Brazilian Semiarid Region Research Articles

Effect of Different Irrigation Programs on Structural Characteristics, Productivity and Water Use Efficiency of Opuntia and Nopalea Forage Cactus Clones

The objective of this study was to evaluate the structural characteristics, yield and water use efficiency of forage cactus under daytime and nighttime irrigation in a Brazilian semiarid region. The experiment followed a completely randomized design in a 3 × 2 factorial scheme, with ten replications: three clones of forage cactus (“IPA Sertânia”—IPA, “Miúda”—MIU, “Orelha de Elefante Mexicana”—OEM) and two irrigation schedules (daytime and nighttime). Irrigation was applied once a week using a graduated cylinder. The structural characteristics (i.e., plant height and width, total number of cladode—TNC; cladode number per emergence order—CN1, CN2 and CN3; cladode area—CA; cladode area index—CAI), productive characteristics (fresh mass production per plant—FM and dry mass—DM) and water use efficiency (WUEFM and WUEDM) were obtained from the plant harvests. Our results showed that the irrigation schedules did not lead to significant differences in most of the response variables (p > 0.05), except for the TNC (13.2 und), CN2 (7.4 und) and CAI (1.58 m2 m−2) of MIU. It was observed that OEM presented the highest yield, WUEFM and WUEDM (p < 0.05). Adopting the OEM clone, regardless of the irrigation schedule, is the strategy that achieves the best production.

An assessment of radiological risks and chemical toxicity due to naturally occurring radionuclides in surface waters of a semiarid region in Brazil

Santa Quitéria, a city in northeastern Brazil, faces significant challenges in ensuring the availability of potable water due to its semi-arid climate and limited water resources. This study investigates the radiological quality of surface waters commonly used by the population for drinking and by animals for hydration. Water samples were collected from six different locations over a 25-month period, and the concentrations of naturally occurring radionuclides were measured using spectrophotometric analysis, total alpha, and gross beta counting. The mean activity concentrations of Unat, 226Ra, 210Pb, 232Th, and 228Ra were determined to be 9.89∙10−2, 5.35∙10−2, 5.86∙10−2, 6.89∙10−3, and 2.81∙10−3 Bq∙L−1, respectively. Statistical methods, such as cluster and factor analysis, were applied to understand the distribution patterns of these radionuclides. The study also estimated dose rates from radionuclide intake, with a maximum value of 108.5 µSv·y−1, and compared the results against dose limits set by relevant organizations. Furthermore, the risks of morbidity and mortality from radionuclide intake were assessed, revealing the need for optimization at one sampling point where the health risks exceeded intervention thresholds.

Remembering Droughts and Abundance: Ecological Memory in the Semi-arid Region of Northeast Brazil

In Floresta, a municipality in the semi-arid region of Northeast Brazil, the past is considered a time of greater regularity of the climate, natural wealth of the Caatinga biome, and solidarity among the residents of the city’s rural area. Memories of certain historical events can refer to an ‘ancient time’ in which ‘abundance,’ despite the calamities generated by droughts throughout the occupation of this territory, is considered one of its main socio- ecological attributes. In the context of the violent climatic transformations of contemporaneity, analyzing the actions of the memory of old inhabitants of the Brazilian semi-arid region will be a way of first, ethnographically questioning the history of droughts to which the entire ecology of this region has been reduced by historiography and national literature; second, inquiring the human centrality of modern memory—still today a defining theoretical paradigm of social and cultural studies of memory in anthropology. To this end, memories of droughts and abundance will be articulated with the concept of “duration” (la durée) of French philosopher Henri Bergson to think of memory and the duration of time as a way of ecologically living the past, the present, and the future.

