Crop nutrients are elements which are essential in providing healthy and vigorous plants. They initiate all processes vital for crop development. Therefore, the plant needs nutrients throughout its growing cycle.
Plant nutrients are available in various forms and nutrient ratios. Among the various plant nutrients, whether based of organic or mineral composition, they all can be applied to crops in two ways, including:
- Granular application
- Foliar application.
Granular application of plant nutrients is the most widespread way of feeding the plants. Farmers use this fertilization type to apply nutrients before and during the seedbed preparation practices as well as for supplementary feeding. Granular fertilizers have many positive effects on plant growth, but sometimes they are not enough to provide healthy crop development. For that reason, farmers may apply crop nutrients by foliar application.
Since plants take in nutrients more efficiently through plant pores (stomata) on their leaves than through the root, foliar fertilization is a great way to rapidly boost plant growth.
Foliar nutrient sprays are often applied as mixtures, of plant nutrients with compatible adjuvants. Adjuvant acts as a sticker, thus preventing the leaking and washing off of spray solution from the plant.
When to Apply Nutrients by Foliar?
The need for foliar application of plant nutrients occurs when there is a lack of a particular nutrient in the soil or when plant roots are not able to absorb the required amounts of nutrients needed due to unfavorable conditions. Since plants are not able to tell us when they have the lack of nutrients, they have developed specific way to show us though. When the lack of nutrients happens, plants show visual symptoms and certain growth disorders including:
- Reduced height
- Reduced vegetative growth
- Leaf discoloration
- Reduced root growth.
Visual symptoms can often be confused with a pest attack or abiotic symptoms, such as drought, poor drainage, or soil salinity. However, a farmer needs to have a lot of experience and farm knowledge to be able to diagnose and manage correctly.
An additional and more expensive farm practice used to confirm the lack of nutrients is plant tissue and chemical soil analysis.
Foliar fertilization is a simple nutrient corrective technique used in crops during the growth cycle when soil application is ineffective, impossible, or expensive.
Prior to foliar nutrient application, certain environmental factors need to be considered such as:
- Relative humidity, since it affects the permeability of the plant surface
- Temperature, since it regulates the uptake of applied plant farm nutrients
- Light intensity
Advantages of Foliar Nutrient Application
Foliar fertilization is a method of direct nutrient application onto the plant leaves. The foliar spray may contain supplemental doses of macro- and micronutrients, plant hormones, stimulants, and other beneficial substances.
Plants show very positive effects with this type of fertilization. Those effects include:
- Higher resistance to diseases and insect pests
- Improved drought tolerance
- Improved soil salinity tolerance
- Higher resistance to physiological disorders
- Rapid utilization of applied nutrients and therefore rapid correction of observed deficiencies
- Being highly effective for the immobilized nutrients in the soils, such as iron
- Providing faster responses with applied crop nutrients, only 3-4 days required
- Better plant nutrient absorption at early crop growth stages, when plant roots are not well developed.
Consequently, the final result of the above-mentioned effects is increased crop yield and enhanced crop quality.
Disadvantages of Foliar Nutrient Application
Despite many positive effects, foliar application, as a good farm practice, can also have certain disadvantages. Therefore, farmers have to pay attention prior to using this type of fertilization. Otherwise, the following effects may occur:
- The foliar applied nutrients will have a reduced influence on plant growth, unlike soil applied.
- The wind is a major influence of the uniformity of distribution of the nutrient solution. Hence, on a windy day care should be taken to avoid spraying.
- The foliar application is most successful for micronutrients, whereas soil application is effective for both macro and micronutrients
- Plant response to the foliar application is often only temporary. In cases of severe nutrient deficiency, several foliar applications are needed.
Farm Practices to Get the Best Out of Foliar Fertilization
The effect of foliar application on the plant is dependent upon species, fertilizer form, concentration, and frequency of application, as well as the stage of plant growth. A common farm practice is to apply plant nutrients at specific plant growth stages, i.e. at vegetative (root development, shoot development) and generative stages (flowering, fruit setting, maturity).
Foliar fertilization is also used in plant recovery from transplant shock, hail damage, and other bad weather conditions which may affect the plant.
Foliar fertilization is an important farm practice important for management of sustainable and successful crop production. This is a desirable farm measure due to its positive effects on the entire crop production. It will not only increase the efficiency of plant nutrient uptake and reduce soil pollution but also maximize the crop yield and decrease the total cost of crop production.