dc.contributor.author | Wandahwa, P | |
dc.date.accessioned | 2013-05-27T12:21:07Z | |
dc.date.available | 2013-05-27T12:21:07Z | |
dc.date.issued | 1988 | |
dc.identifier.citation | A thesis submitted in partial fulfilment of the requirements for the degree of master of science | en |
dc.identifier.uri | http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/26234 | |
dc.description.abstract | A number of so i I physical properties in relation
to tillage were assessed under no cropping, single
cropping and double cropping of lowland rice on a
vertisol in the Kano plains of Western Kenya. The
investigation of physical properties took place on
soil samples of 0-15 cm, 15-30 cm, 30-45 cm, 45-60 and
60-75 cm depths.
The study revealed that al I the sites had high
clay content <> 60%) therefore belonged to a clay
t ex t u r a I c Iass. These were classified agronomically
as heavy soils. These soils are good for lowland rice
growing but difficult to cultivate for an Upland crop
and take long to dry increasing the turnaround time
between rice and an Upland crop.
Comparison of the management systems revealed no
significant
porosity.
compaction
compaction
changes in bulk density and total
These compaction indices and relative
values calculated confirmed no soil
under double cropping despite increased
passage of the cultivation machines. Lack of
compaction was attributed to the soils high propensity
for structure recovery.This makes them suitable for
double cropping of rice. Maximum dry density values
xv
obtained ranged from 1.29 to 1.33
gm/cm 3 and were
termed low hence the soils suitability for Upland crop
production.
Cropping intensity lowered organic carbon content
which subsequently lowered the soil's plastic limit
reducing the soils friability range. Liquid Ii m it
increased within the top 45 cm depth. The combination
of reduced plastic limit and increased liquid I i m it
widened the Plastic Index increasing the moisture
content range at which the soils remain plastic.
Double cropping treatment was found to have low
soil strength at the 15-30 cm depth throughout al I the
effective normal stress. This was suspected to be the
cause of tractor sinking. Single cropping treatment
was found to have high shear strength tha t was
attributed to the lo n g e r drying periods, wh i Ie
cropping was found to have increased water stability
of aggregates. | en |
dc.language.iso | en | en |
dc.title | Comparison of single and double cropping of rice on the physical properties in relation to tillage of a vertisol | en |
dc.type | Thesis | en |
local.publisher | Soil Science, Universoty of Nairobi | en |