Mapping soil chemical properties and leaf quality parameters relation to tobacco production in Sri Lanka: a GIS approach
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Date
2015
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Tobacco (Nicotianatabacum L) holds an unparalleled position among crop plants and in overall
terms, the status achieved by this single species is truly remarkable (Akehurst, 1981). This crop
significantly influences on world trade as a leaf basis product and is also a commercially widely
grown crop as a non–food field crop (Akehurst, 1981).The chemistry and fertility of soils greatly
influence the tobacco plant growth, leaf size, yield and physical, chemical and manufacturing
properties of tobacco leaf.Among factors that influence on tobacco productivity, soil fertility and
fertilizer use contribute nearly 50% of the yield and quality improvement of tobacco crop
(Krishnamurthy and Deosingh, 2002).
Thus, by changing the soil properties and water quality, the yield and the quality of the final
product can be greatly changed. Identifying lands with suitable soil propertiesfor the cultivation
will help to understand the correct fertilizer application. Fertilizer recommendation based on soil
test is important for improving the fertilizer use efficiency and thereby to increase the yield and
quality of tobacco.
An understanding of spatial distribution of soil properties in the field is important for refining
agricultural management practices. Soil variability is the outcome of many processes acting and
interacting across a continuum of spatial and temporal scales and inherently scale-dependent
(Cambardella et al., 1994).
Therefore, the study of relationship between the soil chemical properties and leaf quality can
provide a scientific basis to find potential lands for quality tobacco production.This research
presents the future potential tobacco growing areas based on the tobacco leaf quality
distribution.
Materials and methodology
In this study,Galewala and Mahiyanganaya tobacco growing areas were chosen as sample
area.Data were collected from primary and secondary sources. Soil property data which
wererecorded Ceylon tobacco company’s (CTC) lab reports were collected as secondary data.
Global Positioning System (GPS) coordinates were taken fromthe field as primary data. Soil
analysis was undertaken by collecting soil samples in studyareas from 15 cm deep from the soil
surface. The soil samples were collected from ten different places of one land with
approximately 1kg of weight. Soil samples were analyzed for pH, organic matter, electrical
conductivity, soil texture, calcium, magnesium, potassium, sodium, calcium/magnesium ratio,
magnesium/potassium ratio, phosphorous, acid saturation, cupper, ferrus, manganese and zinc.
Leaf quality data were taken from the CTC lab reports and identified the leaf nicotine
percentage, chloride percentage and sugar percentages from the plants in selected locations.
Major soil chemical properties which affectontobacco leaf quality were identified by correlation
analysis in MINITABstatistics. Soil chemical property and tobacco leaf quality distribution
maps were processed using interpolation technique in ArcGIS. Interpolated leaf quality maps
were reclassified in four suitability rankings i.e. most suitable, suitable, moderately suitable and
fairly suitable as shown in Table 01. Finally all leaf quality layers were integrated in a GIS
environment to generate the potential map.
Description
Keywords
Agriculture, Export Agriculture, Crop Production, Soil Science, Tobacco Production