Pasture is a piece of land on which forage crops or grasses or mixture of grasses and legumes grow. In other words, it refers to an area of land covered with forage crops which are usually grasses and legumes that are grazed or fed on by livestock such as cattle, sheep and goats.
Forage crops on the other hand are plants cultivated for their vegetative portions and used in fresh or preserved forms for feeding livestock.
Uses of Forage Crops
Forage crops have the following uses:
- Livestock Feed: Forage crops are usually used for feeding livestock like cattle, sheep and goat. Hay, straw and sillage are prepared from forage crops.
- As Cover Crops: Most forage crops, especially leguminous plants, serve as cover crops which add nutrients to soil and control weed growth.
- Conservation of Soil Moisture: Most forage crops, especially leguminous plants, help to conserve soil moisture by preventing evaporation.
- Prevention of Erosion: Some forage crops, especially leguminous plants, help to prevent water and wind erosion.
- As Green Manure: Forage crops, especially when they are young could be ploughed into the soil as green manure.
- For Roofing Farmsteads: Some forage crops like guinea grass and elephant grass are usually used for roofing farmsteads as a result of their strong stems and plenty leaves.
- As Bedding Materials: Most forage crops serve as bedding materials for animals.
Types of Pasture
There are two main types of pastures. These are:
1) Natural Pasture: Natural pasture is also refered to as natural grassland or rangeland. In this pasture, grasses and legumes grow naturally on their own and are fed upon by farm animals, i.e, grasses are not planted by farmers. Examples of natural grassland are the savanna areas of Nigeria.
Characteristics or Features of Natural Pasture
- Natural pasture or grassland contains poor quality grasses and legumes.
- It contains soil types that are low in fertility or nutrients.
- It contains wide varieties of grasses and legumes, some of which may not be eaten by livestock.
- It has good regenerative ability.
- Productivity of natural pasture is very low and resistant to drought.
- Forage crops in natural pasture can withstand trampling by farm animals.
- Natural pasture may contain some grasses which cannot be easily eradicated.
- New growth is stimulated by burning.
2) Artificial Pasture: This is also referred to as established or sown pasture. In this pasture, grasses and legumes are deliberately planted and managed by man to be fed on by livestock.
Characteristics or Features of Artificial Pasture
- It contains high quality grasses and legumes.
- It contains no weeds except some shade trees.
- Selected grasses and legumes are grown in adequate proportion.
- It has high regenerative ability after being fed on by animals.
- It can withstand trampling by farm animals.
- It is properly managed for high productivity of the forage crops e.g. fertilization, irrigation and rotational grazing.
Quality of a Good Pasture Plant
A good pasture plant must have the following qualities:
- Ability to regenerate fast after being browsed.
- Ability to withstand trampling effect of the grazing animals.
- A good pasture plant must be highly palatable.
- It must possess high value of nutrients.
- Ability to withstand extremes of climatic conditions.
- It should have moderate moisture content or succulent.
- It must have a high leaf to stem ratio.
COMMON GRASSES AND LEGUMES OF LIVESTOCK AND THEIR BOTANICAL NAMES
- Elephant grass (Pennisetum purpureum).
- Guinea grass (Panicum maximum).
- Giant Star grass (Cynodon plectostachyum).
- Carpet grass (Axonopus compressus).
- Spear grass (Imperrata cylindrical).
- Bahama grass (Cynodon dactylon).
- Northern gamba (Andropogon gayanus)
- Southern gamba (Andropogon tectorum)
- Centro (Centrosema pubescens).
- Stylo (Stylosanthes gracilis).
- Kudzu or puero (Pueraria phaseoloides).
- Calopo (Calopoganium mucunoides).
- Muccuna (Muccuna utilis).
- Sun hemp (Crotalaria juncea).
Characteristics of Some Pasture Crops
- Guinea grass (Panicum maximum): It is a dominant pasture grass in the rainforest zone. It is a bunchy or erect or tufted grass. It has a very vigorous growth of about 2m tall. It is perennial and has short underground rootstock. It is drought-resistant with high leaf to stem ratio. It is propagated by seeds or stolon. It is palatable to livestock and also good for making of hay.
- Elephant grass (Pennisetum purpureum): It is a widely distributed pasture grass throughout the rain forest zone. It is erect and of about 3-5m tall. It is a perennial grass with cane-like stems and dull green or purplish leaf blade. It is a highly leafy, palatable and aggressive grass. It is a high yielding grass, propagated by stolon and it is good for making silage.
- Giant Star grass (Cynodon plectostachyum): It is a spreading, drought-resistant, perennial grass with a long and rapidly-growing stem. This grass can grow more than one metre high. It is most easily propagated by cuttings and once established, it spreads very quickly, thereby making it difficult to control. It makes a nutritious pasture grass and responds well to fertilizers, especially the phosphate fertilizers.
- Carpet grass (Axonopus compressus): It is a perennial and a creeping type of grass. Its stems are creeping, short, compressed and two-edged. The stems have the tendency to root at the nodes. The grass does best on soil where the moisture is near to the surface but not on swamps. It is very aggressive and not nutritive. Hence, it is not so much recommended for pasture.
- Centro (Centrosema pubescens): Centro is a vigorous and an aggressive-growing legume. It is a creeping and twining plant with trifoliate leaves that are attached to the stem by a pulvinus. Stem and leaves are hairless. It is leafy, perennial, shade-tolerant and drought-resistant legume. It is self-seeding as the pods split open by explosive mechanism during dry weather and the seeds germinate during the following rainy season. It is palatable and highly nutritious to ruminants. It is highly nodulated and does well in combination with guinea grass.
