Forage Diversification to Build Resilient & More Productive Pastures

Authored by: Jose Dubeux, M. Moitinho, L. Garcia, M. Cunha, M. Sales, K. Trumpp, C. Mendes, K. Sganzerla, O. Ramsey, C. Freire, B. Cheptoo, M. Medeiros, G. Souza, D. Rodrigues, C. Cargnelutti, M. Ruiz-Moreno, UF/IFAS North Florida Research and Education Center-Marianna Forage Team

–

Introduction

diverse forages during transition to summer — Figure 1. Pasture in Marianna during the spring/summer transition. During this transition, this pasture has seven forage species (oats, annual ryegrass, red, crimson, and ball clovers, bahiagrass, and rhizoma peanut). Credit: Jose Dubeux, UF/IFAS

Forage species have different tolerance levels to pests, diseases, and weather conditions. They also grow best at different times of the year and have different rooting depths. They may also serve different functions in promoting pasture growth. For example, forage legumes in association with soil microbes fix atmospheric nitrogen, reducing the need for nitrogen (N) fertilization. Deep-rooted grass and/or brassicas can help reduce compaction by breaking the hard-pan layer. Some species are more adapted to shade or poor drainage conditions than others. Selecting forage species for your pasture is like putting together a team of athletes. Each player has a different role and performs best when their strengths are needed. The species should complement each other and not compete for the same ecological niche. In the end, you have a pasture that is resilient and more productive, and less susceptible to environmental stresses such as drought, flood, cold temperatures, or pest and disease pressure. It is key to identify the functions of each potential forage species candidate and to group species that complement each other to enhance the system’s overall productivity.

–

What is a resilient and resistant pasture?

Does your operation bend or break under stress? Resilient pastures bend but bounce back quickly when exposed to stress and/or disruptions. The capacity to recover rapidly from stress is key to restoring growth potential and maintaining system stability. The extent to which pasture productivity decreases under stress defines its resistance. More resistant pastures have a buffering capacity, meaning their productivity declines less under stress than less resistant pastures (Figure 2). In Florida, several stresses affect forage-livestock systems, including variable rainfall (flood, drought), extreme temperatures (too hot, too cold), nutrient stress, and pests and diseases.

Figure 2. Example of resilient and resistant pasture systems. The blue line represents a diverse forage mix and shows greater resiliency and resistance than the orange line, which represents a single-species pasture.

–

Spatial and temporal complementarities

Plants that grow at different times of the season complement each other, and the result is greater pasture productivity. A good example for our region is overseeding cool-season forages on perennial pastures to increase winter productivity. We can also fine-tune and diversify forage species within each season. For example, small grains grow earlier than annual ryegrass. Likewise, crimson clover grows earlier than ball clover, and mixing these forages is a good strategy to extend the grazing season (Figure 3).

Figure 3. Seasonal growth and complementarity among forages in the Southeast.

–

Spatial complementarity is also important. Plants with deeper root systems can explore soil layers that shallow-rooted species cannot. Different functions also help enhance pasture resistance and resilience. Biological nitrogen fixation, for example, adds N to the system. Plants with tubers, such as tillage radish, can help to break hard soil layers. Grasses typically help build soil structure and promote soil aggregation (Figure 4).

Figure 4. Spatial complementarity and different functionalities across forage species.

–

Take Home Message

Diversifying forage systems provide insurance against environmental stressors, including extreme weather events, nutrient stress, and pests and diseases. Diverse pasture systems bounce back quickly from disruptions and don’t decrease productivity as fast as single-species systems, showing greater stability. The Florida Panhandle is a blessed region for growing forages, with the potential to develop year-round forage systems. However, you cannot do that with a single forage species! You need to diversify the system, both across seasons and within the season, to get the most out of your pastures!