In order to evaluate the effect of irrigation water salinity in interaction with different potassium and calcium ratios applied through fertigation in eggplant, an experiment was carried out at the Department of Environmental and Technological Sciences of the Federal Rural University of the Semi-Arid Region, in Mossoró, RN, Brazil. The experimental design was randomized blocks, in a 5 x 4 factorial scheme, with four replicates. The treatments were obtained by the combination between five ionic ratios of potassium and calcium (F1 = 4.2/1; F2 = 3.5/1; F3 = 2.8/1; F4 = 2.2/1; F5 = 1.8/1) and four levels of irrigation water salinity (S1 – 0.5; S2 – 2.0; S3 – 3.5; and S4 – 5.0 dS m-1). The following variables were evaluated: number of fruits per plant, fruit length, fruit diameter, fruit fresh weight and yield. Yield, fruit length, fruit fresh weight and number of fruits decreased with the increase of salinity in all the treatments. Salinity significantly affected fruit diameter, which increased only under fertigation with potassium-rich solutions.

QUALIDADE DE TOMATE EM FUNÇÃO DA SALINIDADE DA ÁGUA DE IRRIGAÇÃO E RELAÇÕES K/Ca VIA FERTIRRIGAÇÃO  FRANCISCO ITALO GOMES PAIVA1; FRANCISCO DE ASSIS DE OLIVEIRA2; JOSÉ FRANCISMAR DE MEDEIROS2; ANA JACQUELINE DE OLIVEIRA TARGINO1; SANDY THOMAZ DOS SANTOS2 E RICARDO CARLOS PEREIRA DA SILVA3 Programa de Pós-Graduação em Manejo de Solo e Água, Universidade Federal rural do Semi-Árido, UFERSA, Mossoró, RN. italo-gp@hotmail.com; ana_jacqueline2@hotmail.com Departamento de Ciências Agronômicas e Florestais, Universidade Federal rural do Semi-Árido, UFERSA, Mossoró, RN. thikaoamigao@hotmail.com; jfmedeir@ufersa.edu.br; sandy_thomaz@hotmail.com Programa de Pós-Graduação em Agronomia, Universidade Federal da Paraíba, Areia, PB. ricarlos_agro@hotmail.com   1 RESUMO A qualidade do tomate está diretamente relacionada com a qualidade da água utilizada na irrigação e com o suprimento adequado de nutrientes, principalmente o potássio e o cálcio. Este trabalho foi desenvolvido em ambiente protegido na UFERSA, em Mossoró, RN, com o objetivo avaliar a qualidade do tomate em função de diferentes relações iônicas de potássio e cálcio (K+/Ca2+), sendo: F1=1,5:1; F2=1,25:1; F3=1:1; F4=1:1,25 e F5=1:1,5 e quatro níveis de salinidade da água de irrigação (S1-0,5; S2-2,0; S3-3,5 e S4-5,0 dS m-1). O delineamento experimental utilizado foi em blocos casualizados, em esquema fatorial 5 x 4, totalizando 20 tratamentos, com quatro repetições. A relação K+/Ca2+=1:1 correspondente a concentração desses nutrientes recomendada para a cultura em cultivo de tomateiro hidropônico. Foram avaliadas as variáveis relacionadas a qualidade de frutos (sólidos solúveis, vitamina C, acidez titulável, pH e relação AT/SS). O uso de água com salinidade entre 2,0 e 3,5 dS m-1 aumenta a qualidade do tomate pelo aumento da razão SS/AT. As fertirrigações com maiores concentrações de K favorecem a qualidade dos frutos para salinidades até 3,5 dS m-1, mas não afetam a qualidade de tomate na salinidade 5,0 dS m-1. Palavras-chave: solanáceas, uso de águas salinas, potássio, cálcio  PAIVA, F. I. G; OLIVEIRA, F. A.; MEDEIROS, J. F.; TARGINO, A. J. O.; SANTOS, S. T.; SILVA, R. C. PQUALITY OF TOMATO AS FUNCTION OF IRRIGATION WATER SALINITY AND K/CA RATIO IN FERTIGATION  2 ABSTRACT The quality of tomato is directly related to the quality of the water used in irrigation and to the adequate supply of nutrients, mainly potassium and calcium. The objective of this work was to evaluate the quality of tomatoes as a function of the different ionic ratios of potassium and calcium (K+/ Ca2+), with: F1 = 1.5:1; F2 = 1.25:1; F3 = 1: 1; F4 = 1:1.25 and F5 = 1:1.5 and four irrigation water salinity levels (S1-0.5, S2-2.0, S3-3.5 and S4-5.0 dS m-1). The experimental design was a randomized complete block design in a 5 x 4 factorial scheme, totaling 20 treatments, with four replications. The K+/Ca2+ ratio = 1:1 corresponds to the concentration of these nutrients recommended for cultivation in a hydroponic tomato crop. The variables related to fruit quality (soluble solids, Vitamin C, titratable acidity, pH and AT / SS ratio) were evaluated. The use of water with salinity between 2.0 and 3.5 dS m-1 increases tomato quality by increasing the SS/AT ratio. Fertigation with higher concentrations of K favor fruit quality at salinity up to 3.5 dS m-1, but do not affect tomato quality at 5.0 dS m-1 salinity. Keywords: solanaceae, use of salt water, potassium, calcium

