On-Farm Composting: Economics and Effects on Vegetable Produce Yield, Cut Flower Quality, and Soil Physical and Chemical Properties.
The plan for the second year of this two-year project was to do fully replicated trials comparing my own farm compost with commercial compost produced and sold by local companies. As with Year 1, weather was a big factor determining the selection and timing of the produce varieties selected for planting.
Some modifications were made to the plan I submitted at the end of 2008:
a) At the suggestion of James Quinn, MU Extension horticulturalist, an additional commercial compost treatment was added.
b) The size of each plot was increased to 10’X10’ and four replicates were prepared for each treatment.
c) Finally, in contradiction to the title of my proposal, and due to the logistical difficulty of data collection, cut flowers were not evaluated in this project.
The 50’X60’ garden plot was fall plowed in 2008 and seeded with winter rye. This cover crop was mowed down in early May and tilled with a rototiller to incorporate residues into the soil. Approximately two weeks later, the garden was given a final tilling and laid off in a grid, with four east-west rows marked off into five 10’X10’ plots per row. Each row was separated by a 2 ft. path covered with doubled landscape fabric.
As for 2008, soil samples were collected for analysis in January of 2009. The garden was divided into four equal sections (quadrats) and composite samples were taken from each of the four quadrants. Soil amendment rates were calculated based on soil test recommendations. Treatments were applied to four replicates each of: controls, Bradfield Vibrant Veggie organic (alfalfa-based) fertilizer, Early Bird compost (composted poultry litter), MicroLeverage humified compost, and my farm-prepared compost (see the 2008 summary report for details of preparation). Supplemental bone meal was added to farm compost and MicroLeverage treatments to bring application to the desired level for phosphorus. Supplemental greensand was added to Early Bird, farm compost, and MicroLeverage to bring application to the desired level for potassium. Treatments were added to designated plots and incorporated with light mixing with a tiller and rake. Treatments were randomly assigned within each row, and each row had one each of every treatment (Fig. 1).
[Editor’s Note: To see the Figures and Tables, open the attachment or contact NCR-SARE to receive a copy of the full report by e-mail or mail at: firstname.lastname@example.org or 1-800-529-1342.]
Cherokee purple tomato plants were raised from seed in a small greenhouse. As spring progressed and weather delayed garden preparation and planting, the tomato plants grew to a height of 18”-24” and were ‘leggy’ but quite healthy. Transplants were not set out until late June (June 26-30). At that time I stripped the plants of all but the top 4-5 leaves and buried roots and stem horizontally about 4” deep.
Three plants were set in the north half of each 10’X10’ plot, with roots oriented to the north side. Soaker hoses were laid east-west across the root zone of each row and a layer of weed mat fabric was put down over the hose and root area, with the plants rising through slits cut in the fabric. The process of planting as described here took four days to complete. Plants were staked after 4-5 days, and trained up the stake using baling string ties. Thereafter, additional ties were added as necessary as the plants grew until they outgrew the stakes.
Total fruit weight and number was recorded for each plot on three successive (weekly) harvest dates. Weights were recorded separately for each grade of tomato (#1 marketable, #2 seconds, #3 unusable). After the third picking, tomatoes were picked on an as-needed basis for canning and sales, but no data were collected. Tomato data will be analyzed to determine if there is a statistically significant difference between treatments. Data will also be broken down by grades and analyzed by grade to determine the relationship between market value and the economy of compost purchase versus on-farm compost production.
The last green tomatoes were stripped from the vines in late September and the vines were cut and removed from the plots. At this time, soil samples were collected from the north half of each plot and submitted for analysis.
Due to the lateness of the spring bed preparation, no other crop was planted at that time. As weeds began to be problematic, the south half of each plot was tilled and planted with a cover crop of buckwheat. In late August, the buckwheat was mowed, chopped down, and turned in using a spading fork. Following a final tilling, a fall garden was planted in early September. Three rows each of turnips, beets, and carrots were planted in north-south orientation in the south half of each plot.
