84 research outputs found
Jóias pré-históricas de Montes Claros de Baixo, Vimieiro, Arraiolos.
76 (1-2) Jan.-Jun. 1966, p. 157-163
Paleo e Mesolítico Português. Descobrimentos, Bibliografia. Iª Parte.
46 (3-4) Jul.-Dez. 1936, p. 221-230
Castro de Vila Nova de S. Pedro IX. Forno de cozer cerâmica.
67 (1-2) Jan.-Jun. 1957, p. 83-94
Congresso Nacional Espanhol de Arqueologia, 3.º. Do Castro de Vila Nova de S. Pedro à Citânia de Sanfins.
63 (3-4) Jul.-Dez. 1953, p. 683-698
Paleo e Mesolítico Português. Descobrimentos, Bibliografia. IIª Parte.
47 (1-2) Jan.-Jun. 1937, p. 8-24
Peach orchard evapotranspiration in a sandy soil: comparison between eddy covariance measurements and estimates by the FAO 56 approach
The evapotranspiration from a 3 to 4 years old drip irrigated peach orchard, located in
central Portugal, was measured using the eddy covariance technique during two irrigation
seasons, allowing the determination of crop coefficients. These crop coefficient values
differed from those tabled in FAO Irrigation and Drainage Paper 56. In order to improve
evapotranspiration estimates obtained from FAO tabled crop coefficients, a dual crop
coefficient methodology was adopted, following the same guidelines. This approach
includes a separation between the plant and soil components of the crop coefficient as
well as an adjustment for the sparse nature of the vegetation. Soil evaporation was
measured with microlysimeters and compared with soil evaporation estimates obtained
by the FAO 56 approach. The FAO 56 method, using the dual crop coefficient methodology,
was also found to overestimate crop evapotranspiration. During 2 consecutive years,
measured and estimated crop coefficients were around 0.5 and 0.7, respectively. The
estimated and measured soil evaporation components of the crop coefficient were similar.
Therefore, the overestimation in evapotranspiration seems to result from an incorrect
estimate of the plant transpiration component of the crop coefficient. A modified parameter
to estimate plant transpiration for young, yet attaining full production, drip irrigated
orchards is proposed based on field measurements. The method decreases the value of
basal crop coefficient for fully developed vegetation. As a result, estimates of evapotranspiration
were greatly improved. Therefore, the new approach seems adequate to estimate
basal crop coefficients for orchards attaining maturity established on sandy soils and
possibly for other sparse crops under drip irrigation conditionsinfo:eu-repo/semantics/publishedVersio
Subsídios para uma Carta Arqueológica do Concelho de Vila do Conde. I Estação Paleolítica de Modivas.
74 (1-2) Jan.-Jun. 1964, p. 143-148
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