect irrigation efficiency and, consequently, physiological responses of tree seedlings. Six species with different mean leaf angles were submitted to three irrigation depths (6, 9, and 12 mm) applied daily by micro-sprinklers in a completely randomized design in a split plot scheme. The following variables were evaluated: leaf water potential, stomatal conductance, relative water content in the leaf, daily transpiration, leaching fraction, and total dry mass. In tree species seedlings with positive mean leaf angles, smaller irrigation depths are already able to increase leaf water potential, stomatal conductance, leaf relative water content, and transpiration efficiency. In contrast, when the mean leaf angles are negative, it is necessary to apply larger irrigation depths so that seedling physiological responses do not reduce the production of total dry mass.

Abstract Soil nitrogen isotope composition (δ15N) is an essential tool for investigating ecosystem nitrogen balances, plant–microbe interactions, ecological niches, animal migration, food origins, and forensics. The advancement of these applications is limited by a lack of robust geospatial models that are capable of capturing variation in soil δ15N (i.e., isotopic landscapes or isoscapes). Due to the complexity of the nitrogen cycle and general scarcity of isotopic information, previous approaches have reconstructed regional to global soil δ15N patterns via highly uncertain linear regression models. Here, we develop a new machine learning approach to ascertain a finer‐scale understanding of geographic differences in soil δ15N, using the South American continent as a test case. We use a robust training set spanning 278 geographic locations across the continent, spanning all major biomes. We tested three different machine learning methods: cubist, random forest (RF), and stochastic gradient boosting (GBM). 10‐fold cross‐validation revealed that the RF method outperformed both the cubist and GBM approaches. Variable importance analysis of the RF framework pointed to biome type as the most crucial auxiliary variable, followed by soil organic carbon content, in determining the model performance. We thereby created a biogeographic boundary map, which predicted an expected multiscale spatial pattern of soil δ15N with a high degree of confidence, performing substantially better than all previous approaches for the continent of South America. Therefore, the RF machine learning framework showed to be a great opportunity to explore a broad array of ecological, biogeochemical, and forensic issues through the lens of soil δ15N.

Background Brazil is a low- to medium-income country and has the second largest pet food market in the world with 8% of world pet food consumption. The lowest-income social class spends around 17% of their domestic budget on pet food and other items related to pets. Consumers are frequently misled by advertising as there is no precise information about the main sources of protein, carbohydrates and fat in the labels, and the Brazilian pet food industry can legally claim that their products contain certain items like salmon or beef even if they use just a flavoring compound. Methods The stable isotope methodology compares the stable isotope ratios of carbon (13C/12C) and nitrogen (15N/14N) between source and product. The 13C/12C ratio of a specific product (e.g., dog food) reveals the proportions of C4 (maize) and C3 (soybean, rice and wheat) plants in that product and the 15N/14N ratio reveals the proportion of the compounds derived from animals. With this isotopic data, we used MixSIAR, a Bayesian stable isotope-mixing model, to estimate the proportion of maize, grains, poultry and beef in dog food. Results The δ13C values of dry dog food ranged from −24.2‰ to −12.8‰, with an average (± standard-deviation) of −17.1‰ ± 2.8‰. The δ13C values of wet pet food ranged from −25.4‰ to −16.9‰, with an average (± standard-deviation) of −21.2‰ ± 2.4‰, which was significantly lower (p < 0.01). The δ15N values of the dry and wet food ranged from 1.7‰ to 4.2‰, and from 0.5‰ to 5.5‰, respectively. The average δ15N values of dry food (2.9‰ ± 0.5‰) was not higher than the wet food (2.6‰ ± 1.3‰) (p > 0.01). The output of the MixSIAR showed a low proportion of bovine products in dry dog food samples. On the other hand, poultry was obviously the dominant ingredient present in most of the samples. Maize was the second dominant ingredient. Wet and dry dog food showed similar isotopic analysis results. The only difference was a lower proportion of maize and higher proportion of grains in wet dog food. Discussion The main finding is that dog food in Brazil is mostly made of approximately 60% (ranging from 32% to 86%) animal-based and 40% (ranging from 14% to 67%) plant-based products. Poultry and maize are the main ingredients. Poultry is added as a by-product or meal, which avoids competition between dogs and humans for meat products, while they can compete for maize. On the other hand, a large proportion of plant-based products in dog food decreases the energy and environmental footprint, since plant-based food products tend to be less harmful compared to animal-based products. Labels can mislead consumers by showing pictures of items that are not necessarily part of the product composition and by not showing the detailed information on the proportion of each ingredient. This information would allow customers to make their own choices considering their pet’s nutrition, the competition between animals and humans for resources and environmental sustainability.

