The first of the 4Rs is to determine the Right Source of nutrients used for the crop system’s specific needs. Although it is also important to consider the other Rs of right rate, time, and place, there is good reason for source to be listed as the first R in the 4R program.
Selecting the right source ensures the fertilizer used matches the needs of the crop by applying plant-available nutrients or in a form that converts into a plant-available form while in the soil. The right source of nutrients can also balance the supply of plant essential nutrients, providing plants with nutrients available in the best form for absorption.
The physical and chemical properties of soil are also considered when selecting the right source of nutrients for a specific field. For example, applying the right source principle would lead to avoiding the application of nitrates on flooded soils and surface applications of urea on high pH soils. It is also important to recognize the synergistic interaction between some nutrient elements and sources such as the interaction between P and zinc and the increasing of P availability from N.
Another way to utilize nutrients from the right source is to acknowledge compatibility of nutrient sources when blended. Certain combinations of sources will attract moisture when mixed. This will lead to uniformity being limited when the blended material is applied. Granule size should also be uniform to avoid product segregation during application.
When producers apply the 4R principle of Right Source, nutrients are most beneficial to plants and are utilized to the fullest, leading to economic benefit. By improving utilization of nutrients by plants, yields increase and nutrient runoff decreases – a win/win situation.
Examples of how to utilize nutrients from the right source:
- Utilize nitrogen stabilizers for liquid and dry fertilizers
- Use phosphate efficiency enhancement additives to increase first season benefit of the fertilizer
- Use custom blend of ammoniacal nitrogen, liquid phosphorus and potash that are mixed with proven nitrogen inhibitors and stabilizers
- Apply minor elements based on soil and tissue test results
Sources:
https://nutrientstewardship.org/4r-pocket-guide/