Semiarid Region Of Northeastern Brazil Research Articles

Dynamics of natural infection by Toxoplasma gondii in goat herds in the semiarid region of northeastern Brazil: transitional antibody observation.

This study aimed to describe the transmission of T. gondii in naturally infected goats in the semiarid region of northeastern Brazil, through evaluating the serological status of these animals from one to 12 months of age. Seven goat farms were selected. During the first visit, an epidemiological questionnaire was applied. Blood samples were collected from pregnant goats and from their female offspring every month, to monitor them for anti-T. gondii antibodies, using the indirect fluorescence antibody test (IFAT). Out of 66 pregnant goats evaluated, 47% (31/66) (95% CI: 34.6% - 59.7%) were positive and out of 93 female offspring, 61.3% (57/93) (95% CI: 52.4% - 69.2%) were positive, in at least one month during the evaluation period. Among the positive female offspring, 43.3% (27/57) (95% CI: 39.7% - 56.9%) presented environmental infection and 56.7% (30/57) (95% CI: 43.4% - 66.3 %) probably had only colostral antibodies or vertical transmission. It was observed that 92,6% (25/27) from environmental infections occurred until reproductive age (six months) (p<0.0001). It was also noted that there is a correlation between the titration of mothers and offspring, until four months of age (p<0.0001). Large fluctuations in the presence of antibodies were observed among the animals over the months monitored. It can be concluded that the prevalence of anti-T. gondii antibodies within the herds was greater than what has been expressed in specific prevalence studies and that most goat become infected up to the six months of life in the studied area.

Seasonal variation in population structure and sexual maturity of Sylviocarcinus pictus (Decapoda: Trichodactylidae) in a Neotropical intermittent river

Sylviocarcinus pictus is a South American freshwater crab recently recorded for the first time in the Caatinga biome. Our objective was to characterize the population and reproductive biology of S. pictus from the semi-arid northeastern region of Brazil and verify the influence of seasonal environmental changes in this population. The crabs were collected from a stretch of Guaribas River, PI, Brazil, every month between October 2013 and September 2014. The crabs were identified, sexed and the carapace width (CW) was measured. Physiological sexual maturity was determined based on the gonadal development stage. A total of 178 crabs were obtained (111 males and 67 females), with a sex ratio biased towards males 1.66:1. The number of crabs collected was higher in the months of drought. Males and females reach physiological sexual maturity with 36.80 and 34.20 mm of CW, respectively. The occurrence of individuals with developed or developing gonads throughout the study indicates that these crabs reproduce continuously during the year, although recruitment was higher in February and May. Our results indicate that this population uses a reproductive strategy to optimize its reproductive fitness in an intermittent environment.

Effect of Droughts on Crime: Evidence from a Semi-Arid Region of Northeastern Brazil

Effect of Droughts on Crime: Evidence from a Semi-Arid Region of Northeastern Brazil

Clinical and toxicological findings in nitrate and nitrite poisoning in cattle in Northeastern Brazil

ABSTRACT: We report two outbreaks of nitrate and nitrite poisoning in Paraíba, Northeast Brazil. The first, due to Pennisetum purpureum (elephant grass), and the second, due to P. purpureum and Brachiaria spp. (brachiaria grass), both occurred during a prolonged drought. In the first outbreak, the irrigation of the pastures with wastewater and sewage contributed to nitrate accumulation. The second outbreak occurred in pastures cultivated in the border of a dam, that had been submerged for long time accumulating large amounts of organic matter in the soil. Other probably risk factors for nitrate accumulation included the use of chemical fertilizers and herbicides and burning of the vegetation. In the first outbreak, four calves out of a total of 42 cattle died, and in the second outbreak 49 out of 243 cattle, including adults, yearlings, and a 2-day-old calf died. The clinical signs included dyspnea, cyanosis, ataxia, and falls, leading to death. The presence of nitrates was detected in both outbreaks using the diphenylamine test. Quantitative tests were performed in the second outbreak using a portable nitrate meter, and high nitrate concentrations were found. The characteristic macroscopic findings and absence of microscopic lesions and response to treatment with methylene blue were key to the diagnosis of poisoning by nitrates and nitrites. We conclude that poisoning by nitrates and nitrites in ruminants in the semiarid region of Northeastern Brazil is frequent due to the cultivation of grasses in the border of dams that had been covered by water for long periods or in areas irrigated by wastewater and/or sewage. In addition, the use of a portable measuring device is an effective alternative for the quantification of nitrates in pastures.

