Resumen El agua en las regiones semiáridas contiene sales en exceso. Cuando no se dispone de agua de buena calidad, es necesario utilizar estrategias que permitan el uso de agua salina. El objetivo de este estudio fue evaluar los efectos de la aplicación del regulador del crecimiento vegetal en el cultivo de albahaca bajo estrés salino. El experimento se llevó a cabo en un diseño de bloques al azar, en la matriz “Compuesto Central de Box”. Se evaluó la altura de la parte aérea, el diámetro del tallo, el área de la hoja, las masas secas y las características químicas del suelo. La salinidad del agua de riego provoca la reducción de los parámetros de crecimiento de la albahaca, con la excepción de la masa seca de inflorescencia. Las aplicaciones del regulador del crecimiento vegetal tienen efecto sobre el crecimiento de la albahaca cuando las plantas se riegan con agua salina.

Abstract The water in semiarid regions contains salts in excess. When good quality water is not available it is necessary to use strategies that can make feasible the use of saline water. The aim of this study was to evaluate the effects of the application of the plant growth regulator on the culture of basil stressed with salt. The experiment was carried out in a randomized block design by the matrix “Central Box Compound”. Shoot height, stem diameter, leaf area, dry masses and soil chemical characteristics were evaluated. The salinity of the irrigation water causes reduction of the basil growth parameters, with the exception of the inflorescence dry mass. Plant growth regulator applications have effect on basil growth when plants are irrigated with saline water.

ABSTRACT Bell pepper (Capsicum annuum) is one of the most consumed vegetables around the world. Balanced fertilization is essential for growing this vegetable. The objective of this study was to evaluate the yield and morphological attributes of bell pepper under doses and times of application of biological fertilizers. Two experiments were carried out with applications of biological fertilizers prepared from manure and enriched organic compounds with cattle manure and sheep manure. The experimental design was a randomized complete block design, in a 4 x 3 + 1 factorial scheme, with three replications, referring to doses of biological fertilizers (100, 200, 300 and 400 L ha-1), times of application (0, 30 and 60 days after transplanting - DAT) and control. The evaluated variables were: total fruit weight (TFW), number of commercial fruits (NCF), number of non-commercial fruits (NNCF), fruit weight (FW), fruit diameter (FD), fruit length (FL), resistance of fruit peel (RFP), number of flower buds (NFB) and productivity (P). Biological fertilizers caused positive effects on TFW, NCF, FW and P of bell pepper. The application of cattle manure at 60 DAT and sheep manure at 30 DAT promoted a larger fruit diameter. The FW, FL and RFP were influenced by the doses and times of application of biological fertilizers. The application of biofertilizers is efficient in the production of bell pepper.

RESUMEN El rábano es una hortaliza de ciclo corto que presenta excelentes propiedades nutricionales y medicinales. Es considerada rústica, pues tolera condiciones adversas, con énfasis en la posibilidad de poder ser regado con agua salada, principalmente cuando se asocia a la atenuación del estrés causado. En este contexto, el presente trabajo tuvo como objetivo evaluar el efecto de conductividades eléctricas del agua de riego y de dosis de ácido ascórbico en el desempeño agronómico e intercambios gaseosos del rábano. El experimento fue conducido en un ambiente protegido, en el Centro de Ciencias Agrarias de la Universidad Federal de Paraíba, Areia, Paraíba (Brasil). El diseño experimental fue hecho en bloques aleatorizados, con cinco dosis de ácido ascórbico (0,0; 0,29; 1,0; 1,71 y 2,0 mM) y cinco conductividades eléctricas del agua de riego (0,5; 1,3; 3,25; 5,2 y 6,0 dS m-1), con cuatro repeticiones. El crecimiento, los intercambios gaseosos y la producción fueron evaluados. Las dosis de ácido ascórbico no fueron significativas. El aumento de las conductividades eléctricas del agua de riego disminuyó el desempeño agronómico y los intercambios gaseosos, salvo para fotosíntesis neta, eficiencia del uso del agua y eficiencia instantánea de carboxilación, que no presentaran importancia. Hubo una relación de la fotosíntesis neta, transpiración, concentración interna de CO2 y eficiencia del uso del agua con la conductancia estomática. El desempeño agronómico y el intercambio gaseoso del cultivo de rábano son influenciados por la salinidad. La aplicación de ácido ascórbico a través de la hoja no influye en el rendimiento agronómico y los intercambios gaseosos del rábano a las dosis probadas.

