Increasing Cropping Diversity Under Continuous No-till Improves Soil Health and Crop Productivity.

Cropping diversity is importance to improve functional stability of no-till systems. The long-term effects of continuous corn, corn-soybean and corn-soybean-wheat rotation with cover crops on soil health and crop productivity under no-till were evaluated (1995 to 2014). Composite soil samples were collected at 0 to 15 and 15 to 30 cm depths from geo-referenced sites of each replicated plot were analyzed for microbial biomass, basal respiration, metabolic quotients, enzyme activity and earthworms (as biological soil quality); total organic C and N, active C and N, and greenhouse gas emissions (as chemical soil quality); and particulate organic C and N, bulk density, aggregate size distribution, and macro-aggregate stability (as physical soil quality). Corn, soybean and wheat yield data were collected and normalized as relative crop yield. The soil and crop data were normalized to calculate soil quality based on both inductive and deductive approaches. Data normalization was performed based on "higher values of soil and crop yield data are better indicators of soil quality" except soil bulk density and specific maintenance respiration rates. Results showed that low external input with increasing cropping diversity under continuous no-till had significantly higher soil quality values than that of high external input mono-cropping systems. Biological soil quality values had changed to a great extent as compared with chemical and physical soil quality values. Greenhouse gas emissions were less under no-till with increasing cropping diversity. Relative crop yield values were also higher with increasing cropping diversity with cover crops.