Gas exchange and yellow passion fruit production under irrigation strategies using brackish water and potassium

The occurrence of water sources with high concentrations of salts is a common problem in the semi-arid region of north-eastern Brazil. The search for management strategies that can minimize the effect of salt stress on crops is therefore extremely important. As such, this study aimed to evaluate gas exchange and production in the yellow passion fruit ‘BRS GA1’as a function of irrigation strategies using brackish water and doses of potassium. The research was carried out under field conditions in Sao Domingos, in the state of Paraiba, Brazil, using a randomized block design in a 6 × 2 factorial scheme, with treatments comprising six irrigation strategies using water (irrigation with low-salinity water throughout the cycle – WS; irrigation with high-salinity water during the vegetative stage – VE; during the flowering stage – FL; the fruiting stage – FR; during successive vegetative/flowering stages - VE/FL; successive vegetative/fruiting stages - VE/FR) and two doses of potassium (60% and 100% of the recommended dose of 345 g K 2 O per plant per year), with four replications and three plants per plot. Two levels of water salinity (1.3 and 4.0 dS m -1 ) were used during different phenological stages of the crop. Irrigation with water at 4.0 dS m -1 reduced the leaf water potential, leaf osmotic potential, stomatal conductance, transpiration, and rate of CO 2 assimilation of the yellow passion fruit, regardless of the irrigation strategy. The continuous salt stress during the vegetative and flowering stages compromised production in the yellow passion fruit.

Hiponatremia em ovinos no Nordeste do Brasil

ABSTRACT: Mineral deficiencies are important causes of productive losses in ruminant farming, especially in semiarid regions. This study aimed to determine Na, K, and Cl serum concentrations, plus the salivary concentrations of Na and K in sheep raised in a semiarid region of Northeastern Brazil, and to report the epidemiology, clinical and the pathological aspects of an outbreak of hyponatremia in sheep. For this, serum and salivary samples of 55 sheep were collected in 6 different farms in the region. Na, K, and Cl concentrations were determined by colorimetric test, using commercial kits in a semi-automatic biochemical analyzer. The mean serum concentrations ranged from 131.5±13.1mEq/L to 172.4±9.3mEq/L for Na, 6.28±1.3mEq/L to 13.9±1.4mEq/L for K, and 91.6±54.8mEq/L to 113.6±1.5mEq/L for Cl. The mean salivary concentrations ranged from 119.4±9.5mEq/L to 161.8±15.2mEq/L for Na, 10.1±3.1mEq/L to 22.3±2.3mEq/L for K, and the ratio Na:K ranged from 6.0±1.3mEq/L to 11.8±4.1mEq/L. These results revealed that most sheep raised in the farms in this region are marginally depleted in sodium. In one farm, sheep had severe clinical signs of Na deficiency consisting of haggard appearance, craving for salt, polydipsia, polyuria, dry cough, inappetence, pica, weakness, difficulty to rise and move, severe emaciation, and dehydration. On autopsy, the ruminal content was generally impacted, giving to the content an aspect of clay balls. Four sheep presented hypertrophy of the adrenal glands. Histopathologically, the width of the zona glomerulosa was expanded, there was loss of the architecture and loss of adrenocortical cell cords. The epithelial cells in the zona glomerulosa and fasciculata were pyramidal, and contained hypereosinophilic cytoplasm and hyperchromatic nuclei. These data demonstrate the occurrence of Na deficiency in different degrees in sheep farms in the State of Pernambuco and highlight the importance of providing NaCl to avoid outbreaks of hyponatremia.

