SG (Slot)

RESEEDING OF CRIMSON CLOVER, AND ITS RESIDUAL EFFECTS ON SOIL
PROPERTIES AND CORN (Zea mays L.) GRAIN YIELD IN A CLOVER/CORN RELAY
INTERCROPPING SYSTEM.
J.D.T. Kumwenda*, D.E. Radcliffe••, W.L. Hargrove•••, and D.C. Bridges•••
• Chitedze Agric. Res. Stn., P.O. Box 158, Lilongwe, Malawi.
•• Univ. of Georgia, Dep. of Agron., Athens, Georgia, USA.
••• Univ. of Georgia, Dept. of Agron., Exp. Stn., Griffin, Georgia, USA.
ABSTRACT
Reseeding of crimson clover (Trifolium incarnatum L.) In a cloverjcorn relay lntercropplng system
would be an Important management practice to avoid replanting each yr. Thus, a study was conducted
on a Typic Kanpaleudult and Typic Kanhapludult, to evaluate reseeding of clover and its residual effects
on soil and corn when killed at various rates. Corn was relay planted Into chemically killed-strips, with
paraquat, (at 25, 50, 50, 75, 90, or 100% of the area killed), live clover or bare fallow for 3 yrs. Killing
was accomplished 2 wks before or at planting. Live clover or that left between rows of corn was
allowed to reseed. Reseeded clover also received the same chemical strip-kill treatments before
planting corn. Ground cover of reseeded clover was estimated to vary from 1 to 100% depending on
the time and percentage of strip-kill. Averaged over yrs, ground cover estimates of reseeded clover
kill at 0, 25, 50 or 75% varied from 65 to 100%. Soli C, N, and percentage of water stable aggregates
increased with reseeding of clover, and these values were often higher than those of similar treatments
of the Initial clover or in some cases bare fallow. Corn grain yields followed similar trends. Based on
results of reseeding, corn grain yield, residual effects of clover, management of chemical strip-killing,
50 to 75% strip-kill appeared to be the best treatments.
INTRODUCTION
In their review, Hargrove and Frye (1987) reported that the use of winter legumes
as N sources for subsequent nonlegume crops, and for water and soil conservation,
has increased markedly in recent years. Part of this response has been due to
escalating costs associated with the production of inorganic fertilizer-N and concern
over soil erosion.
Consequently, many management practices for using winter legumes in multiple
cropping systems with nonlegume crops have evolved to improve the profitability of
using legume crops. One of the management practices that is of interest in the
Southeastern USA is reseeding of crimson clover when grown in rotation or
intercropping systems with nonlegume crops (Touchton et al., 1982). Reseeding of
crimson clover should reduce costs of establishing clover each year (Touchton et al.,
1982). Further, reseeded clover should germinate before the optimum time of
seeding clover in October and thus, produce more fall growth before severe winters
(Touchton and Wells, 1985). As a consequence, reseeded clover should produce
more dry matter and accumulate more fixed N in the following spring than seeded
clover (Oyer and Touchton, 1990), resulting in more residual effects of soil C and N
(Langdale et al., 1987).
Reseeding of clover in grass/clover mixtures has been reported (Van Keuren and
Hoveland, 1985). Comparable studies for row crops are very few. Research studies
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