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ABSTRACT Exposing seeds to agents that elicit tolerance to abiotic stress, such as phytohormones and organic acids, during hydration and dehydration cycles can determine their response to later stimuli, e.g. exposure to salt stress. The aim of this study was to evaluate the action of priming cycles with different eliciting agents of salt stress tolerance on seeds of the cowpea varieties Sempre Verde and Pingo de Ouro. The seeds were subjected to the following treatments: 0.0 mM NaCl (control); 100 mM NaCl (salt stress); salt stress + three seed-priming cycles (PC) in water; salt stress + PC in gibberellic acid; salt stress + PC in hydrogen peroxide; salt stress + PC in salicylic acid; salt stress + PC in ascorbic acid. The following variables were analysed: germination, growth, dry weight, salt tolerance index, total soluble sugars, total free amino acids and proline. Salt stress (100 mM NaCl) reduced germination, length and biomass accumulation in the Sempre Verde and Pingo de Ouro varieties. These showed the best response to the priming cycles with gibberellic and salicylic acids, which promoted greater germination potential, length and biomass under a salt stress of 100 mM NaCl, affording greater tolerance via osmotic regulation, especially in the Sempre Verde variety.

Freshwater depletion becomes a significant challenge as the population grows and food demand rises. We evaluated the responses of lettuce cultivars (Lactuca Sativa) under saline stress in photosynthetic responses, production, and ion homeostasis. We used a randomized block design in a 3 × 5 factorial scheme with five replications—the first factor: three cultivars of curly lettuce: SVR 2005, Simpson, and Grand Rapids. The second factor consisted of five treatments: T1—control (water of 0.53 dS m−1); T2—saline stress (water of 4.0 dS m−1); T3—saline stress + ascorbic acid; T4—saline stress + gibberellic acid; and T5—saline stress + salicylic acid. The Grand Rapids lettuce cultivar tolerated water salinity, obtaining the highest production. The Simpson lettuce cultivar was sensitive to salinity, reducing biomass production under saline stress by 11.47% compared to Grand Rapids. Salicylic acid was more effective at mitigating saline stress in the Simpson lettuce cultivar than ascorbic and gibberellic acids, with a 24.85% increase in production compared to saline stress. The findings suggest that the Grand Rapids lettuce cultivar is more resilient to saline conditions, while salicylic acid can significantly enhance production in the sensitive Simpson cultivar under saline stress.

ABSTRACT The umbu-cajazeira (Spondias sp.) is a fruit tree native to the semi-arid of Brazil, with significant environmental and agro-socioeconomic potential for the region. Determining leaflet area (LA) is essential for understanding the interactions between plant growth, physiology, nutrition, and environment. Thus, this research aims to construct allometric equations that non-destructively estimate the umbu-cajazeira (Spondias sp.) leaflet area, considering the leaflet dimensions (length and width). The leaflets were collected from mother plants of umbu-cajazeira (Spondias sp.) and individually measured for length (L), width (W), and LA using digitized images. These data were submitted for descriptive and regression analysis. The LA was estimated using, linear power, and exponential regression models based on the L and W of the leaflets. The best model and equation were chosen based on the following selection criteria: coefficient of determination, Willmott agreement index, root mean square error, and mean absolute error. The power model using LW presented the best equation ŷ = 0.76 * LW0.98 to estimate the leaflet area of umbu-cajazeira (Spondias sp.). This study provides a reliable, accurate, fast, and non-destructive approach for agronomic researchers and growers to determine the LA of the species.

IntroductionSalicylic acid has shown promise in alleviating water stress in cultivated plants. However, there is a lack of studies confirming its effectiveness in cowpea plants grown in field conditions. Therefore, this research aimed to evaluate the use of salicylic acid as a water stress mitigator in cowpea cultivars under different irrigation depths in field conditions.MethodsFour cowpea cultivars (BRS Novaera, BRS Tapaihum, BRS Pujante, and BRS Pajeú) were subjected to different treatments: control (W100: 100% replacement of crop evapotranspiration – ETc), W50 (50% of ETc), W50+SA2 (50% of ETc + 276 mg L-1 of SA), and W50+SA4 (50% of ETc + 552 mg L-1 of SA). The treatments were combined in a 4×4 factorial scheme with three replications, arranged in a randomized block design.ResultsWater restriction had a negative impact on the water status, growth, gas exchange, and production of the cultivars while also leading to changes in the antioxidant metabolism and osmolyte concentration. The application of SA enhanced antioxidant activity and the synthesis of osmotic adjusters under stress conditions. The most effective concentration was 276 mg L-1 in stage R2 and 552 mg L-1 in stage V7, respectively. The BRS Pujante cultivar showed increased productivity under water restriction with SA application, while the BRS Tapaihum was the most tolerant among the cultivars studied.DiscussionIn summary, our findings underscore the importance of using SA to mitigate the effects of water restriction on cowpea cultivation. These discoveries are crucial for the sustainability of cowpea production in regions susceptible to drought, which can contribute to food security. We further add that the adoption of new agricultural practices can enhance the resilience and productivity of cowpea as an essential and sustainable food source for vulnerable populations in various parts of the world.

Selenium (Se) is a beneficial element for plants and is essential for human nutrition. In plants, it plays an important role in the formation of selenocysteine and selenomethionine and in the activation of hydrolytic enzymes, which can aid in seed germination and reduce abiotic stress during germination. The objective of this study was to evaluate the effects of the application of selenium sources and rates to the soil on the physiological quality of cowpea seeds. The experimental design was a randomized block with four replications and a factorial scheme (7 × 2). Two sources of Se (sodium selenate and sodium selenite) and seven rates (0, 2.5, 5, 10, 20, 40 and 60 g ha−1) were used. Physiological characterization was carried out by first counting of germination, germination, emergence, accelerated aging, cold testing, electrical conductivity, length and dry biomass of shoots and roots. Germination after accelerated aging increased with selenate, even at higher rates, whereas selenite provided benefits at lower rates. Selenation linearly increased germination after the cold test and linearly reduced electrolyte leakage as the Se rate increased. The soil application of Se is beneficial for cowpea seed quality. Compared with those treated with sodium selenite, cowpea plants treated with sodium selenate through the soil produce more vigorous seeds. The application of 10 g ha−1 Se in the form of sodium selenate provides seedlings with faster germination and root development and is an alternative for rapid stand establishment.

Ethnopedology offers a unique opportunity to recognize and highlight invaluable local soil knowledge (LSK). We aimed to classify three soil profiles in a Brazilian irrigated district with salt-affected soils based on smallholder farmers’ LSK and scientific knowledge. The study occurred in the Baixo-Açu irrigation district in Brazil’s semi-arid region. Three soil profiles were characterized by researchers (etic approach) and farmers (emic approach) in the following areas: P1 profile (area under banana cultivation), P2 profile (fallow area), and P3 profile (native forest area). Smallholder farmers identified the studied areas with salt problems based on the salt precipitation on the surface, changes in leaf color, and incidence of indicator plants of salinized areas. Researchers classified P1 profile as Pantohypereutric Calcaric Leptic Cambisol (Loamic, Humic), P2 as Pantohypereutric Calcaric Leptic Cambisol (Loamic, Humic), and P3 as Leptic Calcic Chernozem (Loamic). Smallholder farmers classified the P1 profile as “Terra de Salitre” (Salt Soil), the P2 profile as “Terra de Piçarro” (Saprolite Soil), and the P3 profile as “Terra Boa” (Good Soil). The results indicate that valuing local soil knowledge is effective and crucial for improved scientific research and land use, highlighting the importance of recognizing and utilizing their expertise and experience.