The availability of accurate techniques to discriminate between marked laboratory-reared flies and unmarked wild flies captured in monitoring traps is essential for programs that integrate the Sterile Insect Technique (SIT) to manage fruit flies. In this study, the feasibility of using a stable isotope marking technique for the South American fruit fly, Anastrepha fraterculus (Wiedemann), was assessed. Wild flies were collected from apple orchards, which are a target of a SIT project in southern Brazil. To verify if adult flies could be labelled by the stable isotopes from larval diets, larvae were reared on two different C4-based diets and fruits in laboratory. To evaluate the influence of the two most common attractants applied to capture A. fraterculus (grape juice and CeraTrapTM) and the most common preservation method in fruit fly collections (ethanol), laboratory-reared flies were immersed in McPhail traps containing the respective treatments for two periods of time. Samples were analyzed in an elemental analyzer coupled to a Continuous Flow Isotope Ratio Mass Spectrometer (CF-IRMS) at CENA/USP. The δ13C signatures of flies reared on artificial diets differed significantly from the δ13C of flies whose larvae were reared on fruits and from wild flies. In contrast, the δ15N values were less conclusive and the technique could not rely solely on them. In all cases considered, the δ13C and δ15N signatures from males did not differ from females. Despite the alterations caused by the attractants tested and ethanol, laboratory-flies could be distinguished from the wild ones based on δ13C signatures. This is the first comprehensive study to demonstrate that it is possible to distinguish wild A. fraterculus from flies reared on larval diets containing C4 sugar. The first experimentally derived trophic discrimination factors were also obtained for this species. Thus, intrinsic isotope labelling can serve as a backup to conventional dye marking.

Objetivo: Estudar a automedicação para dor entre estudantes de cursos de medicina e enfermagem da PUCSP em comparação com estudantes das outras áreas de conhecimento. Material e métodos: Esses dados foram obtidos em dois grupos: A - estudantes da área da saúde e B - estudantes da área de ciências humanas e exatas. Utilizou-se um questionário elaborado pelos autores. A análise estatística usou o teste do qui-quadrado e de Fischer. Resultados: Na área de saúde há um predomínio do gênero feminino, e nas outras áreas um predomínio masculino. Na área de saúde a maior parte dos estudantes cursa medicina, e nas outras áreas engenharia. Observa-se um alto índice de automedicação em ambos os grupos, constatando-se que os participantes do grupo da área de saúde usam significativamente mais opioides e anti-inflamatórios que os demais estudados. Conclusão: A frequência do uso de medicamentos para dor é maior no grupo de estudantes da área de saúde, e a automedicação é praticada igualmente entre estudantes da área de saúde e das demais áreas.

The Atlantic rain forest is the most endangered ecosystem in Brazil. Its degradation has started since 1500 when the European settlers arrived. Despite of all land use changes that have occurred, hydrological studies carried out in this biome have been limited to hydrological functioning of rain forests only. In order to understand the hydrological consequences of land-use change from forest to pasture, we described the hydrological functioning of a pasture catchment that was previously covered by tropical rain forest. To reach this goal we measured the precipitation, soil matric potential, discharge, surface runoff and water table levels during one year. The results indicated that there is a decrease in surface soil saturated hydraulic conductivity. However, as low intensity rainfall prevails, the lower water conductivity does not necessarily leads to a substantially higher surface runoff generation. Regarding soil water matric potential, the pasture presented higher moisture levels than forest during the dry season. This increase in soil moisture implies in higher water table recharge that, in turn, explain the higher runoff ratio. This way, land-use change conversion from forest to pasture implies a higher annual streamflow in pasture catchments. Nonetheless, this increase in runoff due to forest conversion to pasture implies in losses of biological diversity as well as lower soil protection.

Site-specific height-diameter models may be used to improve biomass estimates for forest inventories where only diameter at breast height (DBH) measurements are available. In this study, we fit height-diameter models for vegetation types of a tropical Atlantic forest using field measurements of height across plots along an altitudinal gradient. To fit height-diameter models, we sampled trees by DBH class and measured tree height within 13 one-hectare permanent plots established at four altitude classes. To select the best model we tested the performance of 11 height-diameter models using the Akaike Information Criterion (AIC). The Weibull and Chapman-Richards height-diameter models performed better than other models, and regional site-specific models performed better than the general model. In addition, there is a slight variation of height-diameter relationships across the altitudinal gradient and an extensive difference in the stature between the Atlantic and Amazon forests. The results showed the effect of altitude on tree height estimates and emphasize the need for altitude-specific models that produce more accurate results than a general model that encompasses all altitudes. To improve biomass estimation, the development of regional height-diameter models that estimate tree height using a subset of randomly sampled trees presents an approach to supplement surveys where only diameter has been measured.