Suscetibilidade de caprinos à intoxicação por Tephrosia cinerea

ABSTRACT: Spontaneous and experimental poisoning by Tephrosia cinerea in the northeastern semiarid region of Brazil has only been described in sheep. Pathologically, such poisoning leads to ascites and centrilobular liver fibrosis. However, these effects require an experimental study in goats. This study aimed to determine the goats’ susceptibility to the ingestion of T. cinerea and the minimum toxic dose, describing the main clinical and anatomopathological findings. Poisoning was reproduced experimentally in one sheep that received 10g/kg of the ground plant and in two goats, the first receiving a dose of 5g/kg and the second receiving 10g/kg of the ground plant. The sheep presented abdominal distension 34 days after beginning the ingestion of the plant, developing sternal decubitus, breathing difficulty, opisthotonos, mandibular trismus, salivation, dysphagia, vocalization, and pedaling movements on the 50th day of the experiment. Fluid accumulation was observed in the abdominal cavity and liver via necropsy, with an irregular, slightly whitish capsular surface. Histologically, the main lesions observed in the liver were moderate fibrosis, marked sinusoidal distension, accompanied by marked hemorrhage, sometimes forming bridges between the centrilobular regions, associated with a dissociation of hepatocyte cords. There were discrete Alzheimer’s type II astrocytes in the gray matter in the region of the occipital cortex in the nervous system. Goat 2 showed apathy, drowsiness, and weight loss; on the 62th day, lateral decubitus evolved to sternal decubitus, with a rotation of the neck towards the flank. At necropsy, marked edema was observed on the face and dewlap, and a slight accumulation of liquid; slightly yellowish material was observed in the abdominal cavity. There were discrete blackened areas on the capsular surface in the liver. Histologically, the liver showed mild centrilobular fibrosis associated with mild dissociation of hepatocyte cords and mild vacuolar degeneration of the hepatocyte cytoplasm. Goat 1 showed no clinical signs; at necropsy, discrete multifocal areas were observed in the liver on the capsular surface. Histologically, diffuse intracytoplasmic vacuolar degeneration of hepatocytes was detected. The clinical picture and anatomopathological findings differ between the species, proving the lower susceptibility of goats to Tephrosia cinerea ingestion (compared to sheep), with differences in the pathogenesis and epidemiological aspects of poisoning.

Hunting, capture, and wildlife use by communities in a semi-arid region of Northeastern Brazil

ABSTRACT Human beings have established interactions with animals for all of human history, using their products in various ways and passing on this knowledge from one generation to the next. Hunting is one of the oldest interactions. We analyzed aspects and motivations associated with hunting and capture activities in northeastern Brazil. Hunters mentioned 44 species of wild animals that are hunted and/or captured in the municipality, especially birds followed by mammals and reptiles. Of this total, 38 species were present in the lists of threatened species. The main motivation for hunting was food. The results of our study reflect the cultural and socioeconomic importance of hunting and capture activities for traditional communities and also the pressure that these practices can represent for populations of wild animals. This highlights the need for further studies accompanying the development of strategies for the conservation and sustainable use of local fauna.

Soil and crop spatial variability in maize irrigated with domestic effluent

Wastewater use in agriculture is a high-potential alternative for coping with water scarcity. The present study aimed to evaluate the impact of using wastewater and sewage sludge on soil attributes in an irrigated maize plantation in the Brazilian northeastern semi-arid region, at an experimental reuse unit. Two experimental plots were installed with the following treatments: wastewater and sludge, and irrigation with wastewater only. The presence of sludge reduced the salt content and promoted an increase in the soil organic matter content, reducing the salinization risk. Biometric parameters showed no spatial dependence. On the other hand, soil moisture, electrical conductivity, sand content, clay content and sodium and potassium contents showed strong spatial dependence for the treatment with sludge application.

