Knowledge about the effect of chemical conditioners on the reduction of the deleterious effects caused by salinity on crops is of great importance for the expansion of the cultivation of vegetable crops such as zucchini in the semi-arid region of the Northeast. In this context, the objective of the present study was to evaluate the effect of the foliar application of hydrogen peroxide as a mitigator of salt stress on the gas exchange, production, and postharvest fruit quality of zucchini cultivated in a hydroponic system. The study was conducted in NFT-type (Nutrient Film Technique) hydroponic system in a greenhouse, in Pombal — PB, Brazil. The experimental design was completely randomized, in a 4 × 4 factorial scheme, corresponding to four levels of electrical conductivity of the nutrient solution - ECns (2.1 (control); 3.6; 5.1 and 6.6 dS m−1), and four concentrations of hydrogen peroxide - H2O2 (0; 20; 40 and 60 μM), with three replicates. Nutrient solution with electrical conductivity above 2.1 dS m−1 caused a reduction in gas exchange and the total number of fruits of zucchini. An increase in nutrient solution salinity levels increased the total soluble solids content of the fruits and the initial fluorescence of zucchini. Under conditions of nutrient solution salinity above 2.1 dS m−1, hydrogen peroxide could not mitigate the effects of salt stress. Application of 20 μM of H2O2 when the plants were grown in a nutrient solution of 2.1 dS m−1 promoted higher total fruit weight and basal diameter of the fruits.

Saline water has been used in irrigation due to the limited availability of fresh water, especially in arid and semi-arid regions. However, the use of this type of water can affect crop growth and development. Studies have tested the use of chemical conditioners to minimize the negative effects of salinity on plants. In this scenario, the present study examined the role of hydrogen peroxide in mitigating the negative effects of salt stress on zucchini plants grown in a hydroponic system. The study was carried out in a greenhouse in Pombal - PB, Brazil. The NFT (nutrient film technique) hydroponic system was employed. A randomized complete experimental design was set up with a 4 × 4 factorial arrangement consisting of four levels of electrical conductivity in the nutrient solution (ECns: 2.1 [control], 3.6, 5.1, and 6.6 dS m-1) and four concentrations of hydrogen peroxide (H2O2: 0, 20, 40, and 60 μM), in three replicates. Foliar spraying with H2O2 at 60 and 40 μM associated with the nutrient solution of 2.1 dS m-1 increased stem diameter and root length, respectively, at 47 days after transplanting. However, at ECns higher than 2.1 dS m-1, the application of H2O2 at the concentrations of 60 and 40 μM intensified salt stress, reducing stem diameter and root length. Nutrient solution salinity levels above 2.1 dS m-1 reduce photosynthetic pigments; the number of leaves; leaf area; the length of the main branch; and the dry biomass of stems, leaves, and roots of zucchini plants. Chlorophyll b and carotenoid contents are the variables most sensitive to changes in salinity levels.