ABSTRACT The radish is a short-cycle vegetable that has excellent nutritional and medicinal properties. It is considered rustic, meaning it tolerates adverse conditions with the possibility of being irrigated with saline water, which creates stress. In this context, this study aimed to evaluate the effect of electrical conductivities in irrigation water and doses of ascorbic acid on the agronomic performance and gaseous exchanges of radishes. This experiment was carried out in a protected environment at the Agricultural Sciences Center of the Federal University of Paraíba, Areia, Paraíba (Brazil). The experiment design used randomized blocks with five doses of ascorbic acid (0.0, 0.29, 1.0, 1.71 and 2.0 mM) and five electrical conductivities in the irrigation water (0.5, 1.3, 3.25, 5.2 and 6.0 dS m-1), with four replicates. The growth, gas exchange and production were evaluated. The doses of ascorbic acid were not significant. The increase in the electrical conductivities of the irrigation water provided a reduction in the agronomic performance and gas exchanges, except for the net photosynthesis, water use efficiency and instantaneous carboxylation efficiency, which were not significant. There was a relationship between the net photosynthesis, transpiration, internal concentration of CO2 and water use efficiency and the stomatal conductance. The agronomic performance and gaseous exchanges of the radish culture were influenced by the salinity. The foliar application of ascorbic acid did not influence the agronomic yield and gaseous exchanges of the radishes at the tested doses.

RESUMO A produção de hortaliças é uma atividade impactante, que se caracteriza pelo uso intensivo do solo, alta demanda de insumos e requer adoção estratégica de manejo, sobretudo em sistemas de produção sustentável, em que os pilares da sustentabilidade (ambiental, social e econômico) devem ser respeitados. Neste sentido, o objetivo desse trabalho foi avaliar indicadores econômicos da produção de alface adubada com espécie espontânea da Caatinga (Calotropis procera: Flor-de-seda) e cultivada em duas épocas (primavera e outono-inverno), no município de Serra Talhada-PE. O delineamento experimental foi em blocos casualizados, com os tratamentos arranjados em esquema fatorial 4 x 4, com três repetições, sendo o primeiro fator: as quantidades de biomassa do adubo verde (5,4; 8,8; 12,2 e 15,6 t ha-1 em base seca); e o segundo: seus tempos de incorporação ao solo (0, 10, 20 e 30 dias antes do transplantio da alface). Além do rendimento de massa verde e dos custos de produção, foram determinadas as rendas bruta e líquida, taxa de retorno e índice de lucratividade. A quantidade de 15,6 t ha-1 de C. procera possibilitou maior rentabilidade à produção orgânica de alface, sendo considerado ideal incorporar o adubo verde 11 (primavera) e 15 (outono-inverno) dias antes do transplantio da hortaliça. O cultivo de primavera promoveu retorno econômico superior ao plantio de outono-inverno, demonstrando viabilidade econômica mesmo na menor quantidade de C. procera.

ABSTRACT Vegetable production is an impactful activity, characterized by intensive land use, high input demand, and it requires strategic management adoption, especially in sustainable production systems, where the pillars of sustainability (environmental, social and economic) must be respected. In this sense, the objective of this work was to evaluate economic indicators of lettuce production using Caatinga spontaneous species (Calotropis procera: rooster tree) as fertilizer and cultivated in two seasons (spring and fall-winter) in the municipality of Serra Talhada, PE. The experimental design was in randomized blocks, arranged in a 4 x 4 factorial scheme, with three replications. The first factor was the biomass amounts of green manure (5.4, 8.8, 12.2 and 15.6 t ha-1 on a dry basis); and the second was their incorporation times in the soil (0, 10, 20 and 30 days before lettuce transplanting). The green mass yield, production costs, rate of return, and net profit margin were determined. The amount 15.6 t ha-1 of C. procera allowed higher profitability to the organic production of lettuce, and it is considered ideal to incorporate the green manure 11 (spring) and 15 (fall-winter) days before transplanting the vegetable. The spring crop promoted a superior economic return to the fall-winter planting, demonstrating economic viability even in the smallest amount of C. procera.

