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Mango production presents challenges, such as the maturation of the mango branches, which, combined with good nutrition and biochemicals involved in this process, such as carbohydrate and starch favor the development of the plant. Therefore, the use of non-destructive, fast techniques to determine the levels of these components in the plant, such as spectroscopy, can optimize the analysis of these components. Therefore, this work aimed to develop predictive models for determination of starch and carbohydrate contents in “Palmer” mango leaves using vis-nir spectroscopy subjected to different potassium sources. The work was carried out in the region of San Francisco Valley, using the following steps: (1) leaf sampling; (2) spectral analysis; (3) lab determination of carbohydrate and starch contents; and (4) development of predictive regression and classification models. The predictive regression models used were Principal Components Regression (PCR) and Partial Least Squares Regression (PLSR). Supervised discriminant models were also developed to classify mango leaves according to different potassium sources used, using linear discriminant analysis (LDA). Vis-NIR spectroscopy showed low values for the non-destructive evaluation of “Palmer” mango leaves using PCR and PLSR for carbohydrate and starch prediction with R2 of 0.58 lower than the models considered excellent (R2 >0.90); The development of classification models did not allow the discrimination of different sources of potassium in “Palmer” mango leaves with an accuracy of 64.2%.

Background. The melon plant is herbaceous annual plant with a large social and economic relevance in Brazil, specially to the Northeast in of the country. Given the importance of this culture to the region, there is enormous demand for information trying to define a productive system that presents cost-saving, increases productivity, and achieve the minimum standards of fruit quality. In this scenario, a lot of researches were made as a way of trying to potentialize the organic production systems. Objective. The purpose of this work was to verify the different melon cultivars/types behavior, when it comes to the quality and production when cultivated under irrigation in organic production system. Methodology. The work was developed between the months of July and October in 2014, in the Hortvida rural propriety. The experimental design was a randomized block with treatments applied to seven different types of melon (Zelala Harpér, Magisto F1 Cant, Medellín Pele de Sapo, Hibrix F1 Amarelo, Yelogal F1 Gália, Magritte F1” and Solarnet Gália) with four repetitions. Morphological, qualitative and yield characteristics of melon fruits were analyzed. Results. The highest yields were obtained for cultivars Medellín Pele de Sapo (45.19 t ha-1) and Hibrix F1 Amarelo (34.24 t ha-1). Implications. The system of organic production of irrigated melon in the semiarid region of Rio Grande do Norte maintained the productivity of most cultivars above 25 t ha-1, however, the content of soluble solids was higher for only three cultivars. Conclusions. The cultivar Medellín Pele de Sapo was the most productive one, but it also presented low soluble solids content.

The aim of this study was to evaluate the influence of pre-harvest application of plant biostimulant Crop Set® and different plant spacings on the production attributes and postharvest quality of watermelon ‘Quetzali’. The experiment was set up in a completely randomized split-plot (3 × 2 × 4) design, corresponding to three plant spacings (0.40, 0.45 and 0.50 m), application of the plant biostimulant (with and without) and four storage periods at 10°C and RH 90% (0, 14, 21 and 28 days). Fruits were assessed after harvest in terms of average mass of fruits, number of fruits per plant and yield, and throughout the storage periods for flesh firmness, soluble solids content (SSC), titratable acidity (TA), SSC/TA ratio, pH and total soluble sugars (TSS). The average mass of fruit (4.02 kg) was higher in the larger spacing without application of biostimulant. The pre-harvest application of plant biostimulant negatively influenced SSC of fruits, depending on the plant spacing and storage periods. For TA and TSS content, the effect of this product varies with plant spacing and storage days. The lower plant spacing provided higher TSS to the fruits.

This work was carried out with the objective to study the foam-mat drying of Cereus jamacaru pulp fruit with albumen (2%) and “Super Liga Neutra” (2%) with whipping time of 5 min, dried in oven with air circulation at 70; 80, and 90 °C with three different foam thicknesses (0.5; 1.0 and 1.5 cm). The drying curves were fitted with the Page, Henderson and Pabis and Cavalcanti Mata models. Drying time was influ- enced by the foam thickness and process temperature being the process faster for smaller thickness and higher temperature. He Cavalcanti Mata model presented the best fit of the experimental foam drying kinetics data.

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.

Yellow or sour passion fruit is a climacteric fruit with a high rate of respiration and ethylene production, and postharvest technology is needed to extend its shelf life. This study investigated the properties of a biocomposite film with chitosan (CH) incorporated with beeswax (BW) and graphene oxide (GO) nanoparticles for use as an edible coating to extend the shelf life of yellow passion fruit at 22 °C and 70% RH for eight days. CH films associated with BW showed lower water vapor permeability (WVP) than films with CH alone. However, adding GO to the CH + BW biopolymer matrix improved the WVP, decreased the solubility (12.8%), and increased the opacity of the film by 9% compared to those of the CH film. Fruits coated with CH + BW or CH + BW + GO exhibited a reduction in respiration rate, a slower ripening process by approximately 3 days, and a significant decrease in weight loss. This also resulted in a higher soluble solids content and increased antioxidative capacity of the pulp. The incorporation of GO into the CH + BW matrix resulted in a more pronounced delay of fruit ripening, as evidenced by the lower depigmentation of the peel at eight days, with a lightness approximately 10.7% lower at 54.92, a chroma value 16.5% lower at 49.33, a hue angle 7.2% higher at 92.56, a soluble solid (SS) content 16.7% higher at 11.32°Brix, and an acidity 31.9% higher at 4.18% compared to the control. Furthermore, the biopolymer packaging led to a higher consumer acceptance score for the fruit.

Sweet sorghum (Sorghum bicolor [L.] Moench) is a plant that can be an alternative for the production of bioethanol in semi-arid regions. The objective of this work was to evaluate sweet sorghum 'BRS 506' under salt and water stress. The experimental design was in randomized blocks, in a factorial scheme (4x4), with the first factor referring to the electrical conductivities of the irrigation water (1.5; 3.0; 4.5; and 6.0 dS m-1) and the second refers to irrigation depths (53, 67, 85 and 95% of crop evapotranspiration). Gas exchange, leaf water status, leaf sugars and plant growth were evaluated. Salt and water stress cause negative effects on the growth of sweet sorghum 'BRS 506'. Salt stress causes disturbances in gas exchange and sugar levels. Sweet sorghum 'BRS 506' is tolerant to combined salt and water stress.

