Q12. Relevance of adding fertilisers NPK etc to soil biology. What effect?

Answer: Any salts adding in large amounts will damage soil microbes to a greater or lesser extent. Metals such as copper will affect all fungi and phosphates have a negative effect on mycorrhizal fungi in particular. Mycorrhizal fungi have a role in the soil of scavenging for phosphates and supplying them directly in plant available form to plant roots in exchange for carbohydrates which fungi cannot manufacture because they are non- photosynthetic. Any disruption to this symbiotic relationship causes loss of mycorrhizal fungi leading to loss of soil structure and loss of water holding capacity. Look at literature in the journal ‘Acre’, J. of Soil Microbiology, and others, for peer reviewed papers. If you add 10% of the recommended rates of NPK to a good compost and then distribute the amended compost or compost tea to your soil, you will improve the soil without damaging the soil microbes.

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