<p>A cultura do feijão-vagem possui ampla adaptação edafoclimática, podendo ser cultivado durante todo o ano em grande parte dos estados brasileiros, entretanto, fatores como o manejo do solo, sendo este fundamental para obtenção de maior sucesso de produção e o volume inadequado da água de irrigação limita sua produção principalmente nas regiões semiáridas. Com isso, o presente trabalho objetivou avaliar a influência de fontes de adubação orgânica no desenvolvimento do feijão-vagem cv. ‘Macarrão’ submetido a diferentes níveis de água de irrigação. Os tratamentos avaliados foram: duas fontes de adubação orgânica (esterco caprino e bovino) mais a testemunha (sem adubação) e quatro níveis de água de irrigação (40%; 60%; 80% e 100% da capacidade de campo). Foi adotado o delineamento experimental em blocos casualisados, com arranjo fatorial 3 x 4, sendo o primeiro fator as fontes de adubação orgânica mais a ausência da mesma e o segundo fator os quatro níveis de água de irrigação, com quatro repetições totalizando 48 unidades experimentais. Aos 40 dias após a semeadura foram avaliadas as seguintes variáveis: diâmetro do colo, número de folhas, comprimento da raiz, massa fresca da parte aérea, massa fresca da raiz, massa fresca total, massa seca da parte aérea, massa seca da raiz e massa seca total. Plantas de feijão-vagem cv. ‘macarrão’ apresenta maior desenvolvimento quando cultivada a 100% da capacidade de campo, onde associada a adubação orgânica via esterco caprino favorece a produção de plantas com maior qualidade.</p><p align="center"><strong><em>Influence of organic fertilizer in the development of snap beans in different irrigation water levels</em></strong></p><p><strong>Abstract</strong><strong>: </strong>The snap bean crop has extensive edaphoclimatic adaptation and can be grown throughout the year in most Brazilian states, However, factors such as soil management, which is critical to getting the most successful production and inadequate volume of irrigation water limits its production mainly in semiarid regions. Thus, this study aimed to evaluate the influence of sources of organic fertilizer in the development of plants of bean pod cv. 'Macaroni' under different irrigation water levels. The treatments were: two sources of organic fertilizer (manure goats and cattle) more witness (without fertilizer) and four irrigation water levels (40%, 60%, 80% and 100% of field capacity).  The experimental design was adopted in randomized blocks with factorial 3 x 4, the first factor the organic fertilizer  more witness thereof and the second factor the four irrigation water levels, with four repetitions totaling 48 experimental units. At 40 days after sowing the following variables were evaluated: stem diameter, number of leaves, root length, fresh weight of aerial part, fresh root mass, total fresh mass, shoot dry weight, root dry mass and total dry mass. plants of bean pod cv. 'Macaroni' It has higher development when grown to 100% field capacity related to irrigation water, where associated with organic fertilizer via goat manure favors the production of plants with higher quality.</p>

The cultivation of melon is one of the main agricultural activities in Northeast Brazil, adapting well to the environmental conditions of the region. Local varieties, also called creoles, are widely used in domestic consumption, including cucumber melons. However, one of the limiting factors for agricultural production in the region is the salinity of the soils and water used for irrigation, directly interfering with the germination process of the seeds. In this context, the objective was to evaluate the influence of salinity on the germination and evolution of the imbibition process of cucumber melon seeds. The experiment was conducted in a completely randomized design with five electrical conductivities of irrigation water (ECw = 0.0; 0.5; 1.5; 3.5 and 4.5 dS m-1), with four replications of 50 seeds. The seed water absorption and increment curve and the percentage, first count, average speed index, average time, average speed and relative germination frequency were evaluated. The data were submitted to analysis of variance and, in cases of significance, regression analysis. The cucumber melon is tolerant to salinity, but the vigor of the seeds is reduced with the increase of CEa. The water absorption lasts for 41 hours and the increment of 0.013 g of water per seed until root protrusion begins. In the evolution of the imbibition of the seeds, an extension of the duration of the process was observed with the increase of the saline concentrations.

Organic fertilizersare a viable alternative to reduce the expenses associated with synthetic fertilizers, besides improving the chemical, physical and biological attributes of the soil and promoting the increase of productivity in the cultivation of vegetables. The aim of this research was to evaluate the effect of goat manure applicatiosn on lettuce yield, cv. Cristina. The experiment was conducted at the Center for Agri-Food Science and Technology, Federal University of Campina Grande in the municipality of Pombal, PB, Brazil. The experiment was conducted in randomized blocks with treatments composed of five goat manure percentages (0, 25, 50, 75 and 100%), considering 100% of the recommended dose being 36.50 ton/ha de goat manure, in five replications, using a spacing of 0.25 &times; 0.25 m between plants. Harvesting was performed 30 days after transplanting the seedlings. The following parameters were analyzed: aerial part height, plant diameter, number of leaves, aerial fresh weight, root fresh weight, total fresh weight, aerial dry weight, root dry weight, total dry weight, root volume and productivity. The data were submitted to polynomial regression analysis. When the lettuce plants cv. Cristina were fertilized with 75% of the N ratio required for maximum production, the goat manure application produced the greatest development and increase productivity.