Crop Rotations: Effects on Soil Health and System Productivity

Abstract

Background: Crop rotation (CR) is a key conservation practice for sustaining soil health and productivity, but evidence on its effects is scattered across many soils, crops and climates.

Objective: To review how CR influences soil physical, chemical and biological characteristics and the productivity of cropping systems.

Methodology: Published field and long-term studies on rotations of cereals, legumes, vegetables and oilseed crops were reviewed and synthesised under soil physical, chemical, biological and productivity headings.

Results: Diversified rotations, particularly those including legumes and forage crops, generally reduced bulk density and improved porosity and hydraulic properties, although short-term trials showed little effect on macroporosity. Such rotations increased soil organic carbon (by up to 22% over maize–wheat), total nitrogen, available nutrients, exchangeable bases and enzyme activities (dehydrogenase by 52–79%). Rotation affected soil pH, electrical conductivity and cation exchange capacity in a system- and depth-dependent manner. Longer rotations reduced weed cover (from 40% to 20%) and soil-borne diseases (by 10–52%), and diversified rotations improved the robustness of crop productivity by 14%.

Conclusion: CR is an effective, multi-benefit strategy for sustainable soil management. Responses depend on crop sequence, soil type and duration, and the microbial mechanisms of disease suppression need further study.