Role of integrated crop-livestock system on amelioration of heat stress on crossbred Brazilian sheep in semiarid region of northeastern Brazil

• Physiological parameters were lower in the animals under ICL system. • ICL did not promote heat stress in the morning. • The presence of trees in the ICL system promoted thermal comfort to the animals. • Greater sheep ability to dissipate the heat under ICL. • Sustainable sheep production. The aim of this study was to evaluate the effect of livestock rearing system, sheepfold vs . integrated crop-livestock system, on heat tolerance and physiological traits of crossbred sheep (Santa Ines x Dorper) in the semiarid region of Brazilian Northeastern. Forty crossbred hair ewes (Santa Ines x Dorper), 15–48 months old, were assigned to two treatments: 20 in treatment I (SF – Sheepfold) and 20 in treatment II (ICL - integrated crop-livestock system with tall coconut palm trees). Physiological and environmental evaluations were conducted on 21 consecutive days. Respiratory rate (RR), rectal temperature (RT) and heart rate (HR) were recorded at 06:00 am and 05:00 pm, while air temperature and relative humidity were recorded from 06:00 am to 05:00 pm. Temperature and Humidity Index (THI) in the SF and ILC indicated severe stress for sheep regardless of the period of the day, and although THI in integrated crop-livestock system was 1% lower than in the sheepfold, there was no statistical differences between the treatments. Ewes from integrated crop-livestock system had lower RR and HR than sheepfold ewes at 06:00 am and 05:00 pm. The afternoon period led the animals to more dangerous situation of thermal stress condition in both treatments, however we suggest that the presence of trees in the ICL system promoted an amelioration of heat stress on grazing ewes.

Cross-sectional survey for sheep leptospirosis in the northeast region of Brazil

Sheep farming has shown expressive growth, even in the Northeast region of Brazil, with rainfall below expectations in the last decade. This growth has been observed not only in the number of herds, but also in the number of properties involved in sheep farming. Although expressive, the production of small ruminants still presents low levels of performance, mainly due to the occurrence of diseases, which constitute an obstacle to this activity. The aim of this study was to determine the factors associated with the seroprevalence of leptospirosis in sheep in Northeastern Brazil. Blood samples were collected from 3438 sheep in 190 herds from 48 municipalities, belonging to the states of Ceará, Paraíba, Piauí, Rio Grande do Norte and Sergipe. Serological diagnosis was performed using the microscopic agglutination test (MAT). In 76.3 % (95 % CI = 69.79–81.81) of the herds there was at least one animal seropositive for at least one of the Leptospira spp. serogroups and 14.94 % (95 %CI = 13.8–16.18) of the animals were seropositive. The state of Paraíba had the highest herd (95.7 %) and animal (26.6 %) prevalences, followed by Ceará (93.9 % and 23.7 %, respectively). The most frequent serogroups were Autumnalis (18.68 %), Australis (17.9 %) and Pyrogenes (15.18 %). There was no association between the studied variables and the herd-level prevalence of leptospirosis. High herd and animal-level seroprevalences was found for sheep leptospirosis in the semiarid region of Northeastern Brazil, and there is a need to implement control and prevention measures, such as quarantine, serology, vaccination and adequate treatment, in addition to the introduction of proven healthy animals, mainly in the states of Paraíba and Ceará, aiming to reduce the prevalence of disease.

Impacto econômico e aspectos epidemiológicos da mastite e artrite encefalite caprina na região semiárida do Nordeste Brasileiro

Dairy activity in the semi-arid region has gained prominence due to its profit potential; however, there are still sanitary problems that result in significant economic impact. Thus, this study aimed to assess the economic impact and to conduct an epidemiological study of caprine arthritis-encephalitis (CAE) and subclinical mastitis in dairy goat herds of the semi-arid northeastern region of Brazil. The study proceeded with the collection of blood (n = 351) and milk samples (n = 321) from 15 rural properties with up to 50 animals, risk factor assessment, economic profile analysis, and georeferencing of the properties. The blood serum obtained was subjected to the AGID test. The milk samples were cultured on blood agar, and the reading was performed 24 hours after incubation. Overall, 3.4% of the animals were seropositive for CAE, and 15.8% were diagnosed with subclinical mastitis. 71.95% of the positive animals belonged to properties with a semi-intensive rearing system, weekly cleaning of the facilities, and no pre- or post-dipping. Subclinical mastitis caused by the main agent Staphylococcus spp. was associated with the breed type of the animals, highlighting two risk factors: purebred animals (OR = 12.52) and the milking performed close the soil (OR = 18.07). A reduction of up to 35.34% was observed in the income of dairy properties, constituting a considerable economic impact. Due to these sanitary problems, the economic impact demonstrates the need for a sanitary management program focused on these infirmities.

