Wetland farming is the process of cultivating crops in soils that are flooded by natural water flow for the majority of the year. Crops such as rice, sugarcane, etc are usually grown in a wetland. Wetland farming is a type of agriculture carried out on or next to a body of water. Wetlands provide a range of valuable ecosystem services, such as the provision of food and clean water, the retention of soil and the cycling of nutrients. Wetlands are areas where water has a major influence on the soil, associated plant and animal life, and on the farming system. They include flood plains and wet grasslands as well as lakes, rivers, ponds, swamps and bogs. By their nature, wetlands often remain unimproved – never reseeded or heavily fertilised, thus providing a resource now more appreciated and valued. Wetlands deliver a wide range of ecosystem services that contribute to human wellbeing. These include provisioning services such as food, fresh water, fi bre and fuel; regulating services such as water purification and waste treatment, climate regulation, retention of soils and sediments, protection from storms and floods; supporting services such as soil formation and nutrient cycling (nitrogen, phosphorus and carbon); and cultural services such as aesthetic and spiritual values, education and recreation.
Ecosystem services provided by wetlands that can benefit agriculture and contribute to human wellbeing. Wetlands can:
• support fertile soils, reduce erosion and retain sediments and nutrients as well as reduce the potential for salinity and acid sulphate soils
• support aquaculture or grazing
• provide habitat for harvestable plant and animal species
• provide drinking water for stock
• provide shade, wind buffering, protection from floods and habitat for birds
• act as natural filters in waste water treatment
Agriculture focuses on managing and enhancing provisioning ecosystem services. While we can increase agri cultural production – thus increasing the provisioning services – perhaps by using more fertilizers to obtain higher yields for crops grown in seasonal wet lands or by withdrawing larger amounts of water for irrigation, there is the risk that the ecological character of the wet lands will be altered to the point where we lose essential regulating and sup porting services. And this can in turn result in the subsequent loss or degradation of those very provisioning services that were so important in the first place. There are many ways in which poorly managed agriculture can negatively impact wetlands. This can lead to changes in the ecological character of a wetland and the possible permanent loss of its benefi ts to people.
Water quantity impacts: Decreases in flows due to the building of dams and abstraction of surface water and groundwater for irrigation or other purposes, increases in river flows or water levels due to irrigation return fl ows or dam releases, and changes in the timing and patterns of river flows can all signifi cantly alter and sometimes damage the ecological character of wetlands. Many coastal wetlands depend on the nutrients and sediments carried down by rivers to maintain their ecological character. Intensive agriculture activities including intensive aquaculture often lead to increased loads of pollutants such as pesticides, fertilizers, antibiotics and disinfectants. Not only do these affect the ecological character of both inland and coastal wetlands, they also have impacts on human health and the quality of drinking water supplied from wetlands.
Wetland conversion and disturbance: Agricultural activities which can disturb wetland functions and ecosystem services include the drainage and conversion of wetlands to cultivated land or aquaculture; the introduction of invasive plant and animal species; the introduction of human and animal disease vectors; and the disturbance of breeding, migration and feeding patterns of wetland fauna. For example, the rapid expansion of intensive shrimp farming has contributed to the loss of large areas of coastal wetlands in several places, with an associated loss of wetland ecosystem services such as coastal storm protection, fisheries, and mangrove forest products.
