Submitted to: Biology and Fertility of Soils
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 14, 2002
Publication Date: January 2, 2003
Citation: Sikora, L.J., Filgueira, R.R., Fournier, L.L., Rawls, W.J., Pachepsky, Y.A. 2003. Soil surface properties as affected by organic by-products. International Agrophysics 16, 289-295.
Interpretive Summary: Adding organic by-products like manures and composts to soils generally results in improved soils physical and biological properties. Soils are easier to work, they hold more water, and have a greater abundance of organisms. Very few studies have investigated whether organic by-products increase the surface area of soils. The greater the soil surface area, the greater the surface for water and microorganisms to attach. Therefore, greater surface area is thought to be more beneficial. In our studies, a greater surface area was recorded in soils amended with organic by-products for four years. Increases with fertilizer application was also recorded. The increases in soil surface area could not be attributed to total increase in organic matter, nor total addition of ash from the organic by-products. Data suggested that the quality and not quantity of organic matter or ash may have some bearing on soil surface area change. For instance, crab waste compost had the largest increase in soil surface area and it contains a considerable amount of calcium compounds. Further studies in the change in soil surface area are necessary to better understand how organic by-product addition to soils change this important physical property.
Beneficial effects of amending soils with organic by-products includes improvement of chemical and physical factors. Very few studies have studied changes in soil surface area after amendments of manures or composts. Soil samples were taken from plots before and after four year's application of manures, composts or nitrogen fertilizer. A corn-wheat-soybean rotation was grown. Soil samples were tested for changes in water retention at 15 bar, bulk density, C content and soil surface area using nitrogen gas adsorption at 73K. Increasing water retention and decreasing bulk density were related to total organic matter amendment. Increases in SSA were noted in all soils sampled. Soil surface area changes were not related to either C increases or ash amendments. Crab waste compost amendment increased SSA the most, a 4.45 m2 g-1 soil C increase. Fertilizer increased SSA 0.5 m2 g-1 soil C increase. The calcium mineral content of crab waste compost may be a factor in increasing the SSA. No single factor appeared to explain the increase of SSA in these field soils.