This study aimed to evaluate lettuce production in different pot volumes and different irrigation frequency under saline stress. The experiment was carried out at the Department of Environmental and Technological Sciences of the Federal Rural University of the Semi-Arid, in Mossoró, RN, Brazil. Randomized block experimental design was used in factorial scheme of 2 × 3 × 3, with 3 replicates. Treatments were consisted of 2 water’s salinity levels (0.5 and 2.0 dS m-1), 3 frequencies of irrigation (6, 9, and 12 daily events), and 3 different pots (0.5, 1.0, and 3.0 L). Data from parameters evaluated at harvest were submitted to variance analysis and means were compared. We verified that when the lower saline water (0.5 dS m-1) was used lettuce production increased when cultivated in pots of 3.0 L and submitted to 6 daily events of irrigation. When 3.0 dS m-1 water was used the best results were obtained in 0.5 L and nine daily events of irrigation. The combination of 0.5 L pot and six or nine daily events of irrigation better inhibited the damaging effects of salinity.

This study aimed to evaluate the use of saline solutions enriched with calcium nitrate in the production of lettuce grown in coconut fiber. The experiment was carried out from July to August 2017 in a greenhouse, at the Federal Rural University of the Semi-Arid Region (UFERSA), Mossoró-RN, Brazil. A randomized block design was used, in 2 × 5 factorial scheme, with three replicates. Treatments resulted from the combination of two lettuce cultivars [Elba (Curly) and Irene (Crisphead)] and five nutrient solutions (S1- standard nutrient solution; S2-S1 + NaCl (28.48 mmol L-1); S3-S2 + Ca(NO3)2 (6.89 mmol L-1); S4-S2 + Ca(NO3)2 (9.15 mmol L-1); S5-S2 + Ca(NO3)2 (11.43 mmol L-1)]. Plants were harvest 30 days after transplantation and the following variables were analyzed: head diameter, stem diameter, number of leaves, fresh weight, dry weight, leaf area, specific leaf area and leaf succulence. The cv. Irene (Crisphead) is more tolerant to nutrient solution salinity compared with the cv. Elba (Curly). Nutrient solutions enriched with 50 and 100% of Ca(NO3)2 promoted better performance of the cultivars Elba and Irene, respectively, fertigated with saline nutrient solution.

ABSTRACT:In the olericulture, in general, is practiced intensive fertilization, which creates a risk of salinization and change of high pH, which if not well monitored can cause production losses, excessive spending on fertilizers and environmental contamination. We developed this study with the aim of controlling fertigation on watermelon through the behavior of the electrical conductivity (EC) and pH in the soil solution obtained through porous ceramic cups extractors. The EC and pH values were corrected by the current soil moisture for the moisture field capacity, due to different moisture values at the time of extraction. The monitoring comprised 19 assessments d uring 80 days of cultivation. We can control the pH and EC of the soil and maintain them at optimal levels for the crop through real-time monitoring of the soil solution. The monitoring enabled the achievement of a balanced fertigation.