Water retention properties of an acidic vineyard soil modified by sugar foam liming

Abstract

Soil pH is one of the most important factors that influences the use of a particular soil for Viticulture. An acidic vineyard soil is usually amended before planting to raise the pH. This amendment, which is called liming, also modifies other properties such as the calcium content, flocculation of colloids, structural stability, microbial activity and nutrient contents, amongst other factors, and can modify the behavior of the soil from the point of view of moisture retention.

The main objective of this study was to assess the influence of sugar foam (waste from the sugar beet industry) on the moisture retention properties of three profiles of an acidic amended soil used for growing vines. The water retention curves of the soil were determined with Richards’ pressure plates and values for the gravimetric moisture at field capacity, gravimetric moisture at the permanent wilting point and available water retention capacity were calculated. The water retention properties in both the original soil, under natural vegetation, and the amended vineyard soil were compared.

The gravimetric moisture at field capacity was 36.5% in the original soil compared to 23.5% average in the amended profiles; the gravimetric moisture at the permanent wilting point was 15.1% in the natural soil versus 10.35% in the vineyard limed soil and the available water retention capacity was higher in the natural soil (21.5%) than in the soils amended with sugar foam (13.1%). The organic matter content of the original soil (9.7%) and its low bulk density (0.81 g·cm^–3 compared to 1.52 g·cm^–3) are the most influential factors in this study and they explain the observed behavior. Changes in water retention properties were not a limiting factor for the crop, whereas the increase in the pH was found more suitable for vineyard cultivation.