Critical levels and fertility classes of soils with high-activity clay in the Brazilian semi-arid region

ABSTRACT Soil fertility evaluation is important for adopting conservation management and adequate nutrient supply. The objective of this study was to identify critical levels and soil fertility classes using the boundary line method for rainfed crops (corn, cowpea and sabiá [Mimosa caesalpiniifolia]) in the Brazilian semi-arid region. A database of 226 soil fertility analyses of samples from the 0.00-0.20 m soil layer, and corn, cowpea and sabiá yields from Ceará State was used to generate interpretation classes (at 80 and 95 % of maximum yield). In a scatter plot, soil nutrient concentrations (x-axis) and relative crop yields (y-axis) were correlated, and the border points fitted to a quadratic model. Proposed interpretation classes were classified as very low, low, adequate, high and very high, except for Na + , whose adequate class was considered tolerable. Generated models showed coefficients of determination (R 2 ) for the chemical properties ranging from 0.54 to 0.92. Based on the interpretation classes, the critical level was determined as 6.3 for pH, 10.8 g dm -3 for OM, 20.9 mg dm -3 for P, 81 mg dm -3 for K, 55 mmol c dm -3 for Ca 2+ , 24 mmol c dm -3 for Mg 2+ and 8 mg dm -3 for S-SO 4 2- . Interpretation classes for soils with high-activity clay in the Brazilian semi-arid region were superior to those in the reference literature. Boundary line method established fertility classes and critical levels for soil chemical properties in more than one crop, using the concept of relative yield.

Evaluation of The Initial Growth of Umbuzeiro Rootstocks

Objective: The objective of this study is to investigate the growth of umbuzeiro rootstocks after the application of rock dust and biofertilizer. Theoretical Framewor: In this topic, the main concepts that underpin the research are presented. Techniques to improve the productivity of species native to the Brazilian Semiarid region stand out, providing a solid basis for understanding the context of the investigation. Method: Spondias tuberosa Arruda fruit seeds were germinated in a seedbed and 30 days after emergence, they were transplanted into polyethylene pots. The experiment was carried out in differentiated randomized blocks, with four levels of rock dust and the presence and absence of biofertilizer, distributed in 3 blocks, evaluating the variables of plant height (AP) and stem diameter (DC). Results and Discussion: The results revealed that for AP, treatments were significant for 30 and 60 days, while for DC they were significant for 30, 120 and 150 days. In the discussion section, these results are contextualized in light of the theoretical framework. Research Implications: Practical and theoretical implications are discussed, providing insights into how the results can be applied or practical influences in the field of plant physiology. These implications could encompass the use of rock dust and biofertilizer in agriculture. Originality/Value: This study contributes to the literature on a native fruit species with economic and environmental potential, which still has gaps in knowledge about its nutritional requirements. The relevance of this research is evidenced by the increase in productivity and local social and economic development.

Maize Morphophysiological Changes Modulated by Cover Crops Rotation in Northeast Brazil

Cover crops have gained attention due to their potential benefits for the soil and physiological performance of subsequent crops. This study aimed to evaluate the physiological and productive aspects of maize grown in succession to cover crops in northeastern Brazil. A randomized complete block design with four repetitions was employed, in which the treatments consisted of the following cover crops: sunn hemp, spectabilis, pigeon pea, Brachiaria sp., jack bean, millet, and fallow. Physiological aspects and production components of maize were evaluated at the tasseling (VT) and smooth grain (R3) phenological stages. Millet cover increased carotenoid content in maize leaves by up to 78% at R3. Maize grown after pigeon pea, millet, and Brachiaria sp. showed up to 42% greater CO2 assimilation efficiency compared to jack bean. Carboxylation efficiency increased by up to 34% in maize grown after millet and Brachiaria sp., while water use efficiency improved by up to 76% in maize after sunn hemp and pigeon pea at R3. Sunn hemp, spectabilis, and jack bean reduced soil temperature by 2 °C compared to fallow. The highest maize yield was observed after jack bean, with an 8% increase over fallow. These findings demonstrate the benefits of incorporating cover crops into maize cultivation systems in the semi-arid region of Brazil.

