Planting times and spacing of carrot crops in the São Francisco Valley, Pernambuco state, Brazil.

Climate variations over the year and plant density tend to strongly affect the agronomic performance of carrot crops. Thus, the objective of this work was to evaluate the performance of the cultivar Brasilia in crops under mild (winter) and high (summer) temperatures. An experiment was conducted from May 2011 to February 2012, using a randomized block design and treatments arranged in split plot, with three replications. The plots consisted of planting seasons (winter and summer) and the subplots of plant spacing (4, 6, 8 and 10 cm). The height of plants presented a linear decrease, from 53.4 to 51.0 cm, with an increase in spacing in summer planting, while in winter the greatest height (50.7 cm) was obtained with spacing of 8.0 cm between plants. The lowest commercial yields were found in summer crops and with the widest spacing between plants. The smallest spacing between plants (4 cm) had yields of 45.9 Mg ha -1in summer and of 63.1 Mg ha-1 in winter crops. The winter planting had higher fresh root weight (89.9 g root - 1 ) compared to the summer (81.4 g root - 1 ), reaching higher weight with increasing plant spacing. Higher yields are achieved with plant spacing of 4 cm during winter. The carrot can be grown throughout the year in the Submiddle of the São Francisco Valley.

Effects of row spacing and nitrogen topdressing fertilization on the yield of upland rice in a no-tillage system.

This study aimed to evaluate the effect of row spacing and nitrogen topdressing fertilization of two materials (genotype 07SEQCL441 CL and cultivar BRS Esmeralda) on the plant height, yield components, grain yield, and quality of an upland rice crop grown in a no-tillage system. Trials were conducted for two growing seasons under field conditions in a 3 x 4 factorial, randomized, complete block design, with four replications. For each material, treatments consisted of the combination of row spacing (0.225, 0.35, and 0.45 m) with nitrogen (N) applied as topdressing (0, 50, 100, and 150 kg ha-1). The lowest row spacing (0.225 m) for genotypes 07SEQCL441 CL and BRS Esmeralda provided a higher number of tillers, number of panicles m-2, and grain yield of rice. Increasing rates of N in the topdressing improved the rice grain yield for both cultivars, but for 07SEQCL441 CL, the grain yield was positively affected only to applications up to 50 kg N ha-1. Row spacing and N rates did not affect the rice grain quality. Therefore, these results indicate that the narrowest row spacing used (0.225 m) with N fertilization as topdressing increased the rice grain yield most in the no-tillage system.

Caracterização da estrutura demográfica e ocupação da área basal em cinco áreas de mata ciliar da região Nordeste paraense.

As matas ciliares são encontradas nas margens dos rios e mananciais e são responsáveis por proteger os cursos d'água do assoreamento, da obstrução de alguns trechos do rio pelo aumento no volume de terra e outros sedimentos carregados pela correnteza. Realizou-se o inventário florístico próxima ao leito do igarapé na região nordeste paraense, nas respectivas áreas de monitoramento: Ceará, Monte-verde, São Francisco, Ver-o-peixe e Vitório. Objetivou-se neste trabalho caracterizar a estrutura demográfica e ocupação da área basal em cinco áreas de mata ciliar da região nordeste paraense. Com base, nestes dados coletados (diâmetros, espécie) foram calculadas a abundância e área basal absoluta e relativa dos indivíduos identificados por local e tamanho de classes diamétricas e/ou altura. Foram registrados 1.213 indivíduos, sendo a maior proporção encontrada na área São Francisco que obteve 10.039 indivíduos por hectare, enquanto à área basal destacou-se Ceará com 34,2%. A distribuição da demografia apresentou alta similaridade na proporcionalidade da distribuição dos indivíduos nas classes de tamanhos (muda, vara, árvore) e averiguamos que a quantidade de indivíduos apresentados por área não necessariamente implica no acúmulo da maior área basal.