Q40. How do chemical and conventional fertilisers affect the soil food web?

Answer: 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 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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