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Abstract
Nkongolo, N.V., M. Yamada
and I. Nakagawa. 2007. Spatial variability
selected soil physical properties and root growth of sweet corn. JEMREST
3:276-285.
The spatial variation of soil
properties has been largely studied, however the corresponding variation in
crop growth response has not received much attention. The objective of this
study was to assess the spatial variation of soil physical properties and
that of sweet corn root growth. The study was conducted on a light-colored
Kuroboku soil (Low-humic Andosols) at the National
Agriculture Research
Center, Tsukuba (Japan). Soil samples and roots of
sweet corn were collected along a 0.90 m width and 41m long ridge at 0.30 m
spacing. The ridge was divided into three portions amended with 1430 Kg of
N-P2O5K2O fertilizer (CF) in the first 12-m,
no amendment (NA) in the next 12-m and 1111 Kg/ha of animal manure (AM) in
the last 17m, respectively. Coefficients of variation (CV) ranged from 3 to
12% for soil physical properties and from 38 to 58% for root dry mass of
sweet corn (RDM). Autocorrelogram functions (r(h)) showed that in CF portion,
all soil physical properties could be sampled together at six lags or 1.80 m
for independent observations, except for soil gravimetric water content (qg)
and RDM. However, in NA and AM portions, autocorrelogram functions (r(h))
showed cyclic patterns, suggesting the presence of compacted/non-compacted zones
within the ridge as the result of wheel traffic. Air-filled porosity (¦a)
in NA (p=0.05, r= -0.35) and qg in AM (p= 0.05, r=0.45) were
correlated with RDM. A short variability in soil physical properties resulted
in higher variability in corn root growth.
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