- Vegetables: tomatoes
- Production Systems: general crop production
[Editor’s note. Open the attachments to see the following appendices. Appendix A, Initial Soil Tests; Appendix B, Data Collection Form; Appendix C, Combined Results; and K-State Averages.]
This project was initiated as a result of a discussion initiated by Ted Carey, then Horticulture Research and Extension specialist at Kansas State University. Five farms, all certified organic growers of fruits and vegetables and all interested in production of crops in high tunnel hoop houses, were drawn together to investigate some of the challenges in organic production in high tunnels. These market farms are located in the greater Kansas City metropolitan area and represent a range of sizes as well as marketing strategies. Sandheron Farm and Hoyland Farm are both located in Jefferson County, Kansas and both grow vegetables and fruit for Rolling Prairie Farmers Alliance CSA. The former is smaller and newer, farming only 3-4 acres of bottom land surrounded by hills on the 30 acre farm. Hoyland Farm has been in operation since 1976, consists of 69 acres (not all in vegetables), and markets through the CSA as well as the farmers market and local groceries and restaurants. The Kansas City Center for Urban Agriculture and Kansas City Community Farm is located in the city limits of Kansas City, Kansas and has extensive experience with high tunnels on the 2-acre urban farm. They have a CSA and sell at local farmers markets as well as to restaurants and other outlets. Bear Creek Farm is located in Osceola, Missouri, and also has extensive high tunnel experience on the 6-8 acres of vegetables and fruits. Bear Creek sells at farmers markets, to chefs, and wholesale, and also grows certified organic seed. Woods Mood Gardens is located in Higginsville, Missouri, and has been selling organically grown vegetables and fruit as well as beef, chickens, and eggs since 1994. Woods Mood emphasizes its minimal reliance on off-farm fertilizers.
All of the cooperating farms were certified organic at the time of the project and had been using sustainable practices for many years.
The initial primary goal of this project was to assess ways that high value growing environments—specifically high tunnels—affect the cost-benefit ratios of certain inputs, technologies (i.e., fertigation), and labor practices. After plans were revised, the goal of the project focused on comparison of harvests (quantity and quality) of tomatoes using compost alone, compost and fertigation with fish emulsion or tofu whey, and foliar feeding with fish emulsion, compost tea, or a liquid fertilizer product fermented from pineapple waste products.
Process. The project was initiated in early November, 2005, when Ted Carey brought together the five participating farms to discuss using high tunnel hoop houses installed on each of the farms as part of a previous project to conduct further research addressing needs identified in the project goal. Although each farm had specific issues they were interested in investigating, all of them had in common questions of soil fertility and composition (including potential problems of frequent irrigation), as well as the need to optimize cost/benefit ratios in using technology like high tunnels. A result of this initial meeting was a rough plan to develop a cooperative research project and apply for SARE funding. Stu Shafer, Sandheron Farm, agreed to act as group leader in writing the grant proposal and subsequent reports, with the technical assistance of Ted Carey and other researchers from Kansas State University and the University of Missouri.
The initial plan was to provide relatively inexpensive liquid fertilizer injectors for each farm. All of the farms would use at least one common liquid fertilizer source (fish emulsion), and either the same or different crops would be grown in controlled 2X plots to test the effectiveness of fertigation. In addition, we initially thought each farm could do separate trials involving the use of alternative fertilizer sources, including tofu whey (a byproduct of tofu manufacture), compost tea, vermicompost tea, and on-farm sourced manure tea, as well as foliar feeding in addition to liquid fertilization through the irrigation water. There was also some discussion of inside/outside comparisons as well as testing of soil salinity. Soil tests were planned for the beginning and end of the project.
As plans proceeded and we awaited word on our SARE grant proposal, we began to focus on the question of N-fertilization in tomato crops specifically, and the need to have a replication of fertigation in that crop on each of the farms. We discussed which cultivar would work best and settled on Celebrity Bush, a determinate variety common in commercial production. Dr. Carey made arrangement for a graduate student at K-State, Sharon Knewtson, to collect the initial soil samples, as well as to prepare data sheets for the farmers to use. Carey and Knewtson would also assist the farmers in setting up the research plots to ensure the pattern of experimental and control plots and replication. The possibility of individual farm trials of additional methods and practices was left open to the initiative of the specific farms.
