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The effect of tillage
systems and mulching on soil microclimate, growth and yield
of yellow yam (Dioscorea cayenensis) in Midwestern
Nigeria
Odjugo, P. A. O.
Department of Geography and Regional Planning, University of
Benin, P. M. B. 1154, Benin City, Edo State, Nigeria. E-mail:
paoodjugo@yahoo.com.
Tel: +23408023718654.
Accepted
6 November, 2008 |
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Yellow yam (Dioscorea cayenensis) is one of the major
varieties of yam produced in Midwestern Nigeria mainly by
traditional farmers. Most of these traditional farmers
employ zero tillage system and mulching after planting. But,
is this the best practice for optimising yield? This paper
examines the effect of tillage systems and mulching on soil
microclimatic conditions, growth and yield of yellow yam. To
generate the needed data, the physiological approach was
employed. An experimental farm that measured 35 x 47 m was
established at Agbor, Delta State, Nigeria, for two planting
seasons 1997/98 and 1998/99. The microclimatic parameters
monitored include air and soil temperatures and relative
humidity while the physiological parameters measured were
emergence, growth rate, leaf area accumulation and yield.
Time series, multiple correlations, chi-square, ANOVA, least
square range test and stepwise regression analysis were the
statistical tools employed in analysing the data. The
results showed that soil moisture at 0-15 cm depth was
significantly higher in zero tillage (40 g/g), followed by
ridge (30 g/g) and mound (24 g/g) but the reverse was the
case with soil temperature where mound tillage (34.2°C)
had the highest temperature followed by ridge (31.4°C)
and zero (29.5°C).
Mulching also significantly influenced the soil
microclimatic condition. While soil moisture enhanced yam
emergence, soil temperatures favoured the growth, leaf area
accumulation and yield. Mound tillage significantly gave the
highest yam tuber yield (12.0 t/ha-1), followed
by ridge (8.8 t/ha-1) and zero (5.0 t/ha-1).
Partially mulched treatment significantly produced the
highest yam tubers (10.3 t/ha-1), followed by the
unmulched (8.1 t/ha-1) and mulched (7.4 t/ha-1)
treatments. The best practice recommended for the production
of ware yams is mound tillage that is partially mulched.
This recommended practice yielded more than the local
practice by 44.6%.
Key
words:
Tillage systems, yellow yam, Midwestern Nigeria, soil
microclimate, mulching, yam yield. |
