Potassium and sulfur management of alfalfa; Farmer-driven testing of management methods

2013 Annual Report for LNE11-307

Project Type: Research and Education
Funds awarded in 2011: $119,984.00
Projected End Date: 12/31/2015
Region: Northeast
State: New York
Project Leader:
Dr. Quirine Ketterings
Cornell University

Potassium and sulfur management of alfalfa; Farmer-driven testing of management methods


Over the past ten to fifteen years, sulfur (S) deposition rates have drastically decreased throughout the region and a yield response to S addition is now likely. In addition, although our agricultural soils, especially those with some clay, can supply large amounts of potassium (K), producers and agricultural advisors are reluctant to eliminate K use for large K consumers like alfalfa fearing reduced yield and/or winter kill but increases in fertilizer prices have people wondering about K needs for their crops.

This year we continued to evaluate the impact of K addition on forage quality, tissue K and S levels and stand composition at the Aurora Research Farm, the Valatie Research Farm and an on-farm location in western NY. All harvests were completed, soil samples were taken and analyzed, and data are being summarized.

At the Aurora site, a response to S was clearly visible (much darker colored alfalfa) while a yield response was documented where both S and K were applied. At other locations, no yield benefits were seen although tissue testing was clearly impacted by S addition.  Additional soil analyses are still ongoing and we are also waiting for the forage quality data.

Due to the drought in the summer of 2012, we had to postpone our statewide sampling to this year.

This year, a total of 23 farms (2 fields per farm) were sampled for tissue K and S, soil K and S, yield and forage quality. Initial summary tables are being put together and results will be shared with our stakeholders over the winter as summary tables are finalized. The large participation this year resulted in a statewide dataset that will be used as benchmarks for K and S management. Talks were given on sulfur management and on-farm research (and adaptive management, the term used by NRCS) as part of winter meetings for extension audiences consisting of consultants, extension educators, and farmers. Potassium fertilizer sales data are being documented as well.

Objectives/Performance Targets

Of the six participating farms, four will re-examine their K management and reduce production costs by $100/acre or more. Of the 25 farms that evaluate two alfalfa fields each in years 2 and 3, 15 will re-examine their fertility management, leading to K use reduction of 50 lbs K2O/acre (redistribution of manure, reduction of fertilizer use). Of 60-80 trainees in the on-farm workshops, a minimum of 10 will become actively involved in on-farm experimentation by year 4 of the project. And, of 300 farmers surveyed in year 4, 30% will express intentions to fine-tune K2O and S use in the next 1-3 years. This is expected to lead to a reduction of K use of 50 lbs K2O/acre on at least 25% of all alfalfa acres (taking into account some acreage will need more K than is currently supplied), resulting in an estimated total statewide cost savings of $3.4 million or more.


Milestone: (1) Five farmers and one research station, working with farm advisors and campus staff, will host on-farm trials (plus K, no K) on six fields per farm, in 4 replications per farm, for 2 years (for a total of 72 trials). Progress: We completed all field trials this year. The only measurements to take are those of 1st cutting in 2014, to complete the 2-year cycle for the latest trials.

Milestone: (2) In addition, 25 farmers will evaluate two fields per farm (farmer selected) for K, S and micronutrient status (years 2 and 3) using an effective combination of tissue and soil testing. Progress: In total 23 farms were sampled (two fields per farm, soil, tissue, forage). Data are being summarized and results will be shared with the participating farms and farm advisors, and with the larger extension and farming audiences next year.

Milestone: (3) In year 2-3, 60-80 farmers and farm advisors will be trained in on-farm research, through participation in four on-farm workshops, and have the tools to conduct on-farm testing. Progress: We expanded our on-farm research network, building on the knowledge we gained with the trial setup used for this project. The small-plot on-farm design worked amazingly well with our audiences, typically because the results, if there are differences, are very visible, causing greater interest in the work. Talks were given on conducting on-farm research at various meetings (including web-based deliveries). The photos of the S deficiences at the Aurora Research Farm were shared and used for discussion with extension audiences (impact beyond the project; expansion of our NY On-Farm Research Partnership).

Milestone: (4) Of all alfalfa growers, 60% will become aware of the existence and results of the project by year 4 (through work with consultants, extension and farmers and extension and popular press articles). Of these farmers, 300 will be surveyed (postcard survey) for intent to use project results to evaluate K management at home, in year 4 of the project. Progress: Many of our consultants and extension educators know about the project, and the collection of 43 fields for the 3rd cut assessment shows the interest in the project. We are currently working on the summaries for the on-farm sites as well as the tables that present the benchmarking values (3rd cutting).

Impacts and Contributions/Outcomes

Our biggest pride has been the growing number of people that are now engaged in on-farm research (this project and others that are now following), illustrating a growing willingness among farm advisors and farmers to be a partner in the on-farm research. Building on the succes of the past years, more than 44 on-farm trials were initiated using the same protocols, but then to evaluate N rates for winter cereals grown as double crop in the rotation. This is the way to move forward, gaining buyin and a critical mass for research at the same time. It also speeds up the implementation process. We initiated the NY ON-Farm Research Partnership several years ago, and continue to develop working relationships among the many collaborators while also trained them in on-farm research for impact beyond this project. Our two student interns this summer learned through interactions with consultants and extension educators as well. The experience of one of the students was documented in another impact statement: http://nmsp.cals.cornell.edu/publications/impactstatements/DiegoGris.pdf.


Dr. Jerry Cherney

Cornell University
503 Bradfield Hall
Crop and Soil Sciences Department
Ithaca, NY 14853
Office Phone: 6072550945
Website: http://www.forages.org
Karl Czymmek

Senior Extension Associate
PRODAIRY, Cornell University
328 Morrison Hall
Animal Science Department
Ithaca, NY 14853
Office Phone: 6072554890
Website: http://nmsp.cals.cornell.edu