Soil Biological Health: Influence of Crop Rotational Diversity and Tillage on Soil Microbial Properties

Abstract

Core Ideas We studied the impact of three rotations and two tillage systems on soil biological health after 25 yr. A significant rotation × tillage interaction was found for microbial biomass C and N, hot‐water‐extractable C, and urease and β‐glucosidase activity. Adoption of no‐till and diversified crops improved these soil health properties. Crop rotational diversity and tillage management influence soil microbial properties. Three crop rotations [maize (Zea mays L.)–soybean (Glycine max [Merr.] L.) (the 2‐yr rotation); maize–soybean–oat (Avena sativa L.) (3‐yr rotation); maize–soybean–oat–wheat (Triticum aestivum L.) (4‐yr rotation)] in combination with no‐till (NT) and conventional tillage (CT) were used to assess the impact on soil health parameters such as microbial biomass C (MBC) and microbial biomass N (MBN), C fractions, and urease and β‐glucosidase enzymes. Soil samples were collected in the maize and soybean phases at planting and harvest in 2016 at surface depth (0–7.5 cm). A significant tillage × rotation interaction was observed for all the parameters. At planting, under the maize phase, NT with the 4‐yr rotation increased MBC by 86% and MBN by 20% compared with the same cropping system (4‐yr) under CT. The hot‐water‐extractable C fraction under NT was, respectively, 19, 27, and 71% higher at maize harvest, soybean planting, and soybean harvest than under CT. Urease activity under the 4‐yr rotation with NT was 55% higher than that under the 2‐yr rotation with NT and almost doubled that under the 4‐yr rotation with CT. Beta‐glucosidase enzyme activity was higher under the 2‐yr cropping system with NT than in the other treatments at planting and harvest in the maize phase. A diverse cropping system (maize–soybean–wheat–oat, the 4‐yr rotation) managed with NT could benefit soil health by improving MBC, MBN, hot‐water‐extractable C, and urease and β‐glucosidase enzyme activity.