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Assessing the Extent and Magnitude of Degradation Occuring in the Wetlands of Kerala State PDF Print

Wetlands in their natural state bring substantial benefits to the society. Nevertheless, there is growing concern over conversion of wetlands. This study examines the case of different wetland conversion in Kerala. The conversion of wetlands involves not only irreversibility in the environmental or ecological processes but also uncertainty. Availability of good quality freshwater is going to be one of the most important resource limitations of the State. Large scale degradation of land consequent to urbanization, and aquatic pollution due to industrialization has currently resulted in the scarcity of drinking water. The problem will be more acute in the near future, if proper and timely precautionary steps are not taken.

The wetlands are the fragile ecosystem of the State. These ecosystems are presently in the process of degradation due to various reasons. The different types of wetlands existing in the State are paddy fields, mangrove forests, kole lands, lakes, lagoons, backwaters etc. These wetlands especially, the paddy lands are being extensively converted since the last two decades for other purposes such as human habitation, industrial purposes, conversion to perennial crops etc. Such a process in addition to shrinkage in area has led to other problems like drought, floods, land slides, etc. The water table has gone down and the State is facing acute problem for drinking water. It has been found that the above mentioned conversion process is one of the major reason for this problem. Hence it is felt that the present study has great significance in mitigating these problems and to make the State of Kerala a sustainable ecosystem.


  1. To identify and categorize the wetlands (as represented by paddy fields) occurring in the State of Kerala on 1:10,000 scale.
  2. To assess the extent of degradation occurring in the wetlands (paddy fields)
  3. To generate a digital database of the wetlands(paddy fields) of Kerala
  4. To document the reasons for the various degradation process taking place

Results and Observations

The study limits itself to the conversion of paddy lands for other purposes district wise in the state since the manner of paddy cultivation carried out is different in each physiographic unit characterized by unique soil type and other geomorphic features. The study was carried out with the help of remote sensing tools supported by Geographic Information Systems (GIS). The findings of the study are based on mapping and analysis of the paddy fields generated for two time periods. The mapping analysis makes use of remote sensing imageries from IRS LISS III on the scale 1:12500 and also topographic maps on the scale 1:25000. The paddy fields of the early 1970s are mapped using the topographic maps of 1970. A digital database is created simultaneously for the paddy fields. The changes that have occurred to the paddy fields and their current state are mapped out using the LISS III imageries. The conversions of paddy to the various land use classes are identified with the help of imageries supported by ground truth verification. The mapping exercises and the analysis are carried out on an Arc GIS platform, which also enabled the creation of a digital database which can be easily retrieved, stored and used for any future studies.

Outcome :-

Wetlands of Kerala are mainly used for growing paddy and for prawn culture. About 3.5 lakh hectares of land is used for agriculture in the state. This accounts for nearly 50 percent of the total area under wetlands in the state. There are six major rice eco-systems in the state, which include, the Midland-Malayoram ecosystem, the Kuttanad agro ecosystem, the Onattukara Rice ecosystyem, the Pokkali rice ecosystem, the Palakkad plain and Chittoor rice ecosystem and High range rice ecosystem. Of these the Pokkali ecosystem is found along the coastal belt of Ernakulam and Thrissur districts. These areas witness salt-water intrusion and consist of marshy land. The total area of the region is about 8903 hectares. A single rice crop is raised (viruppu) after which prawn culture is carried out in the same fields.

Paddy status in Kerala

The extent (present area) and magnitude of degradation (converted lands) of paddy fields in Kerala state are shown below:


  (1970)                     (2005) Converted  Area                 Fallow
Thiruvananthapuram 16516.01 2840.90 12335.87 1339.24
Kollam 20488.87 9405.13 11083.74  
Pathanamthitta 14318.93 8092.96 5990.79 235.18
Alappuzha 48498.81 42592.21 5334.03 572.56
Kottayam 33976.43 29947.66 3337.36 691.41
Idukki 8476.51 3821.04 4462.17 193.29
Ernakulam 49417.54 29977.28 17350.53 2089.73
Thrissur 61936.32 39815.52 19051.93 3068.87
Palakkad 101803.53 68294.08 32787.38 722.07
Malappuram 62298.79 22471.86 37666.77 2160.15
Kozhikkode 18955.82 5769.37 12223.20 963.23
Wayanad 26278.70 13941.77 12336.93  
Kannur 23428.78 11919.01 11215.42 294.35
Kasaragod 22737.82 3199.98 19185.31 352.54
Total Area 509132.87 292088.78 204361.44 12682.63

High input cost, low product price, non-availability of labourers in peak seasons, inadequate and inappropriate techniques to handle high yielding variety (HYV) seeds, high susceptibility of HYVs to pests and diseases, inadequate institutional support, non-availability of inputs in time and lack of predict are some of the major reasons for the decline of paddy cultivation in Kerala.

