Author(s): Jan Lukas Wenzel; Thomas Piernicke; Julia Pohlitz; Kristin Hasselbusch; Falk Bottcher; Daniel Spengler; Christopher Conrad
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Abstract: Increasing world population and food demand require solutions to secure world nutrition with less water use. For potato growth and yield and quality ensuring, optimal conditions are between 50% plant available water content and field capacity. Thus, close attention to soil hydraulic properties, weather and phenological characteristics is mandatory for an efficient irrigation management using soil moisture or evapotranspiration-based irrigation management tools. As a first step toward combining soil moisture- and evapotranspiration-based approaches, we present the results of a field experiment (27 ha) during the growing season in 2021 on a loamy-sand starch potato field in Mecklenburg-Western Pomerania, Germany. Four different irrigation levels were set up using a gun sprinkler irrigation system. In addition to the farmer´s common irrigation (100%), two deficit (80% and 90%) and one abundant (120%) irrigation levels were applied. The 100% irrigation corresponds to a total irrigation level of 119.39 mm (cumulative water supply = 374.49 mm), supplied during five events, each scheduled according to monitored root-zone moisture and weather forecast. The laboratory determined soil hydraulic properties are typical for a loamy sand with soil moisture of 0.207 m3 m-3 at field capacity, 0.039 m3 m-3 at permanent wilting point, and a saturated hydraulic conductivity of 173 cm d-1. The soil moisture dynamics were simulated in each treatment using the evapotranspiration-based AMBAV model and the soil hydraulic properties-based HYDRUS-1D software environment. In-situ soil moisture measurements, observed in three-time replicates per experimental plot in 10 cm increments up to a depth of 60 cm, were used for validation.
Year: 2022