Creeping bentgrass growth in sand-based root zones with or without biochar

Authors: Vaughn, Steven; DINELLI, F DAN - North Shore Country Club; Tisserat, Brent; JOSHEE, NIRMAL - Fort Valley State University; Vaughan, Martha; Peterson, Steven - Steve

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2015
Publication Date: 10/28/2015
Publication URL: http://handle.nal.usda.gov/10113/62347
Citation: Vaughn, S.F., Dinelli, F.D., Tisserat, B., Joshee, N., Vaughan, M.M., Peterson, S.C. 2015. Creeping bentgrass growth in sand-based root zones with or without biochar. Scientia Horticulturae. 197:592-596.

Interpretive Summary: Current United States Golf Association (USGA) specifications recommend that golf green root zones consist of a minimum of 90% sand to provide sufficient drainage and reduce compaction. Because sand has inadequate water and nutrient retention for satisfactory turf performance, organic matter, most commonly sphagnum peat moss, is added to the sand during golf green construction. Other organic amendments, including various composts and municipal biosolids, have also been utilized and/or evaluated. A disadvantage for using organic amendments is that they decompose over time, reducing their effectiveness. Biochar is the carbon-rich residual product created under anaerobic conditions by the pyrolysis of phytobiomass. Addition of biochar can greatly increase water and nutrient retention, especially in sandy soils. An additional advantage of using biochar instead of other organic amendments is its resistance to microbial decomposition and hence longevity in golf greens. In this study we evaluated simulated golf greens in which three different biochars were added at 1, 5 and 10% (v/v) to pure sand or sand amended with 15% peat moss. Adding biochar enhanced both the water and nutrient retention capacities. Five weeks after seeding creeping bentgrass, plants grown in one of the biochar treatments had significantly greater fresh and dry weights, shoot heights and root lengths than the 100% sand control. In all but one of the biochar treatments root lengths were significantly greater, with the roots of one treatment approximately three times the length of the control. Based on these results it appears that the addition of certain biochars would improve water retention and increase overall plant growth in golf green root zones.

Technical Abstract: Organic amendments such as peat moss and various composts are typically added to sand-based root zones to increase water and nutrient retention. However, these attributes are typically lost within a few years as these amendments decompose. Biochar is a high carbon, porous coproduct from the pyrolysis of phytobiomass, and due to this porosity has excellent water and nutrient retention. Additionally, unlike other organic amendments, biochar is extremely resistant to microbial decomposition. Pure calcareous sand (control) or mixtures of three different biochars and sand at 1, 5 and 10% volume biochar/total volume were prepared. Bulk densities decreased while percent pore space increased with the addition of all three biochars at all of the addition rates. Water retention was greater than the control in all but one of the biochar treatments, and several of the biochar mixtures had values for compaction resistance similar to pure sand. Creeping bentgrass (Agrostis stolonifera L. 'Pure Distinction') plant heights, root lengths, and fresh and dry weights were evaluated in mixtures grown hydroponically in polyvinyl chloride tubes (112 mm outside diameter, 99 mm inside diameter) filled 30 cm deep with 1 cm diameter pea gravel, over which 30 cm of either pure sand or sand/biochar mixtures were added to mimic a United States Golf Association root zone. Five weeks after seeding, plants grown in several of the biochar mixtures had significantly greater fresh and dry weights, shoot heights and root lengths than the control. Based on these results it appears that the addition of certain biochars would improve water retention and increase overall plant growth in sand-based root zones over a much longer period of time than other organic amendments.