Grown in different regions of Brazil, mango is of great importance at the national level. However, mango cultivation is directly related to physiological factors such as photosynthesis, stomatal conductance and chlorophyll. Physiological factors are related to the nutritional balance of the plant. Among the nutrients, potassium (K) can be highlighted, which, despite not being a structural element for the plant, stimulates, or is part of several physiological plant processes. Therefore, an experiment was carried out with the purpose of evaluating, in the vegetative period of 'Palmer' mango, the effect of different sources of K to accelerate the maturation stage of mango branches and verify their influence on physiological indexes and chlorophyll. Treatments consisted of three ripeners and a control, which were applied directly to the branches and leaves of “Palmer” mango trees. The variables analyzed were chlorophyll A, B and Total indexes; Internal concentration of CO2; Stomatal conductance; transpiration rate; Net photosynthesis; Instantaneous Carboxylation Efficiency and Water Use Efficiency. After collecting, and analyzing the data, it was concluded that the vegetative period of the “Palmer” mango tree, in relation to the different evaluation dates, was not influenced by potassium sources. The use of T4 treatment (SpeedFol® induction mango) can provide a greater increment of chlorophyll A, B and Total than KCl and K2SO4.

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.

Water scarcity is one of the main abiotic factors that limit agricultural production. In this sense, the identification of genotypes tolerant to water deficit associated with irrigation management strategies is extremely important. In this context, the objective of this study was to evaluate the morphology, production, water consumption, and water use efficiency of colored fiber cotton genotypes submitted to irrigation strategies with a water deficit in the phenological phases. Two experiments were conducted in succession. In the first experiment, a randomized block design was used in a 3 × 7 factorial scheme, corresponding to three colored cotton genotypes (BRS Rubi, BRS Jade, and BRS Safira) in seven irrigation management strategies with 40% of the real evapotranspiration (ETr) varying the phenological stages. In the second experiment, the same design was used in a 3 × 10 factorial arrangement (genotypes × irrigation management strategies). The water deficit in the vegetative phase can be used in the first year of cotton cultivation. Among the genotypes, ‘BRS Jade’ is the most tolerant to water deficit in terms of phytomass accumulation and fiber production.

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.

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 The soil attributes can be easily changed according to its management and use, compromising the productive capacity of the areas. The objective of this research was to evaluate the variability and interrelationships of soil physical, chemical and structural attributes in agroecosystems in the Brazilian Semiarid region (Rio Grande do Norte State), pointing out the most sensitive attributes in the environment distinction through multivariate analysis. The research was carried out in the rural community of Piracicaba, Upanema municipality, Rio Grande do Norte State, Brazil. Four agroecosystems were selected: Native Forest Area (ANF), Corn Bean Consortium Area (ACBC), Pasture Area (AP) and Cashew Area (AC). Undisturbed and deformed soil samples were collected in the 0.00-0.10, 0.10-0.20 and 0.20-0.30 m layers, and the physical, chemical and structural attributes were analyzed. The data were submitted to multivariate statistical techniques, using the correlation matrix, cluster analysis, factor analysis and principal component analysis. Factorial analysis revealed the most sensitive attributes in distinguishing agroecosystems: microporosity, field capacity (FC), permanent wither point (PWP), available water (AW), sand, clay, flocculation degree (GF), Ca2+, Mg2+ and sum of bases (SB) (F1) and soil density (SD), total porosity (PT), macroporosity, electrical conductivity (EC) and total organic carbon (TOC) (F2). Cluster analysis formed three distinct groups. The TOC was discriminant to group the native forest and cashew tree areas, showing the influence of soil management. The other environments were grouped according to the texture differentiation, influencing the attributes variability.

Worldwide, Brazil holds the fifth position in melon fruits exportation, further expanding its products to provide for the growing demand. This expansion is the result of the development and application of new technologies, including the management of the use of biostimulants. However, for melon crops, the information in the literature on the use of biostimulants remains limited to the effects of different doses on fruit quality at the time of harvest. Therefore, this study aimed to evaluate the influence of different methods of pre-harvest application of two biostimulants on the production and postharvest conservation of fruits of yellow melon cv. Iracema. The treatments consisted of a combination of three factors: two plant biostimulants (Crop Set® and Spray Dunger®), two application methods of the products (fertigation and spraying), and five times of postharvest storage (0, 14, 21, 28 and 35 days). An additional control treatment corresponded to plants without biostimulant application. The fruits were evaluated for production and physicochemical attributes: average mass, yield, flesh firmness, titratable acidity, soluble solids content, SSC/TA ratio, pH, total soluble sugars, and weight loss. Fertigation is the recommended application method of biostimulants for yellow melon due to its effect on the increase of average mass, yield, flesh firmness, soluble solids content, and total soluble sugars of the fruits in relation to the spraying method.

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.

O Nordeste brasileiro destaca-se na produção e exportação de melão. Parte dos solos desta região onde se concentram os plantios da cultura é de origem calcária, assim como a água de irrigação utilizada. Estas condições, ao longo de cultivos sucessivos, podem causar a alcalinização do solo devido ao acúmulo de cátions de caráter básico do complexo de troca, como Ca, Mg, K e Na, em solos que já são ricos em bases, influenciando a disponibilidade de nutrientes e, consequentemente, a produtividade das culturas. Baseado no exposto, o trabalho teve por objetivo identificar as relações catiônicas (K:Mg:Ca) do solo que melhor correlacionam com atributos indicadores de produção de melão Gália. Para isto, foram realizados dois experimentos, em dois anos consecutivos (2017 e 2018), em delineamento em blocos ao acaso, com cinco tratamentos e cinco repetições, consistindo das seguintes relações catiônicas (K:Mg:Ca) para o experimento I, cujo solo apresentava 0,40 cmolcdm-3 de K: T1 (1:3:34); T2 (1:3:21); T3 (1:3:9); T4 (1:0,8:9) e T5 (1:11:34) e experimento II, em que o solo tinha 0,56 cmolc dm-3 de K: T1 (1:1,6:29,8); T2 (1:1,4:13,3); T3 (1:1,4:8,5); T4 (1:0,5:8,5); T5 (1:4,8:29,8). Foram avaliadas as seguintes características: análises químicas do solo durante a fase de floração e final do ciclo, concentração de nutrientes na folha diagnóstica na fase de frutificação, produção total, produção comercial, massa média total, massa média comercial, número de frutos total e número de frutos comercial por planta. As relações catiônicas influenciaram a massa média total e comercial dos frutos apenas no experimento I, mas não o rendimento, indicando que os teores absolutos altos de K e médio a alto de Mg, quando combinada com a água de irrigação do aquífero arenito Açu, associada à fertirrigação, já são suficientes para suprir a necessidade dos nutrientes K e Mg, dispensando, assim, correção da relação catiônica.

The experiment was conducted in 2014, in a completely randomized factorial design (5x6), with three replications. The factors were soil classes (Typic Ustipsamments, Typic Haplustults, Typic Haplustepts, Typic Ustifluvents, and Typic Haplusterts) and levels of irrigation water salinity (0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 dS m-1). Increasing salinity of irrigation water caused increase in leaf contents of macronutrients in all soils. Adequate leaf contents of N, K, and Mg were observed in plants grown in all soils except K in Typic Haplusterts and Mg in Typic Ustipsamments. Appropriate P levels were observed only in Typic Haplustepts, and Ca only in Typic Haplustults and Typic Ustifluvents. Increased salinity of irrigation water caused increased leaf contents of micronutrients in all soils except copper in Typic Ustifluvents, iron in Typic Haplusterts and Typic Haplustults, and manganese in Typic Ustipsamments and Typic Haplustults.

The objective of the present study was to evaluate the salinization process and the changes in the chemical properties of an Acrisol cultivated with melon irrigated with water of different saline concentrations. The experiment was carried out in the field conditions using the experimental design of randomized blocks, arranged in split-plot. The plots were composed of salinity levels of irrigation water, expressed in terms of water electrical conductivity (ECw): 0.54; 1.48; 2.02 dS m-1; and the sub-plots for melon cultivars: Sancho and Medellín (Toad Skin), Mandacaru (Yellow), Nectar (Galia) and Sedna (Cantaloupe). Soil samples were collected at the beginning and end of the crop cycle to evaluate the changes in the physical-chemical properties of the soil. The electrical conductivity of saturation extract in the soil profile varied for each cultivar, observing high salinity values in soils with cultivars with lower water demand (Sedna and Nectar). The salinity of the soil was lower than the electrical conductivity of the irrigation water in the treatments with high values of ECw. The soil pH values showed little reaction in relation to the initial values. The exchangeable sodium percentage values were approximate twice the sodium adsorption ratio of the saturation stratum.

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.

Bell peppers are sensitive to salinity; therefore, it is necessary to find alternatives to reduce saline stress. An experiment was conducted in a greenhouse at Federal Rural University of the Semi-Arid Region, in Mossoró, Rio Grande do Norte State, Brazil, to evaluate the effects of salinity and K+/Ca2+ ratios on bell pepper production. The experimental design consisted of randomized blocks in a 5 x 4 factorial scheme with four replicates, corresponding to five K+/Ca2+ ratios (F1 = 3.3/1, F2 = 2.8/1, F3 = 2.2/1, F4 = 1.8/1, and F5 = 1.5/1) and four salinity levels in the nutrient solution using NaCl (1.75, 3.25, 4.75, and 6.25 dS m-1). The following parameters were evaluated: the number of fruits (total, marketable and unmarketable), the mean weight of fruits (marketable and unmarketable), fruit production (total, marketable and percentage of marketable fruits) and a salinity tolerance index. Generally, nutrient solution enrichment with K+ or Ca2+ did not cause significant increments in bell pepper yield. The fertigation treatments F2, F3, and F5 led to a higher bell pepper tolerance to salinity, allowing waters with higher salt concentrations to be used without causing a reduction in the yield.

The quality of seedlings of tree species is crucial to succeed in reforestation project or commercial exploitation. This work was to evaluate the influence of two environments (AMB-1, greenhouse; AMB-2, plastic camera installed inside the greenhouse) and concentrations of nutrients applied by fertigation (0; 50; 100 and 150% of a patterns nutrient solution) in the production of seedlings of Tabebuia aurea using design was completely randomized, with four replications. The following growth characteristics were evaluated: height, stem diameter, number of leaves, leaf area, dry matter aerial part, dry root matter, dry root weight, total dry matter, height/stem diameter ratio, specific leaf area, leaf area ratio and Dickson quality index (IQD). Data analysis revealed that there was significant interaction between the factors for most variables. The use of the plastic chamber (AMB-2) provided greater growth of Tabebuia aurea seedlings. Fertigation solutions with nutrient concentrations varying from 80 to 100% of the standard solution provide better quality Tabebuia aurea seedlings.

The northeastern semiarid region faces some of the droughts of the last centuries, resulting in serious reductions of agriculture yields. The water scarcity for agricultural requires rational use practices and reuse of water, such as use of domestic effluent sewage. Alternatively, the use of treated domestic sewage effluent utilizing for irrigation of forage species, such as the forage cactus, can be highlighted. In order to evaluate the effects of fertirrigation with treated sewage effluent on mineral nutrient composition of forage cactus (Opuntia Tuna L. Mill, Mexican elephant ear), an experiment was carried out utilizing a split plot 3 x (4 + 1) with a randomized complete block design randomized block and four replications, being three planting density (66,667.00, 52,282.00 and 33,333.00 plants ha-1) and two water sources associated with irrigation frequency of plates fixed on 3.5 mm per irrigation (Frequencies of 2.3 days with water tap and 7, 14 and 21 days with Sewage Effluent) and cactus cultivated in Rainfed agriculturerainfed (control). The analyze of the nutritional contents of cladodes indicated that there was a significant effect of the intervals from irrigation events only for Ca and Mg concentrations. The highest levels of Ca and Mg were found with the irrigation frequency of 2.3 using tap water. The macronutrients concentration in greater quantity by the forage cactus were N e, K followed by, Ca, Mg and P. The nutritional balance indicated excess of K and P and deficiency of N, Ca and Mg, in this order.

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.

Objetivou-se avaliar a eficiência do uso de nitrogênio (N) e potássio (K) em pimentão cultivado em ambiente protegido, em função de diferentes manejos de fertirrigação. Utilizou-se o delineamento em blocos casualizados, em esquema fatorial 3 × 6, com quatro repetições. Os tratamentos consistiam na combinação de três manejos de fertirrigação (M1 - fertirrigação a partir da marcha de absorção; M2 - fertirrigação a partir do monitoramento da concentração de íons de N e K na solução do solo; M3 - fertirrigação a partir do monitoramento da condutividade elétrica da solução do solo), com seis níveis em porcentagem de N e K (N0K0, N50K50, N100K100, N150K150, N200K200 e N300K300) da dosagem desses nutrientes recomendada para a cultura do pimentão. As variáveis mensuradas foram: rendimento, eficiência agronômica, eficiência fisiológica, eficiência de recuperação e eficiência de absorção. A maioria dos índices de eficiência analisados apresentou redução em consequência do aumento das doses. O manejo da fertirrigação, a partir do monitoramento da concentração de íons de N e K, assim como da condutividade elétrica na solução do solo, mostrou-se mais eficiente do que o manejo baseado na marcha de absorção da cultura.

RESUMO O uso de bioestimulantes tem se difundido na agricultura brasileira, promovendo o crescimento e aumento na produtividade das culturas, mas ainda são incipientes estudos sobre o uso destas substâncias em plantas sob estresse, principalmente sobre estresse salino. Objetivou-se avaliar o uso de bioestimulante como agente amenizador do estresse salino na cultura do milho pipoca. O experimento foi conduzido em ambiente protegido no Campus da Universidade Federal Rural do Semi-Árido, em Mossoró-RN. Utilizou-se o delineamento experimental inteiramente casualizado, com os tratamentos distribuídos em esquema fatorial 2 x 4, referentes a dois níveis de salinidade da água de irrigação (0,5 e 4,5 dS m-1) e quatro doses de bioestimulante aplicado via tratamento de sementes (0; 5; 10 e 20 mL kg-1 de sementes), com cinco repetições. Utilizou-se o bioestimulante comercial Stimulate® (0,009% citocinina, 0,005% giberelina e 0,005% de auxina) e as plantas foram coletadas aos 50 dias após a semeadura. Foram avaliadas as seguintes variáveis: altura de plantas, diâmetro do colmo, número de folhas, área foliar, massa seca de colmo, massa seca de folhas, massa seca de raiz, massa seca de pendão, massa seca total e área foliar específica. O uso de água salina na irrigação provocou redução na maioria das variáveis de crescimento do milho doce, independentemente do tratamento de sementes com bioestimulante. O tratamento de sementes com Stimulate® promove o desenvolvimento de plantas de milho pipoca, mais não inibiu nem amenizou o efeito da salinidade sobre as plantas.

Brazil is a major world producer of garlic, however, despite having both the conditions of soil and climate that are favourable to the crop, and having abundant manpower, the country has not yet reached selfsufficiency in garlic production, and it is therefore necessary for it to be imported. The aim of this study was to evaluate 11 garlic cultivars under the conditions found in the town of Governador Dix-Sept Rosado, in the state of Rio Grande do Norte, Brazil. The experimental design was of randomised blocks with four replications. The treatments consisted of the following garlic cultivars: Amarante, Branco Mossoró, Cateto Roxo, Catiguá, Caturra, Centenário, Chileno PR, Chinês Real, Gravatá, Mexicano e Morano Arequipeno. The characteristics being evaluated were: percentage of emerged plants, plant height, number of live leaves, bulb diameter (DB), total plant fresh matter (MFTP), final plant stand (EF), mean weight of differentiated bulbs (MMBD), percentage of differentiated bulbs (PBD), total bulb production (PTB), bulb classification, number of bulbils per bulb (NBB), bulbil classification and pith index. The cultivars Branco Mossoró, Cateto Roxo, Caturra, Centenário, Chinês Real, Gravatá e Mexicano had a higher proportion of differentiated bulbs of a larger diameter, demonstrating greater adaptability to the conditions of Governador Dix-Sept Rosado. The cultivars showing the best agronomic performance, and therefore more suitable for planting in the town of Governador Dix-Sept Rosado, are Branco Mossoro and Centenário.= O Brasil é um dos grandes produtores de alho do mundo, entretanto, apesar de possuir condições edafoclimáticas favoráveis à cultura e contar com mão de obra abundante, ainda não alcançou a autossuficiência na produção de alho, sendo, por isso, necessária a sua importação. Objetivou-se com este trabalho avaliar 11 cultivares de alho nas condições do município de Governador Dix-sept Rosado-RN. O delineamento experimental foi em blocos casualizados, com quatro repetições. Os tratamentos constituíramse das seguintes cultivares de alho: Amarante, Branco Mossoró, Cateto Roxo, Catiguá, Caturra, Centenário, Chileno PR, Chinês Real, Gravatá, Mexicano e Morano Arequipeno. As características avaliadas foram: percentagem de plantas emergidas, altura de plantas, número de folhas vivas, diâmetro de bulbos (DB), massa fresca total das plantas (MFTP), estande final de plantas (EF), massa média de bulbos diferenciados (MMBD), percentagem de bulbos diferenciados (PBD), produção total de bulbos (PTB), classificação dos bulbos, número de bulbilhos por bulbo (NBB), classificação dos bulbilhos e índice de chochamento. As cultivares Branco Mossoró, Cateto Roxo, Caturra, Centenário, Chinês Real, Gravatá e Mexicano apresentaram maior percentagem de bulbos diferenciados com maior diâmetro, indicando maior adaptabilidade às condições de Governador Dix-sept Rosado-RN. As cultivares com melhor desempenho agronômico e, portanto, mais indicadas para plantio no município de Governador Dix-sept Rosado-RN, são Branco Mossoró e Centenário.

Melon plants (Cucumis melo L.) are grown in the state of Rio Grande do Norte (RN), the largest producer of melons in Brazil, with plastic mulch and agrotextiles. Studies of crop evapotranspiration (ET) under these conditions are required to ensure adequate irrigation. This study aimed to determine the crop coefficients (Kc) of irrigated melon plants grown with mulch and agrotextiles in the region of Mossoró, RN, based on the Bowen Ratio Energy Balance (BREB) method. Two experiments were conducted at different times during the 2009/2010 season in a melon producing area (4°59'52" S, 37°23'09" W, and 54 m elevation) to define ET and Kc. Due to the plastic cover and reduced precipitation during the experiments, the Kc obtained by the BREB method was considered the basal Kc - KcbBREB. The results were compared with the Kcb from the FAO 56 Bulletin. There was close agreement between BREB and FAO ET measurements (12 % underestimation by the FAO method for the entire crop season), with sizeable differences only during the initial phenological stage. The mean KcbBREB values of the two field campaigns were 0.26, 0.96 and 0.63 for the initial, midseason and late stages, respectively. The high KcbBREB value in the initial growth phase may be related to the effect of the plastic mulch and agrotextiles on the energy balance at the surface. The relationship between KcbBREB and fc had high correlation, making possible an estimation of the melon Kcb based on the level of crop ground cover.

