Agriculture

Investigators at University of Turin have published new data on soil science

  2009 NOV 26 - (VerticalNews.com) -- According to a study from Grugliasco, Italy, "Fragipan is a widely distributed subsoil horizon that induces severe limitations to plant growth and land use, mainly because of its high bulk density. In this work, we evaluated the pore-size distribution through the analysis of the cumulative curve of intruded mercury volume in some soils with fragipan horizons."

  "This approach provides information also about the arrangement of particles, thus we compared the results obtained for fragipan and nonfragipan horizons to relate porosity and particle arrangement with the specific physical properties of fragipans. The total volume of intruded mercury did not allow to discriminate between fragipan and nonfragipan horizons. However, from the variation of the pore volume as a function of the radius, two modal classes of pores were found, coarse and fine, respectively. The fine-pore class arose from the arrangement of clay particles, and its volume was correlated to clay contents (r = 0.787) and to clay packing density (r = -0.621). The clay fractions in fragipans were less densely packed than in the other B horizons, even if they had similar clay contents. The coarser-pore modal class is known to arise from the interactions between clay, silt, and sand particles, and its volume was different among horizons. Fragipan had a low volume of this modal pore class. In addition, a packing density for the coarser phase of 0.74, corresponding to a rhombohedral packing, was found only in fragipans. Thus, the low permeability and high bulk density of fragipans are linked to specific arrangements of the particles: an open packing of the clay phase is associated to an extremely dense packing of silt and sand," wrote G. Falsone and colleagues, University of Turin.

  The researchers concluded: "This combination is not present in any other soil horizon."

  Falsone and colleagues published the results of their research in the Journal of Plant Nutrition and Soil Science - Zeitschrift Fur Pflanzenernahrung und Bodenkunde (Pore-size distribution and particle arrangement in fragipan and nonfragipan horizons. Journal of Plant Nutrition and Soil Science - Zeitschrift Fur Pflanzenernahrung und Bodenkunde, 2009;172(5):696-703).

  For additional information, contact G. Falsone, University of Turin, DIVAPRA Chim Agriculture, Via L da Vinci 44, I-10095 Grugliasco, Italy.

  The publisher of the Journal of Plant Nutrition and Soil Science - Zeitschrift Fur Pflanzenernahrung und Bodenkunde can be contacted at: Wiley-V C H Verlag GmbH, PO Box 10 11 61, D-69451 Weinheim, Germany.

  Keywords: City:Grugliasco, Country:Italy, Soil Science, University of Turin.

  This article was prepared by VerticalNews Agriculture editors from staff and other reports. Copyright 2009, VerticalNews Agriculture via VerticalNews.com.