{"id":996,"date":"2026-03-16T14:12:46","date_gmt":"2026-03-16T14:12:46","guid":{"rendered":"https:\/\/fourcornerseducation.net\/ESS2026\/?page_id=996"},"modified":"2026-03-16T14:12:51","modified_gmt":"2026-03-16T14:12:51","slug":"5-2-maintaining-fertility","status":"publish","type":"page","link":"https:\/\/fourcornerseducation.net\/ESS2026\/5-2-maintaining-fertility\/","title":{"rendered":"5.2 Maintaining fertility"},"content":{"rendered":"\n

Intensive systems<\/h3>\n\n\n
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In many intensive agricultural systems inorganic (synthetic) fertilisers are used extensively to mainatin soil fertility and boost productivity of the system.<\/p>\n\n\n\n

As the graph below shows on unproductive sheep pasture in the UK can support around 100\/sheep per hectare when treated with synthetic fertilisers containing Nitrogen, Phosphates and Potassium salts (NPK) with the addition of Calcium to reduce the acidity of the soils.<\/p>\n\n\n\n

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Adapted from: Chauhan, J.S. et al.<\/em> (2021) \u2018Sustaining national food security and increasing farmers\u2019 income through quality seed\u2019, The Indian Journal of Agricultural Sciences<\/em>, 90(12), pp. 2285\u20132301. Available at: https:\/\/doi.org\/10.56093\/ijas.v90i12.110311<\/a>.
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While the use of synthetic fertiliser has greatly increased crop yields (Green Revolution, they have not come without a cost.<\/p>\n\n\n\n

Eutrophication of water systems has occurred where farmers have used them in excess rates beyond which plants can immediately absorb them. <\/p>\n\n\n\n

This has led to algal blooms being a common occurrence in some parts of the world as well as increased incidents of toxic lakes and rivers.<\/p>\n\n\n\n

Their use has also altered the biodiversity of grassland systems where they have been used to increase meat and dairy production. Competitively aggressive species are favoured where soil nutrients are artificially increased. <\/p>\n\n\n\n

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Why NPK?<\/h4>\n\n\n\n