Skip to Main Content
Bookmark and Share print small medium large 

HOME / FACTSHEETS / SOIL & FEED TESTING LAB /


Micronutrient Supplements in Potato Fertilizers

Micronutrients Supplements in Potato Fertilizers
Agdex #: 161/540
Author:
History: Revised February 3, 2000
Introduction:
In the process of maximizing yield and quality, potato growers must re-examine every aspect of their production management system, including their fertility program. One aspect of potato fertility is the need for micronutrients.
Traditionally, potato producers in Prince Edward Island have assumed that their crops will receive an adequate supply of micronutrients; either from natural reserves in the soil or as by-products from other materials applied to the land (for example: in fertilizers, manures, limestone, or spray materials). It is important to recognize a crop' s need for micronutrients, either as additives in fertilizers or as foliar sprays.
The Need For Micronutrients:
Survey studies and research conducted in Prince Edward Island during the period 1979-1985 has indicated that a response to applied micronutrients on potatoes can seldom be expected. However, when a micronutrient problem is noted, the elements which are most often deficient are copper, zinc, or boron. Iron and manganese are naturally plentiful in our acidic podzol soils and almost never approach the deficiency level.
The soils which most frequently show micronutrient deficiencies are those which have been heavily cropped and are physically degraded and eroded; whereas those which have received good rotational practices and which have good fertility levels and physical structure seldom are deficient in micronutrients.
The best way to predict soil micronutrient deficiencies is by soil testing. This is often routinely done in the Central and Mid-Western States and Provinces where soil and climate conditions are more predictable than those in Prince Edward Island. Unfortunately, soil tests for most micronutrients appear to be of limited value in predicting micronutrients deficiencies in the Atlantic Provinces. The most reliable method of assessing micronutrient sufficiency/deficiency is by plant tissue analysis.
Recommendations:
At present, there appears to be little justification for widespread use of micronutrient supplements in fertilizers, except in cases where soils have been overcropped and degraded. If a grower wishes to add micronutrients, no harm should occur and it can serve as "insurance" against potential deficiencies. It should be noted, however, that this insurance can cost $40-$60 per hectare and the probability that the potential benefits will justify the cost is questionable in most cases.
 
Specific points to consider include:
  • Add micronutrient supplements to fertilizers only if fields have been heavily cropped or have had micronutrient deficiencies confirmed by plant tissue analysis in previous years.
  • Supplement fertilizers only with micronutrients known to be deficient in our soils (for example: Cu, Zn or B).
  • Add micronutrients to fertilizers only at recommended rates. Just because a little is good, it doesn't mean a lot is better. Toxicities can easily occur with some micronutrients.
  • Monitor the micronutrient status of fields each year by plant tissue analysis. If deficiencies are found, they can be corrected that year by foliar application of nutrients. In any case, the confirmation of deficiencies can be useful for subsequent crop years.
For more details and general information, contact:
Soil & Feed Laboratory at (902) 368-5628
or your District Agricultural Office.
 
back to top