THE MICROENVIRONMENT OF A CEREAL BASED INTERCROP AT SAMARU. NORTHERN NIGERIA
THE MICROENVIRONMENT OF A CEREAL BASED INTERCROP AT SAMARU. NORTHERN NIGERIA
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Date
2000-08
Authors
Ogunwole, Joshua olalekan
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Abstract
Depending on soil and climatic characteristics particularly, rainfall,
crop production in northern Nigeria can be limited by inefficient use of
nutrient especially, nitrogen and phosphorus, or by inefficient use of water.
Intercropping system evolved as a common practice in response to mitigating
those limitations. This is because intercropping may utilize these resources at
greater efficiency and produce higher total yields than the monocrops. The
objective of this study was to characterize the nature of the environment and
examine its effect on productivity under different cropping system with a
view to recommend a component technology to farmers.
The sorghum/maize combination is a popular intercrop in the Northern
Guinea Savanna. From the perspective of what the farmer does, field studies
spanning three seasons (1996-1998) were conducted on a fairly drained Typic
Haplustalf in Samaru. The experimental design was a randomized complete
block design with twelve different cropping systems, which revolved around
two sorghum varieties namely, Ihe local 'farafara' and Ihe improved
SAMSORG-14.
Results of climatic analyses revealed abundant solar radiation (400 cal
cm"2 day"1) in Samaru, which raised its potential for crop production. Analysis
of rainfall events revealed a progressive drier condition with years with
rainfall amount falling below the long term mean (1050 mm) and, the
probability of drought is high at the beginning and end of the growing season.
The soils of the area are structurally poor with low native fertility and poor
water holding capacity.
Generally, crop observaticn have shown greater and efficient use of
resources under intercropping. Peak light interception (780%) was attained at
70 DAS, same for peak leaf area index (3.35). Leaf area index and fractional
light interception followed a sigmoidal pattern; after emergence, they both
increase linearly up to maturity and then decrease at a diminishing rate due
to leaf senescence. Light use efficiency ranged from 4.67g MJ-1 in the Farafara/
Maize/Cowpea-R to 1.75 g MJ"1 in the monocroppcd maize. This further
confirm the efficient use of light resources by intercropping systems.
Local 'Farafara' recorded higher grain yield and seed weight both in
mixture or when planted sole. Stand intercrop favours higher grain yield over
the row planting pattern. The Land Equivalent Ratio (LER) showed
SAMSORG-14/MAIZE/COWPEA mixtures having the highest value of 1.69 in
1996 compared to the 1.60 in the FARAFARA/Maize/Cowpea mixtures. This
indicate a more efficient space usage over the monocrop. In addition, results
of water use (efficiency) showed intercropping to more efficiently use water
than the monocropped component. The Farafara/Maize/Cowpea mixtures
produced 12.5 kg ha'1 dry matter for every unit millimeter of water utilized
while the monocropped Farafara and SAMSORG-14 produced only 7.5 kg ha-1
and 3.9 kg ha-1 dry matter respectively for same unit of water. The higher
performance of the local Farafara tends to be due to its strong adaptation and
restriction to the Northern Guinea Savanna, which is the zone of study.
Results on environmental factors showed a high negative relationship
between intercrop yield and rainfall amount. This shows that rainfall distribution
and not necessarily the amount is the factor that improve crop yield. In addition
time (date of planting) was seen to have a strong relationship to yield. When
crops are planted early, yield obtained doubled those of late sown ones.
Description
A Dissertation submitted to the Post-Graduate School Ahmadu Bello University, in
partial fulfillment of the requirement for the degree of Doctor of Philosophy (Soil
Science).
Department of Soil Science
Faculty of Agriculture
Alimadu Bello University
Zaria. Nigeria
AUGUST, 2000
Keywords
MICROENVIRONMENT,, CEREAL BASED INTERCROP,, SAMARU.,, NORTHERN NIGERIA