Steps for an optimum fertilization
Source: INTA
It is important to develop precise methodologies when it comes to incorporate fertilizers in the wheat fields, because that will allow for optimized costs and returns, and all of this makes better business sense.
The specialists recommend an analysis of the soil to determine its fertility and requirements. We have to do this so that we may know the levels of phosphor and the soil’s capacity to return nitrogen.
Phosphor
- Apply to the sow, an adequate quantity of phosphor to achieve high efficiency levels. Depending on the available phosphor content and efficiency expected, correct the levels according to the next table.
- If soy is going to be sowed after the wheat, apply 30% more of phosphate fertilizer to increment the residuals and benefit considerably soy production.
- If you do not own a fertilizer machine, which is capable of applying fertilizer under and on the sides of de plant, apply phosphor manually. In this case, increase the amount by 30% to compensate the lost of efficiency. Do not apply more than 120Kg per hectare of phosphate.
- If the analysis would have recommended greater quantity, apply it pre-sowing.
Nitrogen
It is not convenient to apply all the nitrogen at once: during sowing, it could damage the germination and not all could be very efficient. For an optimum handling of nitrogen, the next steps are recommended:
- First, we need to determine the nitrogen requirement. Estimate the potential returns by the quintal and calculate how much nitrogen is needed in Kg/ per hectare by multiplying it by 12.
- Autumn’s rains are enough to assure, especially on early sowing, up to 100Kg per hectare of nitrogen. If rain would have been sparse, 50Kg per hectare is expectable.
- Apply between half and two thirds of what remains from last sowing. With this practice you can use, with no problems of potential damage to de seeds, whatever amounts of urea, ammoniac or UAN that you desire.
- If you have machines that can apply two types of fertilizers, separating the fertilizer from seeds line, you can also apply great quantities of urea, avoiding the pre-sowing application.
- The second step is to verify the hydro state and the population of plants so that you can determine the amount of nitrogen to be added, in between 20 to 30 days from the emergency. This should be enough to cover at least two thirds of the total, not inferior to 25Kg per hectare of nitrogen.
- If you decide to apply part of it to the plants, consider the use of nitrogen sources more efficient then urea, like the common nitrate of ammonia or calcareous, incorporated UAN, sulfate or sulfur nitrate of ammonia, if the necessity of sulfur should have been diagnose.
- On manual applications, you have to make sure to regulate the traffic of the machines so to avoid the irregular spay of nitrogen, because that would result in less efficient use of it and less returns.
- The third possible moment is the one before the piping, about 60 days after the emergency. In case a of a sure previous fertilization and if a good perspective of returns or prices is expected, a complementary application of at least 20Kg per hectare of nitrogen is possible.
- Finally and diminishing the possibility of illnesses attacks, an application of urea or ammonia nitrate, together with the fungicide can be use. This is specifically done to increment the percentage of proteins in the grains.
Sulfur
Recent studies indicate that close to half of all northern wheat fields respond to sulfur. To cover part of the nitrogen requirements with sulfate or sulfur nitrate, replacing the urea can be worth it on correctly diagnose cases, like zones with potentially high performance and low levels of sulfur or organic material.
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