Stefan Grübe, Ruhr-Universität Bochum
Lehrstuhl für Siedlungswasser, Bochum, Germany
Economic Analysis of Agricultural Use of Land
on Riverside Areas (assigned to theme
The European Water Framework Directive (WFD) demands, among other things, an economic analysis of water uses. But, hitherto, there was a lack of knowledge with regard to its implementa-tion in the various subcatchment areas. That was why the Ministry for the Environment and Nature Conservation, Agriculture and Consumer Protection of North Rhine-Westphalia launched the Lippe pilot project in 2002 to exemplarily elaborate an economic analysis based on data from the Lippe subcatchment area in the western part of Germany. Apart from developing methods of determining the financial cost recovery rate and ascertaining data needed to describe water uses, the main challenges involved pointing out data gaps and making recommendations for further economic analyses. During the term of the project, all significant water uses in the Lippe subcatchment area were examined and described in economic terms.
One of the most significant sources of water pollution is the diffuse passage of nutrients into the water and groundwater bodies. As a result of the Lippe pressures and impact analysis, nine of 31 groundwater bodies are at risk, because of significant nitrate infiltration. The causes are fertilization and intensive stock farming. A decrease of fertilizers in tillage (especially on the riversides) and giving up stock farming near the riversides might possibly be cost-effective measures to obtain good water quality. However, this would reduce crop yields and revenues from stock farming. In this paper the emphasis is laid on a discussion of how to describe the agricultural use of land on riversides in economic terms. In order to estimate the monetary value of the loss involved, different kinds of information have been considered:
- Area data taken from the Official Topographic-Cartographic Information System (ATKIS) - Types of crops in the Lippe subcatchment area - Statistical data on average crop yields - Average crop market prices - Results of cereal growth experiments on farmland
The areas attributable to the various land utilization categories associated with the bodies of water in the Lippe subcatchment area were determined in respect of strips of riverside land of varying widths (5 m, 10 m, 30 m and 100 m) on the basis of a geographical information system (GIS) and area data from the ATKIS database. On the whole, depending on the width of the strips of riverside land examined, the land use categories consisting of arable farmland, grassland, and areas of forest, woodland and copses account for roughly 83 - 85 % of the area bordering on the bodies of water concerned. Figure 1 shows the percentages accounted for by the six most frequently en-countered land use categories relative to the width of the strips of riverside land.
In the Lippe subcatchment area three types of cereals are commonly cultivated on more than 50 % of the farmland: winter wheat, winter barley and triticale. Table 1 presents detailed figures on agri-cultural land use and average crop yields obtained with and without fertilizers for the riverside ar-eas (100 m) in the Lippe subcatchment area. If the area data concerning farmland in the Lippe subcatchment area and the results of the cereal growth experiments using different amounts of fertilizer are combined, it is possible to calculate the resultant loss of crop yields if no fertilizers are used. This loss is estimated at between 36 and 51 % of the average crop yields obtained. The monetary value of the crop yields obtained with and without fertilization and also the degree to which areas are kept free of any agricultural use whatsoever (tillage, stock farming) are viewed as an indicator of the economic significance of the strips of riverside land concerned.
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(copyright Gunther Maier) |