Principal component analysis and biophysical parameters in the assessment of soil salinity in the irrigated perimeter of Bahia, Brazil

Soil salinity is an environmental concern which can lead to land desertification. It is a common problem in the semiarid region of northeastern Brazil and its impacts extend from the environment to the economy. The objective of this study was to evaluate soil salinity in the dry period in an agricultural area of irrigated Maniçoba perimeter, in Juazeiro, State of Bahia, Brazil. The study was carried out in an agricultural area of the irrigated perimeter in Juazeiro of Bahia, Brazil, where 98 disturbed soil samples were collected in different areas, being 33 samples to obtain Electrical Conductivity (EC) (dS m−1) and regression models, and 65 samples to validate the models. Images from the Landsat-8 and Sentinel-2 satellites were used to obtain the biophysical parameters: NDVI, SAVI, EVI, and GDVI vegetation indices, SI-1, SI-2, SI-3, and IB salinity indices, albedo, temperature (TSUP), and real evapotranspiration (ETR). Descriptive statistics and principal component analysis (PCA) were applied to identify majors EC and biophysical parameters relationships, and select the best predictors to generate equations capable of estimating soil salinity across the irrigated perimeter. The EC showed a high standard deviation and coefficient of variation compared to the other variables, with higher concentrations observed in areas of bare soil, followed by natural vegetation and agricultural vegetation. TSUP and GDVI were the predictors most strongly related to EC, for images Landsat-8 and Sentinel-2 respectively, with R2 of 73% and 71%. The application of the generated models presented satisfactory validation for two distinct areas. The maps obtained were similar in terms of the distribution of soil saline levels, confirming what was observed in the field scale, with a greater level of detail for the map from Sentinel-2.

Bradyrhizobium brasilense as an efficient soybean microsymbiont in two contrasting soils of the southwestern region of Piauí (Cerrado biome)

The goal of this study was to evaluate the efficiency of Bradyrhizobium brasilense strains native to the soil of the semiarid region in northeastern Brazil in symbiosis with soybeans in two contrasting soils in southwestern Piauí. A pot experiment was conducted using a randomized block design in a 10 × 2 factorial scheme. There were 10 nitrogen (N) sources: six native Bradyrhizobium strains [UFLA06-13, UFLA06-15, UFLA06-19, UFLA06-21, UFLA06-22 (B. brasilense), and UFLA06-24 (Bradyrhizobium sp.)], two controls with strain SEMIA 5019 (B. elkanii) and a commercial inoculant [SEMIA 5079 (B. japonicum) + SEMIA 5080 (B. diazoefficiens)] recommended for soybeans, and two controls without the application of an inoculant (one with and the other without the application of mineral N). The second experimental factor corresponded to the use of two soils (Oxisol and Quartzarenic Neosol). All strains showed increased nodulation and shoot nitrogen content in soybean plants in both soils. Most strains promoted higher nitrogen fixation when inoculated in the Oxisol. UFLA06-19, UFLA06-22, and UFLA06-24 were efficient in nitrogen accumulation in the shoots of soybeans in the Oxisol. This is the first report regarding the efficiency of B. brasilense strains in symbiosis with soybeans under different soil conditions.

Evaluation of maternal-filial stress in a dairy goat herd with small ruminant lentivirus infection in the Brazilian northeastern semiarid region

