The subsoil (i.e. the soil beneath the ploughed soil layer) provides a large potential reservoir of nutrients for crops but the conditions for nutrient acquisition are generally adverse due tolow organic matter contents, low nutrient concentration in the soil solution, low microbial activity and high bulk density. However, the structural heterogeneity of the subsoil including biopores created by roots and earthworms requires a more detailed view on nutrient acquisition processes. First results from the DFG research unit ‘Crop Sequence and the Nutrient Acquisition from the Subsoil’ have shown that cultivation of perennial fodder crops with taproot systems can result in enhanced biopore density in the subsoil and increased root-length density of subsequent crops. Observations with endoscopes revealed that 80-90 % of roots growing in biopores established contact with the pore wall thus potentially accessing the nutrients stored therein.
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