Resumen El uso de aguas salinas en la agricultura surge como alternativa al aumento en la demanda de agua, principalmente en regiones áridas o semiáridas. Sin embargo, el uso de agua con alto contenido de sales causa disturbios en las plantas pudiendo llevar hasta la muerte de las mismas. Por esta razón, se buscan alternativas para atenuar tales efectos. Actualmente, los antioxidantes se utilizan para mitigar los efectos de las sales en las plantas; entre estos antioxidantes s el ácido ascórbico ha sido frecuentemente mencionado. Basado en lo expuesto, este trabajo tuvo por objetivo evaluar el efecto del riego con aguas salinas combinado con la aplicación de ácido ascórbico, sobre el desarrollo y actividades fotosintéticas de plantas de rábano (Raphanus sativus L.). El experimento fue desarrollado en ambiente protegido en bloques al azar con esquema factorial incompleto 5x5, con cinco conductividades eléctricas del agua de riego (ECw: 0.50, 1.30, 3.25, 5.20 y 6.00 dS m-1) y cinco dosis de ácido ascórbico (AA: 0.00, 0.29, 1.00, 1.71 y 2.00 mM). Las características evaluadas fueron altura de plantas, número de hojas, diámetro de la raíz tuberosa, índice de clorofila a, b, y total, relación de clorofila a/b, fluorescencia inicial, fluorescencia máxima, fluorescencia variable y rendimiento cuántico del fotosistema II. El uso de agua salina influenció todas las variables analizadas en el cultivo del rábano independiente de la utilización del ácido ascórbico. El uso del ácido ascórbico no fue eficiente como atenuante de los efectos de la salinidad del agua de riego sobre el desarrollo y la fluorescencia del cultivo del rábano. Sin embargo, se observó que la aplicación del ácido ascórbico en la dosis de hasta 1.00 mM promueve el aumento en los índices de clorofilas a, b y total del rábano sometido al estrés salino.

Abstract The use of saline or low-quality water in agriculture is an alternative to increasing water demand, especially in arid or semi-arid regions. However, the use of water with high levels of salts causes disturbances in plants, which can lead to their death; thus, alternatives to mitigate these effects are relevant in current agriculture. Currently, antioxidants are used to mitigate the effects of salts in plants, and among them ascorbic acid has been frequently mentioned. Therefore, the aim of this study was to evaluate the effect of irrigation with saline water combined with applications of ascorbic acid on the development and photosynthetic activity of radish (Raphanus sativus L.) plants. This experiment was carried out in a greenhouse with a randomized block design, with the treatments distributed in a 5x5 incomplete factorial scheme, composed of five electrical conductivities of the irrigation water (ECw): 0.50, 1.30, 3.25, 5.20 and 6.00 dS m-1, and five ascorbic acid (AA) doses: 0.00, 0.29, 1.00, 1.71, and 2.00 mM. The evaluated variables were: shoot height, leaf number, tuberous root diameter, chlorophyll a, b and total content, chlorophyll a/b ratio, initial fluorescence, maximum fluorescence, variable fluorescence and quantum yield of photosystem II. The saline water influenced the analyzed variables in the radish crop regardless of the ascorbic acid application. The ascorbic acid was not efficient in attenuating the deleterious effect of salinity in the irrigation water on the development and fluorescence of the radish. However, it was observed that the concentration of 1.00 mM of ascorbic acid promoted an increase in chlorophyll a, b and total in the salt-stressed radish plants.