Forage crops - Agriculture Form 3
Suggested Learning Activities
Collect specimen of the common forage crops growing naturally or planted in the school farm and mount them in a practical book. Name each sample and describe the forage crop briefly.
2. Grow forage crops which are suitable to the ecological condition within the school compound.
3. Visit the nearby progressive farmers and find out the forage crops used to feed the livestock.
4. Prepare and store hay using tripod method.
In your previous studies you covered the meaning of livestock nutrition and the sources of feed nutrients.Livestock nutrition is the feeding of livestock for different products and ages.
1.Carrying capacity Is the ability of a forage stand to maintain a particular number of livestock per unit area. 2.Defoliation. Is the removal of top foliage in forage crops,through grazing in pastures and through cutting in fodder. 3.Digestibility. Is a portion of food retained in an animals body after taking care of losses through urine,faeces and gases. 4.Direct sowing. Is the establishment of the pasture crop in a clean seedbed where no other crops are growing. 5.Fodder crops. Are forage crops which are grown,allowed to mature,then cut and given to livestock as feed. 6.Forage crops. Are crops grown for feeding livestock. 7.Hay. Is a dehydrated forage having 15-20% moisture content or less. 8.Legume seed inoculation. Is the application of nitro-culture to seeds of legumes to help the legumes fix nitrogen. 9.Mixed stand pasture. Is a mixture grasses and pasture legumes growing together within the field. 10.Oversowing. Is the establishment of pasture legume in an existing grass pasture. 11.Paddock. Is a fenced portion of a pasture land in which animals are restricted for grazing. 12.Pastures. Are forage crops which are grazed on directly by the livestock while still growing on the field. 13.Pure stand pasture. Is a pasture made up of only grass or only legume growing within the field. 14.Reseeding. Is a field management practice involving refilling of the gaps left where forage crops have died. 15.Rotational grazing. Is the practice of allowing livestock to feed on a portion of the pasture for a period of time until the pasture is down to the required level before they are moved to the next portion of pastures. 16.Silage. Is a product of controlled anaerobic fermentation of green forage. 17.Stocking rate. Is the number of livestock units maintained per unit area of land. 18.Topping. Is the removal of stemmy fibrous materials left over after a period of pasture grazing. 19.Undersowing. Is the establishment of pasture under a cover crop. 20.Zero grazing. Is a method of grazing where livestock are kept in a permanent feeding enclosure known as stall where there is provision of water and feeds.
By the end of this topic you should be able to
- Define pastures,
- Classify pastures,
- Identify forage crops,
- Describe the ecological requirements of forage crops,
- Describe the establishment and management of postures and fodder,
- Describe forage utilization and conservation.
One source of food nutrients to livestock is through provision of forage crops. Farmers therefore must be able to identify and classify various forage crops.
Pastures are forage crops which are grazed on directly by the livestock while still growing on the field. Pasture crops do not easily get spoilt when grazed on directly by livestock.
Classification of pasture crops
Pastures can be classified according to;
1 .Pasture stand
2. Nature of pasture establishment
3. Ecological zones where the pasture crop is grown.
- According to pasture stand, there are two classes of pastures namely; pure stand pastures and mixed stand pastures.
- Natural pastures and artificial pastures are classes of pastures, if classification is done according to the nature of pasture establishment.
- adapted to the prevailing environmental conditions,
- fast growing,
- able to give high yields per unit area,
- of high nutritive value.
Planting materials may include;
- Grass seeds
- Grass Splits
- Grass rhizomes
Land prepared for planting grass seeds should have fine tilth since the pasture grass seeds are very small in size.Click the play button to see the video.
Legume seed inoculation
This is application of nitro-culture to seeds of legumes to help the legumes fix nitrogen.Nitrogen fixation in legumes takes place only when its roots are infected by the right strain of Rhizobia. Some Rhizobia strains are naturally found in the soil at pH 5.5-8.0 with adequate calcium, phosphorus, potassium and rainfall.
Sowing of Pastures.
Pasture sowing is the planting of pasture seeds. Common methods of pasture sowing include;
- Direct sowing,
- Under-sowing and Over-sowing.
During under-sowing farmers establish pastures under a cover crop while in over sowing there is establishment of pasture legumes in an existing grass pasture.
Management of pasture crops involves taking care of the pastures after full establishment of the crop in the field.Major management practices in pastures include:
- top dressing,
- controlled grazing and pest control.
