wise use of mires and peatlands - Peatland Ecology Research Group

64 VALUES AND FUCTIONS OF MIRES AND PEATLANDSPhysico-chemical properties: The physicaland chemical properties of soils are mostimportant in the surface layer of the peatland(to a depth of 0.3 metres) where the majorityof roots of cultivated plants are found. Theseproperties depend on:● peat type,● degree of peat decomposition,● ash content,● peat reaction (pH),● peat fertility (nutrient content),● industrial contamination of the soil.The first three factors determine the physicaland water properties, the remaining factorscontrol the conditions of plant growth andthe quality of the yield.Relatively favourable conditions foragricultural production are present in fenswith a low or medium ash content and a smallor medium degree of decomposition. Neutraland slightly acid reaction (pH 5.5-7.0), highersoil fertility and absence of industrialcontamination (heavy metals, persistentorganic pollutants) are commonly regardedas beneficial for agricultural production.Sediments under the peat may containsignificant amounts of sulphur (East England,Indonesia), or carbonates (Hungary, Poland).In shallow organic soils the reduction in thedepth of the organic layer by mineralisation(see § 2.6[ii]) results in the rapid deteriorationof plant growth conditions as the roots ofcultivated plants do not usually penetrate tothe very acid or alkaline soil layers.●Europe: Approximately 14% of Europeanpeatlands are currently used foragriculture. Large areas of peatlands usedfor agriculture are found in Russia ,Germany, Belarus, Poland and Ukraine(Table 3/11). In Hungary (98%), Greece(90%), the Netherlands and Germany (85%),Denmark, Poland and Switzerland (70%) themajority of peatlands are used foragricultural purposes. In these countriesthe high population density required that●wetlands be used for food production.Proportional to the total area of peatlands,the use of peatlands for agriculture is smallin Fennoscandia, the Baltic countries,Russia and the British Isles. The greatmajority of peatlands used for agriculturein Europe consist of meadows andpastures. The area of agricultural peatlandshas decreased steadily in recent years foreconomic reasons and due to increasingnature protection.Tropical agriculture 113 : While the peat innorthern temperate regions is formedlargely from grasses, sedges and mosses,tropical peat generally consists of a rangeof organic debris including trunks, branchesand roots of trees.Indigenous peoples have had longexperience in the reclamation and utilisationof peatlands for agriculture, particularly inthe cultivation of horticultural crops. Inareas which remain under tropicalinundation beneficial products can beextracted from sago and other palms.Approximately 313,600 hectares, or 32% ofthe peat areas in Peninsular Malaysia, arebeing utilised for agriculture, largely forestate crops 114 . In Indonesia large areas ofpeatlands have been cleared foragriculture-based transmigrationsettlement and for the expansion of estatecrops.Lowland peat soils can be productive forwetland rice 115 . Good levels of productivitycan be achieved with horticultural cropswith intensive management. On smallholdings (which in Indonesia, for example,vary from 0.6 to 2 hectares), an integratedsystem of animal husbandry (pigs, cattle,poultry) and horticultural crops canprovide subsistence. Sago palms grownaturally on peat and are simple to cultivateand need little maintenance 116 . Sarawak isnow the world’s largest exporter of sago