Crop Production |
Crop Pattern |
Crop Yield |
Soil Management | Precision Farming |
Relevant Products |
Prepare Sustainable Strategic development Plans for a selected Tea Estate in Mid-country region in Sri Lanka using GIS
Land use is the use of land by humans usually with an emphasis on the functional role of the land in economic activities. Tea based land use types are very complicated as tea estates are associated with different agronomic practices. Prior to planting tea, soil rehabilitating grasses such as Tripsacum laxum or Cymbopogon confertiflorus are establishing in fields.
The percentage of tea crop cover is a major indicator for crop yield. Therefore crop cover percentage considered for land use categorization. Major categories associated in tea estates can be classified as follows;
- Vegetative propagated tea
- Newly planted vegetative propagated tea
- Seedling tea with greater than 80% crop cover
- Seedling tea with 60-80% crop cover
- Seedling tea with 40-60% crop cover
- Seedling tea with less than 40% crop cover
- Diversified tea fields
- Tea nurseries
- Open woodlands
- Eucalyptus plantations
- Albizia plantations
- Forest plantations with mixed crops
- Rehabilitating grasses
- Rock out crops
- Non agricultural lands
- Settlements (houses, lines, offices, factories etc)
- Water bodies (lakes/ reservoirs)
Topographic and soil properties are major factors which affect for vegetation condition. Topographic factors include slope, elevation and aspect. Elevation affects the temperature, slope affects the insolation and runoff of the habitat and aspect affects insolation. Westhall Estate fall in greater than 800m amsl and less than 1600m amsl elevation category.
The angle at which a slope resides can affect soil properties and as a result of this affect crop condition. Slope affects the movement of water on the land surface and through its soils. Sites on crests and ridge tops and steep slopes shed water into the neighboring low-lying areas.
According to the advisory circulars of Tea Research Institute of Sri Lanka slopes greater than 55% are not recommended for plant Tea in mid country tea growing region. This condition was considered for classified slope classes.
Nine aspect classes were identifies according to the compass direction in which slope faces.
Soil survey was done by collaborating with Soils and Plant Nutrition division, Tea Research institute of Sri Lanka for determining the important characteristics of soil, classifying soils into units and establishing and plotting on soil maps. Crops and soil management practices are so sensitive to the differences in soil. Soil maps serve as the basis for different crop management and agronomic recommendations.
The soil series is a group of soils having soil horizons similar in differentiating characteristics and arrangement in the soil profile, except for the texture of the soil surface and developed from a particular type of parent material. The soil series by itself is seldom used as a mapping unit in any survey. Soil series are differentiated mainly on the basis of significant variations in the morphological features of the soil profile (Soil survey manual, 1966). The soil series names are place names taken from the area where the soil is first defined such as Barcaple, Westhall and Hungranoya.
The upper limit and the lower limit of a depth class, applied to any one soil, are fixed in definite figures. These limits need to vary somewhat among soils depending on the other soil characteristics (Soil survey manual, 1966).
Rockiness refers to the relative proportion of bedrock exposures, either rock outcrops or patches of soil too thin over bedrock use, in soil area (Soil survey manual, 1966).
Sustainable Strategic Development Planning criteria
Major landuse planning criteria were developed to achieve following options;
spatial coverage with attribute data were overlaid and criteria
developed as in Figure 3, were used in ARCVIEW query builder and
planning options were selected for Westhall
- Tea area, existing forest area to be continued as it is
- Existing vegetable cultivated area with less than 55% slope category to be continued with proper management practices
- Select land, which occupy scrublands and grasslands to be converted to grasslands for dairy farming
- Select area not suitable for tea with > 55% slope category for future diversification program
- Select area not suitable for tea and < 55% slope category for intercropping with Minor Export Crops (MEC)
- Select area, which is suitable for tea for adopt following options;
- Select tea area with VP and good cover of seedling tea and less yield category for undertaking immediate proper agronomic practices
- Select area with seedling tea with <40% crop cover for replanting
- Select seedling tea area with 60-80% crop cover and 40-60% crop cover as well as less than 1100 made tea kg ha-1 annum-1 average yield for replanting
- Select seedling tea area with 60-80% crop
cover and 40-60% crop cover as well as greater than 1100 made tea
kg ha-1 annum-1 average yield for infilling
Fig 3: Structure Chart for SSDP criteria development
Proposed strategic sustainable development plan and statistics of planning options for the Westhall estate shows in Table 2 and Fig. 4 respectively.
Table 2: Statistics of proposed land use plan for Westhall estate
|Land use planning option
|| Area (Ha)
|Land use types to be continued as it is (Settlements, lake, rock
|Existing forest area
|Good VP/Seedling tea to be continued as it is
|Tea nursery to be continued as it is
|Newly planted tea to be continued as it is
|Selected area for grasslands/ dairy farming
|Selected area for diversification
|Selected area for vegetable with proper soil management practices
|Selected area for intercropping
|Selected area for upgrade with proper agronomic practices
|Selected area for replanting tea
Fig. 4. Proposed land use plan for Westhall Estate
Up-to-date and reliable information is vital for managerial purposes and take efficient decisions. Geographical Information System (GIS) and Remote Sensing (RS) technology can be used as tools for update estate information. In addition developing land use planning system-using SSDP can be used for estates for maximizing their profits and optimizing lands.
Authors would like to appreciate greatly the support given by the Director and the staff of Upper Mahaweli Watershed management Project, Mahaweli Authority, Pogolla, Sri Lanka for utilization their instruments and resources. Financial Assistance grant by Council for Agricultural Research Policy, Sri Lanka (CARP) for conducting this study is highly appreciated.
- Burrough, P.A, Principles of Geographic Information System for Earth Resources
Assessment, Clarendon Press, Oxford, UK, pp.193, 1986
- Soil Survey Manual, U.S. Dept, Agriculture
handbook No.18, Oxford & IBH publishing Co., 36, Chowringhee
rd, Calcutta 16, India, 1966