This work had as objectives to use the Sunn Hemp (Crotalaria juncea L.) to evaluate the residual effect in the soil of levels of water salinity and nitrogen doses, and the occurrence of spatial dependence within the experimental area. In previous years, the experimental area received six consecutive trials, which tested different levels of nitrogen and water salinity on different crops. The same experimental design was applied to this trial, that is, a randomized block design with split-plots (5 x 3), corresponding to the residual effect of water salinity and nitrogen, and four replications. The variables determined were: the plant height on six dates after the sowing, and the dry mass of the shoot, root and the whole plant. The data were firstly subjected to the variance analysis of the residual effects and to the study of spatial variability through geostatistics. The variance analysis did not show significant residual effects of the levels of salinity and nitrogen doses in the soil on the height and dry mass of Sunn Hemp. It was observed a spatial dependence, from moderate to high, in all dates, for height and dry mass of Sunn Hemp.

Melon is one of the most demanding cucurbits regarding fertilization, requiring knowledge of soils, crop nutritional requirements, time of application, and nutrient use efficiency for proper fertilization. Developing support systems for decision-making for fertilization that considers these variables in nutrient requirement and supply is necessary. The objective of this study was parameterization of a fertilizer recommendation system for melon (Ferticalc-melon) based on nutritional balance. To estimate fertilizer recommendation, the system considers the requirement subsystem (REQ), which includes the demand for nutrients by the plant, and the supply subsystem (SUP), which corresponds to the supply of nutrients through the soil and irrigation water. After determining the REQtotal and SUPtotal, the system calculates the nutrient balances for N, P, K, Ca, Mg, and S, recommending fertilizer application if the balance is negative (SUP < REQ), but not if the balance is positive or zero (SUP ≥ REQ). Simulations were made for different melon types (Yellow, Cantaloupe, Galia and Piel-de-sapo), with expected yield of 45 t ha-1. The system estimated that Galia type was the least demanding in P, while Piel-de-sapo was the most demanding. Cantaloupe was the least demanding for N and Ca, while the Yellow type required less K, Mg, and S. As compared to other fertilizer recommendation methods adopted in Brazil, the Ferticalc system was more dynamic and flexible. Although the system has shown satisfactory results, it needs to be evaluated under field conditions to improve its recommendations.

Desde o ano de 2001, na região do agropolo de Mossoró/Assu-RN, o agrotêxtil é utilizado como proteção de plantas contra pragas da cultura do meloeiro. Este experimento teve como objetivo avaliar a produção e a qualidade de dois híbridos de melão Cantaloupe, em cultivo protegido, temporariamente, com agrotêxtil. O trabalho foi realizado na Horta da Universidade Federal Rural do Semi-Árido (UFERSA), em Mossoró-RN, de julho a outubro de 2010. O delineamento experimental foi de blocos casualizados completos, com quatro repetições, dispostos no esquema de parcelas subdivididas no espaço. As parcelas foram representadas pelo número de dias após o transplante das mudas (DAT), em que as plantas permaneceram sob proteção de agrotêxtil (0; 18; 21; 24; 27 e 30 DAT) e, as subparcelas, por dois híbridos F1 de melão Cantaloupe: 'Acclaim' e 'Caribbean Gold RZ'. Foram avaliadas características de produção e de qualidade. Os tratamentos com proteção temporária com agrotêxtil não afetaram a produtividade total dos dois híbridos; todavia, a firmeza de polpa apresentou aumento crescente, enquanto a acidez total titulável, os açúcares solúveis totais, os sólidos solúveis e o pH apresentaram redução com o aumento do tempo de permanência do agrotêxtil sobre as plantas. O 'Caribbean Gold RZ', em comparação com o 'Acclaim', apresentou maior produtividade comercial para exportação, maior massa média de frutos, mais firmeza de polpa, maior acidez total titulável, maior teor de sólidos solúveis e menor pH.

A melancia (Citrullus lanatus) é originária das regiões tropicais do continente africano, sendo cultura de grande importância na China, África, Índia e em outras regiões tropicais do mundo. O trabalho teve como objetivo verificar os teores de macronutrientes durante o ciclo da melancia cultivada com fertirrigação. O delineamento experimental utilizado foi em blocos casualizados em arranjo fatorial de 4 x 4, resultando em 16 tratamentos, com 3 repetições, totalizando 48 parcelas experimentais. Foi feito uma média dos valores para determinação das curvas de teor de nutrientes (g Kg-1) na planta. Os nutrientes nitrogênio, fósforo e potássio apresentaram comportamento similar, com um aumento do teor no início do ciclo e acompanhado de uma redução durante todo o ciclo da cultura, exceto no final, onde apresentaram um pequeno aumento. O teor de cálcio e magnésio apresentaram um teor quase constante, com uma mínima redução ao longo do ciclo.

A melancieira é uma planta cultivada praticamente em quase todo o Brasil, desde regiões mais frias do Rio Grande do Sul até regiões mais quentes do Nordeste brasileiro. O trabalho teve como objetivo estudar o teor de nutrientes na melania cultivada via fertirrigação. O delineamento experimental utilizado foi em blocos casualizados em arranjo fatorial de 4 x 4, resultando em 16 tratamentos, com 3 repetições, totalizando 48 parcelas experimentais. Foi feito uma média dos valores para determinação das curvas de teor de nutrientes (g Kg-1) na planta. O teor de nitrogênio e potássio apresentaram uma redução no inicio do ciclo e um aumento no final. O fósforo apresentou uma redução decrescente apresentando comportamento linear.A massa seca paresentou seu maior valor aos 55 DAT, com resultado médio de 370 g planta-1

The objective of this work was to evaluate the effect of N and P2O5 rates through irrigation water on the uptake of macro and micronutrients by watermelon crop. The study was conducted at the farm Santa Luzia, in Mossoró, in the State of Rio Grande do Norte, Brazil (5° 05’ 57”S e 37° 33’ 16”W). The experimental design was completely randomized blocks with strip cropping (4 x 4) x 2, resulting and thirty two treatments with three replicates. The treatments consisted in the application of four N rates (0; 48; 121; 218 kg ha-1) combined with four rates of P2O5 (0; 88; 220; 397 kg ha-1) with two cultivars of watermelon. No deficiency of N, P, K, Ca, Mg, Fe and Mn in the watermelon leaves was found in any treatment, excepting Cu and Zn. The N and P2O5 rates, as well as the interaction, provide significant effect on contents of macronutrients in the watermelon leaves. Macronutrients most absorbed by the leaves of watermelon were N>Ca>K>Mg>P.