ABSTRACT Effluent from fish farming with saline water is a source of water, also rich in organic matter and nutrients, that can be used in irrigation of cultivated plants and even fully or partially replace mineral fertilization. The objective was to evaluate the growth, biomass production and quality of P. maximum cultivars fertigated with fish farming effluent in a greenhouse experiment, using a randomized block design with eight replicates. Treatments were arranged in a split-split-plot scheme, with three irrigation managements in the plot (irrigation with public-supply water, irrigation with public-supply water + conventional fertilization, and irrigation with fish farming effluent), three cultivars of P. maximum (Tanzania, Mombasa, and Massai) in the sub-plot, and four cutting times in the sub-sub-plot (45, 90, 135, and 180 days after sowing). Plant height, number of tillers, production of fresh biomass, neutral detergent fiber, acid detergent fiber, ether extract, crude protein, dry matter, and mineral matter contents were analyzed. The highest growth, production, and quality of P. maximum grass occurs when irrigated with public-supply water and under conventional NPK fertilization. Fertigation with fish farming effluent reduces the growth and production of P. maximum grass, but allows obtaining better quality forage. It is possible to irrigate P. maximum grass using fish farming effluent with satisfactory yields. The growth of cv. Massai was more sensitive to irrigation with fish farming effluent than those of the cultivars Tanzania and Mombasa.

Plant endogenous mechanisms are not always sufficient enough to mitigate drought stress, therefore, the exogenous application of elicitors, such as salicylic acid, is necessary. In this study, we assessed the mitigating action of salicylic acid (SA) in cowpea genotypes under drought conditions. An experiment was conducted with two cowpea genotypes and six treatments of drought stress and salicylic acid (T1 = Control, T2 = drought stress (stress), T3 = stress + 0.1 mM of SA, T4 = stress + 0.5 mM of SA, T5 = stress + 1.0 mM of SA, and T6 = stress + 2.0 mM of SA). Plants were evaluated in areas of leaf area, stomatal conductance, photosynthesis, proline content, the activity of antioxidant enzymes, and dry grain production. Drought stress reduces the leaf area, stomatal conductance, photosynthesis, and, consequently, the production of both cowpea genotypes. The growth and production of the BRS Paraguaçu genotype outcompetes the Pingo de Ouro-1-2 genotype, regardless of the stress conditions. The exogenous application of 0.5 mM salicylic acid to cowpea leaves increases SOD activity, decreases CAT activity, and improves the production of both genotypes. The application of 0.5 mM of salicylic acid mitigates drought stress in the cowpea genotype, and the BRS Paraguaçu genotype is more tolerant to drought stress.

Cotton is one of the most exploited crops in the world, being one of the most important for the Brazilian Northeast. In this region, the use of irrigation is often necessary to meet the water demand of the crop. Water is often used from underground wells that have a large amount of salt in their constitution, which can compromise the development of crops, so it is vital to adopt strategies that reduce salt stress effects on plants, such as the foliar application of hydrogen peroxide. Thus, the objective of this study was to evaluate the effects of foliar application of hydrogen peroxide on the gas exchange, growth, and production of naturally colored cotton under salt stress in the semi-arid region of Paraíba, Brazil. The experiment was carried out in a randomized block design in a 5 × 5 factorial scheme, with five salinity levels of irrigation water—ECw (0.3, 2.0, 3.7, 5.4 and 7.1 dS m−1)—and five concentrations of hydrogen peroxide—H2O2 (0, 25, 50, 75 and 100 μM), and with three replicates. The naturally colored cotton ‘BRS Jade’ had its gas exchange, growth, biomass production, and production reduced due to the effects of salt stress, but the plants were able to produce up to the ECw of 3.97 dS m−1. Foliar application of hydrogen peroxide at the estimated concentrations of 56.25 and 37.5 μM reduced the effects of salt stress on the stomatal conductance and CO2 assimilation rate of cotton plants under the estimated ECw levels of 0.73 and 1.58 dS m−1, respectively. In turn, the concentration of 12.5 μM increased water-use efficiency in plants subjected to salinity of 2.43 dS m−1. Absolute and relative growth rates in leaf area increased with foliar application of 100 μM of hydrogen peroxide under ECw of 0.73 and 0.3 dS m−1, respectively. Under conditions of low water salinity (0.3 dS m−1), foliar application of hydrogen peroxide stimulated the biomass formation and production components of cotton.

Semi-arid regions have low water availability, and water reuse in irrigation is an alternative to enable satisfactory agricultural yields in the Brazilian semi-arid region. To evaluate the effects of irrigation with sewage effluent and phosphate fertilization on upland cotton (Gossypium hirsutum L. cv. BRS 335), we irrigated the cotton plant only with well water (control) or irrigated it with a solution containing 50 and 100% effluent sewage, in soil with and without pre-planting phosphate fertilization. For plant growth analysis, we considered time as the third factor. The experimental design consisted of randomized blocks, with six replicates, during two cotton cycles in the open field. Plant growth, yield, and fiber quality increased with the application of sewage effluent compared to the control. The control obtained cotton fiber yields of 740 and 741 kg ha−1 in the first and second cycles, using 50% sewage effluent outperformed 240 and 290% of the control and using 100% sewage effluent outperformed 235 and 300% of the control, respectively. Pre-planting phosphate fertilization failed in upland cotton cv. BRS 335. Irrigation using 100% sewage effluent promotes more significant plant growth, production, and quality of cotton fiber.

The objective of this study was to evaluate the synthesis of photosynthetic pigments, gas exchange, and photochemical efficiency of sour passion fruit genotypes irrigated with saline water under the conditions of the semi-arid region of Paraíba state, Brazil. The experiment was conducted at the experimental farm in São Domingos, PB. A randomized block design was adopted, in a 5 × 3 factorial scheme, with five levels of electrical conductivity of irrigation water—ECw (0.3, 1.1, 1.9, 2.7, and 3.5 dS m−1)—and three genotypes of sour passion fruit (Gigante Amarelo—‘BRS GA1’; Sol do Cerrado—‘BRS SC1’; and Catarina—‘SCS 437’. The increase in the electrical conductivity of irrigation water negatively affected most of the physiological characteristics of the sour passion fruit at 154 days after transplanting. Significant differences were observed between sour passion fruit genotypes when its tolerance was subjected to the salinity of irrigation water. There was an increase in the percentage of damage to the cell membrane with the increase in the electrical conductivity of irrigation water, with maximum values of 70.63, 60.86, and 80.35% for the genotypes ‘BRS GA1’, ‘BRS SC1’, and SCS 437’, respectively, when irrigated with water of 3.5 dS m−1. The genotype ‘BRS Sol do Cerrado’ showed an increase in the synthesis of photosynthetic pigments when irrigated with water of 3.5 dS m−1, with maximum values estimated at 1439.23 μg mL−1 (Chl a); 290.96 μg mL−1 (Chl b); 1730.19 μg mL−1 (Chl t); and 365.84 μg mL−1 (carotenoids). An increase in photosynthetic efficiency parameters (F0, Fm, and Fv) of the genotype ‘BRS Gigante Amarelo’ was observed when cultivated with water with high electrical conductivity (3.5 dS m−1).

ABSTRACT Cowpea suffers significant production losses when subjected to salt stress, but the response varies among genotypes. The objective of this study was to evaluate the phenology and production of traditional cowpea seeds under saline water irrigation. The experiment was conducted in two stages, the first one in a greenhouse to evaluate the phenology and production of cowpea genotypes and the second one in the laboratory to assess the viability and vigor of the seeds produced in the first stage. The treatments resulted from the combination of two salinity levels of the irrigation water (0.5 and 4.5 dS m-1) and 14 traditional cowpea varieties (Boquinha, Ceará, Costela-de-vaca, Lisão, Canário, Pingo-de-ouro, Roxão, Branco, Canapum-branco, Canapum-miúdo, Baêta, Coruja, Paulistinha, and Sempre-verde) acquired from traditional farmers in the western region of Rio Grande do Norte, Brazil. Canário, Baêta, and Coruja varieties have a higher number of flowers per plant and earlier flowering. Salinity reduced the number of flowers per plant, increased abortion in all traditional varieties and reduced production in the early varieties Branco, Canapum-miúdo, Baêta, and Coruja. Cultivation under saline water irrigation did not affect the viability of the seeds from the second generation of cowpea, but reduced the vigor of the seeds of the varieties Lisão, Pingo-de-ouro, Roxão, Branco, Canapum-branco, Canapum-miúdo, Baêta and Coruja. The traditional varieties Boquinha, Ceará, Costela-de-vaca, Canário, Paulistinha and Sempre-verde are indicated for the production of cowpea seeds under irrigation with saline water.