Estimation of carbon stocks in the areas of a seasonally dry tropical forest in the Brazilian semi-arid region

In addition to its ecological importance, the Caatinga biome, one of the most extensive seasonally dry tropical forests (SDTF) in the world, has a relevant socioeconomic role as it is used as a primary natural resource by local communities. However, inadequate ecosystem management practices have resulted in gradual loss of natural vegetation in this ecosystem. Carbon stock estimation is a parameter that can contribute as a support tool for managing and maintaining the few remaining natural vegetated areas. In this study, we calibrated and validated the CENTURY model to simulate carbon stocks in areas of the Caatinga, in the state of Pernambuco, and compared the predictive capacity of the CENTURY model with available estimates. In the validation dataset, the average for biomass stocks was 33.1 Mg C ha−1, this value is close to those observed in the literature for the region. The model also performed well when estimating carbon stocks in the soil (r2 = 0.79, p = 0.017). Ecosystem modeling combined with Geographic Information Systems (GIS) is a promising tool for estimating carbon stocks in the Caatinga, where field sampling campaigns are generally expensive and have scarce research funding opportunities. Furthermore, it also allows the evaluation of the effect of environmental changes on C stocks in long-term studies, which is essential for creating and implementing public policies to mitigate and adapt to the impacts of climate change on the ecosystem. However, additional efforts are needed to improve C estimates, especially in areas with a strongly negative water balance.

Characterization of bone lesions and bone mineral density of roadkilled wild animals in the Brazilian semi-arid

Highways are one of the anthropogenic factors that have the greatest impact on terrestrial biodiversity. Barriers, depletion effects, and roads are the most common locations of wild animal roadkill, leading to biodiversity loss in wild vertebrates. However, the corpses of these animals can be used as opportunistic samples, an excellent source of information on topics such as population dynamics, which is one of the aims of road ecology. Nonetheless, there are only a few studies on injuries in roadkilled wild animals. Between 2018 and 2021, road monitoring was performed around three Federal Conservation Units in Brazil. Twenty-four animals, including birds, reptiles, and mammals, were collected. This study aims to characterize the lesions in wild animals that were roadkilled on roads in the Brazilian semi-arid region using necropsy and quantitative computed tomography (QCT). Also, the bone mineral density was measured using QCT and compared with the number of lesions and body condition score. Four types of bone lesions were found in 13 different bones, with an average of 3.25 lesions per bird and 3.75 lesions per reptile and mammal, with no statistical difference between the means (p > 0.05). Providing a database on the main injuries found in wild animals that are frequently roadkilled serves as an aid to wildlife rescue and rehabilitation professionals who contribute to the conservation of species. In addition, the data on road ecology serves as a basis for the implementation of mitigation measures against wildlife roadkills, also contributing to the conservation of species.

Correction: Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Correction: Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Changes in Soil C, N, and P Concentrations and Stocks after Caatinga Natural Regeneration of Degraded Pasture Areas in the Brazilian Semiarid Region

Changes in Soil C, N, and P Concentrations and Stocks after Caatinga Natural Regeneration of Degraded Pasture Areas in the Brazilian Semiarid Region

Leptospirosis seroprevalence and associated risk factors in dairy goats in the Brazilian semi-arid region

Leptospira spp. infection is a worldwide zoonosis that causes economic losses to goat rearing, mainly due to reproductive disorders. Hence, the objective of this research was to determine the seroprevalence and associated risk factors of leptospirosis in a goat milk-producing region in the states of Paraiba and Pernambuco, Northeast Brazil. The microscopic agglutination test was used as serological method and risk factor analysis was carried out using univariable and multivariable analyses. Out of the 937 animals sampled, 102 (10.9 %; 95 % CI = 8.9–12.9 %) were seropositive for Leptospira spp. and the most frequent serogroups were Ballum (41.2 %; 95 % CI = 31.6–50.7 %), Icterohaemorrhagiae (25.5 %, 95 % CI = 17–33.9 %) and Semaranga (23.5 %, 95 % CI = 15.3–31.8 %), with antibody titres ranging from 1:50 to 1:200. Thirty-four of 51 herds (66.7 %; 95 % CI = 53.7–79.6 %) had at least one seropositive animal. The risk factor identified in the multivariable two-level random effect binary logistic regression was the animal being an adult (odds ratio = 4.2; 95 % CI = 1.93–9.13; P < 0.001). Our results provide important information on the epidemiology and risk factors associated with goat leptospirosis seroprevalence in one of the main Brazilian goat milk-producing regions. Furthermore, the need for adopting sanitary control measures, especially those involving sanitary management practices, is highlighted.

Potential In Vitro Antimelanoma Effect of the Essential Oil from Croton grewioides Baill.

