Use in Potatoes

Every type of nitrogen fertilizer is applied and handled differently. These general use recommendations for ESN are based on optimal growing conditions. Your specific conditions and goals should be considered to achieve best results. Always ask your retailer for recommendations​.

 

Proper nitrogen (N) nutrition of potatoes is essential to high yields, optimum crop quality, and maximum profitability. Nitrogen is essential for vegetative growth and protein synthesis. Nitrogen is essential to the photosynthetic factory that converts solar energy to carbohydrates that are stored in the tuber. Potatoes require high N rates, but N timing is a critical factor in potato yield and quality. Potato N need is closely synchronized with specific growth stages. Five general stages are commonly used to describe potato growth and development. The growth stages are: I) sprout development, II) vegetative growth, III) tuber initiation, IV) tuber bulking, and V) maturation. Sufficient N is needed in the initial stages to stimulate leaf growth, but too much N early can cause excessive vegetative growth and delay tuber initiation. Potatoes take up little N in the first month after planting (Growth Stage I), but take up about 60-80% of the total N needs during tuber initiation and tuber bulking (Stages III & IV) when most of the total dry matter is accumulated. Nitrogen uptake is nearly complete by the end of Stage IV. Timing of specific growth stages is approximate and varies with variety and environmental conditions.

ESN can improve the profitability of potato production by supplying the right amount of N at the right time. ESN is designed to release the bulk of its N during the period of greatest crop demand. Controlled N release simplifies N management by replacing the common practice of multiple N applications with one simple application.

 

Nitrogen and Potato Production

Nitrogen management in potato production presents numerous challenges. Most potatoes are grown on sandy soils under irrigation or in humid regions where rainfall is supplemented by irrigation. In addition to delaying tuber initiation, excess N early in the season is prone to greater losses because of limited plant uptake and greater potential for excess precipitation. ESN is a tool that can help overcome these losses if used properly. ESN increases N-use efficiency by protecting most of the N from loss until the period of rapid crop uptake.

Interactions of weather, timing of N demand, and potential for N loss should be considered in determining the most appropriate ESN application. The following recommendations are the result of field-testing in key potato-producing areas. Actual results may vary depending on weather and soil conditions.

 

Canadian Prairies and Upper Northern U.S. Tier States
ESN Application Timing

Potato production is optimized when N supply is maintained at the proper level for each growth stage. This is traditionally accomplished with multiple side-dress applications and/or fertigation. ESN is designed to provide a steady, season-long N supply with a single application when used appropriately.

Studies in this geography indicate ESN usually provides the greatest benefit when applied at planting. Research has shown one-time ESN application at planting can produce greater yields and quality than traditional multiple side-dress or fertigation applications.

 

Application Rates

ESN is generally recommended at rates similar to conventional N fertilizers. When applied at normal recommended rates, increased N efficiency with ESN usually increases yields. ESN can produce yields similar to conventional N fertilizers at lower rates than conventional fertilizers. However, economic analysis usually indicates greater profitability from increased yields at recommended rates than maintaining yields at reduced N rates. Where N efficiency does not limit yields, ESN may provide greater advantage by maintaining yields with reduced N rates.

Under conditions where conventional fertilizers are applied at higher-than-recommended rates to compensate for N losses, lower rates of ESN may be superior because of ESN’s ability to reduce N losses and supply what the crop needs when it is needed. Local field testing should be used to fine-tune ESN programs.

 

Placement

ESN may be broadcast and incorporated or banded.

Incorporation insures consistent contact with soil moisture for the most predictable release. ESN may be banded in or near the row with a greater margin of safety than conventional N fertilizers. The ESN coating reduces the exposure of the seed and seedling to potential salt and ammonia damage.

 

Pacific Northwest (Oregon, Washington)

General Conditions:

  • Arid, intermountain basins
  • Potatoes grown under irrigation
  • 150-180 day growing season
  • Yields 700-1000 cwt/acre (35-50 tons/acre)

Common N Management Practices: 

  • 25-50% of N pre-plant + banded at planting
  • remainder as fertigation based on petiole and/or soil tests

Recommended ESN use:

Full-season, indeterminate varieties (ie Russet Burbank)
Apply 70-100% of N requirement as ESN at emergence.  For very long growing seasons, ESN’s release timing may require some mid- to late-season supplementation.  Monitor crop for potential N needs and fertigate as needed.  Applying all N from any N source at planting may result in excessive early N supply, delayed tuber initiation, and reduced yields. 

 Short-season determinate varieties (ie. Norkotah, Shepody)
Apply 80-100% of N requirement as ESN at planting.  For most situations, additional in-season N should not be needed, but, as always, crop should be monitored for proper N nutrition.   

 

Mountain States and Central Great Plains (Idaho, Utah, Wyoming, Colorado, Nebraska)

General Conditions:

  • Arid to semi-arid intermountain basins and river valleys
  • Potatoes grown under irrigation
  • 130-150 day growing season
  • Yields 300-700 cwt/acre (15-35 tons/acre)

Common N Management Practices: 

  • 25-50% of N pre-plant + banded at planting
  • side-dress at emergence/hilling
  • remainder as fertigation or side-dress based on petiole and/or soil tests

Recommended ESN use:

Full-season, indeterminate varieties (ie Russet Burbank)

Best results have been observed by applying 80-100% of the N requirement as ESN at emergence.  Research indicates applying 80-100% of the crop N need as ESN at emergence can replace conventional multiple side-dress/fertigation applications.  Applying 80-100% of recommended N as ESN at planting has often been as good as conventional programs, but generally not as good as applying ESN at emergence. Excessive early N from any N source can result in excessive vegetative growth, delayed tuber initiation, lower yields and greater potential for N loss. 

