South-central Brazil Research Articles

Integrated Analysis of Solar-Induced Chlorophyll Fluorescence, Normalized Difference Vegetation Index, and Column-Average CO2 Concentration in South-Central Brazilian Sugarcane Regions

Remote sensing has proven to be a vital tool for monitoring and forecasting the quality and yield of crops. The utilization of innovative technologies such as Solar-Induced Fluorescence (SIF) and satellite measurements of column-averaged CO2 (xCO2) can enhance these estimations. SIF is a signal emitted by crops during photosynthesis, thus indicating photosynthetic activities. The concentration of atmospheric CO2 is a critical factor in determining the efficiency of photosynthesis. The aim of this study was to investigate the correlation between satellite-derived Solar-Induced Chlorophyll Fluorescence (SIF), column-averaged CO2 (xCO2), and Normalized Difference Vegetation Index (NDVI) and their association with sugarcane yield and sugar content in the field. This study was carried out in south-central Brazil. We used four localities to represent the region: Pradópolis, Araraquara, Iracemápolis, and Quirinópolis. Data were collected from orbital systems during the period spanning from 2015 to 2016. Concurrently, monthly data regarding tons of sugarcane per hectare (TCH) and total recoverable sugars (TRS) were gathered from 24 harvest locations within the studied plots. It was observed that TRS decreased when SIF values ranged between 0.4 W m−2 sr−1 μm−1 and 0.8 W m−2 sr−1 μm−1, particularly in conjunction with NDVI values below 0.5. TRS values peaked at 15 kg t−1 with low NDVI and xCO2 values, alongside SIF values lower than 0.4 W m−2 sr−1 μm−1 and greater than 1 W m−2 sr−1 μm−1. These findings underscore the potential of integrating SIF, xCO2, and NDVI measurements in the monitoring and forecasting of yield and sugar content in sugarcane crops.

Multisite potassium fertilization effects on sugarcane ratoon yield and economic return in South-Central Brazil

Multisite potassium fertilization effects on sugarcane ratoon yield and economic return in South-Central Brazil

Discriminant Analysis for Severe Storm Environments in South-Central Brazil

Abstract Severe storms produce hazardous weather phenomena, such as large hail, damaging winds, and tornadoes. However, relationships between convective parameters and confirmed severe weather occurrences are poorly quantified in south-central Brazil. This study explores severe weather reports and measurements from newly available datasets. Hail, damaging wind, and tornado reports are sourced from the PREVOTS project from June 2018 to December 2021, while measurements of convectively induced wind gusts from 1996 to 2019 are obtained from METAR reports and from Brazil’s operational network of automated weather stations. Proximal convective parameters were computed from ERA5 reanalysis for these reports and used to perform a discriminant analysis using mixed-layer CAPE and deep-layer shear (DLS). Compared to other regions, thermodynamic parameters associated with severe weather episodes exhibit lower magnitudes in south-central Brazil. DLS displays better performance in distinguishing different types of hazardous weather, but does not discriminate well between distinct severity levels. To address the sensitivity of the discriminant analysis to distinct environmental regimes and hazard types, five different discriminants are assessed. These include discriminants for any severe storm, severe hail only, severe wind gust only, and all environments but broken into “high” and “low” CAPE regimes. The best performance of the discriminant analysis is found for the “high” CAPE regime, followed by the severe wind regime. All discriminants demonstrate that DLS plays a more important role in conditioning Brazilian severe storm environments than other regions, confirming the need to ensure that parameters and discriminants are tuned to local severe weather conditions.

