The Land Use Division was initially set up in September, 1958 in the Department of Agriculture. The early sixties saw greater involvement of the Land Use Division in investigations for major irrigation development projects like the Kaudulla Scheme, Udawalawa Scheme and Mahaweli Development Project. This resulted in greater attention being paid to land classification for Irrigation and determination of irrigation requirement. The culmination in this change in emphasis occurred in March, 1964 when the Land Use Division was transferred to the Irrigation Department, where it has functioned since.
The Land Use Division plays a vital role in all stages of the planning and execution of irrigation project s. Land use plans produced by Land Use Division are used for the initial feasibility investigations, detailed economic appraisal, selection of lands for irrigation, selection of suitable crop patters, calculation of irrigation requirements, decisions regarding lay out, settlement plans etc..,
Soil surveys in various intensities are carried out for collecting data to prepare land use plans.
The siting of irrigation project is determined by the availability of suitable lands among other considerations. Board reconnaissance soil surveys carried out by the Land Use Division help locate the most advantageous sites for such scheme. These surveys also provide information on the sustainability of lands for other uses like non-irrigated agriculture, forestry, wild-life, recreations and urban use.
Preliminary feasibility investigations are normally done on based on the results of detailed reconnaissance soil survey (Detailed soil survey –Low intensity) done by this division. The costs of development are affected by land and soil characteristics that determine the method of irrigation to be used, the cost of land preparation and need for special measures like surface drainage.
The selection of lands for irrigation and detailed layout planning are carried out using detailed medium intensity or detailed high intensity soil and land classification surveys conducted by the Land Use division. Surveys of this level of detail are also useful for settlement planning, detailed land use planning, laying out of research trials etc..
The preparation of land suitability maps for different purposes based on interpretation of soils, climate and other land features in another aspect of the work of this Division. These land suitability maps are prepared not only for agricultural purposes but also non agricultural uses like forestry, engineering uses (roads, buildings, waste disposal, and pipelines), tourism, recreations, wildlife etc.
The hazard of salinity and alkalinity need to be carefully evaluated in any irrigation scheme. Predicting and monitoring conditions in various major schemes constitutes another major area of investigations of this Division. Toxicities other than those due to exclusive built have also set to be studied.
Assessing the quality of irrigation water from tanks, rivers and wells is a vital pre requisite for irrigation planning. The Land Use Divisions carries out investigation in selected irrigation schemes.
Maps of the existing land use are essential in order to assess land development cost and plan settlement in new schemes and to determine encroachments in existing schemes. Land use maps are also very valuable for economic assessment and general planning. Mapping of existing land use, therefore, constitutes a regular activity of the Land Use Division.
This program is maintained by the Land Use Division in order to improve the recommendations maintain all these fields. This program includes the inventorying of the different soils of Sri Lanka and determining their basic morphological, micro morphological, physical chemical and mineralogical properties. It also involves systematic data collection on the results of experiments on, and experience in using different kind of soil. Basic research on irrigation methods and techniques and soil water relations and climate logy is also carried out.
The present program of work
Preparation of soil and land use maps of existing major and medium irrigation schemes for the crop diversification program.
Preparation of soil and land use maps of proposed irrigation projects.
Mapping the soils of Sri Lanka at a series level under national soil survey program.
Soil surveys for drainages and reclamation projects on low lying lands.
Preparation of present Land use maps of existing and proposed schemes.
Program of sampling and analysis of irrigation water from tanks, streams, tube wells etc., The analysis will include determination of S. A. R, Electrical conductivity and classification of irrigation water.
Service to other organization
Land Use Division serves many institutions beside the Irrigation Department. There is nothing unique in this but what is exceptional about the Land Use Division is that it is the premier soil survey organization in the country and it is the exclusive repository of expertise and information in respect of soil survey, land classification and the other aspect of its work outlined above. Consequently, it has national obligations to make this knowledge available to other state and private sector institutions involved in development work.
Laboratory analytical works
The laboratory of the Land Use Division is equipped with sophisticated analytical Instruments in order to analyze soil and water samples for chemical and physical properties.
The tests are carried out,
On soil samples
- PH 1:1 H2O,
- Electrical Conductivity 1: 5 H2O
- PH Saturated Paste
- Electrical Conductivity Saturated paste
- Total Exchangeable Bases
- Base Saturation
- Exchangeable Cations
- Exchangeable Acidity
- Organic Carbon
- Total Nitrogen
- Particle size Distribution
On water samples
- PH , EC, Co3 2- ,HCo3- ,Cl - , So4 2-, No3-, Ca2+,Mg 2+,Na+,K+