Demographic factors and settlement patterns - Population growth, nuclear families, unique settlement pattern and preference for independent houses exerted pressure on land. The richer sections found it convenient and economical to develop paddy fields near motorable roads and developing them as house plots. Extension of existing roads and opening of new roads, construction of buildings for commercial uses and improvement of infrastructural facilities necessitated conversion of more area of paddy fields.

Economic reasons - Over the past three decades, rice growers have been experiencing a difficult situation in which cost of cultivation has been increasing without any commensurate increase in the price of rice. Farmers are of the opinion that at the present rates paddy cultivation is not economically viable. Though there are public and institutional agency committed to the promotion of price cultivation, majority of them have not succeeded in persuading land owners to retain rice cultivation.

Political factors - Laws and regulations restricting land use changes are in vogue in the State. The agencies and institution at the local level like Krishi Bhavan and Village office are not exercising their powers to prevent indiscriminate filling and leveling of paddy field, canals and springs.

Lack of environmental awareness - The Environment is literally the entity on which all subsist and on which our entire agricultural and industrial developments depend. No organism is ever totally independent of the environment. Conversely, there is no environment which is unaffected by the organisms that it supports. In fact, many farmers are not aware of the environmental and ecological function of the wetlands. Most think only in terms of their short-term, individual, economic costs and benefits, not about the societal loss.

Attitudinal changes - At present, all jobs seekers aspire to get government jobs. The land owing younger generations became “absentee landlords”. They prefer to keep land fallow to make investment in rice cultivation. Employment in the farm sectors is seasonal. Demand for labour peaks up during busy seasons to level far beyond supply. The wage share in the total cost has increase several folds since 1950. But in some activities harvesting which follow output sharing practice: workers income have not increased much. Therefore, workers are most unwilling to undertake harvesting job.

Informal tenancy - The practice of informal tenancy is gaining momentum. Landless agricultural labourers interested in the cultivation of crops such as banana, tubercrops and vegetables through and informal agreement take wetland on rent. Though the land is not filled, crops are cultivated on clay bunds prepared fir is easy drainage. Eventually the leased lands are converted to non rice crops.

Conversion leads to further conversion - Midland ribbon valley wetlands (Elas) are a continuous wetland ecosystem. Generally they began from uplands and end up with river basins or sides of other water bodies. Conversion of upland plots affects water supply in plots in the down land. Similarly filling and leveling of down land plots obstructs drainage of uplands. Filling and leveling of plots in an Ela would affect the water holding capacity of neibouring plots. Cultivation in holdings adjacent to converted plots become difficult and expensive.

Reasons for Paddy Conversion

Paddy fields have under gone tremendous changes and were converted to other land uses like coconut, arecanut, cashew, pepper, rubber, mixed crops, banana, tapioca, vegetables, built up land etc. large areas of the paddy fields are lying as fallow land. General reasons for this paddy conversion in Kerala state are mentioned below:

  • Labour problem: high labour costs and scarcity of labourers especially for reaping the harvest are the main labour problems.
  • Low price of paddy, high cost of cultivation and high wage rate etc.
  • Water logging problem: absence of proper bunds, which are most of the time, built temporarily and are ineffective in controlling water flow. Absence of permanent bunds. Around 70 percent of the crops were destroyed due to water logging of the fields in Thanalur panchayat.
  • Salt water intrusion: The main problems affecting paddy cultivation is the absence of basic infrastructure and salt water intrusion due to the Beeyam Regulator problem which has been a problem since 5 to 6 years. The kol lands also face problems due to the highly acidic iron toxic soils. The Beeyam regulator, which is under repair, has led to salt water intrusion during summer.
  • Insufficient irrigation facilities: The conversion has aggravated the irrigation and drainage problems, due to improper maintenance of canals. Much of the canals were encroached and this has affected irrigation and drainage to the paddy fields. The absence of pump houses has also affected the cultivation and also improper maintenance of canal and silting of canals has also affected irrigation and hence paddy cultivation. The sidewalls of canals are not properly maintained. The water holding capacity is low along the canals and has led to water scarcity and drought especially at the time of the second crop.
  • There is low use of HYV seeds and this has resulted in low production or output. Also there is need to develop location specific HYV.
  • Mechanization is a problem especially for reaping the fields, mainly because the paddy reapers cannot be used here due to the small size of the tyres, which get stuck in the mud.
  • Also there is decline in availability of organic manure due to decrease in cattle population. Milk societies should be set up to promote cattle rearing.
  • The scarcity of water during the summer months and decline in ground water level due to these paddy areas is lying uncultivated.
  • Lift irrigation facilities are available for the mundakan crop however absences of sub canals pose a problem for transporting water to the inner reaches.
  • High prices of machineries, fertilizers and pesticides, unavailability of seeds and planting materials on time.
  • Flood draining facility is poor due to conversion and virippu crop is affected.
  • Much of the land is converted to garden lands and brought up by real estate owners. And conversion is a major issue in this area and much of the land is left as cultivable wasteland.
  • Increase in land value due to high population pressure
  • Lack of knowledge about scientific and modern crop production technologies.
  • Destruction of soil properties due to the increased use of chemical fertilizers and decreased use of organic manures.
  • Improper functioning of krishibhavan. The Agricultural officers being over burdened with clerical and accounting works seldom get time for extension activities. Due to lack of extension services, new technologies are not reaching the farmers.
  • Clay mining: The paddy fields, which are getting converted into deep depressions due to clay mining, can seldom be reverted and this in turn affects the ground water level and these lands cannot be used for cultivation again.