Impacts of ground-level ozone on sugarcane production

Sugarcane is a vital commodity crop often grown in (sub)tropical regions which have been experiencing a recent deterioration in air quality. Unlike for other commodity crops, the risk of air pollution, specifically ozone (O3), to this C4 crop has not yet been quantified. Yet, recent work has highlighted both the potential risks of O3 to C4 bioenergy crops, and the emergence of O3 exposure across the tropics as a vital factor determining global food security. Given the large extent, and planned expansion of sugarcane production in places like Brazil to meet global demand for biofuels, there is a pressing need to characterize the risk of O3 to the industry. In this study, we sought to a) derive sugarcane O3 dose-response functions across a range of realistic O3 exposure and b) model the implications of this across a globally important production area. We found a significant impact of O3 on biomass allocation (especially to leaves) and production across a range of sugarcane genotypes, including two commercially relevant varieties (e.g. CTC4, Q240). Using these data, we calculated dose-response functions for sugarcane and combined them with hourly O3 exposure across south-central Brazil derived from the UK Earth System Model (UKESM1) to simulate the current regional impact of O3 on sugarcane production using a dynamic global vegetation model (JULES vn 5.6). We found that between 5.6 % and 18.3 % of total crop productivity is likely lost across the region due to the direct impacts of current O3 exposure. However, impacts depended critically on the substantial differences in O3 susceptibility observed among sugarcane genotypes and how these were implemented in the model. Our work highlights not only the urgent need to fully elucidate the impacts of O3 in this important bioenergetic crop, but the potential implications air quality may have upon tropical food production more generally.

Palynotaxonomy of Calea sect. Meyeria (Asteraceae: Neurolaeneae)

Calea comprises 157 species that occur in the Neotropics. The genus is organized into eight subgenera and 18 sections. Calea sect. Meyeria consists of eight species occurring exclusively in south-central Brazil. In this study, pollen grains from these eight species were sampled from herborized flower buds in pre-anthesis. Pollen samples were acetolyzed, measured, and photographed under a light microscope. Unacetolyzed pollen grains were examined under a scanning electron microscope. The results were used to characterize pollen morphology and construct a palynotaxonomic key for Calea sect. Meyeria. The analyzed pollen grains were monads, isopolar, usually medium-sized, oblate spheroidal, tricolporate, with lalongate endoaperture, the sexine echinate and thicker than the nexine, and six spines in the apocolpium region. The eight species have very similar pollen grains, but some characters are informative for this section, namely pollen size, polar area, sexine ornamentation, and endoaperture characteristics. Despite the similarity of the pollen grains, palynological analysis was able to contribute to the delimitation of Calea species, providing new information for species distinction within Calea sect. Meyeria.

Towards greater sustainability of sugarcane production by precision agriculture to meet ethanol demands in south-central Brazil based on a life cycle assessment

Towards greater sustainability of sugarcane production by precision agriculture to meet ethanol demands in south-central Brazil based on a life cycle assessment

Fertilizer source and application method influence sugarcane production and nutritional status.

The contrasting weather conditions throughout the sugarcane harvest period in south-central Brazil (April to November) influence fertilization management in sugarcane ratoon. Through field studies carried out over two cropping seasons, we aimed to compare the performance of sugarcane at sites harvested in the early and late periods of the harvest season as a function of fertilizer sources associated with application methods. The design used in each site was a randomized block in a 2 x 3 factorial scheme; the first factor consisted of fertilizer sources (solid and liquid), and the second factor consisted of application methods (above the straw, under the straw, and incorporated into the middle of the sugarcane row). The fertilizer source and application method interacted at the site harvested in the early period of the sugarcane harvest season. Overall, the highest sugarcane stalk and sugar yields at this site were obtained with the incorporated application applying liquid fertilizer and under straw applying solid fertilizer, with increments of up to 33%. For the site harvested in the late period of the sugarcane harvest season, the liquid fertilizer promoted a 25% higher sugarcane stalk yield compared to the solid fertilizer in the crop season with low rainfall in the spring, while in the crop season with normal rainfall, there were no differences between treatments. This demonstrates the importance of defining fertilization management in sugarcane as a function of harvest time, thereby promoting greater sustainability in the production system.

Distribution of the greater naked-tailed armadillo Cabassous tatouay (Desmarest, 1804) in South America, with new records and species distribution modeling

ABSTRACT Cabassous tatouay occurs in moist forests, savannas, and grasslands of south, central, and northeastern Brazil, eastern Paraguay, northeastern Argentina, and Uruguay. Despite its wide distribution range, C. tatouay is scarcely recorded in some regions. This study aimed to: present new records of C. tatouay; compile the localities where the species was recorded according to published scientific accounts; and model its distribution range along South America. We present five new records of C. tatouay from Goiás and Minas Gerais states, Brazil. The review of published accounts resulted in 99 studies, which provided 279 occurrences of C. tatouay to Brazil, Argentina, Paraguay, and Uruguay. The great majority of records are from Brazil, mainly from the Atlantic Forest (119), Cerrado (52), and Pampas (49) biomes. Most records from the Cerrado are placed close to or in transition zones with the Atlantic Forest. Five records are within the Caatinga, but restricted to humid montane forest enclaves. The species distribution models indicate that C. tatouay is probably absent to Amazonia and Pantanal. The higher suitability for the species occurs in eastern Paraguay, northeastern Argentina, and south central Brazil, specifically in the Pampas, Atlantic Forest, and the southern part of the Cerrado.