Na cultura da melancia, a nutrição mineral é um dos fatores mais importante que contribui diretamente na produtividade e qualidade dos frutos. O nitrogênio e o potássio são os dois nutrientes mais exigidos, e deve ser aplicado de acordo com as exigências de cada cultivar.O trabalho teve como objetivo avaliar o crescimento e a marcha de absorção de cultivares de melancia sob diferentes doses de nitrogênio e potássio. O experimento, com as duas variedades de melancia, foi conduzido no delineamento experimental em blocos casualizados no esquema de parcelas subdivididas 13 x 2, sendo o primeiro fator representado pela combinação de doses de nitrogênio (N) e potássio (K) em arranjo definido segundo o modelo: 2 x 2k+ 2k + 1, sendo k o número de fatores estudados (N e K). Os totais de N, P e K acumulados no tecido vegetal não variaram com as doses de N ou K aplicadas em fertirrigação.Os máximos valores acumulados de N total foram aos 62 (10,9 g planta-1) e 61 DAT (13,31 g planta-1), para as cultivares Quetzali e Leopard. Para P total o valor máximo ocorreu aos 57 DAT (1,88 g planta-1) e para o K aos 64 DAT (15,15 g planta-1), independentes da cultivar.

As curvas de absorção de nutrientes determinadas para algumas espécies de cucurbitáceas têm mostrado comportamento bem semelhante, onde o acúmulo de nutrientes segue o mesmo padrão da curva de acúmulo de massa seca. O Presente trabalho teve como objetivo avaliar a correlação entre massa e o conteúdo de nutrientes na melancia cv ‘Olímpia’. O trabalho foi conduzido no delineamento experimental em blocos casualizados num arranjo fatorial com cultivo em faixa 4 x 4 em três repetições. Os tratamentos do fatorial consistiram na combinação de quatro doses de nitrogênio e quatro de fósforo, via fertirrigação. Para o estudo de correlação entre massa seca e conteúdo de nutrientes, foi selecionado o tratamento que corresponde às doses de N e P adotadas pelos produtores da região. Verificou-se uma forte correlação entre a taxa de massa seca e acúmulo de nutrientes durante o ciclo da melancia cv ‘Olímpia’, o potássio e o fósforo foram os nutrientes que apresentaram maior correlação com a massa seca e o cálcio apresentou uma menor correlação na parte vegetativa em comparação aos outros nutrientes.

A agricultura irrigada depende tanto da quantidade como da qualidade da água; no entanto, o aspecto qualidade tem sido desprezado devido ao fato de que, no passado, em geral as fontes de água, eram abundantes, de boa qualidade. O trabalho teve como objetivo estudar a condutividade elétrica e razão de adsorção do sódio no extrato de saturação do solo no cultivo da abobora sob diferentes níveis salinos da água de irrigação e doses de nitrogênio. A água de irrigação disponível na Fazenda Experimental é proveniente de um poço perfurado do aqüífero Arenito Açu, com profundidade aproximada de 800 m, com água de boa qualidade, e condutividade elétrica da água (CEa) em torno de0,5 dS m-1. Adotou-se o delineamento experimental em blocos ao acaso, em esquema de parcelas subdivididas 5 x 3, com quatro repetições. Os tratamentos foram constituídos dos cinco níveis de salinidade (0,5, 1,5, 2,5, 3,5 e 4,5 dS m-1), e três níveis de nitrogênio: N1 = 27,37; N2 = 91,25 e N3 = 155,12 kg ha-1 correspondente a 30%, 100% e 170%, da recomendação de nitrogênio. Houve um aumento da salinidade do extrato de saturação com incremento dos níveis salinos da água e adubação nitrogenada. Os maiores valores de CEes foram verificados na CE (4,5 dS.m-1) e 170% da dose de nitrogênio recomendada pelos produtores de abobora. A razão de adsorção de Sódio (RASes) cresceu proporcional com os valores da condutividade elétrica da água de irrigação

A abóbora (Cucurbita MoschataDuch.) pertencente à família Cucurbitácea, formada por cerca de 118 gêneros e 825 espécies, e a salinidade, tanto de solos como de águas, é uma das principais causas da queda de rendimento das culturas, em razão dos efeitos de natureza osmótica, tóxica e/ou nutricional. O presente trabalho teve como objetivo avaliar o efeito da salinidade da água de irrigação na concentração de Na, Cl, N, P e K na cultura da abobora. Adotou-se o delineamento experimental em blocos ao acaso, em esquema de parcelas subdivididas 5 x 3, com quatro repetições. Os tratamentos foram constituídos dos cinco níveis de salinidade (0,5, 1,5, 2,5, 3,5 e 4,5 dS m-1), e os níveis de nitrogênio: N1 = 30; N2 = 100 e N3 = 170 kg ha-1. Escolheu-se a dose N2 para analises de teores de nutrientes sob efeito da salinidade. A salinidade não afetou a absorção em quase todos os nutrientes, exceção, o cloreto, os frutos contribuíram com grande parte dos nutrientes na parte total (Folha+Caule+Fruto), com 82% para P, 75% de K e 66% N e o Potássio foi o nutriente mais absorvido pela planta.Palavras chaves: Salino, irrigação, sódio.

A melancieira é uma planta cultivada praticamente em quase todo o Brasil, desde regiões mais frias do Rio Grande do Sul até regiões mais quentes do Nordeste brasileiro. O trabalho teve como objetivo avaliar os teores de macronutrientes (N, P e K) na folha sob diferentes doses de nitrogênio e potássio via fertirrigação nas cultivares de melancia Quetzali (Com sementes) e Leopard (Sem sementes). O experimento, com as duas variedades de melancia, foi conduzido no delineamento experimental em blocos casualizados no esquema de parcelas subdivididas 13 x 2, sendo o primeiro fator representado pela combinação de doses de nitrogênio (N) e potássio (K) em arranjo definido segundo o modelo: 2 x 2k + 2k + 1, sendo k o número de fatores estudados (N e K). A ordem decrescente dos macronutrientes acumulados pela cultivar Quetzali seguiu a seguinte sequência: N>K e P, já a Leopard seguiu a ordem: K, N e P, a cultivar Quetzali acumulou sua maior quantidade de nutrientes entre 15 a 35 Dias ápos o transplantio (DAT), enquanto a cultivar Leopard acumulou grande parte dos nutrientes entre 15 a 45 DAT, a cultivar Leopard teve uma maior resposta a plicação de N e K, quando comparado a Quetzali.

