Introduction of Forage Plants in Pastures

Environmental Issues To improve quality and productivity of native pastures and rangelands, farmers and ranchers introduce selected pasture plants in the vegetation by oversowing. If the native vegetation is poor in useful plants for grazing and browsing, they can replace it by sown or planted selected species, establishing artificial pastures and fodder banks. These plants are commonly the result of selection and can be exotic. They are chosen for their ability to withstand grazing conditions or cutting, but some of them can become weeds or invading plants. | Environmental Issues Techniques Costs Targeted Livestock System Context of Application Impacts Indicators

Techniques

Different kind of plants are appropriate to be introduced the native flora and improve the pastures : grasses, herbaceous legumes, small shrubs, trees. Technologies used to establish these plants are the following :

- pasture establishment by sowing after land clearing, plowing and preparation of seed bed.
- Oversowing of living vegetation with adapted equipment (see Reseeding and Rehabilitation).
- Oversowing simply by broadcasting seeds after a heavy grazing or burning, by hand, with machine, or by aircraft.
- Planting cuttings, young plants, rooted tillers, or suckers

Treatments of seeds or plants are sometimes necessary to improve the success of establishment : pretreatment of seeds to improve germination, inoculation of legume seeds with appropriate Rhizobia, treatment with insecticides against ants, broadcast of fertilizer (specially phosphate), weeding…

More arid the climate, more uncertain the success of this technique. The sown species must be able to compete with native plants. Pasture improvement with annual species suppose the use of species producing a lot of seeds and able to regenerate from seeds.

Costs

Costs vary in a wide range according to the sowing rate, the land preparation techniques, the cost of equipment, the time of labor.

For example, the cost of seeds can be:

- For grasses US$ 4.05 per kg, for a sowing rate of 5 to 20 kg/ha.
- For legumes, US$ 8.09 per kg, for a sowing rate of 5 to 10 kg/ha.

Targeted Livestock Systems

Grazing systems, particularly in ranching and mixed systems.

Grazing System

LGA | LGS1 | LGS2 | LGS3 | LGH1 | LGH2 | LGH3 | LGT1 | LGT2 | LGT3
N | Y | Y | Y | Y | Y | Y | Y | Y | Y

Mixed System

MCG | MCR | MCC | MFF | MEF
Y | Y | Y | Y | Y

Industrial System

IFP | IPL | IPG | IRM | IDU | ISL | ITN | IMP
N | N | N | N | N | N | N | N

Impact

- Positive environmental impact

- Improvement of biological diversity (increase the number of species in a native vegetation).
- Improvement of vegetal cover, control of erosion.
- Improvement of soil fertility.

- Negative environmental impact

- Reduction of biodiversity (establishment of uniform pastures, introduction of weeds and invading species competing with native species).
- Hazard of introducing weeds, vegetal pests, diseases and predators.

- Impact on livestock production

- Improvement of the quality and quantity of forage for livestock.
- Regulation of forage availability.

Context of Application

- Favorable factors:

- Reduction of the areas (rangeland and pastures) accessible to livestock.
- Decrease of the pasture productivity (degradation).
- Easy access to machines or workers for planting or sowing.
- Availability of plants or seeds.

- Unfavorable factors:

- Difficulty to purchase seeds or plants.
- Insufficient rainfall conditions (arid and semi-arid zones).
- Degradations caused by livestock during establishment.
- Land tenure (communal lands).

Monitoring: EIA, Indicators

- Contribution to the sown or planted species to the total biomass or plant cover.

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