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United States Department of Agriculture

Agricultural Research Service

Research Project: ORGANIC AND REDUCED INPUT FRESH MARKET SPECIALTY CROP PRODUCTION SYSTEMS FOR THE SOUTHERN GREAT PLAINS Title: Micronized compost as an organic amendment for soil media

Authors
item Webber, Charles
item Roberts, B -
item Taylor, Merritt -
item Shrefler, James -

Submitted to: Proceedings of Horticultural Industry Show
Publication Type: Proceedings
Publication Acceptance Date: January 29, 2010
Publication Date: March 1, 2010
Citation: Webber III, C.L., Roberts, B.W., Taylor, M.J., Shrefler, J.W. 2010. Micronized compost as an organic amendment for soil media. In: Proceedings of the 29th Annual Horticulture Industries Show, January 8-9, 2010, Tulsa, Oklahoma. p. 160-162.

Interpretive Summary: There is a growing belief among consumers that organic foods are safer, provide superior nutrition, and their production is more environmentally friendly than conventionally grown foods. All components entering into the organic crop production system must be approved for organic use, including the seed, growth medium, and fertilizer used in transplant production. It is important to have access to organically approved fertilizers that can be used to produce healthy seedlings. The pharmaceutical industry has used micronization to reduce the average size diameter of materials to a few micrometers or the nanometer range to increase effectiveness on products. Greenhouse research was conducted to determine the impact on seedling growth as a result of adding micronized compost to a growth medium for organic tomato (Solanum lycopersicon L.) transplant production seeds ('Florida 47') were planted in an organic potting medium and grown in a greenhouse at Lane, OK. Micronized compost, organic fertilizer, and synthetic fertilizer were applied at 50, 100, 150, and 200 ppm and a control which did not receive any fertilizer. The fertility treatments (MC, OM, and SF) were based on the nitrogen level on the product label and applied as a soil drench to established (3 week old) tomato seedlings. The tomato seedlings were harvested at 7 weeks and top weights and heights determined. All fertilizer treatments were significantly greater than the control (water only) treatment for plant weight and height at harvest. Increasing the application rate of the micronized compost did not significantly increase either tomato seedling plant weights or heights. The micronized compost did not produce significantly greater seedling plant weights and heights compared to the organic fertilizer applications. The synthetic fertilizer produced significantly greater plant weights and heights at the 100, 150, and 200 rates than the micronized and organic fertilizer applications at the same rates. The plant growth differences between the synthetic fertilizer and the micronized compost, and the organic fertilizer may be a result of a number of factors, including inaccurate prescription labeling of the micronized compost and/or the organic fertilizer or the relative solubility of the materials. Regardless of the reason for the low performance of the micronized compost and the organic fertilizer, additional material would need to be added in an attempt to produce equivalent tomato seedlings as the synthetic fertilizer. A producer would be wise to conduct their own small scale fertility trial when using the micronized compost or organic fertilizers for greenhouse seedling production.

Technical Abstract: All components entering into the organic crop production system must be approved for organic use, including the seed, growth medium, and fertilizer used in transplant production. It is important to have access to organically approved fertilizers that can be used to produce healthy seedlings. The pharmaceutical industry has used micronization to reduce the average size diameter of materials to a few micrometers or the nanometer range to increase effectiveness on products. Greenhouse research was conducted to determine the impact on seedling growth as a result of adding a micronized compost to a growth medium for organic tomato (Solanum lycopersicon L.) transplant production. Tomato seeds ('Florida 47') were planted in an organic potting medium and grown in a greenhouse at Lane, OK. Micronized compost, organic fertilizer, and synthetic fertilizer were applied at 50, 100, 150, and 200 ppm and a control which did not receive any fertilizer. The fertility treatments (MC, OM, and SF) were based on the nitrogen level on the product label and applied as a soil drench to established (3 week old) tomato seedlings. The tomato seedlings were harvested at 7 weeks and top weights and heights determined. The experimental design was a randomized complete block with 4 replications. All fertilizer treatments were significantly greater than the control (water only) treatment for plant weight and height at harvest. Increasing the application rate of the micronized compost did not significantly increase either tomato seedling plant weights or heights. The micronized compost did not produce significantly greater seedling plant weights and heights compared to the organic fertilizer applications. The synthetic fertilizer produced significantly greater plant weights and heights at the 100, 150, and 200 rates than the micronized and organic fertilizer applications at the same rates.

Last Modified: 9/2/2014
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