Pasture utilization refers to how pastures are used when they are ready in the field. Pastures are best used when they have the highest nutrient content. Regardless of the type of forage, there is gradual decline in quality with age. Digestibility of pastures declines because of the increase in crude fibre content as the pasture matures. Crude fibre can only be digested through the activities of microbes in the alimentary canal.
The stage of defoliation
Stage of defoliation is the level of growth at which a forage crop is utilized. Defoliation should be done when the crops are of highest nutritive value. Effects of early and late defoliation help to determine the proper frequency of defoliation and thus the best stage of defoliation. Frequent early defoliation leads to gradual weakening of the stand followed by empty patches, weed invasion and eventual reduction in the productive life of the stand. There is high cellulose content in forage crop and low digestibility of dry matter when farmers carry out late defoliation of more than 10weeks.
Intensity of defoliation.
Intensity of defoliation is the proportion of herbage removed through grazing and that of the residual forage for pasture crops. Intensity of defoliation affects the height of the stubble remaining after a period of pasture grazing. Pasture should be grazed until 70% of the herbage is eaten up.70% consumption of pastures by livestock coincides with 5cm stubble for short grasses and 10-15cm stubble height for taller grasses.
Methods of defoliation.
The method of defoliation is dictated by grazing systems used during a period of pasture utilization. Broadly, there are extensive and intensive grazing systems.In extensive system, large tracts of land are required while in intensive system small area of land is used. Individual methods of grazing include continuous grazing and rotational grazing. Common methods of rotational grazing are: paddocking, strip grazing and tethering.
Methods of rotational grazing.
In paddock grazing the farm is divided into a number of fields preferably four or more by permanent fences.
Strip grazing is a more intensive method of rotational grazing. It is recommended for use in high yielding pastures.
In tethering, animals can be tied to a peg or onto a wire using sliding knot. It is popular in areas of high population and where few animals are kept.
In tethering animals are tied using a rope thus confining them to a particular small area. The animals are moved to another spot when the pasture has been reduced to the required level.
Forage conservation is the utilization of forage crops without wastage. Conservation is only relevant to farmers who maintain proper stocking rate since most of them tend to base their stocking rates on the amount of forage available during wet season. Forage can be conserved in form of silage, hay or as standing forage. Conservation helps in distribution of available forage throughout the year and provision of feed for the dry season. It acts as a source of income when conserved forage is sold and ensures better utilization of land.
Conservation of forage in form of forage (standing forage) is the most common method of forage conservation. It involves deferring grazing or cutting a portion of forage for dry season feed. Procedure involved when conserving pastures in form of standing forage include;
- Grazing animals at the end of wet season
- Carrying out topping.
- Top-dressing the forage crop.
- Deferring grazing until dry season sets in.
Utilization of forage
The utilisation depends on the requirement of the animal and forage materials available. The forage material should be properly prepared before feeding the animal to avoid wastage.The exess forage should be stored for the dry season or sold.
Hay is dehydrated forage having 15-20% moisture content or less. This method of forage conservation is mainly applicable to pasture grasses and legumes for example Rhodes grass or green leaf desmodium.
Storing the hay in a shed or on a tripod stand.
Several factors affect the quality of hay. Poor forage species and late harvesting of forage crop normally lead to poor hay quality. Also long drying periods due to cloudy weather conditions cause oxidation of soluble nutrients leading to poor quality hay. Poor storage structure leading to rotting and leaching of soluble nutrients in stored hay significantly lower the quality of hay.
Click the play button to see the video
Silage making is the conservation of green forage as a product of controlled anaerobic fermentation. It is done in a structure known as silo and the process is known as ensiling.Silage making aims at preserving the herbage with minimum loss of nutrients.It takes 2-3 weeks to complete the ensiling process.
The ensiling process may require addition of additives to improve nutritive value of silage when forage having low amount of carbohydrates or having over 70% moisture are used for silage making.
Qualities of a good silage
Several factors affect the nutritive value of forage and therefore its quality.These may include relative proportions of organic acids in the silage,compaction of ensiled materials and the quality of forage used when making the silage.
Qualities of a good silage include:
- Having in order of predominance lactic acid, sussinic acid and formic acid.
- Having pH value of 4.2 and below.
- Be greenish yellow in colour.
- Be free from moulds and of fine texture.
- Having 5-9%lactic acid.
Fodder crops are forage crops which are grown and allowed to mature and then cut and given to animals as a feed.Fodder crops easily get spoilt when fed on directly by livestock.
Herbage production from fodder crops is higher per unit area of land than pastures. Farmers can get good amount of money if they produce conserve and sell fodder crop especially in large scale farming.
Livestock nutrient requirements
Guidelines when calculating livestock nutrient requirements.
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