Why are fertilisers (synthetic & organic) and pesticides not eco-friendly?
Added on 24 January 2023
The discussion on whether using synthetic fertilisers and pesticides (which includes herbicides, insecticides, fungicides etc) destroys long term soil structure and biodiversity continues amongst experts with little agreement. Agriculture has shown that fertilisers certainly increase crop yield (speed of growth, size and quantity) compared to slower natural processes such as allowing organic matter to be decomposed by soil micro-organisms releasing nutrients such as nitrates and phosphates for uptake by plant roots As yet there is no compelling evidence to support that synthetic fertilisers kill soil bacteria and fungi. The view being that plants cannot tell the difference between synthetically produced nitrates and natural nitrates from the breakdown of organic matter by microbes.
Over use of fertilisers in the agricultural setting has been seen to result in leaching of surplus nitrates into water ways resulting in algal blooms. Other concerns such as loss of soil carbon through reduction of organic matter, ploughing and soil compaction from machinery is more to do with other agricultural processes associated with growing crops. The processes involved in manufacturing fertilisers often requires energy intensive use of fossil fuels in their production and and transport is a more justifiable concern. Even organic fertilisers have production and transport impacts on the environment with seaweed based fertilisers considered to having the least impact The safest reason for avoiding or minimising the use of synthetic or even organically products in the garden setting is that they are often not necessary when organic matter is returned to the soil through natural plant decay. Although they do provide nutrients for plant uptake they do little to improve the soil structure which is achieved through organic matter breakdown.
Pesticides whether organic or synthetic cannot tell the difference between beneficial and non beneficial bacteria and fungi that breakdown the organic matter essential to plants. They also require the use of fossil fuels in their production and transport. This with the concerns to human and animal health (such as decline in bee populations and biodiversity in general) it is probably safest to minimise their use and if possible avoid them completely . Because of the abundant quantity and reproduction rate of micro-organisms in the soil it is generally agreed that biodiversity can recover quickly where chemical use has been seen to degrade the soil. Undoubtedly there is still lots to learn about soil science and soil biology but allowing nature to get on with it, as evidenced in attractive, healthy natural and semi-natural biodiverse habitats, uninfluenced by humans, seems a safe bet until the experts can universally agree which products and practices are good and which are bad. In the garden a dense mix of plant species with minimal human intervention allows the build up sustainable biodiversity which ‘good organisms’ preying on ‘bad organisms’ greatly reducing the damage to our ornamental plants. Although we have to show some tolerance to the imperfections of plants as seen in natural balanced and healthy habitats.