O maior acesso ao meio urbano e ao mundo globalizado pode estar colocando em risco o modo de vida das comunidades tradicionais rurais, gerando impactos consideráveis em seus sistemas agroalimentares. Assim, o objetivo deste trabalho foi avaliar as consequências do desenvolvimento nos sistemas agroalimentares de comunidades tradicionais devido ao aumento da urbanização, do maior acesso à economia de mercado e políticas públicas, por meio da caracterização dos hábitos alimentares e formas de produção de autoconsumo. O estudo foi conduzido nos remanescentes de quilombo Kalunga – GO, por intermédio da adaptação do método “recordatório alimentar 24 horas” e observação participante, onde foram caracterizadas as condições socioeconômicas e os sistemas agroalimentares locais. A partir disso, foi possível identificar elementos de transição agroalimentar nas comunidades mais acessíveis ao meio urbano, ou seja, mudanças na produção de autoconsumo e hábitos alimentares locais. Em contraposição, em algumas comunidades foi identificado um panorama de resistência do modo de vida tradicional e reorganização por meio de estímulos à produção agroextrativista.

The study was conducted in the lower basin of the Paraíba do Sul River (PSR), in which 57,000 km2 of the basin is located in the Brazilian states of São Paulo, Minas Gerais and Rio de Janeiro. We proposed to identify the main sources of C and N fluxes in the PSR waters, to evaluate biogeochemical processes in the watershed, and to estimate C and N riverine loads to the Atlantic Ocean in the context of the sugarcane plantation expansion for ethanol production. Riverine water samples were collected at seven stations along 12 months. Physicochemical and limnological parameters, as well as discharge, were measured together with organic and inorganic C and N species in the dissolved and suspended particulate material. C and N concentrations in bed fluvial sediments, and suspended particulate material were measured, and their elemental ([C:N]a) and isotopic (δ13C) compositions were compared with the [C:N]a and δ13C of the following sources: riparian soils, insular flooded soils, aquatic macrophytes, phytoplankton, pasture grass, sugarcane, sugarcane byproducts, and forest litterfall. Temporal patterns in the physicochemical and limnological environment were correlated to discharge. It also was observed that sugar cane production can increase riverine C and N fluxes. Riparian soils inputs were larger than insular soils, which was likely to act as a biogeochemical barrier. Effects of the macrophytes on riverine C and N were unclear, as well as urban sewage disposal effects. Although the PSR loads represented a very small percentage of the fluvial input to global biogeochemical cycles, we suggest that this and other medium sized watersheds in Eastern and Southeastern South America can be significant contributors to the continental biogeochemical riverine loads to the ocean, if their loads are considered together.

The upper Paraná River floodplain is composed of several marginal lagoons, making it a natural breeding ground for many fish species at developmental stages. The aim of this study is to estimate the trophic positions of these fishes based on feed intake (measured via diet) and nitrogen assimilation (measured via δ15N). The monthly samplings were concentrated during the spawning season in the Ivinheima River, which is located in the upper Paraná River floodplain. The specimens were grouped into preflexion, flexion and postflexion stages. Trophic positions were estimated based on the isotope value of nitrogen and on diet. During the developmental stages of P. squamosissimus, there were significant differences in the isotope values of δ15N; for H. edentatus, however, no significant differences were found. During the developmental stages, both species were classified as either at or above the third trophic level. Once this information is obtained for other species and components of the ecosystem, it will not only provide a more precise view of the energy allocation and flow in the ecosystem, but will also make possible for management measures to promote sustainability in this environment.A planície de inundação do alto rio Paraná é formada por várias lagoas marginais, tornando-se um criadouro natural de várias espécies de peixes nos estágios de desenvolvimento. O objetivo do estudo foi estimar as posições tróficas destes peixes, com base no alimento consumido (medido através dieta) e o nitrogênio assimilado (medido através δ15N). As amostragens mensais concentraram-se no período de desova das espécies, no rio Ivinheima, na planície de inundação do alto rio Paraná. Os espécimes foram agrupados em: pré-flexão, flexão e pós-flexão. As posições tróficas foram estimadas com base no valor isotópico de nitrogênio e na dieta. Nas fases de desenvolvimento de P. squamosissimus houve diferença significativa nos valores isotópicos de δ15N, enquanto que, para H. edentatus, não foram identificadas. Ambas as espécies, durante os estágios de desenvolvimento, foram classificadas em igual ou acima do terceiro nível trófico. Estas informações, quando obtidas para outras espécies de peixes e componentes do ecossistema, fornecerão uma visão mais precisa da distribuição e fluxo de energia no ecossistema, além de tornar possível medidas de manejo, que visem promover a sustentabilidade deste ambiente.

