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A Rapid-Test for Screening Biochar Effects on Seed Germination
Citation:
Olszyk, David M, T. Shiroyama, J. Novak, AND Mark G Johnson. A Rapid-Test for Screening Biochar Effects on Seed Germination. Communications in Soil Science and Plant Analysis. Taylor & Francis Group, London, Uk, 49(16):2025-2041, (2018). https://doi.org/10.1080/00103624.2018.1495726
Impact/Purpose:
Biochar is a carbon rich material produced by heating biomass in the absence of, or limited of oxygen (pyrolysis), which has been proposed as an amendment to address a wide range of soil environmental problems including poor fertility, water holding capacity, and plant revegetation of sites contaminated with heavy metals. However, depending on the original feedstock material and heating conditions, biochar may have detrimental as well as beneficial effects on plants. Because successful seed germination is essential for subsequent plant growth and development, seed germination responses are an early indicator of the effects of biochar on plant performance. To facilitated early detection of biochar effects, we developed a “rapid-test” to screen for effects of biochar on seed germination and soil characteristics based on Oregon State University Seed Laboratory procedures. The test was run with a wide range of conditions: two South Carolina soils, eighteen biochars produced from 6 feedstocks made by pyrolysis at 3 temperatures, and 8 common crop species. Germination primarily was affected by soil type with few biochar effects, however the test detected an increase in shoot dry weight for carrot, lettuce, oat and tomato; primarily with biochars produced from poultry litter. The test also detected changes in important soil health characteristics vital for successful growth of plants: soil pH, electrical conductivity and extractable phosphorus increased with a number of biochars, especially those which were based on poultry litter and swine solids. Thus, this rapid-test method is an early indicator of the effects of biochar on not only crops, but especially important soil health characteristics; facilitating the use of biochar in addressing environmental concerns such as revegetation for superfund sites.
Description:
We developed a rapid-test to screen for effects of biochar on seed germination and soils. Crop seeds were placed in containers and covered with 15 g of soil with 1% biochar by weight. Two agricultural soils from South Carolina USA were used. Eighteen biochars were produced from six primary feedstocks [pine chips (PC), poultry litter (PL), swine solids (SS), switchgrass (SG); and two blends of PC and PL, 50% PC/50% PL (55), and 80% PC/20% PL (82)]. Each feedstock was pyrolyzed at 350, 500 and 700°C. There were few biochar effects on seed germination. Shoot dry weight was increased for carrot, cucumber, lettuce, oat, and tomato; primarily with biochars containing PL. Soil pH, electrical conductivity and extractable phosphorus primarily increased with PL, SS, 55, and 82 treatments for both soil types and across species. This method can be an early indicator of biochar effects on seed germination and soil health.
