Alfalfa-based Organic Amendment in Peat-compost Growing Medium for Organic Tomato Transplant Production

作者：Nair Ajay; Ngouajio Mathieu^*; Biernbaum John

来源：Hortscience, 2011, 46(2): 253-259.

DOI：10.21273/hortsci.46.2.253

• dairy compost
• certified organic
• EC
• germination
• media incubation
• seedling
• SPAD

In the last decade, organic production has been the fastest growing segment in U.S. agriculture. With increase in organic acreages there is a strong and growing demand for organically grown transplants. As a result of limited commercial availability of certified vegetable transplants, growers often produce their transplants on-farm. Commercial organic mixes for organic transplant production may not be locally available and are usually expensive. Growers often design their own mixes using compost and other organic amendments. The purpose of this study was to evaluate the incorporation of alfalfa-based amendment in a peat-compost medium for organic tomato transplant production. Growing medium of 2 peat:1 vermiculite:1 compost (by volume) was amended with 0%, 0.6%, 1.2%, 1.8%, or 2.4% weight by weight of alfalfa-based organic amendment and incubated for 0, 1, 2, 3, or 4 weeks. Medium pH and electrical conductivity (EC), seed germination (untreated Solanum Lycopersicon L. 'Mountain Fresh' seed), transplant dry weight, height, stem diameter, and SPAD values were measured. Medium pH increased with addition of alfalfa-based amendment but remained within the range of 5.5 to 7.0. Germination percentages were less than 50% in amended medium that was either not incubated or incubated for 4 weeks. Germination was greater than 75% if amended media were incubated for 1, 2, or 3 weeks. Seeds grown in peat-compost without any amendments had the highest germination rates; however, severe nutrient deficiency suppressed seedling growth. Relative to growth in medium with no amendments, plants growing in the amended medium had increased stem diameter, height, leaf chlorophyll content, and plant dry weight (90% to 160% more), provided the amended medium was incubated for at least 1 week. Application rate of 0.6% or 1.2% of alfalfa-based amendment produced transplants with suitable growth characteristics and met commercially acceptable standards for transplanting and handling at a reasonable estimated cost.

• 出版日期2011-2