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93
Integrating Agroforestry Characteristics into
Agro-well-based Agriculture
Muditha Perera
Lecturer, Department of Geography, University of Peradeniya, Sri Lanka
Abstract
The major challenge for the dry-zone farmers in non-irrigated areas in Sri Lanka is water scarcity.
This situation is a major barrier to the sustainable use of resources and maintaining income
generation activities throughout the year. In this context, these farmers realized the need for
another source of water. The strategy was the construction of large diameter wells (agro-wells)
to tap the shallow groundwater in low-lying areas, either near the small tanks or the small
streams. Since 1982, the rate of construction of agro-wells has accelerated with the interventions
of the Agricultural Development Authority and the Provincial Council. Generally, cultivation
of perennial crops using agro-wells is not common. Only seasonal crops are cultivated and
income was obtained only during a particular period. As a new trend, some farmers in the dry
zone of Sri Lanka used this shallow groundwater opportunity to cultivate perennial crops as
well as seasonal crops throughout the year. Furthermore, farmers aimed to grow woody tree
species for their timber requirements and economic purposes in their own agricultural land. A
lot of farmers have realized that these woody trees such as teak and halmilla may be disturbing
their crops. Therefore, they moved these trees to the marginal areas or tail end of the lands. In
addition, some farmers attempted to maintain animal husbandry such as rearing cows under
the perennial crops, using the shade and grass under the trees. This context provided a unique
opportunity to explore this new land use pattern revealed in the dry zone of Sri Lanka, recently.
Field research for this study was conducted covering 20 agro-well-based agricultural lands
out of the total of 68 in the ‘Aluth Divulwewa sub-watershed’ in ‘Yan Oya watershed’, in the
dry zone of Sri Lanka. The collected data was analyzed using qualitative and quantitative
methods. The land equivalent ratio (LER) has revealed that 90 % of the lands represent more
productivity, and canopy cover has increased up to 41.5 % from 7.9 %. Further, evolution,
composition, characteristics, layers, and spatial arrangements of these land use patterns,
represent 100 % of agroforestry characteristics according to Nair’s classifications. Thus, this
context has successfully proven that these agro-well-based agricultural lands have been
converted into ‘more productive and diversified agricultural systems’ with agroforestry
characteristics.
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M. Perera.
Introduction
The major challenge for farmers in non-irrigated areas in the dry zone of Sri Lanka is water
scarcity. This situation is a major barrier to the efficient use of resources and to maintain income
generation activities throughout the year. The use of a supplementary source of water is
essential. The construction of large diameter wells (agro-wells) to tap shallow groundwater
was identified as a potential solution. Agro-wells were constructed in low lying areas, either
near small tanks or small streams. The rate of construction of agro-wells has accelerated with
the interventions of the Agricultural Development Authority that began in 1982, and later by
the interventions of the Provincial Councils.
Seasonal crops are cultivated using agro-wells. The use of water from agro-wells to
irrigate perennial crops is not common. Therefore, regular income is received only during a
particular period. A new trend is emerging of utilizing the shallow groundwater opportunity
to cultivate perennial crops in addition to seasonal crops. Farmers include woody tree
species for timber requirements and economic purposes. As farmers recognized that woody
trees, such as teak and halmilla, disturb other crops, they moved trees to the peripheral
areas of their lands or to tail ends of surface irrigation ditches. Some farmers attempted to
incorporate animal husbandry such as rearing cows under the perennial crops, using the
shade and grass under the trees. This study explores this emerging land use pattern in the
dry zone of Sri Lanka.
Methodology
The objective of this study was to understand the holistic background of the agro-well based
agriculture, such as a) the nature of shallow groundwater utilization, b) the nature of the
agro-wells, c) historical changes in land use pattern and current land use d) characteristics
of farms including, canopy cover and structures and species composition and e) documented
agronomic practices.