Unfortunately, although notification of the SARE award came in the Spring of 2006, the seasonality of farmers’ plans and the necessity to coordinate among several farms and university researchers resulted in a delay in initiation of the trials. Sharon Knewtson did manage to discuss plans with each of the farmers during the summer and constructed a set of notes toward developing a research protocol, with the following ideas for experiments at each of the farms:
• Bear Creek Farm (Hail): Compare the effects of cow manure tea via drip irrigation and foliar application to fish emulsion fertilizer applied through drip irrigation on tomatoes
• Hoyland Farm (Lominska): Compare the effects of tofu whey waste product to fish emulsion fertilizer applied through drip irrigation on peppers
• Sandheron Farm (Shafer): Compare the effects of to tofu whey waste product to fish emulsion fertilizer applied through drip irrigation on tomatoes
• Woods Mood Gardens (Wood): Consider the usefulness of fish emulsion fertilizer applied monthly through drip irrigation on vegetables fertilized with large quantities of aged chicken litter
• Kansas City Community Farm (Kelly and Dermitzel): Compare the effects of foliar applications of vermipost manure tea and fish emulsion fertilizer applied to tomatoes
Because the planning carried on well into the 2006 growing season, it became evident that experiments could not effectively begin until the following season, 2007. A meeting of most of the farmers and Ted Carey was held at the Great Plains Vegetable Growers Conference in January of that year. Given the complexity of the previously discussed projects and the difficulty of comparing results of the various plans, the group decided a simpler approach was needed and a final procedure was agreed upon.
1. The experimental units in the trial would consist of 4 5-plant tomato plots which we’ll use to take data on tomato yield and quality over the course of the season. The 4 plots would be: a) compost only; b) compost and foliar feeding; c) compost and fertigation; d) compost + fertigation + foliar feeding). The rest of the tunnels could be used for conducting individual experiments, observations and just plain commercial production (except for the case of whey, where we would come up with a separate experiment).
2. The tomato variety we agreed to use was Celebrity Bush. The compost we’d use as our preplant fertilizer was Early Bird Chicken Manure compost (3-4-2). We decided to apply the preplant fertilizer at 60 lb/500 square feet prior to planting, which provided a rate of 156 lb N/acre. We had soil analyses from each of our places from the previous spring, and Carey asked Sharon Knewtson to run a more thorough analysis – Ca, Mg, K and OM – so that we could take a look at those. The soil analysis info from 2006 found that Jim Wood was high in nitrate and Robbins was low.
3. Foliar feeding and fertigation. Here things were a bit messier. Katherine (KCCUA) routinely uses fish emulsion and kelp products bought through Fedco. She may also use some humic acid. Robbins uses Neptune’s harvest fish/kelp mix. The other farms had various practices. For purposes of setting up the experiment, we planned on having the experimental plots in two central rows of the hoophouse a bit toward the interior (so not right on the end). Plots could be adjacent to each other. Both rows would be laid out for drip irrigation, and one would be set up to receive fertigation in addition Basically this is done by splitting the water line at the head of the tunnel, having one header line (with the injector on it) for rows to receive fertigation, and having the rest just receive water. The two plots in the no fertigation row would be a) compost only and b) compost + foliar feeding. The two plots in the fertigation row will be c) compost and fertigation and d) compost + fertigation + foliar feeding.
We agreed to use an inexpensive model liquid fertilization system made by EZ-FLO. We used Neptune’s Harvest fish/seaweed (2-3-1) for the fertigation supplement. By June 2007, the chicken manure compost and fish emulsion had been distributed and the individual farms had installed their irrigation systems according to the research plan, including the E-Z flow systems.
Fertigation started at flowering. After initial difficulties installing and ensuring the E-Z FLOs were working properly, all of the farms reported they were confident the systems were in place and functional. We applied the emulsion beginning at flowering, at a rate of 1.4 lb fish emulsion per row, or 6 lb N/acre/week. In the tofu whey trial, which had tested at 0.074% N, the rate of application was to be 37 lb per row, or 4 gallons to apply 6 lb N/acre/week.
Farmers were provided with a standard data sheet to track harvests and results of their respective trials. The sheets were arranged to collect data on harvests from each of the four plots in each trial, and called for count and weight for grades number 1 and 2, as well as for culls with classification notes for the culls as well as space for comments. K-State set up its own data collection matrix, as their trials included two types of foliar feed. In September Brix refractometer measurements were taken on samples from Kansas City Community Farm and Hoyland Farm. Brix measures were also taken on samples from most of the K-State plots.
