Irrigation performance and gross water productivity in furrow-irrigated ornamental tree production

In the ornamental plant production region of Girona (Spain), which is one of the largest of its kind in southern Europe, most of the surface is irrigated using wide blocked-end furrows. The objectives of this paper were: (1) to evaluate the irrigation scheduling methods used by ornamental plant producers; (2) to analyse different scenarios inorder to assess how they affect irrigation performance; (3) to evaluate the risk of deep percolation; and (4) to calculategross water productivity. A two-year study in a representative commercial field, planted with Prunus cerasifera ‘Nigra’, was carried out. The irrigation dose applied by the farmers was slightly smaller than the required water dose estimated by the use of two different methods: the first based on soil water content, and the second based on evapotranspiration. Distribution uniformity and application efficiency were high, with mean values above 87%. Soil water contentmeasurements revealed that even at the end of the furrow, where the infiltrated water depth was greatest, more than 90% of the infiltrated water was retained in the shallowest 40 cm of the soil; accordingly, the risk of water loss due to deep percolation was minimal. Gross water productivity for ornamental tree production was € 11.70 m–3, approximately 20 times higher than that obtained with maize in the same region

Irrigation performance and gross water productivity in furrow-irrigated ornamental tree production

In the ornamental plant production region of Girona (Spain), which is one of the largest of its kind in southern Europe, most of the surface is irrigated using wide blocked-end furrows. The objectives of this paper were: (1) to evaluate the irrigation scheduling methods used by ornamental plant producers; (2) to analyse different scenarios in order to assess how they affect irrigation performance; (3) to evaluate the risk of deep percolation; and (4) to calculate gross water productivity. A two-year study in a representative commercial field, planted with Prunus cerasifera ‘Nigra’, was carried out. The irrigation dose applied by the farmers was slightly smaller than the required water dose estimated by the use of two different methods: the first based on soil water content, and the second based on evapotranspiration. Distribution uniformity and application eff iciency were high, with mean values above 87%. Soil water content measurements revealed that even at the end of the furrow, where the infiltrated water depth was greatest, more than 90% of the infiltrated water was retained in the shallowest 40 cm of the soil; accordingly, the risk of water loss due to deep percolation was minimal. Gross water productivity for ornamental tree production was € 11.70 m–3, approximately 20 times higher than that obtained with maize in the same region.

Parametrización de kB-1 para estimar el flujo de calor sensible con imágenes AVHRR

La necesidad de evaluar la evapotranspiración a escala regional para la gestión de regadíos ha hecho que sean innumerables los intentos por aplicar imágenes AVHRR-NOAA en la determinación el flujo de calor sensible. La principal limitación de estos métodos es la estimación de la resistencia aerodinámica. El parámetro crítico en la expresión de la resistencia aerodinámica es kB-1. La parametrización de kB-1 ha sido infructuosa a escala regional por no disponer hasta ahora de medidas de flujo de calor sensible a escala del píxel AVHRR en superficies heterogéneas y durante toda una temporada de riegos. Para resolver esta medida de flujo se ha desarrollado el cintilómetro. En la primera parte de este trabajo se estudia la representatividad espacial de las medidas del cintilómetro. El núcleo de esta aportación consiste en la correlación entre el parámetro kB-1, el NDVI y la altura solar. Los buenos resultados obtenidos (r2=0.81) ofrecen una nueva metodología para determinar el flujo de calor sensible. La estimación de kB-1, las imágenes AVHRR y los datos meteorológicos permiten calcular el flujo de calor sensible durante toda la temporada de riegos con errores inferiores al 20%.