Select Soil Enzyme Activities In The Historic Sanborn Field As Affected By Long-term Cropping Systems#

Abstract

Long-term experimental sites are expected to provide important information regarding soil properties as affected by management practices. Recent studies have shown that soil enzyme activities are sensitive in discriminating among soil management effects. This study was designed to examine the effects of long-term fertilization, tillage and crop rotation on the activities of acid and alkaline phosphatases, α-glucosidase, arylsulfatase, and urease in the historic Sanborn Field located on the campus of University of Missouri at Columbia, Missouri, USA. Sanborn Field has been under various cropping and management practices since 1888. Soil samples were collected from 0–10, 10–20, and 20–30 cm depth. In general, enzyme activity significantly decreased with depth under different management systems. Activities of five enzymes studied were significantly and positively correlated with soil organic carbon (C). With regard to tillage practice, activities of all enzymes were significantly higher for continuous corn under no-tillage than for continuous corn under conventional tillage. All five enzymes showed significantly higher activity in plots that received manure applications of 13.5 Mg/ha since 1888 regardless of crop type as compared with inorganic fertilization. The highest values for activities of acid phosphatase, arylsulfatase, α-glucosidase and urease were found in the 3-year rotation plot (corn–wheat–clover), which received manure as only source of fertilizer since 1888. The lowest values for these enzymes were found in the plot under continuous soybean grown under conventional tillage. It was concluded that enzymatic activities were reflective of the cropping systems, management histories, and soil properties observed on the Sanborn Field. #Research supported by USDA/CSREES, Cooperative Research, Lincoln University, Jefferson City, MO 65102, USA.