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Grass Growth and Regrowth for Improved Management

Grass Types - Forage or Turf Grasses

Although grasses used for forage are not fundamentally different from those used for turf, their purposes are, so their management is different. Many species could be effectively used for both if management and purposes are well matched. Grasses used for forage are intended to provide good quantities of high-quality feed for livestock and wildlife while turfgrasses provide utilities such as soil stabilization or air filtering and cooling, decoration, and recreation. Turfgrasses are used for golf courses, sporting areas, lawns, and roadways.

Forage managers want abundant, high quality feed which assumes encouraging the vertical growth of grasses, mostly the leaves. Turf managers want to encourage horizontal growth and control vertical growth. Both can be possible when the growth and regrowth of grasses is understood.

Turf managers want to create a dense, fine textured, uniform, and smooth look. Grasses that are rhizomatous and stoloniferous are key players in thick turfs. They want grasses that are uprightly rigid, with good elasticity and resiliency to improve footing stability and ball roll.

Desired forage grasses are leafy, palatable, and digestible. Persistence of both turf and forage grasses is desirable, as is a healthy stand.

Though the purposes may be different, both turf and forage grasses are often mismanaged. Both require proper selection, establishment, fertilization, pest control, and cultivation although with different goals in mind. Turf grasses are often irrigated and mowed, while pastures may not require as much intensive management.

Management Implications

Turfgrasses are usually low growing and often stoloniferous (bentgrass, bermudagrass), or rhizomatous (bluegrass), or are seeded at such high rates that the individual plants form a firm sod (as with ryegrasses). With frequent, precise, and consistent mowing systems, the grass shoot adjusts by maintaining short sheaths so that the collar zone of the leaf is safeguarded, and the essentially complete lack of culm develoment serves to preserve the shoot apex of flowering shoots. Thus, the above ground meristem is largely preserved and can function to provide prompt competitive regrowth.

Grasses chosen for turf have an abundance of vegetative shoots (as opposed to flowering shoots) and there is little concern about the seedheads in shoots that are induced to flower. Shoots of turfgrasses that have been induced to flower will produce a seedhead no matter the frequency of mowing or stubble height. But, culm internodes in these shoots elongate minimally and the shoot apex remains below the the cutting height until the peduncle pushes the seedhead up to a vulnerable position.

If forage grasses were managed with the same finesse, there would be some positive outcomes. Forage grasses have a tendency to grow tall, and infrequent defoliation provides the opportunity for the grass to reach a stage of development that renders it sensitive to severe defoliation (growing points are sacrificed, or collar zones of elongated sheaths are destroyed so there is no mechanism to ensure continued blade development). This is basically the secret of wise turf management.

Grasses used for forage have a strong tendency to produce flowering stalks. Consequently, the "early-jointing" stage represents a hazard under intensive close grazing. Additionally, the longer rest interval between defoliations may allow the grass to reach a developmental stage when it is sensitive to mismanagement. To mimic the turfgrass management which usually means mowing once a week with a 7-day rest interval, it would require 8 paddocks to accomodate 1 day of grazing with 7 days for rest. The livestock would need to work overtime trying to get enough energy for production from 7 days recovery growth.

During the past decade intensive grazing systems have been developed which essentially mimic turfgrass management. Their goal is to maintain strong plant growth, so grazing or mowing is used to help the plant remain strong. Forage managers that view grazing only from the livestock's viewpoint would gain much by balancing the needs of the plants with those of the animals.

With turfgrasses, it is easy to mow a 3-inch growth back to 1 1/2 inches and thus "take half and leave half." However, with grazing systems it is difficult to adjust the stocking rate to ensure that this goal is achieved. More than likely, a 12" canopy will not be grazed back to 6" in order to preserve essential meristemic regrowth systems. The temptation to maximize conumption is too great.

Turfgrasses are carefully watered because their root system is shallow. Irrigation is scheduled to prevent foliar diseases. Forage grasses are often not cared for in such a careful manner.

Consider these points before grazing or clipping in balancing grass health, yield, and quality:

 

How does Grass Grow?
introductionimportancestructureslife cyclesTypesDevelopmental Phasesphotosynthesiscarbohydratesenvironment

How does Grass Regrow?
defoliationanimal habitsmanagementsummary

Resources:
referenceslinksglossaryteachingspeciespublications

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