Resumo

HUSSEIN-MOUNZER, Oussama et al. Soil water content measured by FDR probes and thresholds for drip irrigation management in peach trees. Agric. Téc. Méx [online]. 2008, vol.34, n.3, pp.313-322. ISSN 0568-2517.

Soil water content was monitored continuously with multisensor capacitance probes, based on the frequency domain reflectometry (FDR) technique, in drip irrigated young peach trees (Prunus persica (L.) Batsch) cv. Flordastar in a semiarid region of Murcia, Spain during 2004. The aim of this work was to study the effect of two irrigation treatments on volumetric soil water content and to determine the irrigation management thresholds of the soil water store (SWS) as monitored by FDR probes. The treatments consisted in restoring the soil water content to 100% (T1) and 50% (T2) of the crop evapotranspiration (Etc) by applying different irrigation doses with similar frequency. The continuous measurements of soil water content by the capacitance sensors reflected properly the impact of different irrigation events on the soil water stored and provide useful information upon the advance of the wetted front, the depth of the root system activity and the fate of the applied water. Through the continuum soil-plant-atmosphere, the variations of the soil water content were used to determine the in situ: "fullpoint" (142 mm 0.5 m^-1), field capacity (132 mm 0.5 m^-1), and "refillpoint" (124 mm 0.5 m^-1) as practical thresholds for irrigation management to match the irrigation doses and frequency with the actual plant water requirements. Graphical determination of irrigation thresholds minimized the importance of small fluctuations in soil water content. For the early ripening "Flordastar" peach cultivar the reduction of water application down to 50% ETc has lead to a progressive depletion of the soil water storage without a significant effect on final fruit yield and increased water use efficiency from 2.7 kg m^{-3 in T1 to 5.0 kg m-3 in T2.}

Palavras-chave : capacitance FDR probe; drip irrigation; fruit yield; irrigation scheduling thresholds; Prunus persica L. Batsch; water use efficiency.

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