ABSTRACT Pitaya (Hylocereus undatus and H. costaricensis) is found in the group of exotic fruits and its cultivation in Brazil is expanding, especially in the semi-arid region of the Northeast. In this region, the problems of water quantity and quality usually cause environmental stresses which limit the survival of plants, especially during germination and seedling establishment. Thus, the objective was to evaluate the mitigating action of pre-germination treatments in pitaya seeds under salt stress. The experiment was conducted in a completely randomized design, in a 2 × 6 factorial scheme, corresponding to two species of pitaya (H. undatus and H. costaricensis) and six pre-germination treatments (T1 = 0.0 MPa (control); T2 = salt stress (-0.4 MPa); T3 = hydropriming + salt stress; T4 = gibberellic acid + salt stress; T5 = salicylic acid + salt stress; T6 = thiamethoxam + salt stress). After 20 days of sowing, germination, germination speed index, shoot length, primary root length, total dry mass, total soluble sugars and total free amino acids were analyzed. H. costaricensis was more tolerant to salinity than H. undatus. Salicylic acid stimulated the germination and growth of H. undatus, besides increasing the soluble sugar content in H. costaricensis. Seed hydropriming attenuated salt stress during germination of H. undatus and favored dry mass gain. Gibberellic acid stimulated the germination of H. undatus and the growth of H. undatus and H. costaricensis seedlings, in addition to increasing the levels of soluble sugars in H. undatus.

The increase in water demand in regions with limited good-quality water resources makes it necessary to study the effect of low-quality water on plant metabolism. Therefore, the objective of this study was to evaluate the effect of water and salt stress on the levels of mineral elements and accumulation of toxic elements Na+ and Cl− in the leaves and their consequences on the production variables of the sorghum cultivar IPA SF-15. The design adopted was randomized blocks in a factorial scheme (4 × 4), with four salt concentrations (1.5; 3.0; 4.5, and 6.0 dS m−1) and four irrigation depths (51.3; 70.6; 90.0, and 118.4% of crop evapotranspiration ETc) in three repetitions. To obtain nutrient, sodium, and chlorine contents in the leaf, we collected the diagnosis leaf from six plants per plot. For production data, we performed two harvests at 76 and 95 days after planting (silage point and for sucrose extraction). We evaluated the dry mass, fresh mass yield, and total dry mass for the two cutting periods and applied the F-test at the 5% significance level. There was an effect of water stress but not saline, making it possible to use saline water for sorghum irrigation. As for the toxicity of ions, the plant showed tolerance behavior to Na+ and Cl− ions. The grain filling phase was more sensitive than the final phase of the crop cycle.

Agronomic biofortification is a technique that helps reduce hidden hunger worldwide. Zinc (Zn) is important for human health and essential for plant development and growth. Thus, this research aimed to evaluate the effects of fertilization with Zn on agronomic performance and the agronomic biofortification of beet. Two experiments were conducted at the Rafael Fernandes Experimental Farm, belonging to the Federal Rural University of the Semi-arid, in Mossoró-RN. Each experiment was designed in complete randomized blocks, with five treatments and four replications. The treatments consisted of Zn doses (0, 1.5, 3.0, 4.5, and 6.0 kg ha−1). Zn fertilization did not affect the total and non-commercial yield of beet; however, the dose of 6.0 kg ha−1 of Zn promoted maximum commercial yield (20.34 t ha−1). At the maximum dose, higher Zn content was also observed in the nutritional status diagnosis leaf and higher Zn accumulation was found in the leaf, tuberous root, and throughout the plant. There was also an effect on postharvest variables. There was only tuberous root biofortification in 2021. The recommended dose in beet cultivation is 6.0 kg ha−1 of Zn.

Saline stress impairs germination and initial plant growth. However, discontinuous hydration cycles induce osmotic tolerance in seeds and can improve the response of maize seeds to saline stress. The objective of this study was to evaluate the action of discontinuous hydration cycles with different salt stress tolerance elicitors on germination, growth, and osmotic adjustment of maize cultivars. Maize seeds of BR 206 and BRS 5037 Cruzeta cultivars were subjected to the following treatments: 0.0 mmol of NaCl (control), 250 mmol of NaCl (salt stress), salt stress + three discontinuous hydration cycles (DHCs) of seeds in water, salt stress + DHCs with gibberellic acid, salt stress + DHCs with hydrogen peroxide, salt stress + DHCs with salicylic acid, and salt stress + DHCs with ascorbic acid. Salt stress reduced the germination, growth, and biomass accumulation in maize seedlings—the BR 206 cultivar outperformed BRS 5037 Cruzeta. Discontinuous hydration cycles with water failed to improve the salt stress tolerance of maize seeds. However, discontinuous hydration cycles with gibberellic acid, hydrogen peroxide, and salicylic acid promoted salt stress tolerance in maize due to increased synthesis of osmoprotectants. Our results revealed salicylic acid is appropriate for discontinuous hydration cycles in maize seeds.

Global climate changes have intensified water stress in arid and semi-arid regions, reducing plant growth and yield. In this scenario, the present study aimed to evaluate the mitigating action of salicylic acid and methionine in cowpea cultivars under water restriction conditions. An experiment was conducted in a completely randomized design with treatments set up in a 2 × 5 factorial arrangement corresponding to two cowpea cultivars (BRS Novaera and BRS Pajeú) and five treatments of water replenishment, salicylic acid, and methionine. After eight days, water stress decreased the Ψw, leaf area, and fresh mass and increased the total soluble sugars and catalase activity in the two cultivars. After sixteen days, water stress increased the activity of the superoxide dismutase and ascorbate peroxidase enzymes and decreased the total soluble sugars content and catalase activity of BRS Pajeú plants. This stress response was intensified in the BRS Pajeú plants sprayed with salicylic acid and the BRS Novaera plants with salicylic acid or methionine. BRS Pajeú is more tolerant to water stress than BRS Novaera; therefore, the regulations induced by the isolated application of salicylic acid and methionine were more intense in BRS Novaera, stimulating the tolerance mechanism of this cultivar to water stress.

Agriculture in semiarid regions commonly face problems because of salt and availability of irrigation water. Considering this, studies on cultures resistant to salt and water stresses involving sweet sorghum are required. Therefore, the aim was to evaluate the growth and other mechanisms of tolerance to salinity and water deficit in BRS 506 sweet sorghum. The experimental design was conducted in Upanema-RN, Brazil, in randomized blocks, where the isolated and interactive effect of 3 salinity levels, expressed as the electrical conductivity of irrigation water (1.5, 3.8, and 6.0 dS m−1), and 3 irrigation depths (55, 83, and 110% of crop evapotranspiration) were evaluated. During the cycle, sorghum adapted to the salinity and deficit irrigation depth, since stem height reduced only −5.5% with increasing salinity and −11.95% with decreasing irrigation depth, and aerial dry mass was affected by interaction only at the end of the cycle. Proline, total amino acids, and total soluble sugars were not differenced by stresses. Additionally, around 68.71% of total Na+ was at roots at the end of the cycle. In summary, sorghum BRS 506 was more tolerant to salt than water stress and used Na+ compartmentalization in root cells as the main tolerance mechanism.

ABSTRACT Information on the effects of climate conditions on the survival of species grown in semi-arid regions is essential and at the same time scarce, especially regarding rustic species such as West Indian gherkin (Cucumis anguria L.). Thus, this study aimed to evaluate germination, growth and biochemical alterations in C. anguria seeds under water stress and different temperature regimes. The experimental design was completely randomized, in 5 x 5 factorial scheme, composed of five osmotic potentials (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and four temperatures (20; 25; 30 °C and alternating temperatures of 20-30 ºC), with each treatment composed of four replicates of 50 seeds. The seeds were sown on paper towel (Germitest®) and germinated in Biochemical Oxygen Demand (B.O.D.) germinators, under 8-h photoperiod. Germination percentage, germination speed index, mean time of germination, seedling length and contents of chlorophylls, carotenoids, proline, free amino acids and free sugars were determined along the experiment. Decrease in osmotic potential reduced germination, growth and contents of chloroplast pigments of C. anguria seedlings, but was more drastic at levels lower than -0.2 MPa. Low temperatures intensify the effects of water stress on the germination of C. anguria seeds. The synthesis of protecting osmolytes increased in C. anguria seedlings but these components did not promote efficient osmotic adjustment in their initial development stage.