Reproductive ecology of the Amaral's Blind Snake Trilepida koppesi in an area of Cerrado in south-eastern Brazil

Studies on reproductive biology have largely contributed to the understanding of snake ecology. However, detailed reproductive data are scarce for many groups, particularly blind snakes. Here, we describe the reproductive biology of Trilepida koppesi (Leptotyphlopidae), a widely distributed species in the savannas of south-central Brazil. We describe its macro- and microscopic reproductive anatomy, female reproductive cycle, potential clutch size, seasonal activity, and sexual dimorphism of a population from south-eastern Brazil. Males have plurilobulated testes. Spermiogenesis occurs in early spring (October), when gonads and kidneys show a textured surface, the sexual segment of the kidney is hypertrophied, and the ductus deferentia are opaque and packed with sperm. Females have only the right oviduct, which shows developed epithelium and uterine glands in spring. Mating likely occurs in spring (October–December), and females store sperm in infundibular receptacles until ovulation between late spring and early summer. Potential clutch size ranges from three to five eggs. Females grow larger than males. The synchrony between spermiogenesis and mating defines the male cycle as prenuptial, which is considered the ancestral state of Squamata. These results agree with the hypothesis of conservative parameters for the group.

New occurrences of Chonetoidea (Brachiopoda) in the Devonian of Bolivia, Peru and Antarctica

Chonetoidea corresponds to one of the most abundant superfamilies throughout the Malvinokaffric Realm (Argentina, Uruguay, Bolivia, Paraguay, Antarctica, Peru and South-Central Brazil). In this paper we provided a better understanding of the diversity of this superfamily during the Devonian in southern Gondwana. For Bolivian specimens, we corroborate both the occurrence of Pleurochonetes anteloi in the Huamampampa Formation, that is, this species may have occurred at least in the Givetian, and the occurrence of Australostrophia mesembria in the Pragian-Emsian of Bolivia. We further identify both Aseptonetes isaacsoni in the Icla/Gamoneda Formation, which represents the oldest occurrence of this species, and Chonostrophia truyolsae in the Belén Formation/Bolivian Altiplano, thereby expanding its geographical distribution. We also provide the first description and illustration of a specimen of Chonetoidea from Antarctica and record the first occurrence of Australostrophia mesembria, Devonochonetinae indet. and Eodevonaria sp. in the Cabanillas Formation of Peru. Because A. mesembria is a typical Malvinokaffric species, this corroborates the extension of this realm into southern Peru.

Treptichnus pedum in the Três Marias Formation, south-central Brazil, and its implications for the Ediacaran-Cambrian transition in South America

The index ichnofossil Treptichnus pedum Seilacher 1955 and four types of Microbially Induced Sedimentary Structures (MISS) - variants of wrinkle and elephant skin structures – are the first fossils described from the Três Marias Formation, topmost unit of the Bambuí Group in south-central Brazil. Despite the stratigraphic importance and widespread occurrence of this unit in the São Francisco Craton and adjacent Brasília Fold Belt, its age is still poorly constrained between the Neoproterozoic and Early Paleozoic. This discovery is significant because the first appearance datum (FAD) of T. pedum has been used to define the Ediacaran-Cambrian boundary. Hence, the presence of T. pedum indicates an early Paleozoic age for the uppermost Bambuí Group and means that the Ediacaran-Cambrian limit must lie deeper in the Bambuí Group, somewhere between this level and that of the terminal Ediacaran index-fossil Cloudina sp. in the Sete Lagoas Formation, near the base of the group. Available age determinations on detrital zircon grains and chemostratigraphic correlations are consistent with an Ediacaran to Cambrian age for this group. Detailed paleontological prospection throughout the group may now proceed within a better constrained time frame and hopefully reveal additional fossil evidence of Cambrian as well as Ediacaran life in the Bambuí Group.

