What is fertilizer exactly and why is it used at all?
A Definition: A substance used to promote plant growth.
If you want to impress people at your next dinner party, it comes from a Latin word meaning “bearing in abundance, fruitful, productive”. Just what any farmer, horticulturalist or home gardener wants really!
Far more interesting and relevant though is this question:
Why Do We Need Fertilizer At All?
Think about plant growth in the wild with no influence by man (or just look at that patch of weeds you’ve been meaning to get to). Plants live and then they die. No-one rakes up the leaves or fallen fruit that aren’t taken away by animals so it all decays on the ground.
The local micro-organisms release the nutrients in the dead plant matter (plus any dead animals) so these nutrients are available to feed the next generation of plants.
And so it goes. A natural, balanced cycle.
Unfortunately our pastures, lawns, market gardens, grain fields and home gardens are not natural at all.
Firstly we harvest. Or to put it from the plants’ point of view … we take away fresh, living plants with all the precious nutrients they got out of the soil.
Secondly we like to keep things tidy so we take away all the messy dead stuff too before our helpful micro-organisms can do their work.
The end result, if we just plant and harvest like this, is that the soil doesn’t have enough nutrients to grow things well. Other things happen too, like the soil isn’t a very attractive place for earthworms and the other smaller, beneficial creatures. The soil also gets too acidic which is tough for the crops we want, but great for weeds.
History Of Fertilizer
The history of fertilizer is fascinating. It’s a useful aid to understanding fertilizer and gives you an idea of the massive impact on mankind and also on the wider environment on earth. It is a history of brilliant technological innovation, great benefits to humanity and also great controversy.
Sounds like a good yarn … and it is!
A Timeline Of The History Of Fertilizer
- Somewhere between 12000 and 8000BC – Agriculture becomes well established. First significant crops grown are wheat, barley, peas, lentils, bitter vetch, chick peas and flax. Humans transition from hunter-gatherers to farmers and traders.People learnt that some soils grew plants better than others, and also that if you kept using the same soil for the same crop year after year, the productivity dropped. So these neolithic farmers would have added things like animal manure, sewage, fish, composts, seaweed, sand, bones, wood ashes, mudstone, slag and others in a long trial and error attempt to grow more and better crops.
- About 800BC to 500AD – In the Golden Age of Ancient Greece and then the Roman Empire a lot of farming and fertilizer practice was documented. Even Plato and Aristotle wrote about the methods being used which involved manure and nirogen fixing crops. Not a lot new was developed until the 1800s.
- 1803-1873 Justus Von Liebig – The father of modern fertilizer realizes the importance of minerals in the soil and that they must be replaced to maintain fertility. “The Law Of The Minimum”, which is still relevant today, explains that if any single element is deficient then it will restrict growth even if all other elements are sufficient.
- Early 1800s – The first ‘phosphate fertilizers’ are used widely in Europe in the form of ground up bones (animal or human ones from battlefields)
- About 1830 – the first chemical fertilizers were made in liquid form. Bones dissolved in sulphuric acid were mixed with potash and sulphate of ammonia or nitrate of soda.
- 1834 – Sir John Bennett Lawes sold the first practical superphosphate fertilizer which he made by dissolving phosphate rock in sulphuric acid. This spawned a whole industry of ‘super’ manufacturers.
- 1870s – First triple superphosphate made in Germany using phosphoric acid
- 1960s – Ammonium phosphate (now the leading phosphate fertilizer in the world) becomes popular.
- 1913 – Ammonia is made for the first time in Germany by direct synthesis of nitrogen and hydrogen. This was the forerunner of the use of ammonia as a commercially viable source of Nitrogen in fertilizer in the form of Ammonium Nitrate in the 1940s.
- 1870 – Urea is produced by heating ammonium carbamate. This is the basis of the current industrial process and Urea fertilizer is the most widely used N fertilizer today.
- Late 1700s – Nova Scotia gypsum, often referred to as plaister, was a highly sought fertilizer for wheat fields in the United States.
- 1844 – Iron discovered to be an important trace element
- 1905 – Manganese discovered to be an important trace element
- 1920s – Copper and Boron discovered to be important trace elements
- 1930 – Zinc discovered to be an important trace element
- 1939 – Molybdenum discovered to be an important trace element
- 1954 – Chlorine discovered to be an important trace element
- 1943 – Due to food requirements in Mexico the ‘Green Revolution’ begins. Fertilizer is one of the 4 pillars that dramatically increase food production around the world over the following decades(the other 3 being irrigation, pesticides and high-tield crops).
These are just some of the important events that make up the history of fertilizer.
What Does Fertilizer Do?
So … we put the nutrients that we’ve taken away, back into our unnatural system. We normally call it fertilizer and it can take many forms, including:
- animal manure
- chemical solid fertilizer which is mainly N, P and K (nitrogen, phosphorous and potassium)
- liquid organic fertilizer (which typically contains a more complete list of nutrients)
Quite simply when we use fertilizer we are trying to promote plant growth in an unnatural system. We do that by attempting to re-create the best possible environment for the plants to do what they do best – turn sunshine, water and CO2 into oxygen and food for everything that lives on earth.
So again what is fertilizer? A substance used to promote plant growth is the short answer, but …. there’s a lot more to the story than that.