University of Georgia — evaluated the growth of transplants during greenhouse production and their ensuing growth and yield after transplantation to fields.
Bloomsburg University — compared manure, fertilizer, and compost for nitrogen forms, odor, corn growth, groundwater leaching, soil organic matter, water holding capacity, and more.
Ohio State University — compared disease suppression in compost-amended potting mixes, MBS’ compost tea, and no-tillage soil.
McGill University — of Canada tested the effects of compost covers relative to leachates, pathogens, and product quality.
University of Georgia
Research by Darbie M. Granberry, University of Georgia; compost made by GroMor Organics; compost process was ACS by Midwest Bio-Systems. Progressive vegetable growers are looking to sustainable practices to grow and market high quality produce more profitably. Growing media materials (e.g. peat moss, perlite, vermiculite) are routinely imported and supplies are limited. On farm, renewable products such as compost would enhance sustainability and reduce production costs.
Objectives of the study were to:
- Evaluate growth of transplants during transplant (greenhouse) production
- Evaluate growth and yield of plants after transplanted to fields
Compost materials were chicken litter, ground yard trimmings, cull vegetables, peanut hay, cotton gin trash, clay, and finished compost. Compost process was the Advanced Composting System (ACS) of Midwest Bio-Systems. It is a highly aerobic and controlled process with monitoring procedures throughout for consistent quality. Controls include:
- Proper recipe formulation
- Process decisions based on readings of temperature, CO2, and moisture
- Aeration and moisture decisions made from readings
- Laboratory analysis
Laboratory analysis graded this particular sample in MBS “Grade C” range. (By MBS’ stringent standards, Grade D compost still shows quality standards higher than 90% of compost produced nationwide.)
Two treatments were compared:
- Commercial transplant growing media normally used to grow pepper transplants
- Identical media amended with 20% high quality compost
June 24, 2000, seeds of bell pepper X3R Wizzard were planted in flats (200 cells per flat) — with and without compost. Seeds were germinated and transplants grown in a greenhouse using current commercial transplant recommendations. (During the first week of germination, all pepper plants received a fertigation of 13-2-13 at a concentration of 100 ppm nitrogen. No additional fertilizer was applied until after transplanting.)
Impact on transplant growth:
- Compost-amended media SIGNIFICANTLY increased plant height and stem diameter, leaf area, leaf dry weight, stem dry weight, shoot dry weight, root dry weight, and plant height.
- 15 days after seeding (DAS)
- No compost height was 1.23″ & canopy width 1.99″
- With compost height was 1.81″ & canopy width 3.08″
- 24 days after seeding
- No compost height was 1.87″ & stem diameter .065″
- With compost height was 3.05″ & stem diameter .084″
- 51 days after seeding
- No compost height was 5.04″ & root dry
- weight .106 gr
- With compost height was 5.54″ & root dry weight .135 gr
- 35 days after transplant (DAT)
- No compost height was 7.6″ & stem diameter .221″
- With compost height was 9.0″ & stem diameter .252
Impact on fruit set — 56 days after transplant, counts were made of the number of fruit of five randomly selected plants in each plot. Plants grown in compost-amended media set more fruit than plants grown without compost.
Early fruit yield — 70 days after transplant jumbo and extra large fruit (no defective or cull fruit harvested). Per plot:
- No compost: 5.46 fruit weighing 2.8 lbs. average
- With compost: 12.80 fruit weighing 6.6 lbs. average
Total yield — In four combined harvests, compost-amended media out-yielded non-amended by 20%.
- No compost yielded 381 boxes per acre
- With compost yielded 457 boxes per acre
In dollars, 76 more boxes per acre equates to approximately $1000 higher gross profit per acre.
Reducing non-point source pollution through soil microbial enhancement.
Participants included Ernest Keller of Lackawanna County Conservation District, Ronald Phelps of NRCS, Mary Wagner of Columbia County Conservation District, Judith A. Kipe-Nolt of Bloomsburg University of PA, two graduate assistants, six undergraduate students, and eight area farmers.
Process: Activated microbial windrow composting was used in this project. Most windrows were turned 20-25 times. Good aerobic conditions were maintained. Gas-permeable, water-shedding covers were used on the compost. Temperatures reached levels above those necessary for pathogen and weed seed destruction. Compost maturity was tested with an alfalfa germination test. Beginning C:N ratios were above 20:1, but lower than ideal. Structure in the windrow also indicated the need for an additional loose carbon feedstock. Clay would also be a recommended additive.
Two replicated field trials, one in each participating county, were conducted to evaluate the effects of compost, manure, and conventional fertilizer applications on soil quality. Compost and manure were applied in the fall and spring at equal rates of total nitrogen (250 kg N/ha). Several physical, chemical, and biological soil quality indicators were monitored during a 2 ½ year period. The results were:
- Water holding capacity and infiltration rates were greatest in the compost plots, manure 2nd, and both compost and manure were significantly greater than in conventional fertilizer treatment.
