Reduce agricultural inputs

Reduce agricultural inputs

There are major concerns for ‘conventional’ (aka industrial/chemical) agriculture due to the imminent scarcity and increasing costs of its bedrock agricultural inputs which will be brought upon by the following ‘peak’ phenomena: peak oil, peak phosphorus, and peak potash each respectively corresponding to the production of N, P and K fertilisers. 

It can’t be said for sure when the peak production of these resources will be reached but their occurrence is inevitable (although it has been argued that peak oil may already have been surpassed in 2018). Following their peak in production lower quality grades of these resources will be sought out since the low hanging fruit of reserves have already been capitalised on. These remaining reserves are more remotely located and much less economical to exploit (less resources are recovered per unit of energy invested), therefore the increasing cost of extraction will similarly raise the price that these resources are sold for. Furthermore, given that fossil fuels are the basis upon which we can extract such large quantities of resources from the Earth’s crust, the increasing scarcity of fossil fuels (along with the need to stop using them due to climate change) means that we will have less energy to do so, precisely when we require even more. 

With this in mind, peak oil has direct implications for the production of ammonia, the basis for N fertilisers. Producing ammonia is a high energy intensive process and its global production accounted for approximately 2% of the world’s energy consumption in 2020 (IEA 2021). So, with fossil fuels becoming scarcer and more expensive, N fertilisers will be more costly and harder to come by. Similar outcomes can be expected for P and K. Estimates for peak P vary widely, but have been predicted to occur between the 2030s and 2100 (Walan et al. 2014) and K could peak globally by 2057 (Al Rawashdeh 2020).

Stockfree organic farming can directly respond to these challenges with its omission of chemical fertilisers and with practices such as growing N fixing green manures, using deep rooting plants to bring up nutrients from the subsoil, and encouraging a healthy soil ecosystem to increase the bioavailability of nutrients. Closing the loop on nutrient flows is also important for ensuring a sustainable food system. For example, retaining P on our lands is perhaps more concerning than N. Given that the availability of P in soil is governed by the rate of rock weathering (a very slow process) and whether it’s in a form that plants can take up (often the soil pH renders P unavailable), it is imperative to conserve our current stocks of it (Elser 2012). When P is taken from the land (primarily in the form of food) and not returned, this will lead to a gradual depletion of the nutrient and thus to crop yields. One potential solution to preserving P is composting human waste into ‘humanure’ as currently this represents a significant loss of P to the oceans.

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