Photo Credit: Joseph Weimer
Providing nutrients to plants when they are needed can make a major impact on the yield of a crop. There are four key principles to consider when ensuring nutrients are available at the right time
- Assess timing of plant uptake.
- Assess dynamics of soil nutrient supply.
- Recognize dynamics of soil nutrient loss.
- Evaluate logistics of field operations.
Assess timing of plant uptake
Matching the nutrients applied to plants with the demand of the seasonal crop requires taking into consideration factors such as planting date and nutrient demands of various growth stages. Targeting plant uptake demand is an important piece when determining the right time to apply nutrients.
Many crops have a slow early uptake, increase to maximum uptake during rapid growth, and decline as the plant matures. The rate of plant uptake of nutrients is not steady of the growing season and applying nutrients to match those needs can make an impressive difference. By targeting nutrient application at specific growth stages, the crop yield and/or quantity may benefit, specifically with the variable application of N.
Environmental impacts of nutrient loss from the soil are also reduced by timing the application of nutrients to match plant need.
Assess dynamics of soil nutrient supply
Soil organic matter can supply many necessary nutrients to a growing crop through mineralization. However, nutrient deficiencies are likely due to the timing of the crop’s uptake compared to the release of nutrients in organic matter.
Soil texture cannot be changed as it is determined by the percentages of sand, silt, and clay in a soil. However, other factors such as organic matter and improving soil health can benefit the soil’s nutrient supplying capacity as well as have an impact on timing options for the application of nutrients. By improving soil’s capacity to retain and supply nutrients to a crop throughout a growing season, there is a less likely possibility of there being a critical need for a specific nutrient.
Soil testing is beneficial for a baseline figure of what is needed for a growing crop, but it does not provide an absolute answer as to how the plant will respond to fertilizer applied. This is why application at the right time is vital to the success of a crop.
Assessing Dynamics of Soil Nutrient Loss
The loss of nutrients from soil are of great concern since this loss not has an impact on economic and environmental factors. Nitrogen and phosphorus tend to be the largest concerns. Surface runoff from fields, leaching of nitrate, and gaseous loss tend to be the primary reasons for N loss. The losses of P are generally less likely, but even small amounts of P can have a large impact on water quality. Surface runoff is the main source of P loss. Application of P below the surface can greatly decrease runoff.
The application of nutrients at the right time is of highest importance when utilizing soils with higher loss potential and/or location near environmentally sensitive areas. These situations would benefit from spring applied N with a side-dress application to reduce N loss.
Evaluating Logistics of Field Operations
Timing decisions can have multiple variables such as the logistics of obtaining fertilizer, field operations, and application equipment and/or services available. As farm sizes have increased, it is more important than ever to pinpoint timing and logistics of planting and fertilizer needs.
The use of slow-release and enhanced-efficiency fertilizer technologies can be of great assistance and provide more flexibility in applying nutrients at the right time. These products have become more economically viable as demand has increased as producers benefit from the flexibility and environmental concerns are decreased with their use.
4R Plant Nutrition – A Manual for Improving the Management of Plant Nutrition (North American Version). International Plant Nutrition Institute. 2016.