Organic farmers grow grassclover in nature areas to remove soil phosphate for development of specious rich grasslands

Summary

While worldwide the current reserves of phosphate rock are being exhausted, many agricultural and former agricultural soils in The Netherlands have been enriched by large quantities of phosphorus as a result of fertilization. In current nature development projects on former agricultural lands, it is thought that this phosphorus prevents development of target-nature types. Therefore nature organizations currently seek ways to remove it. We tested grassclover, organically managed by local farmers, as a tool to extract excessive soil phosphate from nature areas and reimport it into the mineral cycle agricultural farms.
In a small scale experiment we have shown that grassclover with potassium fertilization can remove more than twice the amount of soil phosphate as is removed by traditional mowing without potassium fertilization. We tested the methodology on 60 ha of grasslands in nature areas, ranging in soil phosphorus levels, and measured comparable large decreases in soil phosphate.
We conclude that these results of 3 years measurements show that organically managed grassclover could form an elegant way to help overcome the problems with excessive soil phosphate in nature areas and recycle phospahte.