How the use of chemical fertilizers can be harmful?

Question

How the use of chemical fertilizers can be harmful?

Answer 1

well if you have a look on a label of a bag of inorganic (refined) fertiliser it shows all your nutrients that are in the bag. these include the nutrients and also some waste heavy metals are added for their disposal. the most common ones being lead and cadmium. these heavy metals are present in very small amounts and they are spread in fertilisers to evenly dispose of them at low levels. I don't like it, if they didn't put these heavy metals into fertiliser, fertilisers would have no bad points - in reference to health.

Answer 2

All previous answers look good...

A further point.  Inorganic fertilisers generally take large amounts of energy to produce (and transport), and that comes in the main from fossil fuels.

Those fossil fuels release carbon dioxide into the atmosphere.  Although that CO2 is usually a long way from the farm or garden, it is still a harm being done to the environment by the use of chemical fertilisers.

This really applies even if the chemicals are waste products of other processes -- their sale as fertilisers subsidises the other processes.

It is ironic that we use vast amounts of energy to make fertilisers and often pollute natural habitats with them by over-use -- while at the same time throwing vast amounts of natural fertilisers from human waste down the sewer, and either destroying them, or polluting natural habitats with those too!  And we call ourselves intelligent...

Another effect not mentioned is where fertilisers are used on natural vegetation, such as natural grassland.  In every natural habitat some plants are able to use fertiliser more effectively than others, and these grow vigorously, choking the others.  Many of the more sensitive and valuable wild plants are adapted to very low levels of nutrients, and cannot use high levels.  This means that fertilisers can disturb the natural balance, and so destroy or badly damage the natural habitat.

For example, here in the UK, ancient, species-rich grassland habitats often have a plant called cowslip (Primula veris), which is found only in such habitats.  Farmers fertilise these grasslands to get more grass -- but only one or two applications of fertiliser at quite low levels will remove the cowslips altogether, leaving lush but species-poor grassland.  Good cowslip fields used to be common, but almost all have been destroyed over the last few decades through inorganic fertiliser use (as well as through other industrial agricultural processes).

Answer 3

One of the big general agricultural problems is the shortcutting to get a big harvest. Many years back when studying plants with respect to growing a crop it was discovered over a period of time that plants had nutritional needs to be met in order to grow well and produce. Given that a (food) plant grew, why did it and what did it need? Well we found out, and discovered that those simple things, nitrogen compounds, potassium, and phosphorus (and then the many micro nutrients over time as well as soil pH) where simple chemical additives, cheap and often found as byproducts of other industries. Added to the soil they really got plants growing and now we have huge yields. So a lot of time and effort ended up going into this industry, fertilizer was born. Well that is just a paraphrase for what went on and not quite correct, but in the end we short cut on nature and it took a whole lot of years before we had a better understanding of what we were really doing.

By adding chemicals to the soil we make our own soil solution. Back up a second and look at plants. The niche they fill in their environment is that they live in the soil which is a collection of rotting, decaying, organic material (in many stages of decomposition), sand, clay (stone products from the weathering of the base rock material of the area), animal f***s and bodies, etc. This soil niche is shared by bugs and worms, bacteria, fungus, animals, etc. Suffice to say it is complicated. And with that it gets rained on and snowed on. And for millions of years this has all worked together to make what is soil. When it gets wet, this liquid, the "soil solution" is what a plant gets it's nutrients from. And it's gases too, as it's roots need oxygen just like it's leaves do.

When you shortcut the whole process and just add chemicals to make your own soil solution it grows nice plants but the soil suffers. The bacteria and fungus die and/ or get out of balance and the larger organisms meet the same fate. Chemicals are usually used in conjunction with plowing, and the two together destroys the soil consistency. The micro-pores and macro-pores then must be plowed into the soil or the texture of that soil will not allow gases to go in and out to support the roots. Even the use of organic materials need to be monitored to keep from hurting a delicate balance that has been built over millions of years, a balance that the basic genetics of plants has come to demand for their survival. The problems can be seen looking back now on history. With the Dust Bowl Years, a lot of people went hungry. The problem was the agricultural practice of the plow and the chemicals, and when nature dried the area up (low rainfall) and the wind kicked in, the land blew away. And this problem still happens here and there, with creeping deserts, and such.

Agriculture abused still dogs us in many forms and I could write a book about it (noooooo, not another book about farms gone bad), but that is a long winded answer to your question.

Answer 4

Used correctly, “store bought fertilizer” isn’t harmful aside from the heavy metals which were placed into the fertilizer. Most states have or in the process of making heavy metals-etc to be mixed into the fertilizer.  

Used incorrectly,  fertilizer will leach into waterways and fertilize unwanted undesirable aquatic plants. Algae, etc is a huge challenge in many areas, robs the water of it’s oxygen which is harmful to fish.  Over use will kill a plant as good as or better than soil steriliants, effectively killing everything including the soil.  The same can be said for organic matter, too much and under the right conditions organic fertilizer will also leach or migrate into the water, causing much the same effect as commercial fertilizers. There is the additional hazard of harmful organisms also leaching with the organic fertilizer.  

As was pointed out commercial fertilizers don’t “add” any tilth (organic matter) to the soil, however organic matter is VERY VERY LOW in actual plant nutrient value. Organic matter is good as soil actually needs air pockets in between the soil particles to be a healthy soil. Very heavy clay soils are not the best growing soils as there are no air pockets between the soil particles so the plant roots starve for oxygen.

BMP is a “mix” of both organic and commercial,, one for soil health and one for plant health

Answer 5

The main disadvantage is that they add no nutrients to the soil, only a quick fix for the plant.  When using organic fertilizers they break down and increase the health, texture, and fertility of the soil.

Answer 6

I think some of the other answers missed the point of your question.  I'll try to give you several short answers.

1)  You can apply too much -- more than the plants need and more than can be retained by the soil.  This excessive fertilizer can be moved off site by both surface water and ground water.

2)  At certain stages of a crop (using cotton for example) if you apply nitrogen fertilizer, it will cause the cotton plant to try to keep growing and putting on new bolls rather than shutting down and maturing the bolls already on the plant.  This can lead to late season insect problems, late maturity of the crop that affects harvestability and quality.

3)  Use of a chemical fertilizer when none is needed can cost unnecessary dollars to the farmer.

4)  Some chemical fertilizer is made from natural gas.  This leads to an additional use of a limited resource.

Answer 7

Chemical fertilizer and store bought fertilizer are NOT the same thing, despite so many answers assuming this.

Organic fertilizer, despite a previous answer, has LOTS of nutrients.  Organic fertilizer covers blood meal, bone meal, composted road kill, cow (or other animal) manure...  Any fertilizer derived from an animal or plant is organic (not organic as in all natural but organic as in having an organism as it's component part).

So, chemical fertilizer is a fertilizer which is Only the nutrients and the phosphorous and other growth enhancers, generally put together in a lab, which doesn't originate from plants or animals.

It can be a liquid, a foam, or pellet solids.  But, it doesn't add anything to the soil.  The fertilizer itself doesn't bond to the soil and what isn't used immediately by the plants is washed away.  This concentrated wash off from chemical fertilizers is dangerous and deadly to aquatic life.

One of the Main problems with chemical fertilizers is the phosphates.  Phosphates are needed for good plant growth, but, if these phosphates get into water they create a terrible over growth of algae (phosphates make for good plant growth).  This algae bloom can disrupt the entire aquatic ecosystem.

So, basically, chemical fertilizers contribute to soil errosion (the same problem that caused the dust bowl) because they encourage the over use of land without adding anything to help bind the soil and chemical fertilizers damage aquatic ecosystems.