By: Willie D Joshua
Agricultural Land Use Planning for Northeast Sri Lanka
The economy of the Northeast of Sri Lanka is largely dependent upon agriculture. Unplanned use of land has the potential to cause irreparable damage to the land and hamper its optimal use. Land use requires planning that involves identifying the most appropriate and sustainable use to which the land is put, without causing degradation.
Although the basic data on soils, climate and water resources for Land Use Planning in the Northeast is available, some data will have to be generated for specific locations. Also, socio-economic data needs to be obtained through investigations, studies and pilot projects. In carrying out the pilot project, one must be mindful that the location of the pilot project is representative of the entire region. The new land use approach driven by optimal utilisation of rain and groundwater will differ from the conventional tank-based agriculture. In this scenario, livestock will be an essential component to secure “good living” income for farmers
The economy of the Northeast of Sri Lanka depends to a large extent on agriculture and agriculture-based industries. Therefore, developing lands for agriculture and human settlement needs careful land use planning on a scientific basis.
What is Land Use Planning
Land, in general, is used for agriculture, forestry, home garden, housing, sites for industries, livestock, village centre including playgrounds, roads, etc. Land use planning is the choosing of the most appropriate and sustainable use to which the land is put, without causing degradation. Unplanned and haphazard use of land may cause irreparable damage to the land. The benefits that can be derived from the land may also be not optimal.
Agricultural Land Use Planning
A hypothetical example: The initial investigation of an undulating area indicates that the upper parts of area consist of rocky land with many visible exposed rocks. Somewhat lower areas are not rocky but gravely with shallow soils. Further down, lands have good deep soils while the low-lying lands are subject to waterlogging during the rainy season. In such a situation, the land use for the rocky land has no other option but to be used for forestry and timber. Shallow land can be used for housing and home garden or pasture etc. The deep soil can be used for anything including good upland crop cultivation while the low-lying poorly drained land can be used for rice cultivation. Such decision on the use of the selected land for different purposes according to site’s condition such as soil, landform, climate etc is a simple example of rational land use planning.
Each of the methods of crop production will need different land use planning but may have many features in common. In the Jaffna peninsula, the availability of good groundwater has made irrigated agriculture of cash crops as the chosen land use practice. In areas where the groundwater is saline, as in the coastal area, rainfed cultivation is the only choice. In the mainland of the Northern Province (south of Elephant Pass), irrigated cultivation of rice using stored water from man-made reservoirs (tanks) and shifting cultivation (chena) under rainfed conditions were practised from ancient times. The land use development pattern for the mainland Northeast was also similar to rest of the dry zone of Sri Lanka.
With the commencement of the Mahaweli River Diversion Project, the funding agencies insisted on using the soil qualities as one of the important criteria in feasibilities studies of the project. As a result, land use planning has now become an essential component in all planning of agricultural development in the country. In addition, the knowledge of the soil characteristics and water availability are used to develop appropriate agricultural practices to ensure good soil and water management.
Presently, the basic data on soils, climate and water resources for Land Use Planning of Northeast are already available. However, some data that are specifically relevant to Northeast may need to be generated for specific locations. Socio-economic data may have to be obtained through investigations and studies through pilot projects. The new land use will differ from the conventional tank-based agriculture and be more dependants on optimal utilisation of rain and groundwater. Livestock will be an essential component in the land use pattern to obtain “good living” income for the farmer
For the purpose of implementing any land use plan, we lack specific data on socio-economic parameters. For example, we don’t have answers to questions such as
- What should be the anticipated income for the farm family so that agriculture can be a profitable and dignified concern enabling the farmer to achieve his ambitions like any other white-collar worker?
- What should be the extent of land as a farming unit for each family that would generate that income?
- Will the water resources for each farm be adequate for the planned agriculture and domestic use?
- What should be the exact agricultural practices that would generate that income from the land? This will include cropping pattern, utilisation of rain and groundwater, labour requirement other than family manpower, livestock (what kind and how many) etc.
Answers to these questions can only be obtained either from the already existing similar land use or through the establishment of pilot projects in representative areas to generate the information.
The Northeast can be roughly grouped into 5 Regions of similar environmental characteristics based on soils, landform and water availability. ( See attached map on the last page) They are
- Jaffna Peninsula (a. inland b. coastal)
- Mullaitivu-Chundikulam-Elephant Pass-Pooneryn-Mannar coastal belt
- Mutur-Batticaloa-Akkaraipattu ( a. inland b. coastal )
Of the above 5 Regions, the entire Region 1 and the coastal areas of Regions 2 and 5 have already a well-established land use pattern. Any further development of the remaining small extents in this area will be generally of the same land use pattern. Only Regions 3, 4, and the inland areas in 5 have a considerable extent of land that needs to be developed and settled.
