Tillage and land use effects on soil microporosity in Ohio,
USA and Kolombangara, Solomon Islands
, Rattan Lal
School of Natural Resources, The Ohio State University, 2021 Coffey Rd., Columbus, OH 43210, United States
Received 1 October 2003; accepted 27 April 2005
Micropores are important to soil moisture retention and plant growth. Microporosity and pore size distribution were evaluated
using mercury intrusion porosimetery on aggregates from 35-year-old experiments started in 1962 at Wooster (40.5 8N, 82 8W) and
South Charleston (39.8 8N, 84 8W) in Ohio, USA and from three land use practices on Kolombangara (8 8S, 157 8E) in Solomon
Islands. Tillage treatments in Ohio included: moldboard plowing (MP), chisel plowing (CP), and no-till (NT) with continuous corn.
The land use treatments in Kolombangara included: natural forest (NF), traditional farming (TF) and topsoil removal (TR). Pore size
measured in aggregates ranged from 0.2 to 100 mm in diameter. Median pore radius was signiﬁcantly (P < 0.05) larger for NT than
for MP and CP treatments at Wooster, but not at South Charleston. Tillage treatments had signiﬁcant effect on the volume of both
storage and residual pores for both sites in Ohio. Volume of storage and residual pores were higher for Wooster than South
Charleston soil. At Kolombangara, the NF treatment had signiﬁcantly larger median and peak pore radii, and microporosity than TF
and TR treatments. There was, however, no signiﬁcant difference among treatments in the volume of pore size distribution. These
data support a recommendation for adoption of no-till or conservation tillage in soils of the temperate region, and of minimal
disturbance and effective erosion control in soils of the tropics.
# 2006 Elsevier B.V. All rights reserved.
Keywords: Tillage; Land use; Porosity; Pore size distribution; Structure; Tropical soils; No-till; Conservation tillage; Mercury intrusion
Porosity refers to the voids between particles and
structural units of a soil. The size and distribution of
these voids, particularly of those between particles or
structural units, are important to plant growth because
they affect the storage and movement of water and
gases, and root growth. Presence of transmission pores
or elongated and continuous pores (pores ranging from
50 to 500 mm) is important to water movement within
the soil proﬁle and gaseous exchange (Pagliai et al.,
1984). Quantitative information about the amount, size,
conﬁguration or distribution of the pore space is more
important in characterizing the soil as a medium for
plant growth than particle size distribution (Danielson
and Sutherland, 1986). Soil structure is deﬁned in terms
of its functional attributes comprising soil porosity and
pore size distribution (Lawrence, 1977; Greenland,
1977). Ringrose-Voase and Bullock (1984) and Pagliai
et al. (1984) reported that porosity and pore size
distribution were the best indicators of soil structure,
because the size, shape and continuity of pores affect
important soil processes. Thus, adverse changes in soil
structure can be recognized by quantifying reduction in
Soil & Tillage Research 88 (2006) 80–84
* Corresponding author. Tel.: +1 614 292 9069;
fax: +1 614 292 7432.
E-mail address: email@example.com (R. Lal).
Present address: P.O. Box 1480, Honiara, Solomon Islands.
0167-1987/$ – see front matter # 2006 Elsevier B.V. All rights reserved.