In terms of grazing management, there are two key factors that impact grass productivity and longevity: rest and residual height. If we step back to basic biology, we all know that plants make energy through photosynthesis. The warehouse for this work is the leaf, which is removed in grazing. Plants realize that this is a possibility and have stored carbohydrates in their roots and, for most grasses, in the bottom 2” of the plant. This stored energy is used to regrow new leaves and once those begin photosynthesis, the energy is replenished. If enough REST is not given, that process cannot be finished and the plants eventually run out of energy, lose vigor and yield. In grasses where the energy stores are in the bottom 2”, making sure to not overgraze and remove that storage is critical. Utilizing a rotational grazing plan will make this rest and residual height easier to manage. Temporary fencing is one the most flexible and economical methods to implement a pasture rotation.
Each species of forage has unique growth characteristics, advantages and pitfalls. There is no single forage that can meet all of our needs. Diversity, not just within a pasture, but throughout the farm is the hinge that makes the stocking rate and grazing management techniques work. The majority of farms have a large perennial base, and the most successful also have a small to moderate percentage of the acreage in annual grasses. These annuals are higher quality but the yield tends to be more impacted by the immediate weather patterns. Perennials are dependable once established, but growth windows are more limited than acreage kept in an annual rotation.
Even with diverse forages, the appropriate yearly stocking rate, and excellent grazing management, there are forces of nature that farmers cannot control. The same strategies from one year may not be as effective in the next. Farming is all about creating a plan and having goals, but also being flexible and adapting to the immediate conditions.