Low Substrate Nitrogen Corrective Procedures
Brian E. Whipker, James L. Gibson, Paul V. Nelson, Todd
J. Cavins, and John M. Dole
Disclainer: Growers should read and follow all label
directions. Test the corrective procedure on a small number of plants
prior to applying it to the entire crop.
|The amount of fertilizer supplied is lower than the
crop's nutrient demand (crops are categorized as light, medium or
heavy feeders), or at a particular stage of development (high N demanding
crops can deplete substrate N levels, especially near bloom).
||1. Increase fertilization frequency (use more frequent
fertilization irrigations instead of clear water irrigations).
2. Increase fertilizer rate.
3. Avoid leaching the substrate with clear water irrigations.
4. Recheck the EC values to make sure they are within the acceptable
|Leaching too great.
||1. Avoid leaching the substrate with clear water irrigations.
2. Recheck the EC values to make sure they are within the acceptable
||1. Check the EC of the clear water and the fertilizer
solution. Fertilizer solution EC minus clear water EC = EC contribution
of the fertilizer. Compare this value with the tables on the fertilizer
bag to determine the fertilization rate being applied.
|Fertilizer mixing rate error and too little fertilizer
||1. Check if the amount of fertilizer used, the size
of the concentrate bucket, and the proportioner setting are correct.
|Slow release of N from slow release fertilizer is due
to low temperatures or use of wrong product (eg. 90 day release instead
of 30 day release).
||1. Avoid clear water irrigations to avoid leaching the
2. Provide supplemental fertilizer with a water soluble fertilizer.
|Don't forget to check out the Plant Root Zone Management
(PRZM) Manual for more information! Want to know more? Click
© Copyright NC State University, 2002
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