TITLE:
Effect of Organic Matter Amendment on Hydraulic and Pore Characteristics of a Clay Loam Soil
AUTHORS:
Moniruzzaman Khan Eusufzai, Katsumi Fujii
KEYWORDS:
Organic Matter; Hydraulic Conductivity; Volumetric Water Content; Saturated Water Flux; Porosity
JOURNAL NAME:
Open Journal of Soil Science,
Vol.2 No.4,
December
31,
2012
ABSTRACT: The
objective of this study was to examine the effect of compost, rice straw and
sawdust amendment on hydraulic and pore characteristics of a clay loam soil.
Amendments were applied at an application rate of0.2 m3/m3 (apparent soil volume)
in three rectangular plots each comprising an area of3.0 m2. Water retention characteristics
were measured by hanging water column and centrifuge method. Hydraulic
conductivity was measured by disc permeameter at -15.0, -6.0, -3.0 and0 cmof water pressure heads. Volumetric
water content increased in all amended soils, compared with the control.
Unsaturated hydraulic conductivity was almost identical for straw and sawdust
at all pressure heads, although that for compost amended soils were much
higher. Field saturated hydraulic conductivity (Kfs) was
higher in organic matter amended soils as were number of macropores (14.7% - 29.2%). Contribution of each
pore class to the total saturated flux was evaluated from the hydraulic
conductivity and water retention measurement. A new alternative weighed factor
(We) was proposed to estimate the actual contribution of
macro- and mesopores to the total saturated water flux. The Wg was found to be more representative for calculating pores contribution to
saturated water flux than that of hydraulic conductivity measurement. Although there
is only a small fraction of the total porosity, amendment increased effective
macro- and meso-porosity (qe).
Pores in the amended soils were hydraulically active and water movement was
dominated by gravity. Collectively, our results demonstrated that organic
matter generated as agricultural by-product could effectively be used to
improve soil quality