A ocupação desordenada do solo, assim como a ausência de práticas conservacionistas, têm levado à degradação dos recursos naturais. Nesse contexto, tem se atribuído às florestas ripárias presentes nas áreas de preservação permanente o efeito de uma panaceia na proteção dos recursos hídricos. Neste artigo, por meio de uma revisão, tenta-se esclarecer os efeitos hidrológicos da recuperação das florestas situadas nessas áreas, no que concerne à quantidade de água e à manutenção dos recursos hídricos no contexto de microbacias hidrográficas. Mostra-se a influência das florestas, de uma maneira geral, sobre a quantidade de água e o regime de vazão em bacias hidrográficas. Na sequência, evidencia-se que as florestas ripárias possuem efeito hidrológico similar ao das florestas de uma maneira geral. Entretanto, com o objetivo de garantir a proteção dos recursos hídricos, salienta-se que, para bacias com cobertura do solo diferente de florestas naturais, mais importante do que restaurar florestas nas áreas de preservação permanente é manter altas taxas de infiltração de água no solo. Nesse sentido, como as bacias hidrográficas são heterogêneas em vários aspectos (tipos de solos, declividade, uso da terra) não é possível obter uma proteção efetiva e integral da água simplesmente realizando o plantio de espécies características de zonas ripárias em áreas de preservação permanente, mas sim manejando bacias hidrográficas como um todo. Por último, apontam-se algumas lacunas sobre as quais a hidrologia pode ajudar a ampliar o conhecimento do papel hidrológico das florestas ripárias em microbacias hidrográficas.The lack of soil occupation planning, as well as the absence of soil conservation, have caused natural resources degradation. In this context, riparian forests located within the permanent preservation areas are described as a panacea for water resources protection. In this paper, we clarify the hydrological effects of these forests focusing on water quantity and water resources maintenance in small catchments. After, is shown that riparian forests present the same hydrological effect of forests in general. However, aiming to guarantee water resources protection we point out that for catchments with land uses that are not natural forests, the most important action is to maintain the high water infiltration rates. As catchments present high variability regarding the soil, topography, land use, it is not possible to obtain effective water protection by simply restoring forests in the permanent preservation areas, but we do obtain it by managing the whole small catchment. Last but not least, we exhibit some gaps that hydrology may contribute to fill in an effort to increase the knowledge of riparian forests role in small catchments.

The main objective of this paper was to evaluate the level of occurrence of the organochlorine compounds in samples of sediments, bivalves and two fish species collected in the Piracicaba River basin (São Paulo, Brazil). The isomers alpha and gamma of HCH and Heptachlor were most frequently detected in samples of sediments and specimens of bivalve and fish. Therefore, although the levels of these compounds found were not critically high, they are still found in the environment. This fact suggests that they are still being used, despite the fact that the use of these compounds was outlawed more than twenty years ago.

