How Can Variable Rate Fertility Benefit Your Farm?

Many of our growers are already experiencing the benefits of VR fertility, however some have yet to be convinced. A description of the process may help clarify how this practice can be beneficial. First, electrical conductivity and topography/elevation data are collected across the field. Electrical conductivity is used to estimate soil properties such as clay content, salinity, and water holding capacity. These field characteristics impact crop production in a predictable way and so their variability is used to identify management zones.

Management zones can be used for many different applications, however fertility is common.

Soil samples are utilized to determine background nutrient levels and confirm influential soil characteristics in each zone. Fertility recommendations are made separately for each management zone based on the soil data and predicted yield potential, and are used to create prescription maps. Rates can be varied separately for different nutrients, depending on the products used and seeder set up.

The goal may not be to reduce fertilizer use overall, but to reallocate to areas where it would be more beneficial. For example, zones with lower yield potential such as saline areas and dry hilltops, or areas with nutrient accumulation (depressions) may receive lower rates while areas with consistent productivity would receive higher rates. You are reducing risk by allocating inputs to parts of the field where they are more likely to pay off.