On-Farm Composting: Economics and Effects on Vegetable Produce Yield, Cut Flower Quality, and Soil Physical and Chemical Properties.
First of all it would be appropriate to say that some activities and methods described in the original proposal were modified as a result of weather-related factors encountered during the 2008 growing season. However, the basic plan was followed and full-scale field trials for Year 2 of the study should be consistent with the project document.
The project has two objectives. The first is to determine whether it is more economical to buy compost or to make it. The second is to compare the impact of different soil amendment regimes (compost, fertilizer, or nothing) on soil properties. The second objective will not be accomplished until data has been analyzed for Year 2 trials; however, the first objective has already been at least partially accomplished.
On-farm compost was available for Year 1 method development trials. However, since this compost was produced before the project was funded, there were no records kept for the time required to maintain and process this compost. However, the Year 1 compost was analyzed, along with a purchased commercial compost, to determine relative compost quality. During the first project year, compost piles were maintained to prepare compost for Year 2 trials. Records were kept of the time spent preparing, maintaining, and processing this compost. In the fall of 2008 finished piles were sifted through a ¼ mesh screen, bagged, and placed in 5-gal. buckets in a root cellar to mature over winter. A total of seventeen 5-gal. buckets were produced, weighing about 20-25 lb each for a total of 340-425 lb. Time spent in producing the compost was approximately 13 hours at a labor cost of $10 per hour, or about $130 total. If one uses a somewhat median weight of ~390 lb, that figures out to roughly $10 per 30 lb of compost.
When compared to a 30-lb bag of high-quality commercial compost (MicroLeverage® Humified Compost) at $35 per bag, there would seem to be considerable savings in using farm-prepared compost over purchasing, if results of the field trials indicate that crop performance is comparable for the two. Analysis will be done this spring on the aged compost to be used in the 2009 trials.
For the first year’s preliminary work, I wanted to evaluate several types of crops and then choose one of these for Year 2 trials. I picked several types of crops that I raise and sell at our local farmers’ market. These included leaf crops (spinach and chard), root crops (beet and carrot), cut flowers (zinnia and sunflower), and solanaceous crops (tomato and pepper).
The garden area (~54’ X 45’) was laid off into a grid of 7X7, or forty nine plots. Plot size was 5’X6’. Plots were sequentially numbered and each number was randomly assigned to an amendment/crop combination, with two replicates of each combination. Beds were slightly raised by removing soil from 2-ft-wide aisles between the plots and adding it to the plots. Weed control cloth was placed in the aisles along the 6’-long sides of the plots.
Duplicate plots were planted for each amendment/crop combination. Root, leaf and flower crops were direct-seeded at an appropriate time in spring (April-May); tomato and pepper plants were farm-raised in a small greenhouse and transplanted out in May. Both varieties of root crop were seeded into the ‘leaf’ plots in two 5’-long rows of each variety. This same planting scheme was also used for root and flower plots. Tomatoes and peppers were planted into separate plots, with four pepper or four tomato plants per plot. Tomatoes were caged for support. All plots were straw mulched.
Because of the unusually wet, cool spring in 2008, it was not possible to incorporate soil amendments before planting, so fertilizer and compost were applied as a side dressing at appropriate rates according to Extension or label recommendations, respectively. Farm and commercial compost were applied at the same rate based on similar moisture content. Fallow (no crop) plots were also amended with farm compost, commercial compost, organic (alfalfa-based) fertilizer, or no amendment.
Weather continued wet and cool into early summer and germination of root, leaf, and flower seeds was very poor. It became apparent that what little crop was produced would not give any meaningful data. Naturally, the grass and weed had no problems, continued to grow really well all summer. Broadleaf weed were mostly controlled by hand weeding. A second planting was attempted with soybeans by tilling up strips across leaf and root crop plots and hand seeding the soybeans. (What flowers germinated in those plots were left for aesthetic reasons.) The soybeans also had poor germination, and finally I gave those plots up and used a weed-eater and lawn mower to keep grasses and weeds under control.
Tomatoes and peppers were transplanted out on May 5 and May 21, respectively. Cold, windy days following tomato planting caused considerable stress and plants were subsequently severely affected by early blight. Peppers had no disease problems and thrived. Yield data (number of fruit and weight of #1 grade fruit) was collected from tomato and pepper plots as long as the plants produced. Tomato vines ripened fruit that was set early, but did not continue to set blooms and were done producing by Aug. 7. Peppers continued to produce until frost killed the plants.
At the end of the season, plots were cleared of remaining vines and debris. The garden was fall-plowed and tilled to thoroughly mix soil across treatment plots and turn under the grass sod that had developed. The garden was raked smooth and seeded with winter rye.
Most of what I have learned so far has to do with the logistics of carrying out the project. Poor germination of root, leaf, and flower crops resulted in no data being collected for those, but what I did do convinced me that these crops would require considerable effort and present some specific problems in doing the data collection and analysis for them. I have also obtained data analyses of the composts I am using, which show some interesting comparisons. Finally, I have worked out a more efficient system of maintaining and handling compost on a larger scale than I have done before. I learned quite a bit about tomato disease and some things NOT to do in a project such as this one.
Data Summary (See Tables 1 and 2)[Editor’s Note: For copies of the Tables, please contact the NCR-SARE office at: firstname.lastname@example.org or call 1-800-529-1342.]
Although 2008 data were from only duplicate plots, there were some interesting trends for both tomato and peppers in response to the different amendments.
• For tomatoes, organic fertilizer treatments produced higher numbers of fruits than the controls (and than for either compost), but average weight per fruit was similar to the controls.
• For peppers, purchased compost (Microleverage Humified Compost) produced higher numbers of fruits than farm compost (and than controls and fertilizer), but the farm compost average fruit weights were much higher.
WORK PLAN FOR 2009
I have chosen tomatoes or peppers (or a combination) as the crop choice for fully replicated Year 2 trials, since I have established a system and satisfactory methods for planting, soil treatments, data collection, etc. Both tomatoes and peppers have sufficient local market demand to consume the volume of fruit that sould be produced.
The winter rye crop will be tilled under as soon as weather permits in the spring. Plots will be laid off (8’X10’), with 2’ walkways between plots. Initial soil samples will be collected from each of 16 plots. Farm compost will be analyzed from two different batches and then composited. The composite will also be analyzed. Amendments will be incorporated into the soil prior to setting out transplants. Tomato and/or pepper plants will be started in a small farm greenhouse. Yield data (fruit number and total fruit weight per plot) will be collected and analyzed statistically to detect significant differences between treatments.
Since the results of first year trials were so poor, I have had little information to share. I have had a number of neighbors and friends visit and have shared what I am doing and what I hope to achieve with them. I also received an email enquiry from a person wishing to apply for a grant using compost teas, and I responded with a fairly comprehensive summary of my project and some suggestions for the inquirer’s proposal.
This next summer I plan to have one or more Field Day visits arranged through Extension and hope to host a compost workshop through that office. I will be preparing a PowerPoint presentation for as many Missouri outlets as possible, including our Columbia Farmers’ Market Fall Roundup in October, the Farmers Forum at the Small Farm Expo at the Boone County Fairgrounds in November, and, hopefully, the Great Plains Vegetable Growers Conference in St. Joseph. MO held in January of 2010. I plan to submit articles detailing my results to Growing for Market, and Small Farm Today magazine.