- Tropical Kudzu (Pueraria phaseoloides): It is a vigorous climbing and perennial legume. Its stems and leaves are densely hairy and spread over the soil to form a good cover crop. Leaves are trifoliate. It is sensitive to soil moisture, stress and cannot survive drought condition. It is propagated by seeds, and its roots are nodulated. It is usually avoided by cattle on range, and it can be used as hay and silage.
- Stylo (Stylosanthes gracilis): It reaches 60 – 89cm in height. When kept short through regular cutting or grazing, it develops into a leafy plant, which is highly nodulated. Leaves are trifoliate and creep along the ground. They are drought-resistant, propagated by seeds and perform better in dry areas. It takes livestock a little while to get used to the taste.
FACTORS AFFECTING THE DISTRIBUTION OF PASTURE
Factors affecting the distribution of pasture can be grouped into three main classes:
- Climatic Factors: The type of climate in an area influences the type of vegetation in that particular area. For example, Sudan type of climate favours the growth of grasses and legumes while Equatorial climate does not. Elements of climate which can directly influence the distribution of pasture are rainfall, wind, temperature, relative humidity, day length, sunlight, etc.
- Soil or Edaphics Factors: This refers to the level of fertility of the soil. Fertile soil tends to support pasture growth while poor soil does not. Soil factors which may influence the distribution of pasture are soil pH, soil texture, soil structure as well as the slope of the land (topography).
- Biotic Factors: Biotic factors like diseases, pests, parasites, predators generally influence the distribution of pasture. The activities of man such as bush burning and overgrazing generally have adverse effects on the distribution of pasture.
FACTORS AFFECTING THE PRODUCTIVITY OF PASTURE
These factors include:
- Persistence: This is the ability of the pasture crops to survive and spread by vegetative means.
- Aggressiveness: This is the ability of pasture to compete favourably with other weeds. High aggressiveness ensures continuous availability of the pasture crops.
- Resistance to Trampling: This refers to the ability of pasture to resist continuous trampling by farm animals during grazing and still remains available to livestock to feed on.
- Seed Viability (or profuseness): Seeds of pasture should be viable over a long period of time. It should be easily propagated to ensure high pasture productivity.
- Resistance to Drought: Pasture which is able to withstand drought helps to maintain high productivity and ensures all-season availability of forages for livestock.
- Pests and Diseases: Absence of pests and diseases within a pasture ensures their increased productivity.
- Accurate Stocking: An accurate number of animals should graze a specified area of pasture. Overgrazing does not ensure increased productivity of pasture.
- Good Management: Proper management practices such as regular weeding, roguing, irrigation, good grazing and fertilization should be practised to ensure increased productivity of pasture.
ESTABLISHMENT OF PASTURE
Before pasture can be established, the following factors should be considered:
- Adaptation of Species: Legumes and grasses should be adapted to the local environment.
- Palatability: Legumes and grasses to be established must be palatable and nutritious for animals.
- Compatibility: The grass-legume mixture in the pasture must be compatible to each other.
- Time of Maturity: Grasses and legumes to be established should be able to mature within the shortest possible time.
- Life Cycle of the Species: Annuals with annual plants or perennials with perennial plants should be mixed together when establishing pasture. This is to ensure continuous availability of pasture.
The establishment of pasture takes the following sequence
- Site Selection: Select a suitable site which should be well-drained with good loamy soil.
- Clearing of Land: The land should be cleared. Cut back the site with hoes and cutlasses.
- Removal of Debris: Debris on the site should be removed or it could be gathered and burnt.
- Cultivation of Site: The land, field or site should be cultivated by way of ploughing, harrowing and if possible ridging.
- Planting of Pasture Crops: Planting of the desired pasture, grass or legume is carried out.
- Supplying: Plant materials that fail to germinate should be supplied with new planting materials.
- Planting of Legumes: Leguminous plants should be planted, especially in the case of grass and legume mixture.
- Promotion of Tillering: The grasses should be cut back at regular intervals to promote tillering.
- Weeding: Weeding should be done at regular intervals, especially at the early stages of the pasture.
- Fertilizer Application: Apply fertilizers at the appropriate rate by broadcasting.
- Irrigation: Light irrigation or watering of the planted seeds or stolons should be done, especially in arid areas with low rainfall.
- Paddocking: The pasture should be broken into convenient units for good grazing management like rotational grazing.
Determination of Plant Population
In the establishment of pasture, it is very important to know the quality of pasture or forage crop to plant in a specified area of land.
In doing this, it is very important to understand certain principles and formula required to ensure an adequate plant population in an area of farmland.
A piece of land to be used to establish a pasture of Centrosema pubescens was surveyed to be circular:
- if the radius of the land is 100m and the spacing of the pasture legume is 80cm by 40cm, what is the population of the legume at one seed per stand?
- If the germination percentage is 60, calculate the expected plant population.
COMMON MANAGEMENT PRACTICES IN PASTURE
Some common management practices in pasture to ensure continuous supply of grasses and legumes to livestock include the following:
- Burning: Burning should be done once in a year, especially when the forage crops are over-mature and fibrous. This is to encourage regrowth of the grasses and legumes.
- Fencing: This is the partitioning of the pasture into sections called paddocks to facilitate rotational grazing.
- Application of Fertilizer: Application of fertilizers in the pasture ensures rapid and succulent growth of pasture because of increase in the fertility of the soil.
- Weed Control: Weeds should be removed regularly from the pasture to prevent competition with forage plants for nutrients and space.
- Pests and Diseases Control: These should be prevented to ensure rapid growth of pasture crops.
- Irrigation: Pasture farm should be irrigated, especially during the dry season to ensure the availability of fresh and succulent grasses all the year round.
- Adequate Stocking: The correct number of animals should be placed on a pasture to graze. Overgrazing should be prevented.