Given the scarcity of water resources in semi-arid regions and the potential of water reuse as a strategy to solve this problem, this study aimed to evaluate the effects of domestic sewage effluent on growth, yield, and quality of two crisp lettuce cultivars. The research was carried out in greenhouse conditions utilizing an experimental design with randomized blocks in a 5 x 2 factorial scheme, with five concentrations from treated domestic effluent blended with tap water (0, 25, 50, 75 and 100% of treated domestic effluent) and two crisp loose lettuce cultivars (Scarlet and Cristal) done in triplicate with five plants per trial. The lettuce plants were growth in trapezoid-shaped PVC channels filled with coconut fiber substrate and organic compost (2:1) for 35 days after transplanting. The experimental results indicated that irrigation with 30% sewage effluent diluted in tap water gives higher growth and yield of lettuce. The Cristal cultivar shows growth, soluble solids, and chlorophyll higher than the Scarlet cultivar. The application of treated domestic effluent does not affect the post-harvest quality of the lettuce to both cultivars.

Mineralogical studies are incipient and necessary in the Apodi Plateau, Brazil. This study aimed to evaluate the interrelationship between the mineralogy of the clay fraction and its structural and chemical attributes and to differentiate two important pedo-environments in the semi-arid region of northeastern Brazil (Ferralsol and Cambisols of the Apodi Plateau-RN) using the multivariate technique. We evaluated the interrelationships between mineralogy and the structural and chemical attributes of the soil and differentiated between agroenvironments. We collected soil samples from six profiles in diagnostic horizons of the Ferralsols and Cambisols. In the mineralogical analysis of the clay fraction, X-Ray Diffraction was used to identify mineral peaks of clay and iron oxides. The physical and chemical properties of the soils were determined. The multivariate statistical technique was applied to process the data. The clay minerals identified were hematite, goethite, kaolinite, and illite. The principal component analysis allowed for the separation of environments according to soil density, Fed and Mg2+ for developed soils, and potassium, weighted average diameter, microporosity, total organic carbon, sodium, the sum of bases, calcium, total porosity, aeration, potential acidity, and Feo discriminated developing soils. This study revealed that the clay fraction influenced the structural attributes of the soil according to the degree of soil development. Two profiles presented atypical situations: High contents of crystallized iron in Cambisols and illite peaks in Ferralsolos. These mineralogical results are not commonly found in the literature, highlighting the potential for further studies. The answers concerning the mineralogy of semiarid soils in Brazil and the world show similarity.

Future emission scenarios can interfere with the yield of major crops. In this study, we investigated the future impact of increased air temperature and relative humidity on melon phenology and water demand in the Brazilian semi-arid region. We applied the PRECIS (Providing Regional Climates for Impact Studies) climatological model to develop the Intergovernmental Panel on Climate Change emission scenarios—B2 optimistic emission scenario and A2 pessimistic emission scenario—and we assessed the climate change effects on the phenology and water demand of two melon cultivars. The “Orange County” hybrid, the Honeydew melon, grew from 2006–2007, and the “Néctar” hybrid, the Galia melon, grew in 2008. These cultivars were also considered using the actual emission scenario. We found that the B2 and A2 emission scenarios will cause a cycle decrease of 15.49 and 25.35% for the “Orange County” hybrid and a 9.84 and 18.03% decrease for the “Néctar” hybrid. Future changes to the climate will increase the melon crop coefficient and daily rate of evapotranspiration. Regarding the “Orange County” hybrid, the cycle shortening overcomes the daily water demand increases, decreasing water demand by 13.7–18.3%. Regarding the “Néctar” hybrid, cycle shortening will be proportional to the increase in water demand. The Honeydew melon will be more sensitive to air temperature and relative humidity increases than the Galia melon.

Salt stress during pre-harvest limits the shelf life and post-harvest quality of produce; however, silicon nutrition can mitigate salt stress in plants. Thus, we evaluated the effects of salinity and fertilization with Si, in pre-harvest, on the morpho-physiological characteristics of onion bulbs during shelf life. The experiment was set up in randomized complete blocks, with treatments arranged in split-split plots. The plots had four levels of electrical conductivity of irrigation water (0.65, 1.7, 2.8, and 4.1 dS m−1). The subplots had five fertilization levels with Si (0, 41.6, 83.2, 124.8, and 166.4 kg ha−1). The sub-sub plots had four shelf times (0, 20, 40, and 60 days after harvest). Irrigation water salinity and shelf time reduced firmness and increased the mass loss of onion bulbs during shelf life. Salt stress reduced the contents of sugars and total soluble solids of onion bulbs during storage; however, Si supply improved the contents of these variables. Salinity, Si supply, and shelf time increased the concentrations of pyruvic and ascorbic acids in onion bulbs during shelf life. Si doses between 121.8 and 127.0 kg ha−1 attenuated the impacts caused by moderate salinity, increasing the synthesis of metabolites and prolonging the onion bulbs’ shelf life.

Salvia hispanica L. is an alternative crop cultivated by farmers who want to diversify their production. However, this species is sensitive to salinity, which affects its germination negatively. Seed priming with different attenuators is a technique with potential to mitigate the effects of salt stress. Thus, the objective of this study was to evaluate the effect of seed priming with the use of different attenuators on the germination, growth, and organic solute accumulation of S. hispanica seedlings under salt stress. The experimental design was completely randomized, with treatments distributed in a 4 × 5 factorial scheme, corresponding to four seed priming treatments and five osmotic potentials, with four replicates of 50 seeds in each treatment. The seed treatments consisted of presoaking seeds for 4h in salicylic acid, gibberellic acid, and distilled water and the control treatment, which did not involve soaking. These seeds were germinated at osmotic potentials of 0.0, -0.1, -0.2, -0.3, and -0.4 MPa, using NaCl as an osmotic agent to simulate the different salinity levels. Among all the treatments implemented, S. hispanica seed priming with salicylic acid was the most efficient in mitigating the salt stress effects.

The economically profitable production of crops is related, among other factors, to seed quality, the production system, and the water used in irrigation or preparation of nutrient solutions. Therefore, the objective was to evaluate the phenology, production, and vigor of seeds of mini watermelons grown in saline nutrient solution and different substrates. In the fruit and seed production phase, the experiment occurred in a greenhouse with five electrical conductivities of water for nutrient solution preparation, ECw (0.5, 2.4, 4.0, 5.5, and 6.9 dS m−1), and two growing substrates (coconut fiber and sand). We evaluated the physiological quality of seeds previously produced under the five electrical conductivities of water and two substrates. High salinities for the hydroponic cultivation of the mini watermelon cultivar ‘Sugar Baby’ accelerated fruit maturation and crop cycle, decreasing fruit size. However, in both substrates, the seed production of mini watermelons, seed viability, and seed vigor occurred adequately with a reject brine of 6.9 dS m−1 in the hydroponic nutrient solution. The seed production of ‘Sugar Baby’ mini watermelons using reject brine in a hydroponic system with coconut fiber and sand substrates is viable in regions with water limitations.