Distribution extension and a new state record for Amphisbaena mertensi Strauch, 1881 (Squamata, Amphisbaenidae) in central Brazil

We updated the distribution of Amphisbaena mertensi to northeastern central Brazil based on the finding of a specimen in an urban area in the Cerrado. This species had already been recorded in south-central Brazil, Paraguay, and Argentina. Our new record is 300 km away from the nearest point, Araguari, in the north of the State of Minas Gerais, Brazil. We included a distribution map for the species in South America, and a list of the amphisbaenas species found in Distrito Federal and discuss the conservation of this group.

Seed germination of Bidens subalternansDC. exposed to different environmental factors.

Bidens subalternans DC. is a weed found in several tropical countries such as Brazil. Large number of produced seeds and easy dispersion favor the colonization of agricultural fields by this species. To know the factors that affect the germination of B. subalternans can help to understand its ecology, permitting to develop control strategies. Laboratory experiments were carried out to evaluate how the temperature, photoperiod, burial depth, water deficit, and salt stress affect the seed germination of B. subalternans. The means of the treatments of each experiment were shown in scatter plots with the bars indicating the least significant difference (LSD, p≤0.05). The results showed a germination percentage above 77% for a wide alternating temperature (15/20 C to 30/35 C night/day). The highest germination and uniformity occurred at 25/30°C night/day. Only 11% of the seeds germinated at a temperature of 35/40°C night/day. The deeper burial of seeds reduced their germination. Only 17% of the seeds germinated in darkness conditions. However, in constant light and 12 hours of light/dark conditions the germination percentage was over 96%, confirming the light dependence of the B. subalternans during germination. In constant light and 12 hours of light/dark, the germination was over 96%. B. subalternans seeds showed sensitivity to water and salt stress, and their germination was inhibited under a water potential of -0.4 MPa and 100.09 mM, respectively. The sensitivity of B. subalternans seeds to high temperatures, water stress, and salt stress explains the high frequency of this weed in south-central Brazil. The light and sowing depth showed that burial of seeds by mechanical control is a strategy to reduce the high infestation of B. subalternans.

Soil physical quality associated with tillage practices during sugarcane planting in south-central Brazil

Soil tillage operations had been carried out during the sugarcane planting to improve soil's physical quality, thus providing proper conditions for sugarcane growth. Long-term field experiments were designed to assess the implications of tillage operations during sugarcane planting on soil physical quality and the associated effects on sugarcane yields under two soil types in south-central Brazil. In 2013, two treatments were arranged in a randomized block design with four repetitions: (i) conventional tillage (CT) and ii) no-tillage (NT). Undisturbed soil samples were collected representing the row and inter-row positions to a 0.40-m depth (0-0.10, 0.10-0.20 and 0.20-0.40 m) over four crop cycles (from 2014 to 2017). In the laboratory, bulk density (BD), soil resistance to penetration (SRP), macroporosity (MaP) and microporosity (MiP) were evaluated. Additionally, sugarcane yields were measured annually using an instrumented truck equipped with load cells. CT management alleviated soil compaction only in the plant cane cycle, indicating that the intensive machinery traffic performed in sugarcane harvesting nullify the effects of tillage practices. The opening of planting furrow in both tillage systems reduced soil physical limitations, thus favoring the crop development in the row position. The changes in soil physical attributes were observed mostly in the inter-row position. In clayey soil, BD increased by 24 and 16%, and the SRP by 63 and 55% in the 0-0.10 m layer from plant cane to 3rd ratoon for CT and NT, respectively. Similarly, in sandy loam soil, the SRP increased over time in the 0-0.10 m layer for CT and NT, reaching values higher than 2 MPa. Likewise, MaP decreased for values lower than 0.10 m3 m−3 after four years for both soils and tillage systems. Regardless of soil type, tillage management did not show differences in sugarcane yields over the assessed period. Our findings suggest that NT could be a feasible strategy to reduce soil mobilization and its negative implications on several ecosystem services without compromise sugarcane yield.

