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|Title: ||Development OF Coastalpoority DRAINED Lands FOR RICE CULTIVATION IN THE WET ZONE OF SRI LANKA|
|Authors: ||Balasuriya, Indrajith|
|Issue Date: ||28-Feb-2014|
|Abstract: ||In the Wet Zone coastal lowlying lands, located within the most
densely populated part of Sri Lanka, hitherto neither rice cultivation
nor its diverse resource base has been systematically developed. The
main constraints to rice production are sudden floodings, ~oor drainage,
coastal salinity at elevations below +2.0' MSL (Mean Sea Level)
and injurious soil conditions in localized areas within rice tracts.
The pre~ent paddy yields of 15-25 bushels/acre could be doubled
or even trebled with currently available rice varieties and technology,
provided improvements are made to the physical environment, through
water control, and to the chemical environment.
Low available phosphorus appears to be the main nutrient problem
limiting rice yields, particularly on organic soils. However, the
three major nutrients (NPK) need to be applied together, even in sub.
optimal quantities. Silica application might be beneficial. Sources
of nitrogen other than urea, such as ammonium chloride and ammonium
nitrate, the latter on soils where "Bronzing" occurs, need to be investigat~
d. Iron and hydrogen sulphide toxicity occur in sChctered
pockets, the former mainly on mineral soils and the latter predominantly
on highly reduced organic soils.
Erratic rainfall distribution requires the use of supplementary
irrigation for stabilizing yields. Moreover, the optimum utilization
of organic soils, both non-pyritic and pyritic, requires a good water
supply and control to prevent soil drying and consequent subsidence,
salinization and acidification, the latter in pyritic soils.
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Five major cropping systems, using photoperiod-sensitive and
photoperiod-nonsensitive rice varieties of short, medium and long
duration have been identified, Production increases pivot on higher
productivity from these cropping systems rather than changes in the
cropping pattern, as the latter is an adaptation to the macro-environment
which cannot be changed. This requires improved rice varieties
of varying duration - photoperiod-sensitive and nonsensitive, with
adaptability to adverse environmental conditions, pest and disease
resistence and moderate yield potential (i.e. 50-80 bushels/acre,
nett yield) with low levels of chemical inputs.
The small size of holdings and a high risk factor make it imperao
tive to develop alternate sources of on- or off-farm income support
for rice farmers. A central hypothesis in this thesis is that the
improvement of the socio-economic conditions of coastal small rice
farmers, on a sustained basis, would depend on alternate sources of
income rather than rice cultivation alone. The diverse resource base
in the area, particularly the potential for developing fisheries,
aql~culture, horticulture and small animal livestock husbandry, provide
ample opportunity for generating supplementary income. Therefore,
the development strategy should be an integrated development and management
of the entire resource base with the main focus on rice cultivation,
the latter particularly on lands above +1' MSL. The rice
development programme is best implemented as a three stage programme,
-with priority given to lands above +1' MSL where rice is already extensively
The development model should be individual drainage and
reclamation schemes catering to location specific environments, resource
bases and farmer needs. This requires an organization model
with establishment 6f District Lowlying Lands Development Committees
for monitoring and coordinating the multiple resource development
programmes at the district level and a National Lowlying Lands De-".
velopment Authority for overall responsibility and coordination.
Moreover, the multidisciplinary team strategy is most appropriate
for dealing with the diverse and complex problems of developing the
Wet Zone coastal Lowlying Lands.|
|Appears in Collections:||Masters Theses|
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