Cowpea is the main subsistence crop—protein source—for the Brazilian semi-arid region. The use of salt-stress-tolerant varieties can improve crop yields. We evaluated the effect of irrigation with brackish water on the growth, photosynthetic responses, production, and tolerance of fifteen traditional varieties of cowpea. The experiment was conducted in randomized blocks, in a 15 × 2 factorial scheme, composed of 15 traditional varieties of cowpea and two salinity levels of irrigation water (0.5 and 4.5 dS m−1), with five replicates. Plants were grown in pots containing 10 dm3 of soil for 80 days. The reduction in the photosynthetic rate of cowpea varieties occurs mainly due to the decrease in stomatal conductance caused by salt stress. Salt stress increased the electron transport rate and photochemical quenching of cowpea varieties, but stress-tolerant varieties increased the CO2 assimilation rate and instantaneous carboxylation efficiency. The Ceará, Costela de Vaca, Pingo de Ouro, Ovo de Peru, and Sempre Verde varieties are tolerant to salt stress. Salt stress decreases 26% of the production of tolerant varieties to salt stress and 54% of susceptible varieties. The present findings show the existence of variability for saline stress tolerance in traditional varieties of cowpea and that Ceará, Costela de Vaca, Pingo de Ouro, and Ovo de Peru varieties are more suitable for crops irrigated with saline water.

ABSTRACT The physiological potential of seeds is one of the main factors that should be considered at the planting of a crop. This study aimed to evaluate the exogenous application of biostimulant in zucchini, cv. Caserta Italiana, under salt stress conditions. For this, the experiment was divided into two parts. The first one was carried out in the laboratory, using a completely randomized experimental design, in a 5 x 3 factorial scheme (biostimulant doses and seed soaking times), with four replicates of 25 seeds. The second one was carried out in a greenhouse, in a completely randomized experimental design, in a 2 x 6 factorial scheme with four replicates, corresponding to two levels of irrigation water salinity (0.5 and 5.0 dS m-1) and six forms of biostimulant application in seeds and leaves. Treatment of zucchini seeds, cv. Caserta Italiana, with biostimulant (Stimulate®) at the dose of 10 mL L-1, for 8 hours, proved to be viable and resulted in vigorous seedlings when irrigated with 5.0 dS m-1 saline water.

O feijão-caupi é uma importante fonte de proteína, sendo a principal cultura de subsistência da região Nordeste do Brasil, onde a restrição de água e a salinidade são fatores limitantes. A identificação de variedades tolerantes ao estresse salino pode auxiliar na expansão da cultura, além de melhorar o rendimento dos cultivos. Objetivou-se estudar a tolerância de variedades crioulas de feijão-caupi à salinidade da água de irrigação na fase de emergência e crescimento inicial. O experimento foi realizado em casa de vegetação, usando o delineamento inteiramente casualizado (DIC), em esquema fatorial 23 x 2, composto de 23 variedades de feijão-caupi (Canapu Vermelho, Boquinha, Pingo de Ouro, Sempre Verde, Ceará, Baeta, Manteiga, Roxão, Costela de Vaca, Feijão Branco, Coruja, Rabo de Peba Branco, Sopinha, Canapu Branco, Lisão, Canapu Miúdo, Sempre Verde Ligeiro, Vagem Roxa, Ovo de Peru, Rabo de Peba Miúdo, Feijão Azul, Canário e Paulistinha), e dois níveis de salinidade da água de irrigação (S1 = 0,5 e S2 = 5,5 dS m-1), com quatro repetições de 50 sementes. As plântulas foram avaliadas quanto à emergência, o vigor, o índice de tolerância à salinidade e à dissimilaridade. O aumento da salinidade da água de irrigação reduziu a emergência, o vigor e acúmulo de massa seca das variedades de feijão-caupi. As variedades de feijão-caupi Lisão, Costela de Vaca, Canário, Feijão Branco, Ceará e Boquinha são as mais tolerantes à salinidade, enquanto que as variedades Sempre Verde e Manteiga são as mais sensíveis à salinidade na fase de emergência e crescimento inicial.

Melon (Cucumis melo L.) is a crop of great socioeconomic importance in regions with semiarid climate, as found in Northeast Brazil. In this region water deficit is a usual condition as well as the main reduction factor of plant productivity. Due to this phenomenon, irrigation techniques are used to make available the amount of water needed for plant production. Therefore, this research evaluated the physiology and fruit production changes of ‘Juazeiro’ Piel de sapo melon plants under different water replacement rates. ‘Juazeiro’ melon was grown under four reference evapotranspiration replacement rates (40, 60, 80 and 100% of ETo) distributed randomly in blocks with 5 replicates. The plants were cultivated in the field, in an experimental area located in the Brazilian Northeast region, under hot and dry semiarid climatic conditions, and during the growing cycle the ‘Juazeiro’ hybrid melon plants were evaluated for leaf area, biomass accumulation, gas exchange, photochemical efficiency of photosystem PSII and production of fruits per plant. Application of water replacement rates of 100% ETo leads to highest growth, net photosynthesis, and fruit yield of 'Juazeiro' melon. Water replacement at 80% ETo can be used for ‘Juazeiro” melon under semiarid climatic conditions, but with small losses in fruit yield. Water replacement below 80% ETo leads to drastic reductions in growth, gas exchanges, quantum efficiency of photosystem II and fruit yield, which impairs melon production in semi-arid climate environments.

Devido aos problemas climáticos no semiárido brasileiro é de fundamental importância que se busque uma cultura que considere a escassez hídrica e os recursos naturais disponíveis. Deste modo, um experimento em delineamento de blocos ao acaso, com parcelas subdivididas e seis repetições foi conduzido na área experimental da estação de tratamento e reuso de águas residuais do Assentamento Milagres, Apodi - RN, com o objetivo de avaliar o cultivo de algodoeiro herbáceo (Gossipyum hirsutum) fertirrigado com efluente de esgoto doméstico tratado em ambiente semiárido. Foram realizados dois ciclos de cultivo e as plantas de algodão foram nutridas com três diferentes soluções contendo efluente de esgoto doméstico tratado (PSW) + água de abastecimento (TDE) para suprir a evapotranspiração da cultura (ETc) (100% PSW – control, 50% PSW + 50% TDE and 100% TDE) com e sem adubação fosfatada em pré-plantio. Analisou-se o aporte de nutrientes ao solo e o crescimento das plantas. Os resultados indicaram que o efluente doméstico tratado apresenta potencial fertilizante, chegando a aportar ao solo quantidades de alguns nutrientes superiores a necessidade do algodoeiro, quando 100% da ETc foi suprida via fertirrigação com efluente doméstico, resultando em incremento das taxas de crescimento das plantas. Não se constatou interação entre as porcentagens de efluente doméstico tratado e a adubação fosfatada em pré-plantio. O fósforo isoladamente promoveu variação significativa apenas no primeiro ciclo, indicando que há um efeito residual da fertirrigação com efluente doméstico no aporte do nutriente.

Water availability and substrate type are essential factors in seed germination tests, influencing imbibition and seedling development. The objective of this study was to evaluate the influence of two substrates and different water volumes on the germination and vigor of chia seeds. The experimental design was completely randomized in a 2 x 6 factorial scheme, which consisted of two substrates, paper towel (Germitest®) and blotting paper, soaked with six water volumes equivalent to 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 times their dry weight, in four replicates of 50 seeds each. Germination percentage, mean time of germination, shoot length, radicle length, shoot dry matter, radicle dry matter, total dry matter (seedling), and root/shoot ratio were evaluated. Based on our results, germination tests for seeds of chia should be conducted using blotting paper (on paper) as substrate, with a water volume of 2.5 to 4.0 times its dry weight. Chia seedlings grown on blotting paper showed greater growth and dry matter accumulation compared to those grown on paper towel.

There is an increasing use of poultry litter in seedling production. However, studies regarding the effect of different particle-size litter on plant growth are still scarce. This study aimed to evaluate the growth of Moringa oleifera Lam. fertilized with poultry litter doses (0 g dm-3, 40 g dm-3, 80 g dm-3 and 120 g dm-3) with distinct particle sizes (1 mm and 4 mm), with four replications. The following variables were evaluated: plant height; root and stem diameter; leaf, stem, shoot and root dry matter mass; shoot/root dry matter mass ratio; and the Dickson quality index. There was no influence of the particle size on the studied variables, except for plant height. The root diameter decreased with the increase of the poultry litter doses. The accumulation of dry matter mass from the shoot and root increased with the increase of poultry litter doses up to 120 g dm-3. A linear increase of the Dickson quality index, relatively to days and poultry litter doses, was observed. It is recommended to apply 80 g dm-3 of poultry litter to fertilize M. oleifera plants, independently of the granulometry used.