Data sheets were collected and compiled in an Excel spreadsheet by K-State personnel in November 2007. No tests of statistical significance or other statistical analysis have been completed.
Primary assistance for the project was provided by Dr. Ted Carey, Horticulture Specialist for K-State Research and Extension. Dr. Carey facilitated the planning of the project and helped coordinated the process. He also outreach for the project though informal reports to colleagues and at conferences. Sharon Knewtson, a graduate assistant for Dr. Carey at K-State, and Laura Christensen, Extension Assistant, helped in soil tests, the distribution of equipment and supplies, and in the collection and compilation of data, including Brix refractometer tests of samples from the participating farms.
General impressions among the farmers during the trials suggested that fertigated plots were more productive than those that were not fertigated, although the results in some cases were somewhat mixed. Some of the farmers also reported that they thought the fertigated plots provided a slightly earlier yield than the non-fertigated plots.
A review of the final summary data provides the following observations.
Kansas City Community Farm. Tested both fertigation and foliar feeding with fish emulsion. The plot receiving fertigation but no foliar feeding had the highest yield (187.7 lbs) followed by the plot that received neither fertigation nor foliar feed (163.6 lbs). The plot with both foliar feed (fish) and fertigation yielded 143.7 lbs, and the plot with no fertigation had the lowest yield at 107.2 lbs. The sample from the plot with both fertigation and foliar feed had the highest Brix reading: 5. The other samples ranged from 4 to 4.5 on the Brix scale. KCCF did not record differences between grades #1 and #2, but did record weights of culls. Cull rates ranked differently: the fertigated and foliar fed plot had the lowest cull rate, while the fertigated/non-foliar plot had the highest.
Hoyland. Hoyland tested 3 plots: no fertigation, fertigation with whey, and fertigation with fish. None of the plots received foliar feed. They whey fertigated plot had the highest yield of both numbers and total weight of tomatoes: 163 at 48.27 lbs, for an average weight of about .3 lb. Yield from the non-fertigated plot was 131 at 31.72 lbs, averaging .24 lb. Although the fish fertigated plot had the lowest count, 117, their total weight was slightly higher, 32.15 lbs, for an average weight of .27 lb. A sample of Hoyland tomatoes also was Brix tested. Non-fertigated had the highest reading, 4.75. Fish fertigated tested at 4.5, whey fertigated at 4.
WoodMood. Tested both fertigation and foliar feeding with fish emulsion. Fertigated, non-foliar had the highest yields in number and weight of both #s 1 and 2. Average weight of #1s was .5 lb. Lowest yield in count and total weight for both grades was in the fertigated, foliar fed plot, where the average weight per #1 tomato was similar, .49 lb. The non-fertigated, foliar fed plot out-produced the control plot with no fertigation or foliar feed. Although the number of non-fertigated, foliar fed #1 tomatoes was similar to those of the fertigated, non-foliar one (252 and 256), the average weight of the former was slightly lower, at .47 lb. No sample was collected here for Brix analysis.
Bear Creek. Tested 3 plots: control (no fertigation or foliar), fertigation (fish)/no foliar, and fertigation/foliar (both fish). Highest yields (95.58 lbs total; only weight data for #1s and culls were collected) were in the fertigation and foliar feed plot, followed by the control plot (88.14 lbs). Fertigation, no foliar had the lowest yield at 86.68 lbs. The control plot had the fewest culls, while the fertigation and foliar plot had the most culls. No Brix sample was collected.
Sandheron. A greenhouse accident destroyed most of the starts before they could be transplanted, so this farm only had enough for two plots. One was fertigated, the other one not. The fertigated plot out-yielded the non-fertigated one almost two-to-one: 105 lbs compared with 57 lbs of #1s. The non-fertigated plot also had proportionally more #2s and culls. No Brix sample was collected.
K-State. As noted above, the K-State trials were much more extensive and complicated than the others, involving more replications and variables. Results were also mixed. Among the notable observations:
• Highest yields of #1s both in count and total weight were in a plot that was both fish fertigated and foliar fed with compost tea. Lowest yield of #1s (count and weight) were in one of the control plots (no fertigation or foliar).
• A similar pattern was found in averages of the replicated plots. Highest average yields of #1s were also found in the four replicated fertigation/compost tea foliar fed plots. But the lowest average yield was in the four plots receiving both fertigation and fish foliar feed.
