Francisco de Queiroz Porto Filho

Crescimento do meloeiro irrigado com águas de diferentes salinidades

Two successive trials were carried out in a field at Mossoro, RN, Brazil, with the objective of studying growth characteristics of melon crop under different irrigation levels of water salinity. The experimental design was a completely randomized blocks with four replications, with four water salinity levels as treatments (T1=0.6 dS m-1; T2=1.9 dS m-1; t3= 3.2 dS m-1 and T4= 4.5 dS m-1). Growth was inhibited by the negative effect of water salinity levels on leaf area index, shoot dry mass, specific leaf area, and shoot leaf area ratio. The influence of irrigation of the water salinity level along melon cycle was observed for shoot absolute growth rate, but not for relative growth rate and net assimilation rate of shoot.

Crescimento de cultivares de melão amarelo irrigadas com água salina

The effect of five irrigation water salinity levels (N: 1.51, 2.79, 3.93, 5.15 and 7,22 dS m-1), on initial development of two yellow melon cultivars (Gold mine and AF646) was studied. The trial was conducted under field conditions in an orchard belonging to Department of Phytotechnic - ESAM, at Mossoro in the State of RIo Grande do Norte, Brazil, during the period of November 4 to December 12, 1998. Plastic pots with 9 L capacity filled with Alfisol soil (horizon Ap1) were used. Experimental design was a completely randomized block in a factorial scheme, with three replications. Shoot dry matter, leaf area, mean soil salinity and final soil salinity were evaluated through variance and regression analysis. Salinity tolerance was similar for Gold mine and AF646, with a loss of 6.8% of shoot dry matter for unit increase of electrical conductivity of irrigation water. A similar behavior was observed for leaf area. Irrigation water salinity induced linear effect on mean soil salinity and quadratic effect on final soil salinity.

Evolução da salinidade e pH de solo sob cultivo de melão irrigado com água salina

ABSTRACT This work aimed to study the effects of irrigation with saline waters in an area cultivated with melon onsoil salinity and pH. The experiment was conducted in the Santa Julia Farm, Mossoro city, Rio Grande doNorte State, Brazil, during the years 2001 to 2002. Water with different salinity levels (0.6; 1.9; 3.2 and4.5 dS m -1 ) was used throughout the cycle and in incremental way in three periods of melon development,forming 15 treatments, arranged in randomized blocks with four replications. The salinity was measuredat 0, 30, 50 and 70 days after sowing in soil samples collected in layers of 0-15, 15-30 and 30-45 cm.There was greater accumulation of salts in the surface layer (up to 15 cm) in all salinity levels and the useof more saline water produced higher average salinity in the profile. The average values of pH werewithin the range of optimal absorption of nutrients required by melon. Key words : Cucumis melo L., electrical conductivity, water management Revista Brasileira deEngenharia Agricola e Ambiental

Produção e qualidade de melancia cultivada com água de diferentes salinidades e doses de nitrogênio

The use of saline waters in the agriculture is one of the main factors that limit the production and the fruit quality in the State of Rio Grande do Norte, being the selection of tolerant hybrids to salinity and the use of the nitrogen fertilization, alternatives to avoid losses in income and quality of the fruits. Therefore, the objective of this study was to evaluate the production and the quality of the fruits of three cultivars of watermelon (Quetzali, Shadow and Leopard) under different salinities of irrigation water and doses of nitrogen in the region of Mossoro, RN. The treatments consisted in the application of irrigation water with five electrical conductivities (0.57; 1.36; 2.77; 3.86 e 4.91 dS m-1) and three doses of nitrogen (48, 96 e 144 kg ha-1), delineated in randomized blocks, with four replications. The productivity, the number and the mean weight of fruits, as well as the content of soluble solids were evaluated. The mean weight of fruits and the number of fruits affected the loss of income of studied watermelons cultivars. Only the Shadow cultivar had the soluble solids content of fruits altered with the salinity of irrigation water.

CARACTERIZAÇÃO HIDRÁULICA DO TUBO COM GOTEJADORES INTEGRADOS MARCA NETAFIM, MODELO STREAMLINE 80

José Aluísio de Araújo Paula Paulicéia Empreendimentos Ltda. Fone/Fax: (084)316-1021 Av. Alberto Maranhão, 2345. CEP:59.610-000 Mossoró RN Neyton de Oliveira Miranda Departamento de Engenharia Agrícola ESAM Fone: (084)312-2100 59.625-900 Mossoró RN e-mail: neyton@esam.br Maristélio da Cruz Costa Fundação Instituto de Desenvolvimento do Rio Grande do Norte – IDEC – Natal-RN. Fone (084)218-5254. e-mail: maristelio@esam.br Francisco de Queiroz Porto Filho Departamento de Engenharia Agrícola ESAM. Fone: (084)312-2100 59.625-900 Mossoró RN e-mail: engeagro@esam.br José Francismar de Medeiros Departamento de Engenharia Agrícola ESAM Fone: (084)312-2100 59.625-900 Mossoró RN e-mail: jfmedeir@esam.br