Cowpea is a crop with great economic, social and food importance in semi-arid regions, but its production is drastically reduced by the water deficit in these regions, requiring better management strategies that allow the crop’s production. This study therefore aimed to evaluate the photosynthetic efficiency and production of cowpea cultivars under deficit irrigation replacement levels. The experiment tested three cowpea genotypes (G1 = ‘BRS Aracé’, G2 = ‘BR 17 Gurguéia’ and G3 = ‘BRS Marataoã’) and four irrigation depths (40, 60, 80 and 100% of ETc), resulting in a 3 x 4 factorial scheme, arranged in randomized complete blocks design with four replicates. During the experiment, the gas exchanges, chlorophyll a fluorescence and production of the cowpea genotypes under deficit irrigation were evaluated. Carbon fixation in the photosynthetic metabolism of cowpea plants was reduced by accentuated water deficit, regardless of the genotype. The low stress severity was indicated by the lack of effects on chlorophyll fluorescence, indicating that the reduction in the rate of carbon assimilation was due to the stomatal effects. The irrigation with 80% of ETc can be used in the cultivation of the respective cultivars, but with small losses in the production. Among the genotypes, ‘BRS Marataoã’ stands out with respect to yield, with higher values for weight of pods and green beans.

Due to the scarcity of water in the semi-arid region of Northeast Brazil, in both quantitative and qualitative terms, the use of saline water in agriculture should be considered as one alternative for irrigated agriculture. This study therefore aimed to evaluate the photosynthetic pigments, growth and production of West Indian Cherry as a function of irrigation using waters with different salinity levels and potassium (K) fertilization, after grafting. The study was carried out in drainage lysimeters under greenhouse conditions, in a eutrophic Regolithic Neosol with sandy loam texture, in the municipality of Campina Grande, PB. The experiment was set in a randomized block design, to test two levels of irrigation water electrical conductivity - ECw (0.8 and 3.8 dS m-1) and four K2O doses - KD (50, 75, 100 and 125% of recommendation), with three replicates. The dose relative to 100% corresponded to 79.2 mg K2O kg-1 of soil. Irrigation with high salinity water stimulated the biosynthesis of chlorophyll b and carotenoids, while the chlorophyll a content and the growth of the cherry were reduced markedly in the post-grafting phase. The harmful effects of salinity on the total number of fruit and fresh mass of West Indian Cherry fruit were minimized with potassium fertilization.

Objetivou-se avaliar o efeito de substratos e ambientes para a produção de mudas de cajueiro anão precoce. O delineamento experimental foi inteiramente casualizado em um esquema fatorial 6 x 2, referente aos respectivos substratos (S1=25% areia + 50% solo + 25% húmus + 0g MB-4; S2=25% areia + 50% solo + 25% húmus + 50g MB-4; S3=25% areia + 50% solo + 25% húmus + 100g MB-4; S4=25% areia + 25% solo + 50% húmus + 0g MB-4; S5=25% areia + 25% solo + 50% húmus + 50g MB-4 e S6=25% areia + 25% solo + 50% húmus + 100g MB-4) e dois ambientes (Viveiro e Pleno sol), com 5 repetições. Os substratos S1 = 25% areia + 50% solo + 25% húmus + 0g MB-4 e S2 = 25% areia + 50% solo + 25% húmus + 50g MB-4, proporcionaram os melhores resultados de crescimento, acúmulo de matéria seca e qualidade, ás mudas de cajueiro. O ambiente viveiro com tela de sombrite de 50% foi o melhor ambiente para a produção de mudas do Cajueiro anão Precoce. O ambiente pleno solo em condições de clima semiárido é inadequado para a produção de mudas do Cajueiro anão Precoce.

A salinidade do solo e da água ocasionam distúrbios fisiológicos em plantas sensíveis, a exemplo das trocas gasosas em genótipos de citros, podendo-se identificar, a partir dessas variáveis, genótipos tolerantes e a resposta das plantas à salinidade. Assim, objetivou-se avaliar a tolerância de genótipos de citros à salinidade na fase de formação de porta-enxertos. O experimento foi desenvolvido em casa de vegetação, no Município de Pombal, Paraíba, empregando-se o delineamento experimental de blocos casualizados com três repetições e tratamentos arranjados em esquema fatorial, 5x8, relativos à combinação de: [i] cinco níveis de salinidade da água de irrigação (0,8; 1,6; 2,4; 3,2 e 4,0 dS m-1) e [ii] oito genótipos de porta-enxertos de citros: 1. limoeiro ‘Cravo Santa Cruz’ (LCRSTC); 2. tangerineira ‘Sunki’ comum (TSKC) x citrumelo ‘Swingle’ (CTSW) - 028; 3. TSKC x CTSW - 033; 4. TSKC x CTSW - 041; 5. limoeiro ‘Volkameriano’ (LVK) x limoeiro ‘Cravo’ (LCR) - 038; 6. tangerineira ‘Sunki da Flórida’ (TSKFL); 7. TSKC e 8. limoeiro ‘Rugoso da Flórida’ (LRF). Avaliaram-se as trocas gasosas das plantas aos 15, 30 e 60 dias após o início da aplicação de água salina. A salinidade da água reduziu as trocas gasosas de genótipos de citros, sendo mais evidente aos 15 dias após o início do estresse. Os genótipos limoeiro ‘Cravo Santa Cruz’, TSKC x CTSW – 041, LVK x LCR – 038 e o limoeiro Rugoso da Flórida têm comportamento fisiológico satisfatório durante os primeiros 30 dias de exposição ao estresse, sendo moderadamente tolerantes ao estresse salino. Os genótipos TSKC x CTSW – 033 e a tangerineira Sunki Comum são mais sensíveis à salinidade.

The objective of this work was to study the effects of irrigation with saline water associated with phosphate fertilization on the emergence and early growth of cowpea plants. The assay was conducted in the greenhouse of the Department of Environmental Sciences and Technology of the Federal Rural University of the Semi-Arid (UFERSA) in Mossoró-RN, during October and November of 2015. The study adopted a randomized block with treatments arranged in a 5 x 3 grid, corresponding to five levels of water salinity (0.5, 1.5, 2.5, 3.5 and 4.5 dS m-1) and three doses of superphosphate, based upon the soil analysis (60%, 100% and 140% of the recommended dose for the crop 60 kg P2O5 ha-1), with five repetitions. The cowpea plants, cv. Paulistinha, were grown in lysimeters with capacity of 8 dm3. During the first 15 days of the initial stage of development the plants were evaluated for emergence, growth and biomass accumulation. The increase in water salinity above 1.5 dSm-1 reduced the emergence, growth and dry matter accumulation of cowpea plants. The increase of 40% in the recommendation of phosphorus fertilization of cowpea increased the growth and biomass accumulation of shoot plants, regardless of salinity.

Objetivou-se com este trabalho avaliar o efeito da salinidade de água e proporções fósforo/nitrogênio sobre o crescimento, composição foliar de macronutrientes e sódio e a produção da aceroleira. A pesquisa foi realizada em ambiente protegido, em lisímetros preenchidos com Neossolo Regolítico de textura franco-argilosa e baixo teor inicial de fósforo. O experimento foi desenvolvido em ambiente protegido, em lisímetros com Neossolo Regolítico; o delineamento foi o de blocos casualizados com os tratamentos arranjados em esquema fatorial 5 x 4, referente aos níveis níveis de condutividade elétrica da água de irrigação - CEa (0,6; 1,4; 2,2; 3,0 e 3,8 dS m-1) e quatro proporções percentuais de fósforo e nitrogênio P/N (100:100; 140:100; 100:140 e 140:140% P/N), com três repetições. As doses de fósforo e nitrogênio correspondentes a 100% da recomendação de adubação fosfatada e nitrogenada foram de 45,0 g de P2O5 planta ano-1 e 23,85 g de N planta ano-1, respectivamente. As plantas de aceroleira foram conduzidas sob irrigação com água salina durante 365 dias, onde foram avaliadas quanto às características de crescimento, composição mineral foliar e produção. O aumento da salinidade da água de irrigação aumenta os teores de sódio nos tecidos a níveis prejudiciais ao crescimento, composição mineral foliar e produção da aceroleira. Adubação com 140% da recomendação de fósforo e de nitrogênio inibe a ação do estresse salino, promovendo maior produção das plantas de aceroleira irrigadas com água de até 3,0 dS m-1.