O Rio Grande do Norte é um tradicional produtor de abóboras, conhecidas na região como jerimum caboclo e de leite. Esse trabalho teve como objetivo avaliar o efeito da salinidade água de irrigação e diferentes doses de nitrogênio na produtividade da abobora. O delineamento experimental adotado foi em blocos ao acaso, em esquema de parcelas subdivididas 5 x 3, com quatro repetições. Os tratamentos foram constituídos dos cinco níveis de salinidade (0,5, 1,5, 2,5, 3,5 e 4,5 dS m-1), e três níveis de nitrogênio: N1 = 27,37; N2 = 91,25 e N3 = 155,12 kg ha-1 correspondente a 30%, 100% e 170%, da recomendação de nitrogênio, respectivamente.Verificou-se redução do número de frutos e massa média dos frutos para produtividade total, enquanto para produção comercial, apenas para número de frutos comerciais. para produção comercial, a resposta ao N foi mais pronunciada para os menores níveis de condutividade elétrica da água de irrigação, a adubação nitrogenada afetou significativamente os componentes de produção da abóbora, exceto a massa média dos frutos totais e comerciais e a dose N2=100% proporcionou rendimento e número de frutos por planta próximo do máximo

Na cultura da melancia, a nutrição mineral é um dos fatores que mais contribuem na produtividade e qualidade dos frutos. O delineamento experimental utilizado foi em blocos inteiramente casualizados em arranjo fatorial com cultivo em faixas (4 x 4) + 2, resultando em 32 tratamentos, com 3 repetições.Os tratamentos foram formados por quatro doses de nitrogênio – N (N1 - 0; N2 - 48; N3 - 121; N4 - 218 kg ha-1) combinadas com quatro doses de fósforo – P2O5 (P1 - 0; P2 - 88; P3 - 220; P4 - 397 kg ha-1) em esquema fatorial, com duas cultivares de melancia nas subparcelas em faixas. Os frutos da cultivar Olímpia participaram com mais da metade da matéria seca total da planta, já a cultivar leopard, os frutos tiveram menos de50% na participação do matéria seca total da planta. O potássio foi o nutriente mais acumulado nos frutos em ambas as cultivares, seguindo do nitrogênio e calcio. Na cultivar Olímpia, os frutos do tratamento 2 teve um maior acúmulo de N, P e K em relação aos demais tratamentos, já o calcio e magnésio foram mais acumulado nos frutos do tratamento 3, na cultivar Leopard, os frutos do tratamento T3 acumularam maior quantidade de N e P, o tratamento 1 foi Ca e Mg e o Tratamento 2 acumulou maior quantidade de potássio.

Com o desenvolvimento tecnológico e da pesquisa nas cadeias produtivas de hortaliças surgiram novas técnicas e metodologias para o cultivo de mudas, passando de canteiros no solo para produção em recipientes, porém, outro requisito importante é a utilização de substrato. Sendo assim, objetivou-se com a pesquisa avaliar o comportamento das mudas de tomate e couve-folha em diferentes combinações de vermicompostos. O ensaio foi realizado na propriedade rural Hortvida, localizada no município de Governador Dix-sept Rosado – RN. Foi utilizado o delineamento inteiramente casualizado com 20 tratamentos, correspondentes aos substratos a base de esterco bovino (EBO) e esterco de pequenos ruminantes (EPR) em diferentes proporções, sendo eles: 10% de esterco bovino (10EBO) e 90% de esterco de pequenos ruminantes (90EPR) = (10EBO+90PR); 20BO+80PR; 30BO+70PR; 40BO+60PR; 50BO+50PR; 70BO+30PR; 80BO+20EPR; 90BO+10PR; 100BO; e 100PR, sendo estes substratos submetidos à produção de mudas de duas espécies: tomate e couve-folha, com 4 repetições. Decorridos 25 dias após a semeadura, as seguintes características foram avaliadas: número de folhas por planta, altura de plântula, diâmetro do coleto, comprimento da folha, largura da folha, peso da massa fresca da plântula e o peso da massa seca da plântula. Em todos os aspectos avaliados o vermicomposto formado pela constituição de 30% de esterco bovino e 70% de esterco de pequenos ruminantes (30EBO+70EPR), foi o que apresentou melhor desempenho dentre os demais, quando avaliado nos caracteres estudados para as mudas de tomate e couve-folha.

-A cultura da melancia, a exemplo de outras oleráceas, tem na nutrição mineral um dos fatores que contribui diretamente na produtividade e na qualidade dos frutos. O trabalho teve como objetivo avaliar a eficiência agronômica e fisiológicas das cultivares Olimpia e Leopard sob diferentes doses de nitrogênio e fósforo via fertirrigação. O delineamento experimental adotado foi em blocos ao acaso com fatorial 4x4, os fatores estudados foram quatro doses combinadas de nitrogênio (N) e fósforo (P), sendo, respectivamente: T1(0; 0), T2(48; 88), T3(121; 220) e T4(218; 396); duas cultivares de melancieira e cinco épocas após transplantio (23, 30, 37, 46 e 58 DAT). As doses de N e P equivalem respectivamente a 0%, 40%, 100% e 180% da dose adotada pelos produtores locais do polo agrícola de Mossoró-Baraúna. Tratamento T3 (121 kg ha-1 de N e 218 kg ha-1 de P) que corresponde a dose adotada pelos produtores locais da região de Mossoró, foi o que mais incrementou na produtividade de ambas as culturas (Olimpia e Leopard), sendo considerado, agronomicamente, o mais eficiente para alcançar maior produtividade. O tratamento T2 (48 kg ha-1 de N e 88 kg ha-1 de P) que corresponde a 40% da dose adotada pelos produtores de Mossoró, foi o que mais incrementou nutrientes na planta (olimpia e Leopard), sendo considerado, fisiologicamente, o mais eficiente para acumular nutrientes na planta.

O maxixeiro é uma cultura de grande importância nas regiões Norte e Nordeste do Brasil e a sua produção é oriunda, predominantemente, de plantas espontâneas. Em razão disso, são poucas as pesquisas sobre a cultura, principalmente no tocante ao efeito da salinidade. Este trabalho foi desenvolvido na Universidade Federal Rural do Semiárido (UFERSA), em Mossoró, RN, com o objetivo de avaliar o efeito de diferentes níveis de salinidade da água de irrigação sobre o desenvolvimento e o rendimento do maxixeiro. Utilizou-se o delineamento experimental inteiramente ao acaso, com quatro tratamentos (níveis de salinidade da água de irrigação: S1-0,5; S2-2,0; S3-3,5 e S4-5,0 dS m-1). Foram realizadas cinco colheitas de frutos e, ao final do experimento, as plantas foram coletadas e foram analisadas as principais variáveis de desenvolvimento e de rendimento: comprimento do ramo principal, diâmetro do caule, número de folhas, área foliar, massas de matéria seca de folhas, hastes, frutos e total, número de frutos, massa média de frutos e produção. O maxixeiro apresentou-se como cultura sensível à salinidade. Houve respostas significativas para todas as variáveis avaliadas, as quais apresentaram reduções em seus valores, com o aumento da salinidade.