Information about the land cover of a region it is a key information for several purposes. This paper aimed to elaborate land-cover maps using digital satellite images obtained in 1997 from seven watersheds (Piracicaba, Moji-Guaçu, Alto Paranapanema, Turvo Aguapeí, Peixe, and São José dos Dourados) located in the State of São Paulo, southeastern Brazil. Additionaly, this study evaluated the relationship between land-cover and slopes of the terrain of the seven watersheds. A third objective was to estimate the percentage of riparian vegetation currently remaining along the streams in a 30-meter width buffer zone. Three research questions were posed: i) What is the dominant land-cover of these watersheds? ii) Is the riparian vegetation well preserved in the 30m width buffer zone? If not, iii) what is the dominant land-cover in these areas and what would be the cost of recovering such areas? Pasture was the predominant land-cover, occurring in approximately 50% of the entire study area, while sugar cane (Saccharum officinarum) (14%) constituted the second most frequent land-cover. Approximately 50% of the area of the seven basins is considered flat (40%) or smoothly rolling (10%). The terrain only becomes hillier in the Piracicaba and Alto Paranapanema basins, where a little less than 50% have slopes higher than 8%. The total riparian buffer strip zone occupied an area equivalent to approximately 6,200 km². From this total, only 25% is preserved. Pasture is the main land-cover of the riparian buffer strip zone.Informações sobre mudanças no uso e cobertura do solo são fundamentais para vários propósitos sociais, econômicos e ambientais. O principal objetivo deste estudo foi elaborar mapas de cobertura do solo usando imagens digitais obtidas por satélite no ano de 1997 nas seguintes bacias hidrográficas do Estado de São Paulo: Piracicaba, Moji-Guaçu, Alto Paranapanema, Turvo Aguapeí, Peixe, and São José dos Dourados. Adicionalmente, a relação entre a cobertura do solo e a declividade do terreno também foram investigadas. Um segundo objetivo foi estimar a proporção relativa de vegetação ripária considerando-se uma faixa de 30 metros em relação às margens dos corpos d'água. As três principais questões científicas deste artigo foram: i) Qual é a cobertura dominante do solo nas bacias hidrográficas abordadas? ii) As vegetações ripárias encontram-se bem preservadas ripária nas faixas dos 30 metros? Em caso negativo, iii) Qual é a cobertura do solo dominante nessas áreas? A cobertura do solo predominante nas bacias hidrográficas são as pastagens, ocorrendo em quase 50% de toda a área investigada. Seguem-se as plantações de cana-de-açúcar (14%) como sendo as coberturas do solo mais importantes. Aproximadamente metade da área das sete bacias foi considerada plana (40%) ou suavemente ondulada (10%). A área ripária considerando-se uma largura de 30 metros em relação às margens dos corpos d'água ocupa uma área aproximada de 6.200 km². Deste total, somente 25% encontram-se bem preservadas. Dentre as culturas, as pastagens ocupam a maior área na zona ripária. Nas bacias dos rios Moji-Guaçu e Piracicaba a cana-de-açúcar é a principal cultura invasora da zona ripária.

Soil loss expectation and possible relationships among soil erosion, riparian vegetation and water quality were studied in the São José dos Dourados River basin, State of São Paulo, Brazil. Through Geographic Information System (GIS) resources and technology, Soil Loss Expectation (SLE) data obtained using the Universal Soil Loss Equation (USLE) model were analyzed. For the whole catchment area and for the 30 m buffer strips of the streams of 22 randomly selected catchments, the predominant land use and habitat quality were studied. Owing mainly to the high soil erodibility, the river basin is highly susceptible to erosive processes. Habitat quality analyses revealed that the superficial water from the catchments is not chemically impacted but suffers physical damage. A high chemical purity is observed since there are no urban areas along the catchments. The water is physically poor because of high rates of sediment delivery and the almost nonexistence of riparian vegetation.Expectativa de perda de solo e possíveis relações entre erosão, vegetação ripária e qualidade da água foram estudados na bacia do rio São José dos Dourados (SP). Através de recursos de geoprocessamento e da Equação Universal de Perda de Solos, os dados sobre expectativa de perda de solo foram levantados. Para a área de drenagem total e a faixa tampão dos corpos d'água de 22 sub-bacias aleatoriamente selecionadas, analisou-se a cobertura do solo predominante e qualidade do habitat. Devido principalmente à alta erodibilidade do solo, a área estudada é altamente suscetível ao processo erosivo. As análises de qualidade da água revelaram que as águas superficiais das sub-bacias estão quimicamente não impactadas, mas fisicamente degradadas. A alta pureza química deve-se, possivelmente, à ausência de áreas urbanizadas ao longo das sub-bacias e as alterações nas características físicas são, possivelmente, decorrentes das altas taxas de transferência de sedimento aos corpos d'água e à quase ausência de mata ciliar.

