How to Choose the Right Pre-Plant Application (Base Dressing)
Fertilizers can be applied before planting the crop, during planting or during the development of the crop. Applying a certain amount of fertilizer planting or sowing, is often referred to as Pre-Plant fertilization (also known as Base Dressing).
Pre-Plant fertilization can bring the soil to a good nutrient level, before the crop is planted. To ensure high yield, growers need to make sure that they apply fertilizers at the right rate and at the right time.
Applying the required nutrients too soon might result in nutrient losses, fertilizer waste and even in damage to the crop due to salinity. On the other hand, if required nutrients are applied too late, the crop will not be able to reach its yield potential and deficiencies will occur.
ADVANTAGES AND RISKS OF PRE-PLANT FERTILIZER APPLICATION
- Enhance crop development – Pre-Plant fertilizer application can ensure that nutrients are available to the crop when it needs them, from the very beginning.
- Incorporate nutrients into the soil – Potassium and phosphorus are major nutrients that are not readily mobile in the soil. When applied after the crop is established these nutrients tend to remain in the upper layer of the soil and do not reach the active root zone. Nitrogen for example, applied as Urea tends to leach. So Pre-Plant fertilization allows to incorporate fertilizers into the soil and increase their availability to the crop.
- Relatively easy to apply – Since there are no plants in the field, equipment can be entered into the field without fearing of doing any damage to the plants.
- Risks related to nutrient losses – nutrient losses accuring after Pre-Plant fertilizer application can be the following:
- Leaching – Once a nutrient leach to below the active root zone, it is no longer available to the plant. Nutrients, and nitrate nitrogen (NO3) in particular, move down in the soil profile with water. Heavy precipitation events or application of large amounts of irrigation water result in leaching of nutrients to below the root zone. This might occur especially in light-texture soils.
- Run-off – Applied phosphorus might be lost with run-off if not incorporated properly into the soil.
- Volatilization of nitrogen as ammonium – when ammonia is appliedclose to soil surface, it will volatilize and not be available to the plants.
- Damage to seedlings and crop – Fertilizers are salts and as such, they increase the salinity of the soil.
- Application of high rates of fertilizers may affect the development of the crop. When applied incorrectly, Pre-Plant application might result in poor germination and injure seedlings.
- Increases the risk of environmental pollution – Nitrogen leached to ground water, or phosphorus washed by runoff are considered to be a major environmental problem.
- Might stimulate weed growth – Weed growth might increase the competitive conditions in the field.
WHICH NUTRIENTS CAN BE APPLIED WITH PRE-PLANT FERTILIZATION?
Pre-Plant fertilization should be based on soil testing. Soil testing helps you decide which nutrients to apply and what their application rates should be.
As different nutrients vary in their mobility in the soil, the application rate of each nutrient should be considered individually:
- Nitrogen in its nitrate form (NO3-) is very mobile in soil and tends to leach with irrigation or rain water to below the root zone. Pre-Plant fertilization of nitrogen increases the risk of nitrogen losses due to leaching and volatilization, before the crop can use it.
- Phosphorus is not mobile in the soil and remains at the place of application, unless surface runoff occurs. Therefore, it can be applied at relatively higher rates, sometimes even up to 100% of the crop requirement.
- The mobility of potassium in soil is intermediate – it is more mobile than phosphorus, but much less mobile than nitrogen.
The placement method can significantly affect the efficiency of the Pre-Plant fertilization.
There are various methods of fertilizer placement which are commonly used for Pre-Plant fertilization:
- Broadcast – Fertilizers are applied uniformly to the soil surface. Broadcasting can be followed by incorporation into the soil
- Banding – Fertilizer is applied in bands (strips), prior to planting/seeding, near to where the seeds or seedlings are about to be placed.
When deciding on the right placement method, there are a few initial considerations to take:
- Soil type – sandy soils can hold less nutrients than coarse-textured soils. Therefore, lower rates of Pre-Plant fertilization in such soils are recommended.
- Climate history and weather forecast – rainfall increases the risk of nitrogen leaching. Warm weather will increase risk of nitrogen volatilization.
Create an Optimal Pre-Plant Fertilizer Application plan with SMART
Pre-Plant fertilizer application is commonly misused due to guesswork which can results in decreased yields, fertilizer waste, damage to soils and groundwater contamination.
The proper use of Pre-Plant fertilization can be crucial for the development of the crop, and appropriate use of Pre-Plant fertilization methods can bring greater efficiency, better yields and save costs.
In today’s competitive market, growers cannot afford partial success and therefore, should not be content with guess work and estimation. SMART’s newest feature, recommends you the optimal Pre-Plant fertilizer rates, while taking into consideration the dynamic factors of your field.
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