In this instance, the land use planning is primarily for human settlement in a new land with agriculture and animal husbandry as the main source of income. We have reasonably adequate information of soil, landform, water availability and agricultural practices on existing traditional and recent irrigated tank-based agriculture for Regions 3 & 4. Therefore as a first step, it is suggested that we establish one or two pilot projects in each of Regions 3 & 4. These two regions differ in soils, landform and water availability. The new proposed land use of regions 3 & 4 will, therefore, be different.
The location of the pilot projects has to be representative of the entire region. In a pilot project, a typical site of few hectares is selected in the region and all the planned activities are carried out. This should include clearing of the forest, land development and establishment of farms. Few farmers are settled according to the extent of land available. The intention for having pilot projects is to identify practical problems that may be encountered during implementation and other socio-economic information that are presently not available. Described below is the outline for establishing pilot projects in Regions 3 and Region 4
Land Use Plan - Regions 3 and 4
Region 3 is sparsely populated and offers a good opportunity for development and human settlement. Soils in Region 3 are mainly Red-Yellow Latosols with some extents of Vertisols (characteristics of the soils are described below) underlain by sedimentary limestone and sandstone rocks. Source of water for Region 3 is from deep groundwater from the sandstone and limestone aquifer as well as from the seasonal rains stored as perched water table in the deep soil which act like an aquifer.
Most of the lands in Region 4 are similar to the lands in the south adjoining North Central Province. The soils are mainly the Reddish Brown earth- Low Humic Gley Association occurring in catenary sequence in the undulating landform with Alluvial Soils along the rivers and streams. The soils are underlain by non-porous crystalline rocks. Source of water is from rainfall, stored in reservoirs (tanks) or as groundwater limited to low lying locations stored in the unconsolidated weathering rocks which act as aquifers. Agricultural practices in the North Central province can be easily adopted in Region 4.
Region 3 Kokkilai-Mullaitivu-Kilinochchi-Mulankavil-Vellankulam-Murungan
Figure 16 (above) Type of land having RYL. Tube wells aquifers are limestone and sandstone. Perched water source-upper soil (Reference: C.R.Panabokke)
The predominant soils are Red-Yellow Latosol. They are deep and highly permeable to water and of low to medium fertility. However, the physical properties of this soil are very good for agriculture with the use of fertiliser. The landform is flat to very gently undulating. (Fig. 16). The soil is highly erodible. Deep groundwater (tube well) is saline north of Mulankavil. However, the perched water table build up due to seasonal rains can be used for limited supplemental irrigation and domestic purposes through the use of conventional wells. The soils’ porosity act as aquifer to retain some of the rainwater. The amount and duration of the water in the wells will depend on the amount of rainfall in the preceding rainy season and subsequent usage. The yellow latosols, which usually occurs in slightly lower depressions in the landscape have higher and longer lasting water table. During the dry season, the farm activities will generally centre round generating income from livestock. In this type of soil and landform, any size farm as a contiguous unit can be easily established.
There are the small extent of Vertisols which are black clay soils. These soils develop extensive cracks when dry. When wet, becomes impervious clay and traditionally used for rice cultivation
Groundwater from tube wells south of Mulankavil and in some locations in the Yellow Latosol areas even further north of Mulankavil are non-saline. In such locations, larger areas can be brought under commercial farming using water from the tube wells. Because of the high infiltration capacity of the soils, drip or micro-spray irrigation will be most suitable for better water management.
The present irrigation schemes such as Iranamadu and Visvamadu tanks are in this Region 3. However, the land use pattern for the lands under the schemes is quite different, because of the availability of assured water for irrigation. Since Iranamadu is an older scheme, all lands under are under paddy cultivation without any proper land use planning. On the other hand, systematic soil surveys were carried out for the newer Visvamadu scheme. Here according to the land use plan, the Red Latosols were assigned for irrigated subsidiary crops like chillies and the Yellow Latosols that are subject to high water table were allocated for irrigated rice cultivation. Some of the Red Latosols that were above gravity irrigation command were also brought under subsidiary crops through lift irrigation from fore-bays. Irrigation method is very similar to the Jaffna system. Because of the high soil infiltration rates as in Jaffna, small basins are used to avoid over-irrigation. Visvamadu turned out to be a very successful irrigation scheme.
