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

This project continues to find ways to improve the overall quality and yield of sweet potatoes grown in New York. The expanding market for diverse products for an increasing number of farmer’s markets in the area and the reported health benefits of sweet potatoes makes them ideal for this area. However, many growers do not believe they can grow a good quality sweet potato crop in our climate.

In February 2011, information generated from the first year of research was presented to 110 growers attending the Capital District Vegetable and Small Fruit Winter Growers Meeting held in Albany, NY. In the summer of 2011, we completed 3 more research projects including evaluating the use of floating rowcovers, Infrared Transmitting (IRT) Plastic versus traditional black, plant spacing and population study and using transplants compared to the standard slips commonly used. This data and the previous year’s data including additional information from project cooperator Jim Ballerstein of the New York State Agricultural Experiment Station located in Geneva, NY, will be presented in late January 2012 at the New York State Fruit and Vegetable Expo. A half-day meeting focused solely on sweet potatoes is planned for mid March of 2012.

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

• Two grower cooperators were identified in the winter of 2010 to conduct field research including the use of transplants versus slips, floating rowcovers and infrared transmitting mulches and plant population trials.

• In January 2011, 23 growers attended a meeting evaluating the use of crops that could be grown and stored for winter markets. A short presentation was given to the group on sweet potato production and information on variety selection and research from planting studies was discussed.

• February 2011, 110 vegetable growers attended the Capital District Vegetable and Small Fruit Growers Winter Meeting in which a presentation was given of the first year research results. In addition, samples of the varieties grown in the 2010 on-farm research trials supported by this SARE grant were available for growers to look at and discuss with project researchers during the conference.

• In the spring of 2011, an article entitled “Sweet Potatoes: What we have learned so far”, was included in the Capital District Weekly Update in which over 250 growers subscribe to. The article provided growers with detailed information about variety selection, plastic mulch recommendations and spacing options for different plant populations. This information resulted in 16 phone calls from growers around the region asking for more information based on the article.

In 2011, two grower cooperators were asked and agreed to host several different sweet potato research trials. Unfortunately, slips that were ordered from Scott Farms located in North Carolina, in December for mid May delivery were never received. Upon calling the company to find out what had happened, I was told that my order had been delayed and that there was a good chance it would not be shipped due to a shortage of slips in the major sweet potato production areas due to widespread flooding of already planted sweet potato crops. This resulted in a major shortage of slips for growers throughout the Northeast as southern growers purchased a majority of the slips produced for replanting. Fortunately, we did receive our slips, but later than we would have like to receive them but unfortunately not enough for two on-farm trials. Therefore, the field trials were conducted only at Samascott Orchards in Kinderhook, NY.

On-Farm Research Trials:
Infrared transmitting mulch (IRT) vs. standard black embossed plastic mulch with or without floating rowcovers. Sweet potato slips of the variety Covington were planted on June 10, 2011 in raised beds mulched with either IRT or black plastic mulch. Each plot consisted of 2 rows of IRT and 2 rows of black mulch. Floating rowcovers (DuPont 5131) were applied to half of the plots, while the other half were left uncovered. Black mulch without floating rowcovers resulted in the highest marketable root harvest. Plots in which floating rowcovers were applied always resulted in the lowest marketable root weight.

Slip Plant Spacing Trial: Slips of the variety Covington were planted on June 7, 2011 into black plastic raised beds with drip irrigation. Treatments consisted of slips planted in different spacing configurations including: single row down the center of the bed, 6” or 12” apart or a double staggered row of plants placed 8” from the edges of the bed at 12” or 18”. Results were mixed in this trial as the highest marketable yields were a result of a double staggered row 12” apart. However, these roots were mostly in the “Small” category while the single row, 6” spacing resulted in the highest yield of sweet potato roots in the “Large” category followed by the double row, 18” spacing. The single row, 12” spacing resulted in the highest marketable “Jumbo” roots, but the lowest “Large” roots.

Transplants spacing vs. Conventional slips: On June 7, 2011 sweet potato slips of the variety Covington were planted in 50 cell transplant flats at Samascott Orchards. These transplants were then planted in the field on June 24, 2011 into black plastic mulch with drip tape. Treatments consisted of transplants planted in different spacing configurations including: single row down the center of the bed, 6” or 12” apart or a double staggered row of plants placed 8” from the edges of the bed at 12” or 18”.

As a control, slips delivered two days before this trial was planted were planted in a single row down the center of the bed 12” apart. The results of this trial were interesting with transplants in a double staggered row 18” apart resulting in the total highest marketable root yields and also the highest “Large” category (roots that are 1 pound or more, but less than 2 pounds) numbers and total yield. However, no treatments provided any “Jumbo” roots (roots that are over 2 pounds). One objective of using transplants was to try and maximize the number of “Large” roots as that tends to be what growers are looking for. However, the extra management and cost of producing transplants may be greater than the returns in the number of large roots.

Impacts and Contributions/Outcomes

One of the most significant impacts reported by growers was the changing of varieties they are using due to results from research and information provided by this SARE grant. In particular the variety Covington has become one of the most rapid varieties being grown by growers in New York.

Secondly, 5 growers in attendance of one of the meeting mentioned above, who had never grown sweet potatoes or had grown them in the past without much success had indicated they would try them again in 2011.

Samascott Orchards where this research project was conducted have indicated they will try 3 out of their 6 acres of sweet potatoes on double rows, 18” apart. This change was due to the results of this research trial.

Collaborators: