Crops need fertilizers to attain optimum growth and provide a good yield. This is because, as opposed to most natural ecosystems, the nutrients present in the soil of cultivated farms and lawns are not enough to support the proper growth of the constantly rotating plants. The addition of fertilizers in such type of soil ensures that the fundamental nutrients that plants require are readily present in the soil.
However, using too much fertilizer or using the wrong type of fertilizer may result in an exact opposite condition known as fertilizer burn. A plant cannot limit the intake of nutrients and when present in excess, the plant will intake more than what it needs and can use. This is reflected in several visible as well as invisible signs and symptoms of fertilizer burn, all of which lead to a reduction in yield. As a farmer or a gardener, it is absolutely vital to understand fertilizer burn; mainly its identification, the reasons behind its occurrence, and the ways to treat fertilizer burns.
What does fertilizer burn look like?
There are several ways in which the over-fertilized plants show signs and symptoms of fertilizer burn. Fertilizer burn has different appearances in different settings. In a grass lawn, the most common fertilizer burn appears in the form of patches of dead grass that have turned yellowish or brownish. This clearly demarcates the area of the field in which fertilizer has been added in excess. In a container plant, you may see the initial occurrence of fertilizer burn in the form of salt crusts over the soil. This will slowly cause the leaves and stem to change colors, rot, and die. In most plants, the leaves generally turn brown.
On a farm or a garden, you need to look out for wilting in plants, the discoloration of leaves, and also leaves being detached from the stem and falling on the ground.
Fertilizer-burn on plants
The symptoms of fertilizer burn mentioned above are very similar to conditions that generally occur in any problematic plant-like pesticide injuries. So, to easily identify over-fertilized plants as the cause, when it is actually the case, you need to have a proper record of the type and volume of fertilizer used in your plants and shouldn’t ignore other probable causes as well.
When you use an excessive amount of fertilizer on plants, initially the plants achieve high foliage growth, but blossoming will be significantly reduced. This is the sign of fertilizer burn in plants even before visible signs like discoloration and wilting occur. Moreover, the discoloration starts from the margin of the leaves and moves inwards. The foliage growth will now halt and the growth will be stunted. While all these are effects we can see, the main event is happening underground at the plant’s roots as fertilizer root-burn.
Fertilizer root-burn
If you pull your plants out of the ground and the roots are blackened or brown and limp, it can be caused by either excess water or excess fertilizer. If the soil water content is not higher, then it is most likely a case of fertilizer root burn. Fertilizer root burn occurs because when fertilizer is present in excess in the soil surrounding the root, the root cannot properly obtain water from the soil because of the lack of osmotic pressure.
Causes of fertilizer burn
The major cause of fertilizer burn is the excess use of fertilizer for your plants. However, there is more to it than what catches the eye. The effects of high fertilizer usage in your plants can be exacerbated when fertilization is not performed under appropriate conditions. Using even a slight excess amount of fertilizer can be serious when fertilization is carried out:
- to soil containing low moisture content
- on a high-temperature day or when plants are stressed due to excessive heat
- to leaves that are wet
- in the daytime when the sun is direct
- very near to the seeds on pits
Moreover, besides the conditions or methods of fertilizer application, there are other common reasons behind fertilizer burn:
Misjudged lawn area: Quite frequently, people tend to make errors while calculating the amount of fertilizer that their lawn or garden needs because they have already made a mistake while determining the area. Only include the area where fertilizer is intended to be used and not the whole area of the.
Using the wrong fertilizer combination: One of the most common reasons behind fertilizer burn is the lack of attention to detail when applying more than one fertilizer. If you apply two fertilizers that have a common compound, you could inadvertently take too much of the same compound which will result in fertilizer burn because of that specific compound.
