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The 2009 ASHS Annual Conference

Effect of Organic and In-Organic Amendments On Soil and Produce Quality

Sunday, July 26, 2009: 4:00 PM
Laclede (Millennium Hotel St. Louis)
James Rietkerk, B.S., Crop, Science, Crop Science, California Polytechnic State University, San Luis Obispo, CA
Jeffrey Wong, Templeton, CA
Chip Appel, PH.D., Soil, Science, (Soil, Chemistry), Soil Science, California Polytechnic State University, San Luis Obispo, CA
Presenting Author:
James Rietkerk, Graduate Student Crop Science Cal Poly San Luis Obispo CA
Dr. Jeffrey Wong, Professor Crop Science Cal Poly San Luis Obispo, CA
Dr. Chip Appel, Professor Soil Science Cal Poly San Luis Obispo, CA
The mushroom industry produces a large quantity of spent mushroom substrate (SMS) annually.  Most of this material is considered a by-product that companies must dispose of regularly.  SMS may be of great value to crop production by improving soil structure and nutrient availability. Although the mushroom compost was used to improve soil structure in analysis it was determined to have a high salt content. SMS (an organic soil amendment) is commonly used in agriculture to improve soil characteristics; however, SMS has a high salt content. Remin (a non-organic soil amendment) is shown to add micronutrients to soil and remove salts by leaching. This product was applied to a multi-year study using SMS. The objective was to use and organic and in-organic soil amendment to improve soil and produce quality.
The variables tested were as follows: the experiment contains 48 treatments with 16 treatments per compost rate.  The area within each compost rate is approximately 7 beds (40 inches/bed) wide and 250 feet long; .15 acre. SMS + Remin were applied to a 0.7 acre field at various rates with three replications each. SMS was applied in 2006 and 2007 at rates of: 0 tons /acre, 2 tons/acre, 10 tons/acre, and 26.5 tons /acre. SMS applications were based on tomato N Requirements. Remin was applied to each area receiving different rates in 2008. Experimental plots received: (0 lbs. Remin/acre, 500lbs. Remin/acre, 1000 lbs Remin/acre, and 2000lbs. Remin/acre) using randomized block design.
All soil, leaf, and fruit samples were sent to a laboratory to be analyzed for N, P, K, Ca and Mg. The laboratory also analyzed soil pH and electrical conductivity. Yield results were measured for each plot. These methods were used to determine the effects of Remin and its ability to leach salts in the presence of SMS and its effect on yield in the soil by means of a non-synthetic amendment. Data from the first year of the study will be reported.