Ricardo Carlos Pereira da Silva

Manejos da fertirrigação e doses de N e K no cultivo de pimentão em ambiente protegido

This study was carried out for evaluating the effects of fertigation management and levels of nitrogen and potassium on growth and yield of bell pepper in protected environment. The experimental design was in a completely randomized block, with 18 treatments and four replications. Treatments resulted from the combination of three fertigation managements and six nitrogen and potassium doses. There were six harvests, when evaluations were made of fruit number, mean mass and yield, as well as of growth indicators (leaf area, plant height and dry mass). Results showed that, besides the N and K doses, bell pepper growth and yield also depend on the management of fertigation used. Fertigation managements based on concentration of N and K ions using solution extractors, and monitoring of soil electrical conductivity were better than the usual management. Soil solution monitoring must take as reference N and K concentrations between 200 and 250% of recommendation for bell pepper production in hydroponic system.

Crescimento de mudas de moringa em função da salinidade da água e da posição das sementes nos frutos

Choosing seeds is crucial for obtaining good quality seedlings, especially when the seedlings are grown under adverse environmental conditions. This work was carried out to evaluate the influence of salinity on the development of moringa seedlings from seeds located at different positions in the pod. The design used in this study was a completely randomized design with treatments arranged in 3 x 4 factorial scheme, with four replications. The treatments resulted from a combination of three positions in the seed fruit (basal, median and apical) with four salinity levels of irrigation water (0.5, 2.0, 3.5 and 5.0 dS m-1). The growth characteristics evaluated were the following: height (ALT), stem diameter (AD), diameter of the root principal (DRP), number of leaves (NL), leaf area (LA), shoot dry mass (SDM), root dry mass (RDM) and total dry mass (MST). The data were submitted to analysis of variance by F test and means were compared by the Tukey test at 5% of probability for the effect of seed position in the fruits, and to regression analysis for data from the salinity. Interaction was significant for most traits. The salinity of irrigation water caused a reduction in all variables. Seedlings from seeds located in the basal portion of the fruits are more affected by salinity of irrigation water.

EFEITO DO ADUBO VERDE FLOR-DE-SEDA NO SISTEMA CONSORCIADO DE CENOURA E ALFACE

Intercropping is a cropping system that involves cultivating two or more crops in the same area with different cycles and vegetative architectures. One of the ways to increase productivity and efficiency in this cropping system is through green manuring and by properly considering crop combinations, cultivation timing, and planting configuration of the component crops. Thus, the aim of this study was to evaluate the productive performance of carrot and lettuce intercropping systems under different amounts of rooster tree biomass incorporated into the soil and under different spatial arrangements. The study was conducted at the experimental farm Rafael Fernandes, RN, Brazil, in the period from September 2012 to January 2013, in an experimental design of randomized complete blocks in a 4 x 3 factorial scheme, with twelve treatments and 3 replicates. The treatments consisted of the combination of four rooster tree biomass amounts incorporated into the soil (10, 25, 40 and 55 t ha on a dry basis) with three predetermined spatial arrangements between the component crops (2:2, 3:3 and 4:4), which correspond to the rows of carrot alternating with the rows of lettuce. The agronomic performance of the carrot and lettuce intercropping system was optimized in the amount of approximately 46.36 t ha of rooster tree incorporated into the soil. There was no influence of the spatial arrangements on the agronomic efficiency of the carrot and lettuce intercropping. The use of rooster tree as green manure is agronomically viable in intercropped systems of carrot and lettuce.

EFEITO DA SALINIDADE E BIOFERTILIZANTES NA CULTURA DA ABOBRINHA

A abobrinha (Cucurbita pepo L.) é uma planta da família das cucurbitáceas, no Brasil, também é conhecida como abóbora de moita, abobrinha italiana, caserta, abobrinha de tronco (Filgueira, 2008). A abobrinha situa-se entre as dez hortaliças de maior valor econômico, com importância econômica elevada (Carpes et al., 2008). O potencial de expansão dessa cultura entre horticultores deve-se ao fato da mesma apresentar características como precocidade e fácil cultivo, adequando-se a sistema de produção utilizado por pequenos produtores. Muitos produtores têm acatado a irrigação como a tecnologia que mais contribui para o aumento da produtividade, no entanto, a maioria dos produtores rurais de hortaliças realizam irrigações com água coletada em reservatórios superficiais, a qual pode apresentar elevada concentração de sais dissolvidos. Desta forma, a utilização da água salina fica condicionada à tolerância à salinidade pelas culturas e ao manejo adequado da irrigação (MEDEIROS et al., 2007). Abobrinha italiana é classificada como moderadamente tolerante a salinidade, apresentando salinidade limiar da água de irrigação de 3,1 dS m (MAAS & HOFFMAN, 1977). A tolerância à salinidade é variável entre espécies e, mesmo em uma espécie, o efeito do estresse salino é dependente de fatores como estádios de desenvolvimento, fatores ambientais, cultivar, tipo de sais, intensidade e duração do estresse salino, manejo cultural e da irrigação e condições edafoclimáticas (MUNNS, 2005; PARIDA

Armazenamento e métodos para a superação da dormência de sementes de mulungu

DAS, 2005).