Soil Nutrient Status of Organic Farms in Flanders: An Overview and a Comparison with the Conventional Situation

Abstract

ABSTRACT Organic farming is put forward as a sustainable alternative to the conventional way of farming. However, until now there has been practically no research on soil related aspects of organic farming in Flanders. Therefore, in this study, the carbon, nitrogen, sulphur and phosphorus status of the fields on organic farms was measured and was related to characteristics of the farms involved (land use, soil texture, management intensity and time since conversion to organic farming) and was, where possible, compared with the general soil fertility status of agricultural soils in Flanders. The SOC (soil organic carbon) contents tended to be larger in the fields of the organic farms studied than in conventional farming. This content was correlated positively with the management intensity of the fields. However, some of the organic fields still had rather low SOC contents. To increase this content organic farmers will need to apply more organic materials with large C:N and C:P ratios taking into account the strict current manure legislation. The mineral N contents on the organic farms measured in the period between 1 October 2003 and 15 November 2003, indicating the risk of nitrate leaching, were well below the average values of the different land use classes of conventional agricultural soils in East Flanders. The available P content of the organic fields was high to very high as is also the case for conventional agriculture in East Flanders and was strongly related to the management intensity.