Field research for this study was conducted in the Aluth Divulwewa sub watershed in
the Yan Oya watershed in the dry zone of Sri Lanka. Twenty agro-well based farms, out of
the total of 68, were selected using the purposive sampling method. A structured survey
schedule was used to gather respondents’ perceptions as well as historical and current
information. This was supplemented by a field survey, field mapping, aerial photograph
analysis, interviews and field observations. Land equivalent ratio (LER value) was used as
the measure of land productivity. This is calculated as the sum of ratios of yields of an
intercrop and the potential yield of the same crop if planted as a single crop in the same
land area. LER for land with intercrops is obtained by using the following equation by
Nair (1990).
(1) Land equivalent ratio LER = Ry1 + Ry2+ .............. , + Ryn
Where, Ryi is the intercrop yield for ith crop/sole crop yield of the ith crop
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Integrating Agroforestry Characteristics into Agro-well-based Agriculture
Results and Discussions
There are two main factors that determine the distribution of the agro-well based agriculture in
the Aluth Divul Wewa sub watershed area. They are a) the availability of comparatively low
lying lands, and b) availability of roads / accessibility. Aluth Divul Wewa sub watershed is
naturally rich with groundwater because of the two mountain ranges situated in its eastern
and western boundaries. Chena lands situated in low lying land areas were the most popular
lands for excavating agro-wells. Farmers have constructed agro-wells in the vicinity of small
tanks or near seasonal streams. According to Dharmasena (1998) there should be a minimum
distance of 100 m between two wells due to the shallow groundwater situation in the dry zone
of Sri Lanka. This scientific guideline is naturally followed in the study area due to large land
extents. All the farmers have 2-5 acres of lands.
There are two major trends in land utilization patterns, a) the decrease in chena (shifting)
cultivation, and b) increase in the use of agro-wells. The percentage of lands allocated to chena
of all cultivated highlands has declined from 30 % in 1994 to 22 % in 2004. Land under agro-
wells has increased from a mere 0.3% to 6% during the same period.
A large majority of farmers (80 %) cultivate crops using agro-wells as the sole source of
irrigation. Twenty percent of farmers irrigate their fields using both agro-wells and minor tanks.
Farmers usually cultivate chilies, brinjals, soybean, pumpkin, ma-beans, green-gram, bitter-gourd,
bottle-gourds, thibbatu, okra, and manioc as seasonal crops, during either or both maha and
yala seasons. However, farmers in general do not get enough returns to meet all their annual
household needs. Income from seasonal crops is usually spent on debts and day-to-day
requirements. Farmers usually do not accumulate any savings.
In this context some farmers incorporate perennial crops such as coconut, jack, lime,
tangerine, orange, mango, guava, breadfruits, cashew, drumsticks, betel-leaves, and banana,
to increase productivity and to ensure that the flow of income from their lands is smooth.
These farmers invest in perennial crops as a mixed system with seasonal crops. (Figures 1
and 2). In such a system, irrigation has to fulfill the water needs of both seasonal and perennial
crops simultaneously.
Figure 1. A large diameter agro-well with coconut trees in the background.
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M. Perera.
A considerable fraction of farmers reserve a part of their land for timber trees such as
teak. Timber trees are usually grown in the periphery of the farm and at the tail ends of irrigation
ditches. Farmers also plant live fences using Glidsiria sepium, teak, and kohomba (margossa)
with the expectation of meeting firewood and timber needs. In addition, lots of farmers grow
many timber trees in their lands for economic purposes. This was an easy income-generation
activity using degraded areas of their agro-well based lands.
Other than crops, farmers practice animal husbandry as a part of the cropping system.
They especially like rearing cows because of the low cost. Fifteen percent of the farmers in
the study area practice rearing cows in their agro-well based farmland using tree shade and
ground layer grasses in the proximity of the agro-wells. They supplement the household
requirements of milk and get extra income by transporting and selling the cow milk to the internal
or external market, daily or weekly.
These agro-well based lands convert to ‘seasonal and perennial cultivation system with
woody trees’ or ‘seasonal and perennial cultivation system with woody trees and animal
husbandry’ within 5- 6 years. With this background, cropping pattern under these agro-wells,
are being converted to ‘agroforestry systems’.
