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ResumoA combinação adequada de espaçamento entrelinhas com o número de plantas por metro frente a diferentes condições edafoclimáticas é fundamental para a obtenção de maiores produtividades do feijoeiro. Este trabalho objetivou identificar o melhor arranjo espacial e dose de fosfato monoamônico (MAP) para maximizar o potencial produtivo da cultivar superprecoce de feijão-comum BRS FC104. Os experimentos foram conduzidos em Formosa, Cristalina, Santa Helena de Goiás e Santo Antônio de Goiás, em Goiás, no delineamento de blocos casualizados com parcelas subdivididas e quatro repetições. Nas parcelas, foram avaliadas cinco doses de MAP, 100, 150, 200, 250 e 300 kg ha -1 , e, nas subparcelas, cinco populações de plantas, 6, 8, 10, 12 e 14 plantas por metro. Foram conduzidos dois experimentos em cada localidade, com os devidos espaçamentos entrelinhas: 0,38 e 0,50 m. Dentre os componentes da produtividade, o número de vagens por planta foi o mais afetado pelo arranjo espacial de plantas, aumentando seu valor com o incremento no espaçamento entrelinhas e redução na população de plantas. A resposta da produtividade do feijoeiro ao espaçamento entrelinhas foi variável, dependendo da localidade e da dose de MAP. A plasticidade dos componentes da produtividade manteve a produtividade do feijoeiro estável frente às alterações na população de plantas, exceto em Santa Helena de Goiás, onde maior produtividade foi obtida com cerca de 14 plantas por metro. A adubação fosfatada incrementou a produtividade do feijoeiro em Santo Antônio de Goiás. Palavras-chave: espaçamento entrelinhas; grãos por vagem; massa dos grãos; população de plantas; vagens por planta.

Spatial and temporal heterogeneity in the Alqueva reservoir, Guadiana river, PortugalThis study aims to assess the physico-chemical variability of the Alqueva reservoir during its initial filling period. The dataset consists of analytical results from an 11 month survey (Mar 2003-Jan 2004 conducted in the water body, at three levels of depth in the several tributaries and in the discharge section. 21 parameters were monitored on a monthly base, in order to understand the temporal and spatial variability. Another goal of this work was to use a multivariate statistical approach to help understand the relationships between water quality parameters, to group zones according to their similarities and to distinguish between wet and dry season conditions. FA/PCA needs 6 VF/PC to point out 74 % in the wet season, and 7 VF/PC to explain 78.6 % of variance in the dry season. FA/PCA allows grouping the selected parameters according to common features. As a result, mineral content is indicated as the principal source of variability in the wet season, while oxygenation plays the main role in the dry season. DA renders an important data reduction using 10 parameters to provide 93.2 % right assignations during temporal analysis. DA assigns temporal variability to the consequences of water balance on ambient salinities, to stratification influences and to surface runoff. Also, it uses only 4 parameters to yield 71.3 % right assignations during the spatial analysis in the dry season. Conductivity declines in the lacustrine zone, while CBO5, pH and Temperature vary principally in the vertical sense. However, such a spatial pattern is not static. It can become either more defined during the dry season, or less evident during the expansion of the lotic conditions in the rainy period (late spring and summer). Seasonal processes of stratification/mixture determine the temporal changes in the lacustrine zone. The system seems to be affected by periodic pulses of modifications produced by intensive rains and drought. Thus, limnological understanding of these questions is a prerequisite for making wise judgments about reservoir management.

The positioning of pods in common bean directly affects grain losses in mechanized harvesting. However, only few studies have assessed facttors that can affect pods positioning. The objective of this work was to determine the effect of plant density, nitrogen fertilization, and fertilization depth on the distribution of pods of the common bean. The field experiments were carried out in two cropping seasons, 2017 and 2018, during the winter period in the Cerrado region. The experimental design was randomized blocks in a 4x2 factorial scheme, with four replications. The treatments consisted of the combination of four sowing densities (5, 10, 15, and 20 plants m-1) with two depths of fertilizer application (6 and 12 cm). The results allowed inferring that the depth of the fertilization does not affect the distribution of pods in the common bean. Plant density does not affect common bean grain yield. More than a quarter of the common bean pods of the BRS FC104 are positioned close to the ground, below 100 mm, in the area where harvester machines operate. Nitrogen fertilization and plant density affect the distribution of pods in common bean plants. At higher doses of N (90 kg ha-1), plant density should be increased. On the other hand, at lower doses (45 kg ha-1), plant density must be reduced. It is concluded that the sowing density can be an efficient strategy to provide the highest positioning of pods in the upper part of the common bean plants, reducing harvest loss.

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