Indicative Recognition Criteria of Degradation by Compaction of the Greenhouses Soils with Coarse Texture

摘要

Soil with coarse texture (clay<12%) are known under the name of Psamosol [1,2], Arenosol [3] or Psament [4] and belong to loamy texture class or coarser. In the French classification system Arenosol correlate with taxa within the "Classe de sol minereaux" and "Classe de sol peu evolues". These soils have low water-holding capacities, high water permeability, excessive aeration, low content of all essential nutrients, low buffer capacity and are still much less fertile than most soils in the regions they are located in. the sandy or loamy sand soil are susceptible to physical degradation by wind erosion and compaction processes [5]. Soil vulnerability to compaction increase if the fine sand/coarse sand ratio is lower than 10 [6]. Coarse textured soils are considered warm because heat up soil easily due to low water holding capacity. Plants grown on these soils arrive maturity earlier about 2-3 weeks compared to those grown on soils with finer texture in the same climate zone. Since the incipient degradation of the sandy or loamy sand soil is harder noticed by farmers, in this paper we proposed a set of indirect indicators for assessing the status of soil degradation, especially by compaction. Proposed set of indicators refers to plants uniformity, the local presence of areas with stagnant growth plants, the shape areas, the accumulation of slightly soluble salts on the soil surface, uniformity moist band after drip irrigation. Main conclusions: (i) Greenhouses soils with coarse texture (clay content lower than 12%) have high susceptibility to degradation by physical and chemical processes. (ii) Dimensions of moistened soil band, after irrigation administration, is an good indirect indicator for assessing the state of compaction of soils. (iii) We consider that developing a chart to determine the state of soil compaction on indirect indicators is useful for farmers because are easy to follow and to measure.