Wednesday, November 15, 2006
287-16
Gypsum as a Soil Amendment for Economic Crop Production.
W.B Clevenger, The Ohio State University Extension, 06879 Evansport Road, Defiance, OH 43512 and Khandakar Islam, OSU South Centers, 1864 Shyville Rd, 1864 Shyville Rd, Piketon, OH 45661-9749, United States of America.
Gypsum is an important chemical amendment to improve soil tilth. To evaluate the conditioning effect of gypsum to improve the quality of heavy clay soil for economic corn and soybean crop production, a randomized complete block experiment was conducted at Defiance County research and demonstration field, northern Ohio in 2004 and 2005. The treatments were 0 (control), 1 and 2 Mg gypsum ha-1, respectively. Composite core samples at 0-15 cm depth of soil were randomly collected, processed, and analyzed for microbial biomass (SMB), pH, electrical conductivity (Ec), total organic C (TOC), particulate organic C (POC), active (AC) and passive C (PC), bulk density (rb), porosity (ft), and macro- and microaggregate distribution ratio (AR). Results show that SMB and percent SMB:TOC significantly increased by more than 25% in 2 Mg gypsum ha-1 treatment compared with control. Active C in gypsum amended soil increased by 6 to 10% over control. The AR as a measure of soil structural improvement has significantly influenced (6 to 11%) by 2 Mg gypsum ha-1 application. The mass of POC increased (12 to 18%) significantly in response to gypsum amendments of soil. On the other hand, rb, ft, TOC, pH and Ec did not vary significantly by gypsum application.