- Nitrate levels were significantly higher in the deep fraction of manure plots than the compost or fertilizer, with groundwater leaching 16% higher in the manure plots.
- Nitrogen forms: organic N was 97% in finished compost, 42.1% in raw manure with sawdust bedding.
- Odors were present with manure and attracted flies, while compost was odorless.
- Early corn growth was consistently greater in compost plots compared to either manure or fertilizer plots.
- Plant height and dry weight were significantly greater in compost than manure or fertilizer.
- At silage harvest, cob, shoot, and plant total N were highest in the compost plots.
- No differences in soil bulk density or temperature were detected.
- Significant differences in soil organic matter were detected. Compost plots were highest, manure 2nd, then fertilizer.
- Highest levels of calcium and magnesium were found in the compost plots; both compost and manure were consistently and significantly higher in phosphorus and potassium than the fertilizer plots.
- Electrical conductivity was higher in compost and manure treatments than fertilizer, but no cation exchange capacity difference was observed.
- Ratios of nitrogen to phosphorus and potassium were higher in compost than in the manure.
- Earthworm populations were highest in manure, followed by compost; very few earthworms were present in the conventional fertilizer plots.
- Microbial biomass (total material in living microbes) changes rapidly, but is potentially a powerful soil health indicator. Levels stabilized in the fall and were similar in the compost and manure plots, but significantly greater than in the fertilizer plots.
- After 2 ½ years, the soil quality in the conventional fertilizer treatment was poorer than the soil in either the compost or manure treatments.
Ohio State University
Disease suppression and systemic acquired resistance (sar) induced in plants by compost-amended potting mixes, compost water extracts, and no-tillage soil study conducted by a team of Ohio State University scientists, including Weizheng Zhang, M.S., B.S., Dr. Warren A. Dick, and Dr. Harry A.J. Hoitink.
- SAR (Systemic Acquired Resistance) is communicated throughout the plant.When a pathogen infects a plant, certain systems are activated for defense. But often it’s too late—the pathogen outruns the defense.
- The research showed by growing plants in compost, the defense can be ready when the enemy arrives. The biologically available energy in compost sustains the activity of beneficial organisms.
- Beneficial microorganisms are the key — they may eat the pathogens, out-compete the pathogens, or produce antibiotics.
- No one organism can solve all plant problems — their use is specie specific.
- Potting mixes used in the study — spruce or pine bark composts that suppressed pythium root rot and a peat mix that did not suppress pythium.
- Methodology — split root technique. Two week old seedlings were transplanted with the roots divided into separate mixes (one foot in each mix). Combinations were compost and peat, peat and peat, and compost and compost.
- Result — A broad spectrum of beneficial microorganisms in composts may induce systemic resistance in many plant species.
- Compost water extract study — the compost tea was made from compost produced by Midwest Bio-Systems. The water extract as a foliar significantly reduced populations of pseudomonas syringae pvmaculicola ES 4326.
- Result — the mechanisms by which the compost water extract used in the work induced control appear to be different from the disease suppression caused by plants grown in the compost mix. Both sterile and non-sterile extracts reduced disease severity and pathogen population. This suggests the disease suppression is a result of activity unique to the MBS compost process — where microorganisms (and by-products of their activity) are enabling either a block of the pathogen or an antibiotic effect.
Significance of the OSU study — potential for:
- Major reduction in pesticide use by farmers.
- Possibility of controlling plant currently non-preventable diseases.
- Healthier plants through increased organic matter.
- Significantly enhanced disease resistance in plants grown with compost.
The critical reason is the biologically available energy in the compost. It sustains the activity of the beneficial organisms.
McGill University (Montreal)
Researcher — Monique Paré
Purpose — Tested the effects of compost covers on leachate, pathogens, and product quality.
Methodology — In the first year cauliflower residuals and sawdust were mixed and formed into six windrows. In the second year, wheat straw replaced sawdust in twelve windrows. Piles were formed on separate platforms, for which the ground was excavated to create a depression sloping towards the center. A 20 cm layer of fine sand lined the depression and a 10 cm pvc pipe ran from the central low point of the platform to the outside. Half of the windrows were sheltered with semipermeable geotextile covers; remaining piles were uncovered.
- Covered composts had higher mineral content in both years.
- Nitrogen, phosphorus, and potassium levels were significantly higher in the second year.
- In late fall and early winter, the temperature of the compost decreased more slowly when covered.
- Covered compost did not freeze as deeply over winter and warmed up faster than non-covered in the spring.
- Covered compost was drier at the end of the cycle.
- The quantity of leachate was significantly reduced in the covered.