Turnips were harvested on November 14 and Nov. 30. All turnips with roots ? 1” in diameter were pulled. Roots were shaken to remove excess soil and, since very little soil remained adhering to the turnip, roots were not washed. Total fresh weight (biomass) for the plot was recorded. Roots were separated from greens by cutting ~1/2” above the root. Roots were counted and weighed. For the first harvest, tops were culled to remove unmarketable material and the marketable greens were weighed. These data will be analyzed to determine if there is a statistically significant difference between treatments
At the time of this report, beets, carrots, and some remaining turnips are still in the garden. Beets and carrots were slow sprouting but I am protecting these with row cover and still have hopes of obtaining data from these crops.
Grant funds used this year (in addition to monies already used):
Ohaus Balance, $ 265.80
Labor (185hrs @$10/hr), $ 1850.00
Produce Bins. Row cover, $ 67.50
Refreshments for Field Day, $ 14.75
Compost and fertilizer, $ 232.85
Soil and Compost Analyses, $ 497.50
Remaining funds will be used for final harvest and data collection, statistical analysis of data, preparation of PowerPoint presentation, and travel to meeting(s) for presentations.
Cool, wet spring weather delayed planting of tomatoes and an unusually wet summer interfered with summer plantings. However, a productive tomato crop was successfully harvested. Fruit weight and number for each treatment is summarized in Table 1. Data presented is irrespective of grade. Total weight of tomatoes from the three pickings was greatest for Early Bird (140 lb) and Microleverage (141 lb) composts, but Bradfield organic fertilizer was very similar (135 lb). Farm compost (125 lb) was very similar to controls (128 lb). Breakdown of data by grade showed the highest yield of #1 grade for Early Bird treatment (total of 105 lb), followed by Microleverage and Bradfield (96 lb each), with 84 lb and 79 lb for controls and farm compost, respectively.
Data and simple averages for turnips are presented in Tables 2 and 3. Total biomass from two pickings was highest for Bradfield fertilizer (41 lb), followed by farm compost (35 lb), Early Bird (31 lb), controls (26 lb), and Microleverage (25 lb). However, root yield was greatest for Early Bird (25 lb), followed by Bradfield fertilizer (21 lb), farm compost (19 lb), and then Microleverage and controls (13 lb each).
Soil test results are presented in Tables 4, 5, and 6. Pre-season soil analyses in 2008 and 2009 established base levels for comparison with post-treatment analysis (Table 4). No apparent changes were noted in soil pH, organic matter, calcium, or cation exchange capacity over the course of this study. However, there appear to be differences between treatments following the 2009 season with respect to soil concentrations of phosphorus, potassium, and magnesium (Table 5). There may also be treatment differences with respect to micronutrient levels (Table 6), but there are probably insufficient data to detect statistically from this study.
Compost analysis is reported in Table 7. There were some notable differences between 2008 and 2009 farm composts. Considering the fact that input to these composts can vary considerably depending on seasonal variations and type of materials that go into the farm compost, this variation is not entirely unexpected. No conclusions can be drawn from these data and they are insufficient for statistical correlation analysis, but they have some interesting similarities and differences.
WORK PLAN FOR 2010
It still remains to collect as much data as possible from fall-planted root crops. I will be running some stats on tomato and root crop data to determine if variation in the data shows statistical differences between treatments. Yield data needs to be evaluated with regard to market value of the crops. This should help determine the economy of each treatment (return on investment). Finally, the effect on soil quality from each treatment will be examined, although it will probably not be possible to detect much significant change from this relatively short-term study.
Throughout the season, I gave a number of impromptu garden and greenhouse tours and explained my project to friends and neighbors who stopped by and to members of our farmers market. A Farm Field Day was advertised through the Missouri Vegetable Growers newsletter. This was held August 29, and while for once the weather cooperated and the refreshments were great, attendance was disappointing. Only one person showed up. Possibly this was due to the seasonal demands on farmers trying to take advantage of the weather, or maybe they were just ‘farm tour’ed out!
This winter I will be preparing a PowerPoint presentation to share my results. I plan to submit a presentation for next years’ Small Farm Conference in Columbia, Missouri and to share the information in a composting workshop through MU Extension’s Master Gardener program.