|Olszyk, David - Environmental Protection Agency (EPA)|
|Shiroyama, Tamotsu - Environmental Protection Agency (EPA)|
|Novak, Jeffrey - Jeff|
|Johnson, Mark - Environmental Protection Agency (EPA)|
Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2018
Publication Date: 7/11/2018
Citation: Olszyk, D.M., Shiroyama, T., Novak, J.M., Johnson, M.G. 2018. A rapid-test for screening biochar effects on seed germination. Communications in Soil Science and Plant Analysis. https://doi.org/10.1080/00103624.2018.1495726.
DOI: https://doi.org/10.1080/00103624.2018.1495726 Interpretive Summary: In soils that are degraded, biochar is being evaluated as an amendment to improve their fertility and increase crop yields. Unfortunately, there are few rapid tests to determine the effects of biochar on soil and associated plant responses. Seed germination is a critical parameter for plant establishment and may be a rapid indicator of biochar effects. Since evaluating biochars for their potential soil fertility improvement is time-consuming, we developed a rapid (2-weeks) tool using seed germination procedures to screen for effects of biochar on seed germination and soil characteristics. We also examined whether their were any beneficial or detrimental impacts of biochar on soil fertility characteristics such as pH, electrical conductivity (EC) and phoshorus (P). Our research demonstrated that the biochars had few negative effects on seed germination, but increased shoot dry weight for carrot, lettuce, oat and tomato; primarily with biochars produced from poultry litter. The test detected increased soil pH and EC, especially with biochar produced from poultry litter and swine solids, and the response varied with plant species. The test provided an indicator that biochar increased P, especially with the poultry litter and swine solids with very little difference among species. Our technique can be completed in a small space under controlled conditions to reduce environmental variability, and indicate biochar impacts on soil characteristics after a relatively brief period of time. We conclude that since the new technique is flexible, it could be adapted for evaluating other soil-based stressors using a limited amount of soil and contaminant.
Technical Abstract: 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.