Cancer is a group of diseases characterized by uncontrolled cell growth, invasive capacity, and metastatic potential. Despite the continual progress in cancer treatment, high toxicity and resistance to therapy remain recurring challenges. Croton grewioides Baill. is a plant from the brazilian semi-arid region with significant pharmacological potential due to its reported antidiarrheal, antioxidant, and antitumor properties. This study evaluated the antitumor activity of the essential oil from C. grewioides leaves (CgEO) by in vitro assays. CgEO showed higher cytotoxicity in human melanoma cells (SK-MEL-28), with a 50% inhibitory concentration (IC50) of 70.0 μg/mL after 72 hours, but with low toxicity in healthy keratinocytes (HaCaT). Additionally, it was suggested that the antitumor effect of CgEO is associated with the induction of apoptosis, cell cycle alterations, and combined antioxidant action mechanisms. In conclusion, CgEO exhibits antitumor activity with lower toxicity in non-tumor cells.

“Tecnologias Sociais” and The Northeast Brazilian Semi-Arid: A Study on the Cisterns Program

Purpose: To analyze the role of the Cisterns Program as a generator of “tecnologias sociais” in the Northeast Brazilian Semi-Arid. Theoretical framework: Characteristics, mechanisms and requirements of “Tecnologia Social”. Design/methodology/approach: Instrumental single case study in the Cisterns Program, using interviews and document analysis for data collection. Categorical content analysis to evidence analysis. Findings: The results show that the “tecnologias sociais” designed by the Cisterns Program have positive impacts beyond access to potable water. These include, among others, mitigation of desertification and articulation and mobilization between communities. Such findings corroborate the understanding that the Cisterns Program as a “supplier” of “tecnologias sociais” and its relevance to the advancement of the regions where it operates, mainly in the northeastern Brazilian semi-arid region. Originality: This study deepens analyzes of the component elements of "tecnologia social", ways of acting by the groups involved and social implications (results), aspects with little discussion in the literature on the subject. Theoretical and practical contributions: The study summarizes the forms of action, the groups involved, the mechanisms, the bottlenecks in the process, and the impacts related to social technologies in a set of elements that can serve as a guide for the implementation of social technologies in other places. It also identifies mechanisms for creating/strengthening actions and public policy to scale up, disseminate, and optimize these technologies. Keywords: “Tecnologia Social”. Cisterns Program. Northeast Brazilian semi-arid.

Soil Classification Based on Local and Scientific Knowledge in an Irrigated District in the Semi-Arid Region of Brazil

Soil Classification Based on Local and Scientific Knowledge in an Irrigated District in the Semi-Arid Region of Brazil

Soil and vegetation types are predisposition factors controlling greenness changes: A shift of paradigm in greening and browning modelling?

Increases (greening) and losses (browning) of vegetation greenness related to climatic and anthropic changes are processes well documented in the literature. However, the control exerted by predisposition factors on the response of vegetation to these changes has been little studied, and appears to be especially important in anthropized regions. The present study aimed to map greening and browning processes, as well as to characterize and analyze their distribution in heavily anthropized regions regarding two main predisposition factors: soil and vegetation types. The Brazilian Semiarid region was used as a model area, using two novel approaches: a readily reproducible cloud computing approach to map consistent greening and browning processes, and a disaggregation approach in homogeneous units of vegetation, soil and land use types. The results showed that stable greenness dominates (66.8%), but browning is more frequent (29.1%) and intense than greening (4.1%), and may be related to desertification processes in native and anthropized areas. The distribution of greening and browning processes is zonal and heterogeneous. Environmental predisposition factors, mainly the water supply capacity, regionally control the distribution of greening and browning zones. Human-environment interplays locally regulate the intensity and distribution of the processes. We defend the need of a paradigm shift in greening and browning modelling. Further studies should consider the simultaneous and balanced use of predictors related to both predisposition and changes. The need for advances in the interpretability of these models is also evident, given that current approaches fail to elucidate the regulating mechanisms of greening and browning processes.

Occurrence of coccidioidomycosis in a tertiary hospital in the Brazilian semi-arid region: diagnostic challenges

Occurrence of coccidioidomycosis in a tertiary hospital in the Brazilian semi-arid region: diagnostic challenges

Wet creatures in a warming world: How climate change will impact the future distribution of anuran amphibians from Brazilian semiarid region?

