This component of The Four R’s is about selecting Right Source of nutrient to meet your crop’s needs. This principle applies to all nutrients, but this newsletter focuses on nitrogen (N).
Your N inputs might be naturally-derived, synthetic, granular, dry, liquid, gradual-release, the list goes on! Using the Right Source is about selecting the correct plant-available source(s) of N for your soil and crop.
What can happen when you do not have the right type of N source?
Poor N use efficiency:
- May be due to the N source not having the right form of N for that crop, or N not being plant-available at the time the crop needs it.
- Crop yield suffers and/or excess N becomes an environmental contaminant.
- Money is wasted on applying N that the crop is not using.
Imbalance with other nutrients:
- Some inputs have N at ratios that result in under- or over-application of other nutrients.
- One common example is many composts have low N relative to phosphorus (P). To meet crop needs for N using these composts alone, P ends up applied in excess and can result in problematic accumulation of soil P over time.
Decline in soil organic matter:
- Occurs if only granular or synthetic fertilizers are consistently used, with no other meaningful organic matter inputs.
- Soil organic matter decline can negatively impact soil health functions, including those that contribute to crop yield.
Salinity build-up:
- Some inputs have high salt content, and can result in salt accumulation in the soil if used exclusively/repeatedly under poor drainage conditions.
Some of the scenarios above can be a result of using the same type of input for too long, so it is worth noting: although one source of N input might be “right” most of the time, it might not be “right” forever and will need to be swapped out occasionally for another “right” source of N input.
What tools can farmers use to help determine the right N source(s) for them?
Nutrient management calculators:
- Once you know the total N needed for a given field (as discussed in last week’s Right Rate newsletter), you can start evaluating different N sources that will get you to that total.
- Check out this Nutrient Management Calculator, where you can try out different nutrient sources and rates to meet your crop N requirements.
- Pro-tip: Try out combinations of inputs – it is not uncommon to need more than one type of input to meet your crop’s nutrient needs.
Compost/Manure Tests:
- There are two options:
- Take the test yourself.
- Request the supplier to provide an analysis.
- Input the test results into an online calculator, like this Manure Nutrient Calculator to determine the amount of N you can expect to be plant-available this season-not all of it will be available in the first year after application.
Talk to your local agricultural supplier:
- Learn what products are available to you, at what specifications, and at what price points.
Are you thinking about changing your N source, but held back by operational limitations?
There are a few common limitations:
- Cost of alternative inputs.
- Cost of new equipment needed for alternative inputs.
- Cost of consultancy fees, to evaluate potential value in trying out a new N source.
The good news is that you may be eligible for cost-shared funding through the BC Climate Agri-Solutions Fund to overcome these limitations! Click here to learn more about how you can apply for cost-shared funding.
This resource is provided by E.S. Cropconsult.