Ecological impacts of paddy conversion

Decline in specious population in the converted area - Significant differences were found in the number and density of organisms present in the water bodies located in the converted and non-converted areas. During the monsoon season, there is migration and shuffling of organisms between different micro habitat within the wetland ecosystem. Paddy conversion obstructs the free flow of water and hence the distributional density of smaller organisms was significantly low in the waterbodies near the converted area. Larger organisms like fishes were also absent. The stumps of paddy remaining in the field after harvest decomposed during monsoon favouring the growth of cyanobacteria and other phytoplanktons.

Loss of fish and frog - Usually, at the time of monsoon freshwater algae and planktons multiply and spread in the wetlands. Paddy conversion uninterrupted the free flow of water in the ecosystem and hence the growth of ‘seeding’ of organisms. Planktonic organisms form the food of fishes and frog tadpoles. Such food chains and food webs have been shattered due to massive conversion of wetlands.

Growth of mosquito population - The common larvivorous fishes seen in fresh water feed especially on the larvae of mosquitos. Conversion of wetlands dismantled the feeding and breeding place for fishes. In the absence of predator fish, mosquito population increased at alarming rate.

Fall in water table - Groundwater recharging function occurs when water moves from the wetland down into the underground aquifer. By the time it reaches the aquifer, the water is usally cleaner than when it began to filter down from the wetland. Once in the aquifer, it may be drawn for th human consumption, or it may flow lateraaly underground until it rises to the surface in another wetland as groundwater discharge. Recharge is also beneficial for flood storage, because the run-off is temporarily stored underground, rather than moving swiftly down stream and overflowing. This natural balancing act is now disrupted due to wetland conversion. Laterite soil from hilltops is usually used to fill the paddy fields. Since the water retention capacity of that soil is poor, the converted fields become harder, which leads to the growth of more amphibious grass and other weeds through community succession.

Recommendations to Arrest Conversion of Paddy:-

Kerala State is witnessing tremendous land use change owing to the high scale commercialization and associated urbanization. This has led to the conversion of paddy lands to other land use to accommodate commercial establishments. The land use change analysis clearly reveals the pattern and extent of land use changes, its causes and consequences. The major change is the conversion of paddy fields to non-paddy or non-agricultural purposes. The constraints in paddy cultivation and the huge demand for land for non-agricultural purposes especially for settlements due to the population pressure should be taken into account when we formulate an action plan. The qualitative and quantitative aspects of the biophysical resources should be taken into account when we introduce a new land use pattern in the area.

Based on the information generated through this study, some management options has been formulated. But a very detailed study and action plan is required for evolving an appropriate land and water management policy for each district. The following recommendations are put forward to arrest the conversion of paddy.

  1. Organizing awareness campaigns at the Grama Panchayat levels about the impending danger of paddy conversion as affecting ground water storage and the resultant water scarcity. Awareness creation can also be taken up with the help of the popular media.
  2. Stringent legislations need to be made and implemented properly to prevent the conversion of the remaining paddy fields within the localbodies
  3. Promoting group farming of paddy with Governmental support to carry out paddy cultivation in a profitable manner.
  4. Providing monetary benefits to the agricultural farmers practicing paddy cultivation and providing fertilizers for such farmers at subsidized rates.
  5. Introducing special schemes for the agricultural labourers and making paddy cultivation a profitable enterprise.
  6. Procurement of paddy should be taken up by the Government at a rate which is profitable to the farmer and which will pull him out of the poverty trap rather than pushing him into it.
  7. A task force needs to be formed at the Grama Panchayat level, to learn about the problems of paddy cultivation and an appraisal needs to be done with the various stakeholders about the problems afflicting paddy cultivation.
  8. A cost benefit analysis need to be performed so as to get a better idea on where the necessary changes has to be made to bring down the cost and increase the benefits of cultivating paddy.
  9. Making paddy cultivation a sustainable livelihood option is essential to ensure the sustainability of the ecosystem.


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