Multilocation Straw Removal Effects on Sugarcane Yield in South-Central Brazil

Sugarcane straw is a crop residue that has a dual purpose and can be maintained on the fields or used to produce bioenergy. The straw retention in the field provides multiple ecosystem services, and the complex interactions between straw and yield responses are hard to predict by local studies. The aim of this study was to investigate the straw removal effects on sugarcane yield in south-central Brazil. To achieve the objective, a set of 21 field studies was conducted in contrasting edaphoclimatic conditions. In addition, data of seven studies from the literature were included to build a more robust dataset. Since straw removal treatments were not homogeneous in all experiments, they were grouped as follows: NR, no removal (baseline treatment); LR, low removal; MR, moderate removal; and TR, total removal. To facilitate the data analysis, the experiments were gathered in four macroregions: southern Goiás, western São Paulo, central-eastern São Paulo, and northeastern São Paulo. The site location was the most effective individual factor to explain the straw removal effects on sugarcane yields. Compared with NR treatment, the average yield losses induced by LR, MR, and TR were 2, 10, and 13 Mg ha−1 in southern Goiás and 2, 4, and 6 Mg ha−1 in western São Paulo states, respectively. In other regions, no clear pattern was observed, and only site-specific effects were observed. Straw removal affected sugarcane yields in all soil types, but higher responses were observed under best conditions for sugarcane growth (i.e., clayey soils in southern Goiás). Our findings indicated harvesting season has a relevant role on determining yield responses to straw removal and younger ratoons are more responsive to straw removal. Conclusions from this study suggest straw removal recommendations cannot be designed based on isolated factors but require holistic and integrated knowledge to ensure that the straw amount left on field is enough to sustain multiple soil ecosystem services and crop yields.

A new desert-dwelling dinosaur (Theropoda, Noasaurinae) from the Cretaceous of south Brazil

Noasaurines form an enigmatic group of small-bodied predatory theropod dinosaurs known from the Late Cretaceous of Gondwana. They are relatively rare, with notable records in Argentina and Madagascar, and possible remains reported for Brazil, India, and continental Africa. In south-central Brazil, the deposits of the Bauru Basin have yielded a rich tetrapod fauna, which is concentrated in the Bauru Group. The mainly aeolian deposits of the Caiuá Group, on the contrary, bear a scarce fossil record composed only of lizards, turtles, and pterosaurs. Here, we describe the first dinosaur of the Caiuá Group, which also represents the best-preserved theropod of the entire Bauru Basin known to date. The recovered skeletal parts (vertebrae, girdles, limbs, and scarce cranial elements) show that the new taxon was just over 1 m long, with a unique anatomy among theropods. The shafts of its metatarsals II and IV are very lateromedially compressed, as are the blade-like ungual phalanges of the respective digits. This implies that the new taxon could have been functionally monodactyl, with a main central weight-bearing digit, flanked by neighbouring elements positioned very close to digit III or even held free of the ground. Such anatomical adaptation is formerly unrecorded among archosaurs, but has been previously inferred from footprints of the same stratigraphic unit that yielded the new dinosaur. A phylogenetic analysis nests the new taxon within the Noasaurinae clade, which is unresolved because of the multiple alternative positions that Noasaurus leali can acquire in the optimal trees. The exclusion of the latter form results in positioning the new dinosaur as the sister-taxon of the Argentinean Velocisaurus unicus.

Sustainability assessment of sugarcane production systems: SustenAgro Decision Support System

The concept of agricultural sustainability could be summarized as the ability of agricultural systems to maintain their production in the long term without depleting the available resources for future uses. This study proposes a decision support system for assessing the sustainability of the agricultural production and industrial processing of sugarcane in south-central Brazil by providing information structured according to criteria and indicators in the environmental, economic, and social dimensions. The information is organized using three tools: i) spreadsheets for evaluating technological efficiency, production efficiency and costs (Sugarcane Agro-industrial System Efficiency Index); ii) spreadsheet for evaluating sustainability indicators and generating the Sustainability Index; and iii) a combination of both indexes to construct the Sustainability Matrix and Semaphore, and to provide recommendations for sustainability management. The proposed decision support system contains a software (version 1.0, wherein all the information is available in electronic format, which helps to maximize assessment accuracy). Therefore, strategies such as the SustenAgro system, which helps to manage and to guide public policies, can improve the sector and enable suppliers and mills to ensure sustainable growth.