The objective of this study was to evaluate maternal-filial stress and maternal ability in a herd positive for small ruminant lentivirus (SRLV), submitted to a control program for this disease, in the Northeastern semi-arid region, through ethological analysis and quantification of cortisol in the blood plasma and the hair coat. After the parturitions, 4 subgroups were formed according to the order of birth (primiparous or pluriparous) and to natural or artificial suckling: primiparous goats with natural suckling (PriN), primiparous goats with artificial suckling (PriA), pluriparous goats with natural suckling (PluN) and pluriparous goats with artificial suckling (PluA). The attentive posture was higher in goats from the PriA group (30.6%) compared to PriN (15.9%) and PluA (13.7%). The matrices of the PriN group showed lesser positioning behavior when compared to the PluN, (17.8%, 31.6%, respectively) (P ≤ 0.05). As for the behavior of the kids, there was a difference (P ≤ 0.01) for the vocalization parameter between those separated from pluriparous mothers (60.48%) and those kept with the mother (8.54%). The same occurred with the kids of the primiparous mothers (43.20%; 6.99%), for those separated and those kept with their mothers, respectively. The separated kids of pluriparous mothers had a higher record for attempted escape (P ≤ 0.05), attentive posture (P ≤ 0.01), and restlessness (P ≤ 0.01), concerning those kept with their mothers. Primiparous kids were more restless (P ≤ 0.01) and attentive (P ≤ 0.01). The plasma cortisol and hair values did not differ (P > 0.05), except at parturition. It is concluded that the postpartum separation exerts higher levels of stress in the kids, that mothers already have a level of stress related to external factors, and that the postpartum separation does not interfere in the maternal ability of the mothers in subsequent births.

Morphophysiological responses of table beet irrigated with saline water under application of humic substances

The use of saline water is an alternative for irrigating agricultural crops, especially in the Brazilian Northeastern semi-arid region, where water quality is limited in most cases. Thus, the objective was to evaluate the morphophysiological responses of table beet cv. “Wonder” irrigated with saline waters under the application of humic substances. The experiment was conducted under a randomized block design, with six replications in a 6 x 4 x 5 factorial scheme, referring to six electrical conductivities of irrigation water (ECw): 0.5; 1.5; 2.5; 3.5; 4.5 and 5.5 dS m-¹, four humic substances rates (HS) (0; 10; 20 and 30 ml per plant), and five stages of assessment (23, 38, 53, 68 and 83 days after emergency). The characteristics evaluated were: plant height, number of leaves, leaf area, chlorophyll content (a, b and total), stomatal conductance, transpiration, net photosynthesis and CO2 internal concentration, and in the soil, the soil pH and the electrical conductivity of saturated paste extract. The increase of salinity reduced growth, chlorophyll a content, and the stomatal conductance of beet plants. The application rate of 30 ml per plant of humic substances promotes an increase in stomatal conductance. The application of humic substances raises the pH in sandy acidic soils. It is recommended to irrigate table beet plants with water of 0.5 dS m-1 associated with the application of 30 mL per plant of humic substances

Economic nitrogen doses via fertigation for corn cultivation in a semiarid environment

Producers in the northeastern semiarid region of Brazil have been cultivating irrigated corn. The commercialized product comprises mainly green ears and silage. However, the irrigation of crops for dry grain has been questioned regarding costs and price competitiveness in relation to the same non-irrigated product cultivated in other regions. In recent years, the use of drip tapes and fertigation has spread among corn producers in the region. The aim of this study was to determine the N dose, via fertigation, which provides the maximum economic production of corn for dry grain, in two crop seasons (summer and winter), in the semiarid region of Brazil. The experimental design was performed in randomized blocks, with four replications. In both crops, the treatments consisted of four doses of N (0, 80, 160, and 240 kg ha-1) applied in the form of urea. In the hybrid corn (Bt Feroz), the N content was evaluated in terms of leaves, grain yield, gross and net incomes, the rate of return, and the profitability index. Independent of the crop season, the yield of dry grain (5,441.03 kg ha-1) was highest when the corn was fertigated with a dose of 104.05 kg ha-1 N. The highest net incomes of the dry grain were obtained with 80 kg ha-1 N in summer (R$ 1,190.78 ha-1) and 160 kg ha-1 N in winter (R$ 2,757.54 ha-1). The winter crop was more favorable to the economic production of dry grain.