While these are common actions or mistakes that may cause fertilizer burn in your plants, the science behind the occurrence of fertilizer burn due to excess fertilizer is quite simple as well. The key is the dehydration of plants. This is because most of the fertilizers are highly-soluble salts and when present in excess, they increase the osmotic pressure of the soils. In normal conditions, plants’ uptake of water is caused by the difference in osmotic pressure between the soil (low salt concentration) and roots (high salt concentration). As a result, the addition of excessive salts in the form of fertilizers reverses the flow of water and causes dehydration in plants resulting in wilting and yellowing of leaves.
How to treat over-fertilized plants
Fertilizer burn is a serious issue and it should be treated as soon as possible after proper diagnosis. Proper diagnosis is important because it is very easy to misjudge fertilizer burn with excess water or too little water or even pesticide and insecticide damage. Some of the ways to treat fertilizer-burn on plants are listed below:
Watering: Watering the over-fertilized plants serves two purposes. First of all, it helps to increase the amount of water available for roots fertilizer-burn has occurred due to dry soils. More importantly, water helps to treat fertilizer burn by a process known as leaching. Leaching is the downward flow of nutrients by the action of water. By water, the accumulated excess drugs can be leached down to lower soil horizons making the root-zone safe for the roots. However, it is important to make sure that waterlogging doesn’t occur which may further make the matters worse.
Manual removal: This method is applicable only in cases of container plants where the white crust of excess fertilizers that is formed over the soil can be manually removed which prevents it from further adding nutrients to the lower soil.
Removal of the affected plant part: Since there is little to no scope for the recovery of the affected leaves or other plant parts, they should be removed so that the rest of the plant can grow properly by making optimal use of the limited energy.
After stopping additional input of fertilizer into the soil and trying out each of the above-mentioned options, you now need to track the progress of your plants over the next few days and weeks depending on the severity. If the plants do not recover, and there is an extreme case of root rot as well as foliage damage, you may need to remove the entire plants and replant only after treating the bare soil with water or by using mechanical treatment. However, it is not recommended to use chemical methods of adding further chemicals to balance out the level of nutrients available in the soil, as you would do to deal with high or low pH soil. The most effective method is to flush out the excess nutrients by the use of water.
How to prevent fertilizer burn
As it goes without saying that prevention is always better than cure. So preventing fertilizer burn from occurring in the first place is the best option to optimize plants’ health as well as crop yield. Some of the ways of preventing fertilizer burn are as follows:
To state the obvious, the best way of dealing with fertilizer burn is to only use as much fertilizer as the plant needs. It is always a better option to use less than the required amount rather than greater in case of any confusion because you can always add more fertilizer if needed.
There are two ways to balance the amount of fertilizer that a plant gets over its growth period. First, you can divide the application of fertilizers into small amounts over equal periods instead of adding them all at once. Secondly, slow-release fertilizers are a great choice that adds nutrients to the soil gradually.
When applicable, liquid fertilizers must be preferred to solid ones because liquid fertilizers distribute evenly in the soil itself while solid particles require additional irrigation. Irrigate your soil adequately after fertilizing.
While organic fertilizers can also cause fertilizer burn in plants, the chances are significantly lower. So, composting and organic fertilizers can help prevent fertilizer burn.
The conditions of the soil and the environment while fertilizing should be optimum in the sense that droughts and dry soil should not be present. To control this you should take soil sampling.
Finally, since different species of plants require different levels of nutrients for optimum growth and yield, the type and amount of fertilizer should be properly tailored to the needs of your plants.
Fertilizer burn is a serious issue that can be mistaken for other issues like overwatering and excess nitrogen. So, a proper review of the signs and symptoms should be done for an accurate diagnosis. While it is primarily caused by the excessive use of fertilizers for your plants, there may be underlying causes to its severity. Also, fertilizer burn should be treated as soon as possible and nutrient leaching with the help of water is the best option to do so. Finally, whenever planting crops, gardening, or managing your lawn, fertilizer burn should be seriously considered and prevented by limiting the amount of fertilizer you will use.
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