• The same pattern is not found in the yields of #2 quality tomatoes. No fertigation, fish foliar feed had a slight edge in this category. The fish/fish (fertigation and foliar) plots averaged the fewest number of #2s.
• The control plots had the highest average number of culls, but the fish/fish plots surpassed them in the total weight of the culls.
• Highest Brix readings were from samples of one plot each that had no fertigation/maui foliar, a fish/fish plot, and a fertigation/no foliar plot. No apparent pattern is seen in these measures, as there appears to be greater variation within replication sets than between the types of treatments.
Because these results were so mixed, the farmers generally concluded that any benefits from fertigation and/or foliar feeding of tomatoes are hard to recognize. Looking at the combined results, one could conclude that there are likely some benefits of fertigation at least. For example, KCCF yielded 24 lbs more marketable tomatoes from their fertigated plot than from the control plot. At a price of $3/lb, that would be a difference of $72, barely enough to cover the cost of the inexpensive fertigation equipment. The K-State average yield difference was slightly less significant. And these were the two tests that showed the most difference in fertigation. Since some results even showed no improvement from fish fertigation (or even perhaps a loss), it is hard for some of the farmers to justify the time and expense of using this method of soil amendment rather than traditional methods just considering total yield difference. The effect of foliar feeding on quantitative yield is even less encouraging.
There is some indication in the results that there may be a notable improvement in the quality of the fruits from fertigation—a higher proportion of premium graded tomatoes which might yield a more efficient price in the market. Similarly, the suggestion that yields of the fertigated plots were earlier could contribute to premium price points at market, especially in combination with the season extension (earlier crop) offered by high tunnels.
There may also be a similar effect of foliar feeding on quality. Although the results are too inconclusive, it is possible foliar feeding may enhance the quality, including the flavor, of the fruit, as suggested by some of the Brix measurements. Given that foliar feeding appears to have a possibly negative impact (however slight) on total yield, this may imply a trade-off of quality for quantity.
Going into the project, the participating farmers had a healthy skepticism that fertigation alone would provide significant results. That skepticism seems to have been justified, as none of them came out of the project convinced that this technology was any sort of panacea. What may have been more surprising was the observation that foliar feeding had even a potentially negative impact on yield. The reason for that remains a mystery, and this is an area that may call for further research. An interesting line of inquiry might also be to investigate the possibility that foliar feeding could improve quality of the product, and the reasons for that potential benefit.
Unfortunately, we were unable to investigate many of the questions farmers had entering the project, including the impacts of irrigation and specifically, fertigation, on soil quality.
As indicated by the extreme tardiness of this final report, it may be that the biggest lesson of this project is the difficulty of conducting any kind of research among a loosely organized cooperative of independent market farmers. We entered into the project with the assistance of university and extension researchers, and were probably expecting more direction and assistance from them than was subsequently provided.
Some of that disappointment can be attributed to lack of communication. The project leader, specifically, volunteered to share the lead in writing the project design, but failed to anticipate the time commitment needed to make the project successful, especially when it became apparent that a similar commitment was not available from the research and extension experts. What was really needed was someone to truly take the lead in coordinating and ensuring that all necessary steps were taken by a scattered group of very busy growers, and as it turned out no one was able or willing to take that lead. The primary social lesson of this project, then, was that if a group decides to do such a research project together, they should be certain that 1) they have well established lines of communication, and 2) they are all clear about the division of labor and how much time investment is needed, especially by those playing a coordinating role. They should also get a clear commitment from those who are providing expert assistance.
What we learned specifically about the question of fertigation and foliar feeding is summarized in the section above. Some of us will continue to use our fertigation equipment on other crops, and will likely continue to make more or less systematic observations about the results and incorporate those conclusions in our future practices.
Because of difficulties in coordination and communication, we were unable to carry out many of the outreach activities we had originally planned. Specifically, we did not succeed in conducting the field days that would have broadly demonstrated our projects during the research phase.
Also, because completion of this final analysis and report has been greatly delayed, it has not been possible to share the results of the research in any formal presentation or publication. It may be possible to do so now, and the project leader will propose some venue of formal presentation (most likely a roundtable or panel presentation) at next year’s Great Plains Vegetable Growers Conference. It is unlikely that the outcomes of the research would merit any more prominent publication as originally planned.
As a result, the primary means of outreach have been informal sharing of results of our experience through our various networks of interaction among other market farmers.