This study aimed to evaluate, in the second cycle, the growth and production of ‘Orelha-de-elefante Mexicana’ prickly pear (Opuntia sp.) under complementary irrigation with treated domestic sewage. The experiment was carried out in the Milagre Settlement, municipality of Apodi-RN, Brazil, from June 2016 to February 2017. Five treatments were evaluated, corresponding to four irrigation frequencies (2.3, 7.0, 14.0 and 21.0 days) to apply an effluent depth of 3.5 mm, and the control, rainfed cultivation (without irrigation). The experimental design was randomized blocks, with four replicates. After preliminary-primary treatment, the domestic sewage showed acceptable chemical and physical characteristics for fertigation under the conditions adopted in the prickly pear cultivation. 234 days after the 1st cut in the plants, the following morphometric characteristics were measured: plant height and length, width, perimeter, thickness and number of primary and secondary cladodes, and biomass accumulation. Complementary irrigation with treated domestic sewage effluent applied at intervals of 2.3, 7.0, 14.0 and 21.0 days allowed satisfactory growth and production of ‘Orelha-de-elefante Mexicana’ prickly pear; without irrigation, its development was substantially hampered during the dry period. Complementary irrigation with 3.5 mm of domestic sewage effluent applied at intervals of 2.3, 7.0 and 14.0 days led to highest growth and biomass accumulation in ‘Orelha-de-elefante Mexicana’ prickly pear.

Ethnopedological studies in family units tend to contribute to the academy with respect to the importance of knowledge exchange, allowing the understanding on the local reality of a community. The objective of this study was to conduct an ethnopedological study in production units at the Settlement Project Canto da Ilha de Cima – RN, Brazil, and to infer on their interrelationships of knowledge. Participatory workshops and transverse walks were carried out and soils were classified by means of Ethnopedology. The soils were classified using etic and emic approaches, respectively: Inceptisol - CAMBISSOLO HÁPLICO Carbonático típico (Terra Boa or Malhada de Boi) (P1); Oxisol - LATOSSOLO AMARELO Eutrófico típico (Terra de Arisco) (P2); Ultisol - ARGISSOLO VERMELHO AMARELO Eutrófico típico (Terra de Arisco Branco Amarelado) (P3); Oxisol - LATOSSOLO AMARELO Eutrófico típico (Terra de Piçarro) (P4); Ultisol - ARGISSOLO AMARELO Eutrófico abrúptico (Terra de Arisco) (P5) and Inceptisol - CAMBISSOLO HÁPLICO Tb Eutrófico típico (Terra Boa or Velha Chica) (P6 and P7). In the emic survey, farmers described as fertile and better for agricultural activities the soils in the following areas: “Terra Boa” or “Malhada do Boi” (P1) and “Velha Chica” or “Terra Boa” (P6 and P7), corroborating the etic classification, based on the parent material. The soils in these areas were classified as Inceptisols (CAMBISSOLOS), which have higher natural fertility.

Salvia hispanica seedlings have stood out for their potentialities in nutrients for agri-food industries. Nevertheless, studies related to this species are still scarce, especially with respect to agronomic factors that enable its propagation and development. Hence, this study aimed to evaluate germination, vigor and osmotic adjustment of S. hispanica seeds and seedlings subjected to water and thermal stress. The experimental design was completely randomized, with treatments arranged in factorial scheme, corresponding to five levels of polyethylene glycol (PEG 6000) (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and five temperatures (20, 25, 30 and 20-30 °C), with four replicates of 50 seeds in each treatment. Germination test was set on blotter paper, moistened with PEG 6000 solutions at the previously mentioned potentials, under 8-h photoperiod. The following variables were analyzed: germination, germination speed index, seedling shoot length, seedling root length, seedling dry matter and contents of chlorophyll, carotenoids, amino acids, proline and sugars. Polyethylene glycol levels of -0.4 MPa at all temperatures and -0.3 MPa at 30 °C and 20-30 °C enable germination and vigor of S. hispanica seedlings. S. hispanica seedlings are able to perform osmotic adjustment under water stress conditions up to the level of -0.3 MPa, when grown from seeds germinated at temperatures of up to 25 ºC.

Because of the food and industrial importance of tomato, it holds great significance, and is one of the most produced species using the hydroponic cultivation systems. The objective of this study was to evaluate the effects of different concentrations of nutrient solution on the production and quality of cherry tomatoes (Lycopersicon esculentum ‘Samambaia’) grown in a hydroponic system in protected conditions. The experiment was conducted in pots filled with coconut fiber substrate using a randomized complete block design with four replications and six plants per plot. Five concentrations of nutrients were evaluated (50, 75, 100, 125, and 150% of the standard nutrient solution); the solutions produced the following electrical conductivities: 1.8, 2.0, 2.6, 3.4, and 3.9 dS m-1, respectively. At 90 days after transplanting, the tomato fruits were harvested, at which time the production variables and post-harvest quality of mature fruits were determined. The best production and post-harvest quality indexes of cherry tomatoes (‘Samambaia’) were found when using 111% of the standard nutrient solution, corresponding to the concentrations of 9.44, 2.44, 2.22, 6.44, 4.11, 2.44, and 2.78 mmolc L-1, of NO3-, NH4+, P, K, Ca, Mg, and S, respectively; and 66.6, 55.5, 14.4, 1.89, 0.56, and 0.44 mmolc L-1, of Fe, B, Mn, Zn, Cu, and Mo, respectively. Nutrient solutions with electrical conductivity above 2.89 dS m-1 severely reduced the fruit yield of cherry tomatoes.

A busca por alternativas de adubação que diminuam ou até mesmo eliminem a utilização de fertilizantes minerais industrializados é uma realidade dentre os pequenos e médios produtores agrícolas nordestinos. O objetivo do trabalho foi avaliar as respostas morfofisiológicas da melancieira, em um cultivo sucessivo, à aplicação de doses de NPK, utilizando diferentes proporções de adubos minerais e orgânicos. O experimento foi realizado em uma área da Universidade Federal de Campina Grande (UFCG), Campus Pombal – PB (6º 48’ 16”S e 37º 49’ 15”W), durante o período de outubro de 2013 a janeiro de 2014. O delineamento foi em blocos ao acaso, com quatro repetições, dispostos em esquema fatorial 3 × 5. No fator (A), foram alocadas as doses de 50%, 100% e 150% da recomendação de NPK para melancieira e, no fator (B), cinco proporções de adubo mineral e orgânico (100/0, 75/25, 50/50, 25/75 e 0/100). A dose de 50% da recomendação de NPK favoreceu a maior atividade fotossintética das plantas de melancia no segundo ciclo de cultivo. Não houve diferença entre as concentrações de nutrientes estudadas no segundo ciclo da melancieira sobre os aspectos de produção e qualidade dos frutos, podendo-se optar pela menor concentração de nutrientes, 50%. Não houve diferença entre as proporções de adubo mineral e orgânico estudadas no segundo ciclo da melancieira sobre os aspectos de produção e qualidade dos frutos, podendo-se optar pela adubação orgânica sem perdas de rendimento.

The melon crop is normally developed in semiarid regions, where water resources are limited. This scarcity of water is a strong stressor on the crops, and requires the supplementation of existing water supplies with poor quality water, especially saline water. This can impede the growth and production of plants; however, the use of tolerant genotypes may minimize this problem. Thus, a greenhouse experiment was developed at the Federal University of Campina Grande - UFCG, Pombal Campus, Paraiba State, Brazil, in order to study the emergence, initial growth, and tolerance of melon cultivars irrigated with waters of different salt content. We studied three melon cultivars (Gaúcho Redondo, Gaúcho Casca de Carvalho and Halles Best Jumbo) irrigated with five levels of saline water (0.6; 1.2; 1.8; 2.4; and 3.0 dS m-1), arranged in a 3 x 5 factorial scheme, with the treatments distributed in a randomized block design with four replications. The plants seeds were monitored for 30 days after sowing, and at 30 days the growth and salinity tolerance index was evaluated. Cultivar Halles Best Jumbo was the most tolerant to saline water during initial stage of growth, while the Gaucho Redondo was more sensitive to salinity. It was found that saline waters up to 1.8 dS m-1 were suitable for irrigation of melon plants round Gaucho and waters up to 2.4 dS m-1 could be used for irrigation of Gaucho Casca de Carvalho and Halles Best Jumbo crops during the initial growth phase.