The world has been going through a climate crisis that has led to a substantial increase in global temperatures. Consequently, amphibians, ectothermic animals that depend on water to survive/reproduce, are under increasing threat. In this research, we compared the influence of climate change on the geographic distribution between anuran species with occurrence restricted to the Brazilian semi-arid region (Caatinga domain) and widely distributed congeneric species, with occurrence in multiple biomes. We hypothesized that climate change would be more harmful for species of restricted distribution than for those widely distributed. For this purpose, using ecological niche modeling, we designed potential distribution models for current and four future climate scenarios, and compared two metrics (climatic suitability and index of extent of occurrence) between restricted and widely distributed species. The results revealed that the climatic suitability did not differ among current climatic conditions and those expected for 2050 and 2090, nor differed between species with distribution restricted to the Caatinga and widely distributed ones. On the other hand, contrary to our predictions, while species with wide distributions would tend to retract their extent of occurrence in future times, species with restricted distributions would expand their ranges. These results suggest that species with current distribution restricted to Caatinga biome might be relatively favored by the climate changes predicted for the next 80 years. However, we discuss that this result should be interpreted with very caution, because many ecological and conservation requirements need to be guaranteed so that these predictions can actually occur. Our findings contributed to the understanding of the effects of climate change on closely related taxa, with different distribution patterns, revealing particularities of the anuran amphibians that occur in semi-arid environments in response to climate changes predicted for this century.

Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

What do frog calls tell us about males? The advertisement call of Physalaemus albifrons (Amphibia: Leptodactylidae) in the Brazilian semiarid region does not reflect either gonadal investment or energy storage

ABSTRACT Anuran advertisement calls can provide accurate information on the reproductive quality of the male callers, thus providing females with indicators for the selection of mates. Body size is generally correlated with the dominant frequency of male advertisement calls. However, it is unclear whether and to what extent call parameters are associated with gonadal investment and the energy reserves of the males. Given that in tropical seasonally dry environments the wet season is very short, gathering information about gonadal investment and energy reserves of mates should be particularly important. In the present study, we evaluated the relationship between acoustic performance, gonadal condition, and fat storage in the Neotropical frog Physalaemus albifrons from the Brazilian semiarid region, testing the hypothesis that the advertisement call (repetition rate, call duration, and fundamental and dominant frequencies) would be a good predictor of male quality in terms of gonadal investment (testicle length) and energy reserves (mass of fat bodies). Contrary to our predictions, neither testicle length nor the mass of fat bodies was related to any of the acoustic parameters of the advertisement calls of P. albifrons. These results indicate that the advertisement call of P. albifrons does not provide reliable information on gonadal investment or energy storage of males. Possibly, in habitats with little and unpredictable rainfall, males of P. albifrons should present small variation in gonadal and fat storage conditions during its short reproductive window. Our findings contribute to the understanding of anuran reproductive strategies in seasonally dry environments.

Selecting Bacillus strains antagonist to Erysiphe necator (Schw.) Burr. the causal agent of grape powdery mildew

ABSTRACT Grape powdery mildew (GPM) control is based on the preventive use of sulfur and curative application of synthetic fungicides, increasing the risk for producers’ health and environmental and fruit contamination. This work aimed to select Bacillus strains isolated from the Brazilian tropical semi-arid region that are effective antagonists to GPM. In an initial screening performed by spraying bacterial suspensions in detached grape leaves, six strains of Bacillus spp. showed disease symptom reduction higher than 70.0%. Two greenhouse experiments showed that the bacterial strains LCB03, LCB28, and LCB30 showed control efficiency >80%, statistically similar to a commercial formulation with Bacillus amyloliquefaciens QST713. 16s rDNA sequencing showed that strain LCB03 showed 100.0% homology to B. velezensis, while LCB28 has high homology to B. tequillensis (99.93%), and LCB30 had 99.71% homology with B. siamensis. As an average for both greenhouse experiments, weekly application of Bacillus sp LCB03, Bacillus sp LCB28, and Bacillus sp. LCB30 reduced the average incidence by around 50% and more than 80% for GPM severity.