The Effects of Cover Crop C:N Ratios at Termination on Soil Water Extractable C:N and Other Soil Health Parameters at Termination and Six Weeks Post Termination.

There is interest in how grass and legume cover crops and their mixtures affect soil properties in the short term to maximize both soil health and immediate crop production goals. This study evaluated the biomass C:N ratios of the monocultures and two binary mixtures of Seedway 336 triticale  and Dixie crimson clover  and their  effect on the soil water extractable carbon and nitrogen and their ratios. Also analyzed were Solvita CO₂ respiration and Solvita Labile Amino-Nitrogen. The study was conducted on Unadilla silt loam soil. The field was conventionally tilled and seeded into 14 m² plots with triticale at 112 kg/ha and crimson clover at 20 kg/ha and mixtures of triticale 82 kg/ha and crimson clover 9 kg/ha; and triticale 67 kg/ha and crimson clover 22 kg/ha. There were 3 replications per treatment. The biomass was harvested on 5/21/15 and terminated on 5/29/15 with roundup and the standing residue cut and laid on the surface of the plots. Soil samples were collected on 5/21/15 and 7/6/15 to discern changes in C:N ratios in the soil water extract and  the other parameters over time. There was a correlation between the plant C:N and the water extractable C:N with an R² of .52  P =.01 which indicates the test is picking up differences especially between the monocultures. There is also highly significant differences related to time of sampling between all of the parameters measured except for water soluble N.  When comparing their initial values to six weeks following termination, the summer values were lower indicating the importance of timing when sampling.