Cover crops and reduced tillage did not alter soil chemistry in first 3 years

Cover crops have been promoted for increasing soil organic matter, which is critically low in many mid-Southern US row crop production fields. This study was conducted to inform adaptive management in the early transition period of conservation adoption. Temporal change in soil chemistry was investigated with a split-field experiment conducted over a 3-year period in Mississippi corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotational cropping systems that newly implemented winter cover crops and simultaneously reduced tillage. Relative to the untreated (i.e., winter fallow and multiple tillage passes) half of each study field, the chemical soil properties of the treated (i.e., winter cover crop and reduced tillage) half of each study field were not significantly different at the 0.05 significance level. This was true for soil organic matter, all macronutrients, pH, cation exchange capacity, base saturations, and micronutrients, with the exception of iron. Given these results, it is unlikely that growers adopting cover crops while reducing tillage will be able to accumulate significant soil organic matter in the early transition period.