Straw Removal Effects on Soil Water Dynamics, Soil Temperature, and Sugarcane Yield in South-Central Brazil

The use of sugarcane straw as bioenergy feedstock has been encouraged in recent years due to its potential to mitigate greenhouse gases emissions. Nevertheless, the indiscriminate straw removal causes soil damages, impairing crop development and productivity. Experiments in three sugarcane growing locations (Quata-SP, Chapadao do Ceu-GO, and Quirinopolis-GO) were conducted over 2 years to evaluate soil water dynamics, soil temperature, and sugarcane yield under diverse edaphoclimatic conditions. Straw removal of 0%, 50%, and 100% was arranged in a randomized block design with four replications. Dielectric water potential sensors were used to record soil water potential (ψ, kPa) and soil temperature (°C) every 6 h at a 0.15-m depth. Sugarcane yields were measured annually using an instrumented truck equipped with load cells. In general, the complete and partial straw removals were detrimental to water storage and therefore to plant available water causing an increase in soil temperature during sprouting and tillering phases, which are extremely important periods for a good crop establishment and, consequently, for yield increase. For the experimental sites presenting high fertility, greater water holding capacity, high sugarcane yield potential, and considering an extended water deficit in early stages of crop development, the complete straw removal resulted in yield losses of up to 16 and 40 Mg ha−1, respectively. For the experimental site presenting low sugarcane yield potential, even with low water deficit at the beginning of crop seasons, straw removal had no significant influence on sugarcane yield in the short term, since straw did not produce enough improvements to soil in order to enable benefits for water retention.

Enamel dentition microstructure of Mariliasuchus amarali (Crocodyliformes, Notosuchia), from the Upper Cretaceous (Turonian–Santonian) of the Bauru Basin, Brazil

Advanced notosuchians represent a diverse clade of highly heterodont crocodyliforms that were endemic to the South American landmass during the Cretaceous. Mariliasuchus amarali is an advanced notosuchian from the Upper Cretaceous (Turonian–Santonian) of the Bauru Basin, south-central Brazil, and it is known from several well-preserved specimens in distinct ontogenetic stages. Previous functional analyses of the dentition of M. amarali suggested generalist feeding habits. However, microscopic patterns of the enamel, such as crystallite micromorphology and microwear variation along the dental series, have not been investigated in detail so far. Our results evidence that M. amarali enamel is unique among crocodyliforms, and that heterodonty in this species is even more complex than previously thought. External crown morphology, macrowear position, microwear orientation, and enamel crystallite micromorphology support the recognition of four tooth morphotypes, each of these presenting a combination of features never seen before. M. amarali is the first described reptile bearing both true and false denticles in the same tooth, a condition up to now autapomorphic for the taxon that supports its classification into a distinct dental category (ziphomorph). Ontogenetic trends of dentition reveal that heterodonty was kept through the entire life of M. amarali, and that adults and juveniles occupied very similar ecological niches. Hypothesis of M. amarali presenting omnivorous feeding habits, with the inclusion of hard items in its diet, is supported here. The unique combination of dental features in the taxon could have provided an important adaptive advantage in a low resource environment, as it has been postulated for the Bauru Basin.

Is the expansion of sugarcane over pasturelands a sustainable strategy for Brazil's bioenergy industry?

Biofuels are fundamental for meeting societal energy needs within the next few decades, but the sustainability of large-scale land use conversions to supply feedstock crops remains unclear. Quantitative data documenting how biofuel crop expansion will affect ecosystem services (ES) is needed to develop sustainable energy policies. Using pairwise comparisons of published and novel environmental, social and economic indicators, we quantitatively assessed the provision of critical ES related to key aspects of the sustainability of pasture-to-sugarcane transitions in Brazil. We found that with the exception of maintaining biodiversity, conversion of pasturelands to sugarcane fields enhanced many ES. Based on the Sustainability index, aimed to capture changes on key sustainability aspects by considering multiple ES and properly integrating them, we concluded that pasture to sugarcane transitions would increase the sustainability by 78% in south-central Brazil. Our results provide science-based empirical evidence that the expansion of sugarcane into degraded pasturelands is a suitable strategy to enhance Brazil's biomass feedstock supplies for producing bioenergy. Moreover, facing the complex and multidimensional concept of sustainability, our study also illustrates the importance of considering holistically land use change effects rather than individual ESs when establishing sustainable land management practices and bioenergy policies.