In semi-arid regions, irregular rainfall and scarcity of good quality water contribute to the use of saline water for irrigation. In this context, this study aimed to investigate the effects of saline water use in the yield and quality of melon fruits. Treatments consisted of two melon cultivars (Sancho - C1 and Medellín - C2) irrigated with low (S1 = 0.61 dS m-1) and high (S2 = 4.78 dS m-1) salinity water levels, for each phenological stage. The experimental design was split-plot randomized blocks, with six irrigation management strategies and two cultivars (6x2), with four replications. The results showed that the total and commercial number of fruits were influenced by the saline water management strategies. The irrigation management with good quality water, during two days, followed by saline water, for one day, enabled the commercial production of melon, with a reduction of 33% in the good quality water use.

This study evaluated the effects of salinity on the nutrient solution on the production of rocket, grown on different substrates. The test was developed in an environment protected by the Department of Environmental Sciences and Technology, Federal Rural University of the Semi-Arid in Mossoró-RN, housed in a completely randomized design in a factorial 3 x 5 with three replications. Five salinity levels of nutrient solution were used, obtained with or without the fish farming wastewater (S1-0.5, S2-2.0, S3-3.5, S4-5.0 and S5-6.5 dS m-1) and three substrates (SUB1-Mix coconut fibre + sand + rice husk (1:1:1), SUB2-Cambisol and SUB3-SUB1 reused in the previous experiment). Harvesting of rocket was performed at 35 days aftersowing and evaluated the following variables: plant height, leaf number, leaf area, fresh weight, and dry weight. The salinityof the nutrient solution negatively affected the development of the rocket grown, having effect varying according to the type of substrate used. The plants grown on the substrate formed by the mixture of coconut fibre + sand + rice hulls (1:1:1) showed higher tolerance to salinity. The substrate formed by mixing coir + sand + rice husk can be recommended for growing rocket containers, but cannot be reused without treatment. = Objetivou-se com este trabalho avaliar o efeito da salinidade na solução nutritiva sobre a produção de rúcula, cultivada em diferentes substratos. O ensaio foi desenvolvido em ambiente protegido do Departamento de Ciências Ambientais e Tecnológicas da Universidade Federal Rural do Semi-Árido em Mossoró-RN, e instalado em delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 3, com três repetições. Foram utilizados cinco níveis de salinidade na solução nutritiva, obtidos com ou sem uso de água residuária da piscicultura (S1-0,5; S2-2,0; S3-3,5; S4-5,0 e S5-6,5 dS m-1) e três substratos (SUB1-Mistura de fibra de coco + areia + casca de arroz (1:1:1); SUB2-Cambissolo e SUB3-SUB1 reutilizado de experimento anterior). Realizou-se a colheita da rúcula aos 35 dias após a semeadura e avaliou-se as seguintes variáveis: altura de plantas, número de folhas, área foliar, massa fresca e massa seca. A salinidade da solução nutritiva afetou negativamente o desenvolvimento da rúcula, apresentando efeito variado de acordo com o tipo de substrato utilizado. As plantas cultivadas no substrato formado pela mistura de fibra de coco + areia + casca de arroz natural (1:1:1) apresentaram maior tolerância àsalinidade. O substrato formado pela mistura de fibra de coco + areia + casca de arroz pode ser recomendado para o cultivo de rúcula em recipientes, mas não pode ser reutilizado sem tratamento.

The use of saline water for vegetable production is a major challenge for researchers and farmers. Cultivation in inert substrate can be an alternative, since the low matric potential can reduce the effect of salinity on plants. This study was conducted in a greenhouse at the Departamento de Ciências Ambientais e Tecnológicas da Universidade Federal Rural do Semi-Árido, Mossoró-RN, in order to evaluate the performance of two cultivars of rocket grown in substrate and fertilized with nutrient solutions of different salinities . Ten treatments were evaluated in a factorial 2 x 5, two cultivars (C1-Cultivada e C2-Folha Larga) and five salinity levels of the nutrient solutions (S1-1.2; S2-2.2; S3-3.2; S4-4.2 and S5-5.2 dS m-1), usinga randomized design. Harvesting was performed at 30 days after sowing and evaluated the following variables: number of leaves, height, leaf area, total fresh and total dry mass. The salinity of the nutrient solution adversely affected the development of rocket, grown on a substrate, however, cultivation rocket substrate may be performed using electrical conductivity of the nutritive solution to 2.36 dS m-1 without loss in yield fresh pasta. The Folha Larga cultivar produced more total fresh and dry weight in relation to cultivar Cultivada, but to cultivar Cultivada has increased tolerance to salinity than cultivar Folha Larga. = O uso de água salina na produção de hortaliças é um dos principais desafios de pesquisadores e produtores rurais. O cultivo em substrato inerte pode ser uma alternativa, uma vez que o reduzido potencial matricial pode reduzir o efeito da salinidade sobre as plantas. O trabalho foi desenvolvido em ambiente protegido no Departamento de Ciências Ambientaise Tecnológicas da Universidade Federal Rural do Semi-Árido, Mossoró-RN, e objetivou-se avaliar o desempenho de duas cultivares de rúcula cultivadas em substrato e fertirrigadas com soluções nutritivas de diferentes salinidades. Foram avaliados dez tratamentos em esquema fatorial 2 x 5, sendo duas cultivares (C1-Cultivada e C2-Folha Larga) e cinco níveis de salinidade das soluções nutritivas (S1-1,2; S2-2,2; S3-3,2; S4-4,2 e S5-5,2 dS m-1), utilizando o delineamento inteiramente casualizado, com quatro repetições. Realizou-se a colheita aos 30 dias após a semeadura e avaliaram-se as seguintes variáveis: número de folhas, altura, área foliar, massa fresca total e massa seca total. A salinidade da solução nutritiva afeta negativamente o desenvolvimento das rúculas cultivadas em substrato, no entanto, o cultivo de rúcula em substrato pode ser realizado utilizando solução nutritiva de condutividade elétrica até 2,36 dS m-1, sem perda na produção de massa fresca. A cultivar Folha Largaproduziu mais massa fresca e seca total em relação a cultivar Cultivada, porém a cultivar Cultivada apresenta maior tolerânciaà salinidade que a cultivar Folha Larga.