The suggested land use for the non-tube wells area will be the utilisation NE-Monsoon rain for intensive cultivation of high cash crops in a relatively smaller area. After the rains when there is enough water in the wells, supplemental irrigation can be given if necessary. Adjoining this land, a larger area is allocated for the rainfed cultivation of grass and fodder for grazing and making silage for livestock during the dry season. Information on the land extent as a farming unit in this soil, amount of livestock and all agricultural practices with the resources available has to be obtained from a pilot project. Each farming unit should have land for the house, well, cropping and pasture.
Region 4. Trincomalee-Mankulam-Madhu-Poovarasankulam-Vavuniya
The soils are Reddish Brown Earth (RBE) – Low Humic Gley(LHG) Association. The RBE soil is well-drained shallow with a gravel layer underneath. Water permeability is medium. Landform is undulating to rolling and consists of catchment units with RBE and LHG soils. Uppermost part of the slope is RBE that is shallow and gravely/rocky which can be used for road, timber or rainfed fruit trees. Upper and mid slopes are also RBE but good soil for home-garden and agriculture of upland crops with rain and supplemental irrigation from agro-wells. Lower slopes with LHG are poorly drained and are very wet during the rainy season. LHG soils are good for rice cultivation in the rainy season and subsidiary crops during the dry season with irrigation from agro-wells. Groundwater is limited because the basement rocks are not aquifers. Water is in rock fissures and in the weathering rock that is unconsolidated and acts somewhat like aquifers. Weathering rock underlies the LHG and therefore agro-wells have to be located in the LHG.
Present agricultural practices in Region 4 are mainly village tank based systems. The farmer depends entirely on the water from the tank for rice cultivation only. In the dry season, the farmer may use part of his paddy lands for vegetable cultivation at a subsistence level. Optimum use of rainwater is not made for crop production. Use of agro-wells for supplementary irrigation is seldom practised except in the Mankulam – Vavuniya area. Here too, siting of wells is not made on the hydro-geological basis to obtain sufficient groundwater supply for supplementary irrigation and domestic use. The upland adjoining the paddy fields is mainly used for homesteads and rain-fed vegetable cultivation again at a subsistence level.
The suggested future land use is that a group of farmers are settled in a catchment unit with each farmer allocated a block of land consisting of RBE and LHG soils. (Fig.9). His homestead and upland farm will be in RBE and paddy land will be in LHG. His well will be located in his LHG soil. The actual extents of RBE and LHG soils that a farmer should get to generate the anticipated income, the cropping pattern and agricultural practices need to be obtained through an actual pilot project in a catchment unit with farms. The water availability in wells will be an important factor in the land use plan. If a village tank is already present in the catchment unit, the paddy lands will actually be in the LHG and water supply in the agro wells will be enhanced.
RBE-Rocky RBE Home &garden Rainfed+sup-Irrig Rice paddy
Soil Association-soil catena of RBE-LHG landform
Implementation of Pilot Projects
It is suggested that 9 youths from the School of Agriculture be allocated lands for three farms, with 3 youths for each farm and to reside at the site. However, funding, support and participation by an organisation is vital for the project is to be a success. An outline of the project proposal can be given if required.
For Region 4, it is necessary to identify a small catchment or an already existing abandoned tank and the surrounding lands for the project. The tank can be rehabilitated if needed. The RBE and LHG soils in the land have to be identified and the farms blocked out as suggested above. The tentative size of the farms has to be decided based on whatever information is presently available, probably by an agricultural economist. When the number of farms ( 3 farms should be a convenient number to be manageable, even if the land is available for more farms ) have been decided, agro-wells will have to be constructed and the farm families settled. The site can be in the Mankulam-Vavuniya area for easy access and supervision. The action for establishing this pilot project has to be taken either by an NGO or whoever is appropriate.
For these pilot projects to be a success and to obtain meaningful data, the overall responsibility and authority for the pilot projects have to be vested with some recognised body or organisation (NGO) for implementation. Such a body may be able to draw expertise from outside who have good in-country experience. However, you have to be cautious about the so-called experts (expatriate Sri Lankans or others) who have no local experience but promote untested impractical conceptual ideas or introduce practices that are unsuitable to the farmers’ ability and understanding.
It is suggested that a small group consisting of an agronomist, agricultural economist, soil scientist and agricultural engineer is set up to review and formulate all action plans. The same group should be available to advise the person who is employed to be in charge of the pilot projects.
Willie D Joshua BSc PhD is a Soil Scientist/Hydrologist who worked with UN’s Food and Agricultural Organisation (FAO) in Botswana and Bangladesh and was Visiting Professor Agriculture Faculty, Jaffna University He was Head of the Land Use Divisions of Sri Lanka’s Department of irrigation.