Improving the yield and quality of sweet potatoes grown in New York

Improving the yield and quality of sweet potatoes grown in New York

Summary

Research results generated in 2011 by this SARE research grant resulted in more questions being raised about cultural practices for producing sweet potatoes in New York. We requested a no cost extension from SARE on this grant in order to try an answer these questions in 2012. In 2012 we completed a field experiment evaluating 6 different spacing/plant populations based on 2011 data and discussions with several other researchers and sweet potato growers. Our goal is to maximize root production while increasing the marketable roots within the 1 – 1.5 pound range and minimizing small and cull roots. Research results were also shared at a statewide conference in New York and one local meeting in Albany, NY. We also purchased and distributed sweet potato slips in the spring of 2012 to 10 different growers in the 11 county region served by the Cornell Cooperative Extension Capital District Vegetable and Small Fruit Program.

Objectives/Performance Targets

This project will increase the number of farms and acreage of sweet potatoes grown in New York and surrounding states. Eight farms currently growing 10 acres of sweet potatoes will improve stand establishment, root uniformity and marketable yield resulting in increased gross sales of sweet potatoes an average of $4,500/acre. Thirty additional farms which had never grown sweet potatoes will add 0.5 – 1.0 acres of sweet potatoes to their farming operations increasing their crop diversity. Upon completion of the project, a best management guide including cultural practices and a budget analysis will be made available to interested growers.

Accomplishments/Milestones

• On January 25, 2012, 75 growers attended a presentation at the New York State Fruit and Vegetable Expo Specialty Crops Session, summarizing the results of the first two years of sweet potato research generated by this grant. The presentation title was: “What we have learned about growing sweet potatoes”. This was a joint presentation given by Charles Bornt, Vegetable Specialist, Cornell University Cooperative Extension Capital District Vegetable and Small Fruit Program and one of our grant collaborators James Ballerstein of the NYS Agricultural Experiment Station, Geneva, NY.

• March 20, 2012, 22 growers attended the first Sweet Potato School in Voorheesville, NY. Presenters included Charles Bornt, Vegetable Specialist, Cornell University Cooperative Extension Capital District Vegetable and Small Fruit Program, Jonathan Schultheis, Production Specialist, North Carolina State University and Jack Osman Wellness Farm, Stewartstown, Pennsylvania. Growers learned more about the sweet potato industry and how slips are produced in North Carolina. They also learned more about different varieties, cultural practices and marketing outlets from sweet potato grower, Dr. Jack Osman in Pennsylvania.

• April 2, 2012 the first two years of results were posted on the CCE CDVSFP website and can be found under the sweet potato tab at the following url: http://cdvsfp.cce.cornell.edu/

• June – October, 2012: Samascott Orchards, Kinderhook, NY hosted the research trials for the 3 year. The research completed in 2012 compared 6 different spacing/plant populations. Results will be shared during the late winter of 2012 and spring of 2013.

• June – October 2012: Using funds from this grant, we purchased a thousand slips of five different varieties which were divided up into 50 slips each of 3 different varieties and given to 10 different growers. These growers were given verbal instructions of how to grow these slips and were asked to feedback on root quality and yields at the end of the season.

On-Farm Research Trials:

After completing plant spacing (populations) trials in 2011 and presenting this data at several meetings and both formal and informally talking with growers after these presentations, it was clear that growers were interested in this information and encouraged us to continue with this research. Taking these comments and recommendations, we requested a no cost extension on this grant. Our continued goal with this research is to produce the most uniform roots we can and maximize those roots that are within our “Large” grade category (between 1 -2 pounds).

Slips of the Beauregard variety were purchased from Scott Farms, Lucama, North Carolina and planted June 19, 2012 on raised beds with black plastic mulch and drip tape, spaced at 6.5 foot centers (meaning the distance from the center of one bed to the center of the next bed which is a typical spacing for most raised bed mulch uses) at Samascott Orchards, Kinderhook, NY. It is important to note that finished bed width or what was available for us to plant into on each bed was approximately 30 inches wide.

Treatments: Similar to 2011, we wanted to focus on evaluating the use of double staggered rows as compared to single rows at 6 different spacing’s. Treatments included double staggered rows planted 6, 12 or 18 inches apart (each row was planted in 8” from the edges of the bed) and single rows planted down the center of the bed at 6 or 15 inches. Plots were harvested September 10, 2012 and placed with the growers roots to be properly cured. Roots were then graded according to root size and quality on December 10, 2012. Grading size categories included Jumbo, (roots greater than 2.0 pounds), Large (roots between 1-2 pounds), small (greater than 0.25 pounds but less than 1.0 pound) and culls (included roots less than 0.25 pounds, less than 1 inch in diameter, misshapen, damaged etc.). These grading standards are the same as used by our host grower, Samascott Orchards.

Results: While double rows, planted 6 inches apart resulted in the highest overall yield, it also resulted in the highest weight of culls and small roots. Although these small roots are marketable, they are less desirable and often bring a lower price at market. Double rows at 18 inches resulted in the greatest weight of Jumbo roots and second highest weight of large roots while resulting in the second lowest weight of culls and third lowest weight of small roots. Double 12 inch spacing also resulted in highest weight of large roots, but nearly the same weight of small roots and the second highest weight of culls compared to the other treatments.

Taking into account the spacing results from 2011 and 2012 generated by this research grant, it would appear that using double rows and 18 inches apart should improve root uniformity and result in a higher number and weight of “Large” grade roots which is tends to be the more desirable size at most markets.

• 2012 Capital District Sweet Potato School
• 2012 Sweet Potato Research Results
• 2012 Empire Expo Presentation: “What we have learned about grwoing sweet potatoes”

Impacts and Contributions/Outcomes

• Out of the 10 growers that were given sweet potato slips mentioned in this report to try for the first time in 2012, 9 of them reported they were very pleased with the results and would consider growing them again in 2013. However, none of them gave any indication to the acreage they plan to grow in 2013.
• The one grower that indicated he would not grow them again had nothing to do with the root quality or yield, but due to the fact that they close their main market outlet in early October to focus on their U-Pick pumpkin and apple operation. This leaves them without an outlet for sweet potatoes and they were not interested in trying to sell them at their u-pick site.

• Of the 75 people attending the presentation at the NYS Empire Fruit and Vegetable Expo, 12 returned a short survey that was handed out. Of the 12:
o 8 indicated they would try double rows in 2012
o 5 reported they would try new varieties in 2012
o 1 reported using floating rowcovers in the past and 4 indicated they would try them but only for a limited time after planting and later in the fall before harvest
o These respondents reported their acreage from 2011 on the survey was 1,000 square feet to 1.5 acres: all respondents indicated they would increase that in 2012, but did not qualify how much
o All 12 respondents were using black plastic mulch; 8 were using raised beds in conjunction with plastic mulch
o Two respondents were using mechanical means to dig roots; 10 were digging by hand

Collaborators: