The National Soil Monitoring Network NABO has assessed nutrient contents for over 30 years. The time sequences for selected sites show that the nutrient contents develop dependent on land use (Figure). The challenge on agricultural soils is to secure a balanced range of nutrients and to control the input of fertilisers in the soil over time. Lack of nutrients causes reduced crop yields, whereas a surplus can have negative effects on the ecosystem, for example by polluting the ground water.
Due to successful plant breeding, today’s agriculture can produce a multiple of past crop yields. However, the maintenance (of this system) of agricultural food production relies on the input of nutrients such as nitrogen, phosphorous and potassium in the form of fertilisers.