Naturally occurring stable isotope ratios can be a powerful tool in studies of animal nutrition, provided that the assumptions required for dietary reconstruction are validated by studies such as the one presented here. The objective of this study was to document the magnitude of isotopic fractionation between swine diet and their different tissues. For this, the isotopic ratios of carbon and nitrogen of the diet and selected tissues (hair, nail, liver, muscle, fat and cartilage) were determined. The delta13C and delta15N of the diet were -15.9‰ and 1.3‰, respectively, and all delta15N of swine tissues were 2.2 to 3.0‰ enriched in 15N in relation to the diet. Little variation in delta15N occurred among tissues, with exception to liver that was less enriched in 15N than the nail. Nail and hair presented no 13C enrichment relative to diet. Cartilage was ~1.0‰ enriched in 13C as compared to diet. Liver and muscle were on average 2.1‰ more depleted in 13C in relation to diet as well as fat tissues. Some of the C and N isotope ratios of swine tissues differed in organs, but the isotopic fractionation trends among tissues appears to be similar to other mammals. Therefore our data provide a good baseline to interpret stable isotope patterns in domestic mammals (such as swine) in controlled or semi-controlled experiments.O uso da abundância natural de isótopos estáveis pode ser uma ferramenta útil em estudos de nutrição animal, de forma que a base necessária para a reconstrução da dieta alimentar pode ser validada a partir de estudos como o apresentado aqui. O objetivo deste estudo foi documentar a magnitude do fracionamento isotópico entre a dieta e os tecidos de porcos domésticos. Para tanto, foram determinadas as razões isotópicas de carbono e nitrogênio de alguns tecidos selecionados (pêlo, unha, fígado, músculo, gordura e cartilagem). Os valores de delta13C e delta15N da ração fornecida foram -15,9‰ e 1,3‰, respectivamente. O delta15N desses tecidos ficou entre 2,2 e 3,0‰ mais enriquecido do que a dieta. Pouca variação no delta15N ocorreu entre os tecidos analisados, exceto o fígado que foi significativamente menos enriquecido em 15N do que a unha. A unha e o pêlo não apresentaram enriquecimento em 13C em relação à ração, enquanto a cartilagem ficou ~1‰ mais enriquecida. Os tecidos de fígado e músculo foram, em média, 2,1‰ mais leve em 13C em relação à dieta, assim como o tecido adiposo. Várias das razões isotópicas dos tecidos dos porcos diferiram, mas as tendências no fracionamento isotópico entre os tecidos foram similares ao encontrado em outros mamíferos. Portanto as diferenças encontradas no fracionamento isotópico podem servir de base para a interpretação de padrões isotópicos em animais domésticos oriundos de experimentos controlados ou semi-controlados.

Soy occupies the largest area of agricultural land in Brazil, spreading from southern states to the Amazon region. Soy is also the most important agricultural commodity among Brazilian exports affecting food security and land use nationally and internationally. Here we pose the question of whether soy expansion affects only economic growth or whether it also boosts socioeconomic development, fostering education and health improvements in Brazilian municipalities where it is planted. To achieve this objective, we divided more than 5000 municipalities into two groups: those with >300 ha of soy (soy municipalities) and those with

Neste trabalho teve-se como objetivo testar o modelo CENTURY para simular os efeitos das mudanças de uso da terra nos teores de carbono no solo e na produção primária líquida na bacia do rio Piracicaba, SP. O modelo foi parametrizado e as simulações foram realizadas considerando-se áreas de florestas, pastagens e cana-de-açúcar, dada a sua importância econômica. Os resultados obtidos indicaram que a alteração do uso/cobertura do solo provoca a diminuição do estoque de carbono do solo. As simulações realizadas na transição de uma floresta para cana-de-açúcar indicaram um decréscimo de 28% no estoque de carbono nos primeiros 12 anos, e diminuição de 42% com 50 anos de cultivo do solo com essa gramínea. Na simulação da transição de uma floresta para pasto, seguida do cultivo da cana-de-açúcar, verificou-se que na primeira mudança (floresta-pastagem) a perda de carbono foi de 24%, enquanto na segunda alteração (pastagem-cana) a perda foi de 22%. Com relação à produção primária, os resultados obtidos de floresta (6,6 t ha-1 ano-1), cana-de-açúcar (77, 82, 80 t ha-1 ano-1) e pasto (6,5 t ha-1 ano-1), mostraram-se similares aos valores observados no campo por outros autores.

Apesar do crescente interesse nos estudos ambientais em cana-de-açúcar, há poucos estudos avaliando o carbono dissolvido na água subterrânea nesse tipo de cobertura vegetal, principalmente correlacionando o manejo da cultura como a aplicação dos fertilizantes, e os processos hidrológicos. Portanto, este trabalho visa avaliar a dinâmica do carbono orgânico dissolvido na água subterrânea, de modo preliminar. As concentrações de COD variaram de 0,681 a 6,151 mg.L-1. Há correlação positiva entre a precipitação e o aumento da concentração de COD (r = 0,73).