Wednesday, November 15, 2006
240-5
Biomass Incorporation Effects on Surface Soil Physical and Hydraulic Properties.
Moniruzzaman K. Eusufzai, Iwate Univ , Faculty of Agriculture, Iwate, 020-8550, Japan and Katsumi Fujii, Iwate University, Faculty of Agriculture, Iwate, 020-8550, Japan.
Cascade utilization of biomass obtained as agricultural bi-products have the potential to improve soil quality. A study was installed in Iwate University Experimental Farm, Morioka, Japan that sought to examine the impact of incorporation of biomass on physical and hydraulic properties of clay soil. Specifically, we investigated the effects of rate of application on three phase composition, bulk density, water retention and soil resistance. The experimental design was nine split blocks with three organic amendments: Sawdust, Rice straw and Compost applied at three rates 10%, 20% and 30% of soil volume (apparent) and a non amended control. Water retention characteristics were determined by the hanging water column and centrifuge method and soil resistance by a hand-held cone penetrometer. Result indicated that for all the treatments, three-phase composition changed at any rate of biomass incorporation. Compost, straw and sawdust incorporation showed a general trend of reduction of solid phase with the increase of application rate. For 30% (apparent soil volume) incorporation of compost resulted the maximum reduction of solid phase, while that for straw incorporation caused the minimum compared with the non-amended control. Water retention capacity for the compost-amended soil was higher at low potential compared with straw and sawdust amendment. The retention characteristics of the soil can be explained by the Young-Laplace (capillary rise) model. A good correlation was obtained between bulk density and soil resistance for the surface soil due to resistance for surface soils were reduced in response to biomass incorporation that may enhance plant root proliferation. The considerable variability in soil physical and hydraulic properties found in this study instigates the notion of long-term field trials for potential utilization of biomass as effective soil amendments.