Water retention properties of viticultural calcisols from D. O. P. Valdepeñas (Spain)

Abstract

A good knowledge of the soil physicochemical properties, as well as its ability to retain and put the necessary water available to the plants, is essential when it comes at the design of an irrigation plan. The latter must be capable of satisfying the water needs of the crops, avoiding both excess water (which is not used and causes soil´s leaching) and its deficit, since that ends up harming both the crops and their yields.

In growing vineyard for winemaking, the quality of the grapes used will depend on the frequency and the amount of water supplied to the plant. Therefore, this aspect is especially relevant for viticulture in Mediterranean climates where water scarcity is an increasingly limiting reality (which is expected to be worse due to the influence of climate change).

The purpose of the study is the determination of the moisture retention properties corresponding to 33 vineyard calcisols selected as representative from the Protected Designation of Origin “”Valdepeñas”” in Castilla-La Mancha (Spain) and also, related them with other physicochemical soil properties to determine which of them are stadistically correlated.

In this research, standard commercial pressure plate apparatus from Soilmoisture Equipment Corp. (Santa Barbara, California, USA), was used to apply the specified pressures from -10 kPa to -1500 kPa to the soil samples of the surface and subsurface horizons from the 33 calcisols soils (6 of them do not have subsurface horizon). After that, the gravimetric method was carried out on those same soils, and finally, the soil water retention curves were developed.

The moisture values at Field Capacity (-33 kPa), Permanent Wilting Point (-1500 kPa) and Available Water of the surface (A) and subsurface (B) horizons were compared, concluding that soil depth statistically influences these parameters. The available water values of each horizon were related to the most relevant physicochemical properties of the soil in terms of moisture retention (apparent density, sand, silt, clay, organic matter, calcium carbonate and active calcium carbonate) to know whether they were correlated. For the horizon A, silt and active calcium carbonate are positive correlated with available water (r = 0.43 and r = 0.42, respectively), however, calcium carbonate and active calcium carbonate are the most positive correlated properties with the available water of the horizon B (r = 0.68 and r = 0.57, respectively).