The quantitative and qualitative scarcity of water resources is a frequent problem in the semi-arid region of the Brazilian Northeast. The availability of water for irrigation with high salts contents is common, affecting the growth and development of the crops. Thus, it is necessary to adopt strategies that allow the establishment of irrigated cultivation in this region. The objective of this work was to evaluate the effect of water salinity and phosphorus/nitrogen combinations on the ecophysiology of the West Indian cherry grafted in the first year of cultivation. The research was carried out in a protected environment, in lysimeters filled with a Regolithic Neosol of loamy clay texture, having low initial phosphorus content. The experiment was arranged in a randomized block design, arranged in a 5x4 factorial scheme, with five levels of electrical conductivity of the irrigation water - CEa (0.6, 1.4, 2.2, 3.0 and 3.8 dS m -1) and four manures of fertilization with phosphorus and nitrogen (100: 100, 140: 100, 100: 140 and 140: 140% of the recommendation of P/N), with three replications, each plot consisting of one plant. Increased salinity of irrigation water reduced growth, photosynthesis and the production of West Indian cherry. Fertilization with 140% of the phosphorus and nitrogen recommendation minimizes the deleterious effect of salinity on West Indian cherry irrigated with water up to 3.0 dS m-1.

This study aimed to evaluate the growth and physiology of Annona squamosa seedlings under increasing irrigation depths and phosphorus doses. The experiment was conducted in protected environment, evaluating five irrigation depths and four P2O5- doses, arranged in 5 x 4 factorial scheme, in randomized blocks, with four replicates and one plant per plot. Treatments were irrigation depths of 60, 80, 100, 120 and 140% of the real evapotranspiration of the seedlings – ETr and phosphorus doses of 0, 350, 700 and 1050 mg dm-3 of P2O5-. Plants were evaluated at 120 days after transplanting with respect to growth, gas exchanges, leaf water potential and total dry matter accumulation. Phosphorus dose of 350 mg dm-3 promotes satisfactory dry matter accumulation for A. squamosa seedlings, especially under 100% ETr irrigation. Leaf water potential and gas exchanges of A. squamosa are affected by water stress, through both lack and excess of water. Stomatal conductance is the variable most sensitive to the lack of water, whereas photosynthesis and water use efficiency are the most sensitive to the excess of water. Irrigation depth of 100% ETr is ideal to produce A. squamosa seedlings, but the irrigation depth of 80% ETr can be used to produce these seedlings, disregarding small losses of growth.

The objective of the present work was to evaluate the effect of the organo-mineral foliar fertilization and the environment in the lettuce crop. The work was carried out in a soil classified as Quartzipsamments, with loam texture and low initial availability of nutrients. The experimental design used was randomized blocks with a factorial arrangement 2 x 2 x 5, corresponding to two cultivars of lettuce (Crisp Vanda and Crisp Lucy Brown), two environments (with and without shading mesh at 35%) and five concentrations of Ferti Garden liquid fertilizer multipurpose via foliar, (0; 5; 10; 15 and 20% of the product in the solution), with 4 repetitions, containing 20 plants. Soil preparation was done manually and fertilized with 30 m3 hectare-1 of bovine manure, dead cover was also used. The foliar fertilizer was applied three times, at intervals of seven days, through a constant pressure sprayer, from 12 days after transplanting the seedlings. At 33 days after the transplant the plants were harvested and evaluated in the variables of head diameter, number of leaves, fresh matter and productivity. The cultivar Crisp Lucy Brown proved to be more demanding in terms of luminosity and mineral nutrition in relation to the cultivar Crisp Vanda. Therefore, the highest development and productivity of the Crisp Lucy Brown cultivar is obtained without shading mesh, with fertilization before sowing of 30 kg ha-1 of fowl bed and fertilization with 9.1% of the foliar fertilizer. While for the cultivar Crisp Vanda the highest productivity is obtained with shading mesh, and only with fertilization before sowing.

Most plant species are susceptible to the effects of salinity, such as increases in osmotic potentials and deleterious ionic effects, which in turn affect water absorption in plants and, consequently, compromise germination and seedling growth. Hence, this study aimed to evaluate the effects of salinity on the germination, initial growth, and physiological and biochemical components of S. hispanica seedlings at different temperatures. The experimental design was completely randomized, with treatments distributed in a 5 x 4 factorial scheme with five saline concentrations (0.0 (control), 4.5, 9.0, 13.5, and 18.0 dS m-1) four temperature regimes (20, 25, 30, and 20-30°C), and four replicates of 50 seeds per treatment. The experiment evaluated the germination, growth, biochemical components (chlorophyll a, chlorophyll b, total carotenoids, amino acids, proline and sugars) and phytomass accumulation of S. hispanica seedlings. Saline levels higher than 4.5 dS m-1 together with treatment temperatures of 30 or 20-30°C negatively affected the germination, vigor, growth and biochemical components of the seedlings. The 25°C treatment temperature promoted the best conditions for the development of S. hispanica seedlings up to the saline level of 9.0 dS m-1.

The seminiferous propagation of the pomegranate tree is dramatically affected by the presence of a sarcotesta, which often makes this method of propagation unfeasible. Therefore, the aim of this study was to evaluate the production of rootstocks for Mollar pomegranate cuttings under different management techniques in the dry and wet seasons. Two experiments were performed, one in the dry season (August to December 2012, Experiment I), and another in the rainy season (January to June 2013, Experiment II). The experiments used a completely randomized design with four replications and five seedlings per plot. To monitor plant growth and physiology, a factorial scheme using two factors, management of softwood cuttings (cuttings with leaves; cuttings without leaves; and cuttings without leaves, but with an incision at the base) and evaluation times (60, 70, 80, 90, and 100 days after planting [DAP] in Experiment I and 60, 70, 80, 90, 100, 110, 120, 130, 140, and 150 DAP in Experiment II) was adopted. The propagation material was collected from commercial plants, from the median portion of the branch. The cuttings were approximately 15 cm long. Cuttings without leaves with an incision at the base were more suitable for vegetative propagation of Mollar pomegranate trees, regardless of season (dry or wet). Seedlings grown in the rainy season had higher survival rates and higher root and shoot growth. The use of cuttings with leaves for the vegetative propagation of the Mollar pomegranate tree in the dry season is not feasible. The best time to transplant Mollar pomegranate tree seedlings, in the rainy season, is at 130 DAP, at an average height of 45 cm.

Objetivou-se avaliar variações no crescimento, na partição de assimilados e na produção de frutos de melão, tipo Amarelo 'Gold Mine', sob cultivos sombreados por diferentes malhas. O experimento foi conduzido na Horta de Pesquisas do Departamento de Fitotecnia da Universidade Federal de Viçosa, no período de 24/11/2008 a 11/03/2009. Os tratamentos foram constituídos de quatro ambientes de cultivo: controle (pleno sol) e sob as malhas Aluminet(r) 30%-O, Cromatinet(r) 30%-O e Sombrite(r) 30%, com reduções, na radiação solar incidente, de 30,8, 35, e 32,0%, respectivamente. O delineamento experimental foi o inteiramente casualizado, com quatro repetições. Para as características avaliadas periodicamente, utilizou-se o esquema de parcela subdividida com os ambientes alocados nas parcelas e as avaliações periódicas nas subparcelas. Dentre os ambientes sombreados, o cultivo do meloeiro sob a malha Aluminet(r) 30%-O foi o tratamento que mais se destacou em termos de crescimento de planta e produção de frutos