Interventions
All the farmers have integrated trees into these systems and all farmers develop their lands
every year. This situation tends to increase the number of trees in their lands. Farmers have
introduced various ‘food trees’, ‘fruit trees’, ‘under crops’, as well as ‘woody trees’ to this
area, in addition to the seasonal crops (Figure 3).
Farmers cultivate these trees around the agro-well or around the hut (dwelling within
the farmland) according to the water requirment or labor requirement. Crops requiring more
water such as tempering leaves, ginger and sugercane are placed around the well. More labour
required crops such as friut trees are placed around the hut. The result was the emergence of
many diverse crop lands.
Figure 2. Agro-well farming unit with seasonal ground layer crops and perennial crops in the periphery.
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Integrating Agroforestry Characteristics into Agro-well-based Agriculture
A general spatial pattern of the location of different trees in this cropping system can be
identified. The trees with greater water needs and that require a high level of maintenance are
grown around the well. Farmers especially use short crops or trees for this zone due to damages
from leaves and roots to the well. Eighty-five percent of agro-wells showed this pattern. The
composition of several zones that are arranged in concentric rings around the agro-well can
be identified. The species composition of these zones with increasing distance from the agro-
well are:
1. Ginger, sugarcane, arecanut;
2. Lime, pomegranate, banana, guava, bread fruit, betel beds, with seasonal crops;
3. Coconut, banana, lime, mango, jack fruit with seasonal crops and / or animal husbandry;
4. Teak, kohomba, halmilla with or without seasonal crops and;
5. Live fence.
This generalized pattern of all agro-well lands, is illustrated using the sketch diagram in
Figure 4.
Figure 3. Various tree types based on utility.
Figure 4. Generalized spatial distribution of these systems*.
* Source: - Field survey
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M. Perera.
Tree Stratification
Further, there is an obvious pattern of tree stratification in this farming system. Different strata
mimic the morphology and the function a forest. There are five identifiable components in a
well developed land:
1. Seasonal crops/paddy
2. Beetle beds, thibbatu
3. banana, lime
4. mango, jack
5. coconut teak
One hundred percent of well-developed lands represent successful tree stratification.
At least three layers can be identified in all lands. The most common components are, ‘seasonal
crops/paddy’, ‘banana/lime’, and ‘coconut/teak’.
Conservation Farming
Motivated by water scarcity and the need to avoid further land degradation, farmers in the
area use various conservation farming practices. They also need strong boundary fences for
the protection of their crops from wild animals. Inexpensive methods of fencing using trees
including Gliricidia sepium are practiced. In addition farmers are also using the leaves of
Gliricidia and dry grass to enrich the soil of the lands further, and for animal husbandry. One
hundred percent of the farmers use live fences and dry field systems. The dry field system
helps to control soil erosion and conserve limited water resources. Forty-five percent of farmers
use the mulching system, using dry grass and paddy straw to improve their lands. In addition
20 % of farmers have practiced contour earth bunds for controlling soil erosion. (Table 1).
Table 1. Use of conservation strategies.
Conservation Number of lands on Lands on which method is practiced
strategy which method is practiced as a % in total well-developed lands
Live fences 20 100
Earth bunds 4 20
Drains 4 20
Mulching 9 45
Dry field system 20 100
Source: Field survey
Canopy Covert Development
The development of canopy cover helps to conserve soil moisture, reduce soil erosion, and
maintain bio-diversity. The area under the perennial canopy has been increasing in every
agro-well based land. Seventy percent of the lands have more than 30% of land area covered
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Integrating Agroforestry Characteristics into Agro-well-based Agriculture
by perennial crops; while 25 % of the lands have more than 50 % of the land area covered
by canopy.
Land Productivity and Income
The land equivalent ratio (LER) shows that that 90 % of farms reports higher land productivity
than the moncocultured system. Twenty-five percent of the lands indicate LER values of more
than 1.5. The highest land equivalent ratio (more than 1.75) is represented in 15 % of the lands.
This background gives evidence to prove that the agro –well-based agricultural lands are more
productive and effective land use systems when compared to the conventional systems.