Modeling of the Hydrological Processes in Caatinga and Pasture Areas in the Brazilian Semi-Arid

The semi-arid regions of northeastern Brazil have historically suffered from water shortage. In this context, monitoring and modeling the soil moisture’s dynamics with hydrological models in natural (Caatinga) and degraded (Pasture) regions is of fundamental importance to understand the dynamics of hydrological processes. Therefore, this work aims to evaluate the hydraulic parameters in Caatinga and Pasture areas using the Hydrus-1D inverse method. Thus, five soil hydraulic models present in Hydrus-1D were used, allowing the comparison of the single-porosity model with more complex models, which consider the dual porosity and the hysteresis of the porous medium. The hydraulic models showed better adjustments in the Caatinga area (RMSE = 0.01–0.02, R2 = 0.61–0.97) than in the Pasture area (RMSE = 0.01–0.03, R2 = 0.61–0.90). Regarding the hydraulic parameters, for all models, the Pasture showed smaller saturated hydraulic conductivity and water content values of the mobile region than the Caatinga. This fact demonstrates the negative impact of compaction and change in natural vegetation in the Brazilian semi-arid. The dual-porosity model presented the best fit to the data measured in the Pasture area. However, a single-porosity model could be considered representative of the Caatinga area. The results showed that Caatinga areas contribute to maintaining soil moisture and increasing the water storage in semi-arid regions.

Long-term effects of irrigated agriculture on Luvisol pedogenesis in semi-arid region, northeastern Brazil

Long-term irrigation in semi-arid regions leads to shifts in the soil moisture regime, affecting soil attributes and pedogenesis. Drylands are expected to increase worldwide, possibly because of climate change. Few studies have investigated changes in the pedogenic processes due to extensive irrigation in the Brazilian semi-arid region. This study assesses the effects of land use changes (irrigation and cultivation) on the morphological, physical, chemical, and mineralogical properties of soils. We evaluated two soil profiles in the semi-arid region in northeastern Brazil. We investigated an irrigated profile (IP) with long-term irrigation (26 years) and cultivation, and another profile under natural conditions (rain-fed hyperxerophilic Caatinga), that is, a non-irrigated profile (N-IP). The results indicate that land use affected chemical and mineralogical attributes of soils as well as the pedogenetic processes. Both soil profiles showed different behaviors in relation to salts: (1) reduction in soil exchangeable Na content (solodization) in IP, and (2) accumulation of soluble salts (salinization) and increased soil exchangeable Na content (solonization) in N-IP. Land use, possibly irrigation, induced mineralogical alteration pathways, such as the progressive mineral transformations via R0 MLM (mixed-layered minerals), suggesting differences in weathering and mineral evolution. The K-I (kaolinite-illite) and I-V (illite-vermiculite) phases predominated in the clay fraction in both soils and exhibited a greater trend for progressive kaolinization in IP. The other two MLMs (kaolinite-vermiculite, K-V and illite-smectite, I-S) were detected in N-IP and could be a proxy for the lowest weathering degree. This is consistent with the trend for a slight reduction in the SiO2/Al2O3 molecular ratio in IP. Illite was possibly the precursor mineral for other phyllosilicates, such as kaolinite, in IP. Fe-enriched MLM was detected in the decreasing sequence: illite, smectite, and kaolinite layers. The pedogenic trends observed, such as mineral weathering, may be attributed to system response to climate change.

Public policies on water resources for the brazilian northeastern semiarid region

ABSTRACT&#x0D; Objective: The present study has as main objective to identify the strategies taken by the municipal managers to adapt to the periods of greatest water difficulties in the northeastern semiarid, more specifically in the city of Doutor Severiano-RN, showing the importance of the development of these strategies in the region. Methodology / Approach: Research were made on the subject to identify which strategies were developed in the municipality, in addition, some field observations were made to identify the municipal public policies developed over the years. Conclusions: It is concluded with this study that it is essential to know the place and seek the best strategy to develop and apply these policies based on the characteristics of each region, considering the importance that they have for the social and economic development of the semiarid populations. Research limitations: The sample was extracted from works that addressed the topic in question, thus making the parallel of discourse between theory and practice. Originality / Value of the article: The study presents the strategies developed in the city of Doutor Severiano, to adapt to the periods of greatest water difficulties in the region, according to the climatic conditions of the place.