PHYSICAL QUALITY OF AN ALFISOL AS INFLUENCED BY CULTIVATION OF JATROPHA CURCAS L. AT SAMARU, NORTHERN NIGERIA
PHYSICAL QUALITY OF AN ALFISOL AS INFLUENCED BY CULTIVATION OF JATROPHA CURCAS L. AT SAMARU, NORTHERN NIGERIA
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Date
2013-02
Authors
SHEHU, BELLO MUHAMMAD
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Abstract
The decline in soil quality is increasingly seen as a form of soil degradation and is often
related to land use and soil/crop management practices. The research was conducted at the
Research and Experimental Farm of the Institute for Agricultural Research (IAR) Samaru,
Zaria with the aim of evaluating the influence of Jatropha curcas L. (JCL) plantation and
varied management practices under JCL on soil physical quality. To achieve this aim the
research was divided into two trials. The first trial involved five adjacent land uses: Arable
Land (AL), Fallow Land (FL), One Year JCL plantation (OYJ), Two Years JCL
plantation (TYJ) and Three Years JCL plantation (RYJ). The second trial comprised of
three JCL spacing rates (1.5 m x 1.0 m, 1.5 m x 2.0 m and 1.5 m x 3.0 m) and four nitrogen
levels (0 kg/ha, 60 kg/ha, 120 kg/ha and 180 kg/ha). Soil samples were collected at four
depths (0-5 cm, 5-10 cm, 10-15 cm and 15-20 cm) from the various treatments under study
and subjected to field and laboratory investigations for soil physical quality indicators such
as infiltration, organic carbon, bulk density, aggregate stability, moisture retention, S-index
etc. Result revealed that most of the parameters were significantly affected by land use.
Cultivation of JCL averagely increased total nitrogen, infiltration, dry large macroaggregates
(>2 mm), dry macro-aggregates (2-0.25 mm), dry mean weight diameter
(MWD) and dry geometric mean diameter (GMD) by 47%, 26.1%, 28.3%, 13.4%, 18.8%
and 12.2% respectively relative to land under continuous arable cultivation (AL). Fallow
soils (FL) recorded high organic carbon, high soil water retention between -2 to -1500kPa
and, high total residual pores. Infiltration model evaluation showed Kostiakov’s model was
more efficient and proved to be an excellent predictor of infiltration over Philip’s model.
This was manifested as Kostiakov’s model gave value closed to unity for coefficient of
determination-r2 (0.96), Nash-Sutcliffe Efficiency-E (0.94) and lower value for Root Mean
Square Error-RSME (22.37) and Coefficient of Variability-CV (6.76%). Applications of
different spacing and nitrogen rates to JCL did not significantly influence most soil
physical parameters within the three years of plantation establishment.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POST GRADUATE
STUDIES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE
AWARD OF MASTERS DEGREE IN SOIL SCIENCE
DEPARTMENT OF SOIL SCIENCE, FACULTY OF AGRICULTURE,
AHAMADU BELLO UNIVERSITY, ZARIA
FEBRUARY, 2013
Keywords
PHYSICAL QUALITY,, ALFISOL,, INFLUENCED,, CULTIVATION,, JATROPHA CURCAS,, SAMARU, NORTHERN NIGERIA