Agroscope, Institute for Plant Production Sciences IPS, 1260 Nyon, Switzerland

Surface runoff of phosphorus – an evaluation model

“The Soil Protection Service of the canton of Berne is running a soil surveillance program since 1993. Its aim is to record the present condition of the soils and the further development of their fertility. The soil surveillance program serves to determine “”hot-spots””, where immediate action is to be taken, but even more it allows an impact evaluation of already implemented measures of soil, water and air protection. Moreover, it allows an early determination of slow soil pollution or degradation tendencies.<br>The fertile soils of the Bernese “”Mittelland”” are the mechanically most stressed soils in the canton of Berne due to an intense agricultural practice. In a first step, the Soil Protection Service collected data of the degree of degradation of the intensely cultivated land by comparing different soil parameters to those of untilled meadows.<br>The results of the soil surveillance program until 1997 show the topsails of the cultivated land with a reduction in the total pore volume by 10 %. Compared to extremely compacted, unfertile soils (total pore volume less than 30 %) a loss of 25 % of the natural fertility is to be expected. The total biomass of earthworms (lumbricus terrestris) is down 30 %. The organic matter content in the topsails is reduced by as much as 40 %.”

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