Operators of all studied farms obtain year-round incomes. Fifteen percent of farmers obtain
more than Rs. 100,000.00 annually and 60 % of farmers obtain more than Rs. 50,000.00 annually,
using perennial and seasonal crops. In addition, 15 % of farmers earn annual incomes of around
Rs. 50,000.00 from animal husbandry. In addition, these systems contribute vegetables, fruits,
spices, firewood, timber, medicines, milk, shade, organic matter, fodder, soil moisture, wind
breaks, and aesthetic value, as unquantified and unvalued benefits to the farm household.
Conclusion
This study will help to focus attention on issues and solutions on the need for a comprehensive
approach to agro forestry cropping systems with water scarcity. The evolution, composition,
characteristics, layers, and spatial arrangements of these land use patterns, represent 100 %
of agroforestry characteristics according to Nair’s classifications (Nair, 1990). Thus, this context
has successfully proven that these agro-well-based lands have converted into ‘more
productive and diversified agricultural systems’ with agroforestry characteristics.
According to our professionals (Panabokke, 2002), (Dharmasena 1994), there is a sufficient
groundwater situation, in the dry zone of Sri Lanka during the north-east monsoon period,
and a sufficient groundwater level in the vicinity of small tanks, throughout the year. Similarly
there is an adequate groundwater level in the low lands and near the temporary dry streams.
So, similar lands throughout the dry zone are suitable for constructing agro-wells using
appropriate groundwater technology. Then the existing agro-well lands can be converted into
more productive lands, with two or three cultivation periods, combining conservation farming,
perennial trees, woody trees, and livestock.
This proves that, the attractive ‘agro-well-based agroforestry systems’ could be stabilized
under these available agro-wells and potential lands in due course. Furthermore, it would be
timely and very useful to adopt this trend for ‘other degraded watersheds’ in the dry and dry
and intermediate zones of Sri Lanka.
References
American Society of Agronomy. 1988. Agro Forestry Land Use Systems- Symposium Proceedings, Anaheim,
California.
Consultative Group on International Agricultural Research (CGIRA). 2003. Challenge Program on Water
and Food, International Water Management Institute, Colombo, Sri Lanka.
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Dharmasena, P. B. 1994. Groundwater Uutilization for Crop Production – Project Terminal Report, Field
Crops Research and Development Institute, Mahailluppallama.
Dharmasena, P. B. 1998. Resource Management Studies on Agro-well Farming in the Dry Zone of Sri
Lanka – Project Terminal Report, Field Crops Research and Development Institute, Mahailluppallama.
Gunasena, H. P. M.; Sangakkara U. R. (Eds.). 1999. Agro Forestry Research in Sri Lanka, Peradeniya:
University of Peradeniya, Sri Lanka.
Gunawardena, E. R. N. (Ed.). 1990. Irrigation and Water resources, Faculty of Agriculture, Peradeniya,
Sri Lanka.
Hitinayake, H. M. G. S. B. (Ed.). 2003. Progress in Agriculture and Forestry, Eco- forestry Pvt. Ltd, Colombo.
International Water Management Institute (IWMI). 2001. Innovations in Groundwater Recharge, Colombo,
Sri Lanka: International Water Management Institute (IWMI).
Madduma Bandara C. M. 1979. A Study of the Practice of Well Irrigation in the Country around Vavuniya
in Northern Sri Lanka. Sri Lanka Journal of Social Sciences Vol-2-No.2.
Nadarajah, S.; Gamage, H. (Eds.). 1997. Groundwater Utilization for Crop Production in the Dry Zone of
Sri Lanka. M.R.M. Centre, Peradeniya: Natural Resource Management Center/Department of Agriculture.
Nair, P. K. R. 1990. Classification of Agro Forestry Systems. In Agroforestry: Classification and Management,
eds. K. G. MacDicken and N. T.Vergara. New York, USA: John Wiley and Sons.
Panabokke, C. R. 2002. The Small Tank Cascade Systems of the Rajarata, Mahaweli Authority, Colombo,
Sri Lanka. Internet web sites. http://; http://www.unl.edu/nac/agroforestry.html