Alternatively, apply 70-80% of recommended total N rate as ESN at emergence, monitor the crop for potential supplemental N needs, and side-dress or fertigate as needed.  Research indicates 70-80% of total N as ESN at emergence is often sufficient for the entire growing season with no supplemental N application needed.     

Short-season determinate varieties (ie. Norkotah, Shepody)

Apply 80-100% of N requirement as ESN at planting.  For most situations, additional in-season N should not be needed, but, as always, crop should be monitored for proper N nutrition.

 

Northwest Great Plains and Western Canada (Montana, British Columbia, Alberta, Saskatchewan)

General Conditions:

  • Arid to semi-arid intermountain basins and river valleys
  • Most potatoes grown under irrigation, some dryland production
  • 120-130 day growing season
  • Yields 300-500 cwt/acre (15-25 tons/acre)

Common N Management Practices: 

  • 40-60% of N pre-plant + banded at planting
  • Side-dress at emergence/hilling
  • Remainder as fertigation or side-dress based on petiole and/or soil tests

Recommended ESN use:

Full-season, indeterminate varieties (ie Russet Burbank)

Apply 80-100% of N requirement as ESN at planting.  Research indicates applying 80-100% of the crop N need as ESN can replace conventional multiple side-dress/fertigation applications. 

Alternatively, apply 70-80% of recommended total N rate as ESN at planting, monitor the crop for potential supplemental N needs, and side-dress or fertigate as needed.  Research indicates 70-80% of total N as ESN at planting is often sufficient for the entire growing season with no supplemental N application needed.     

Short-season determinate varieties (ie. Norkotah)

Apply 80-100% of N requirement at planting as a blend supplying 50-60% of the recommended N as ESN at planting.  For most situations, additional in-season N should not be needed, but, as always, crop should be monitored for proper N nutrition. 

 

North Central US and Central Canada (Wisconsin, Minnesota, No. Dakota, So. Dakota, Manitoba*, Western Ontario)

General Conditions:

  • Humid, high rainfall
  • Most potatoes grown under irrigation; some dryland production
  • 130-150 day growing season
  • Yields 300-700 cwt/acre (15-35 tons/acre)

Common N Management Practices: 

  • 10-20% of the N banded @ planting in the southern and higher rainfall areas of the region; some areas 40-60% of needed N pre-plant and/or at planting
  • Sidedress application at emergence/hilling (40-50%)
  • Remainder as a second sidedress or as fertigation based on petiole analysis and soil tests (5 to 8 applications)

*Manitoba production systems often fall between those of this region, and those of the "Northwest Great Plains and Western Canada”

 

Recommended ESN use:

Full-season, indeterminate varieties (ie Russet Burbank)

Best results have been observed by applying 80-100% of the N requirement as ESN at emergence.  Research indicates applying 80-100% of the crop N need as ESN at emergence can replace conventional multiple side-dress/fertigation applications.  Applying 80-100% of recommended N as ESN at planting has often been as good as conventional programs, but generally not as good as applying ESN at emergence. Excessive early N from any N source can result in excessive vegetative growth, delayed tuber initiation, lower yields and greater potential for N loss. 

Alternatively, apply 70-80% of recommended total N rate as ESN at emergence, monitor the crop for potential supplemental N needs, and side-dress or fertigate as needed.  Research indicates 70-80% of total N as ESN at emergence is often sufficient for the entire growing season with no supplemental N application needed. 

For shorter growing seasons and varieties less sensitive to excess early N supply, ESN may be applied at planting.      

Short-season determinate varieties (ie. Norkotah, Shepody)

Apply 80-100% of N requirement as ESN at planting.  For most situations, additional in-season N should not be needed, but, as always, crop should be monitored for proper N nutrition.  For shorter growing seasons, apply 80-100% of recommended N as a blend with 50-60% of the total N as ESN.

 

Northeast US and Eastern Canada (Michigan, New York, Pennsylvania, Mid-Atlantic States, New England, Eastern Ontario, Quebec, Maritime Provinces)

General Conditions:

  • Humid, high rainfall
  • Almost all dryland/rainfed production
  • 120-140 day growing season
  • Yields 300-500 cwt/acre (15-25 tons/acre)

Common N Management Practices: 

  • 100% of the N banded at planting or split between preplant and hilling
  • Foliar N based on petiole analysis

Recommended ESN use:

Full-season, indeterminate varieties (ie Russet Burbank)

Best results have been observed by applying 80-100% of the N requirement as ESN at emergence.  Research indicates applying 80-100% of the crop N need as ESN at emergence can replace conventional multiple side-dress/fertigation applications.  Applying 80-100% of recommended N as ESN at planting has often been as good as conventional programs, but generally not as good as applying ESN at emergence. Excessive early N from any N source can result in excessive vegetative growth, delayed tuber initiation, lower yields and greater potential for N loss.  

Alternatively, apply 70-80% of recommended total N rate as ESN at emergence, monitor the crop for potential supplemental N needs, and side-dress or fertigate as needed.  Research indicates 70-80% of total N as ESN at emergence is often sufficient for the entire growing season with no supplemental N application needed. 

For shorter growing seasons and varieties less sensitive to excess early N supply, ESN may be applied at planting.     

Short-season determinate varieties (ie. Norkotah, Shepody)

Apply 80-100% of N requirement as ESN at planting.  For most situations, additional in-season N should not be needed, but, as always, crop should be monitored for proper N nutrition.  For shorter growing seasons, apply 80-100% of recommended N as a blend with 50-60% of the total N as ESN.

Other Areas

Consult your ESN representative for recommendations in this region.