Abstract
AbstractRotation of grass ley with periods of annual crop production can be a means to increased farming system productivity, sustainability, and profitability. This research review offers interpretations of rotation research results for future African agriculture. Some rotation studies were with naturally generated and severely over‐grazed fallows consisting primarily of annual plant species but other studies were with planted and well‐managed perennial grass ley. Generally, the rotations increased annual crop yields with soil improvement. System benefits were similar or greater for ley compared with fallow with generally higher fodder yields with ley. Surface crusting of sandy soil in the Sahel is a major concern that may be worsened by fallow due to the deposition of clay and silt particles. Ley and fallow were terminated in all studies with inversion plow tillage with more tillage for subsequent crops while the rotation benefits may be greater with less tillage. Most studies did not have fertilizer use but annual crop yield response to fertilizer was greatly increased following ley in one study and with no system by fertilizer interaction effect in three studies. The profitability of ley rotations will vary with fodder demand which is rapidly increasing, especially near urban areas. Strip cropping, for example, alternate ley with annual crop strips of 5–20 m width and rotation cycles of 6–10 yr, may often be optimal for erosion control and sediment trapping, protection from uncontrolled grazing, and nearby supply of vegetative planting material for ley re‐establishment. Rotation management can be improved through experiential learning and experimentation.
Highlights
1.1 Ley/fallow rotation globallyThe rotation of managed perennial grass or grass–legume mixtures with annual crops has been practiced and studied as a means to improve soil and farming system productivity, profitability, and sustainability
Opportunities for perennial grass ley rotated with annual crop phases as a means to improve farming systems are abundant in Africa
While land for annual crop production is often scarce, ley rotations are a means to reverse the common occurrence of soil degradation, sustainably improve soil, and increase annual crop yields and often yield response to fertilizer application
Summary
The rotation of managed perennial grass or grass–legume mixtures (ley) with annual crops has been practiced and studied as a means to improve soil and farming system productivity, profitability, and sustainability. Information on ley or herbaceous fallow rotations with annual crops in the tropics has not been well reviewed and such rotations have been less studied in recent decades compared with studies in temperate and subtropical areas. Soil organic matter is likely to increase during the ley stage due to reduced erosion and increased root biomass production with benefits to soil chemical, physical, and biological properties with implications for cropping system productivity and resilience to climate extremes (Dupont et al, 2014; Franzluebbers, 2012; Franzluebbers et al, 2014; Monti & Zatta, 2009; Persson et al, 2008). In Uruguay, following 50 yr of rotating 3 yr of perennial grass ley with 3 yr of annual crops, with fertilizer applied, there were increases of 40% for annual crop yield, 20% for SOC, and 34% for exchangeable K with little effect on soil pH (Grahmann et al, 2020)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
