Degree Type


Date of Award


Degree Name

Master of Science




Soil Science

First Advisor

Antonio P. Mallarino


Lignin-derived ash obtained as a co-product of corn residue used for ethanol production may have value as a soil amendment. Preliminary laboratory analyses indicated that the ash had potential lime value and higher concentrations of K and S compared with other nutrients. The value of the ash to supply K and S and to increase soil pH was evaluated at two Iowa sites compared with commonly applied sources of K (KCl) and S (gypsum) and pure CaCO3. At each site, three 2-year trials were initiated to assess the K, S, and lime values of the ash. Several rates of each material were applied only the first year at all trials. Corn (Zea mays L.) was planted in 2014 and soybean [Glycine max (L.) Merr.] in 2015. Soil samples (15-cm depth) were taken before treatment application, at the V6 stage of each crop, and after crop harvest. Soil was analyzed for K, S, and pH levels Leaf samples taken at the corn R1 growth stage and soybean at the R3 stage were analyzed for K and S concentration. There were large fertilizer and ash K effects on grain yield, soil K, and leaf K but no significant source differences. The ash had liming value comparable to pure CaCO3 or higher. The results for S crop-availability were not conclusive mainly because there was little or no grain yield response to S, but soil and tissue test results suggested less early S supply compared with gypsum.


Copyright Owner

Samuel Groenenboom



File Format


File Size

51 pages