Does it matter where plants get their nutrients? Isn't a nutrient such as nitrogen just nitrogen, no matter where it comes from? Whether the plant takes it up from a previously grown legume crop, from compost or from a synthetic fertiliser, what does it matter?
What would you say to a non-organic gardening friend if you were asked these questions? And what would you make of the following information from a synthetic fertiliser manufacturer's website?
"Fertilisers replace the chemical components that are taken from the soil by growing plants. However, they are also designed to improve the growing potential of soil, and fertilisers can create a better growing environment than natural soil.
They can also be tailored to suit the type of crop that is being grown. Typically, fertilisers are composed of nitrogen, phosphorus, and potassium compounds. They also contain trace elements that improve the growth of plants".
Wow! Isn't it fantastic that these products "can create a better growing environment than natural soil"?
But just when we were thinking of giving up organic growing we read on the same website: "research is currently focusing on reducing the harmful environmental impacts of fertiliser use and finding new, less expensive sources of fertilisers". Uh-oh, could there be a problem?
These are important questions and deserve a serious reply from an organic gardening perspective. Basically, its all a matter of focus. Growers who rely on artificial chemical fertilisers are foeussed on the plants. They view soil mainly as a support medium for fertilisers.
An organic grower's focus is on the soil and the surrounding ecosphere. Our philosophy appreciates the natural order of nature and we work in harmony with it, rather than regarding it as inadequate and requiring constant chemical intervention.
The basic principle of organic gardening is this: feed the soil and let the soil feed the plants. Soil is more important than oil in the long run because it is as much a non-renewable resource as oil.
Chemical fertilisers cannot improve soil fertility. Only organic humus will enhance the life in the soil.
Chemical fertilisers can neither add to the humus content of soil nor replace it. When chemical fertilisers are added to the soil they dissolve and seek natural combination with minerals already present. Chemical fertilisers do not work on the soil but are enforcedly imbibed by plants.
The chemical mixes of most synthetic fertilisers are developed to produce larger and greater yields—without regard for the nutrients that nature designed for producing quality plants. They are quick-acting, short-tenn growth boosters and are detrimental to the soil in the long term.
Chemical fertilisers provide an 'empty' type of food directly to the plants. This is like the empty calories we get from eating pure refined sugar.
In the organic garden, microbes in the soil supply a full menu of nutrients to plants. They decompose dead plant and animal residues to humus, combine nitrogen and carbon to prevent nutrient loss, suppress disease, produce plant growth regulators, develop soil structure, tilth, and water penetration/retention, clean up chemical residues, shift soil pH toward neutral and retrieve nutrients from distant parts of the soil;
Chemical fertilisers destroy beneficial soil life such as earthworms and the micro-organisms essential to the natural chemical processes of good garden soil.
These fertilisers may also contain sulfuric and/or hydrochloric acid, which increases the acidity of the soil significantly.
The change in soil pH can have a ripple effect that not only affects the plant, but living organisms in the soil as well.
Some synthetic fertilisers are so highly soluble that they are often leached away into ground water sources too quickly to benefit the plants significantly.
A type well known for this effect is the NPK 5-10-5 mix, which also can react with deeper levels of clay and create an impervious layer of solids known as 'hardpan'.
Continued use of chemical fertilisers can dramatically reduce the amounts of trace minerals absorbed by plants. It does this by disturbing the natural delivery system that gets the trace minerals to the plants' root hairs.
The green revolution
World population lias increased from 2.5 billion in 1950 to around 6 billion today and food supply has kept pace with the expanding numbers.
This has been termed the green revolution and chemical fertilisers are credited with achieving this. Perhaps forty percent of humanity would not be here today if the green revolution had not occurred.
However, some nations have belatedly discovered that the use of chemical fertilisers has many undesirable side effects.
A report from the Indian Institute of Science says, "The use of chemical fertilisers and pesticides played a very important role in the first green revolution in our country.
The increased use of chemical fertilisers and pesticides improved the yield and the productivity of the farm produce manifold over the last 3-4 decades.
However, it resulted in overdrawing the micronutrients of soil and increasing the alkalinity of the sub-soil layer in the country.
We have reached the plateau in terms of productivity and yield. The excessive use of the chemical fertilisers and pesticides has seeped into our water bodies and thus contaminated our water reserves".
Many tliird-world countries have become dependent on synthetic fertilisers to feed their populations.
The cost of importing these fertilisers puts enormous stress on limited national budgets and is seriously holding back economic growth and development.
It is not surprising that these countries are looking at returning to traditional, locally produced natural fertilisers as a priority.
Chemical fertilisers, unlike natural fertilisers such as compost, are manufactured from unrencw able fossil fuels.
It takes the energy from roughly one litre of oil to produce one kilogram of urea. To produce an acre of corn in the USA an input of 350 litres of oil is required; most of w hich is involved in the manufacture of chemical fertilisers and pesticides.
With future fuel shortages and high prices, market forces will eventually compel all countries to adopt alternatives to synthetic fertilisers.
What are NPK numbers?
Chemical fertilisers and organic fertilisers show their nutrient content with three bold numbers on the package.
These numbers represent three different compounds: Nitrogen, Phosphorous, and Potash (Potassium), which we can also describe with the letters for their chemical symbols N-P-K. The three numbers listed on fertiliser labels correspond to the percentage of these materials found in the fertiliser.
German scientist Justus Von Liebig was responsible for the theoiy that Nitrogen, Phosphorous, and Potassium levels are the basis for determining healthy plant growth.
However, this theory, which dates to the 1800s, doesn't take into account the dozens of other nutrients and elements that are essential to plant growth.
Nitrogen, Phosphorous, and Potassium are not necessarily the most important elements required for plants to grow well. In fact, elements such as carbon, hydrogen, oxygen, sulfur, magnesium, copper, cobalt, sodium, boron, molybdenum, and zinc are just as important to plant development as N-P-K.
When looking at both organic and chemical fertiliser labels, you'll notice that the NPK numbers don't add up to 100 percent. So, what is the rest of the fertiliser made up of? Well, that depends on the fertiliser.
Chemical fertilisers can have any number of additional ingredients including dirt and sand. These fillers for chemical fertilisers are necessary so that the nutrients aren't so concentrated that they will damage or 'burn' your plants, your skin, and anything else they touch.
Organic fertilisers don't need fillers
Organic fertilisers don't need fillers, as they are made up of a variety of natural components that in one way or another will all benefit your plants.
Organic fertilisers usually have a lower NPK number, but they are long-term soil nourishers, not a quick fix. There/fore, big NPK numbers don't necessarily mean a better fertiliser.
You may not be able to solve all the world's problems by gardening organically in your backyard, but by avoiding chemical fertilisers, at least you will be a part of the solution rather than a part of the problem. OH
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