FORAGE CROPS.

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FORAGE CROPS.

FORAGE CROPS, Pastures are harvested directly by livestock through grazing.

  • Fodder are harvested by cutting and feeding to livestock.

PASTURES.

Pasture classification.

Pastures can be classified in three main ways.

  • According to the pasture stand.
  • According to pasture establishment.
  • According to the ecological zones/altitudes.

Classification according to pasture stand.

  • Pure stand.
  • Mixed stand.

Pure stand pasture has only one type of grass or a mixture of different grasses.

Mixed stand is where grasses and legumes are grown together.

Classification on the basis of establishment.

  • Natural pastures.
  • Artificial pastures.

Natural pastures grasses and legumes grow naturally and extensively. Are mainly mixed stand pastures.

Artificial pastures (leys) are grasses and legumes planted by man purposely for livestock feeds.

Classification on the basis of establishment.

  • High altitude grasses pastures and legumes.
  • Medium altitude pastures. S Low altitude pastures.

High altitude pastures.

Pastures found at high altitude of2500M above the sea level. Suitable for dairy and sheep farming.

Examples.

Grasses.

    Common name                       botanical name.

  1. Kikuyu grass. (Pennisetum clandestinum). 
  2. Nandi Setaria. (Setaria   sphacelata). 
  3. Molasses grass. (Melinis minutiflora). 
  4. Giant Setaria. (Setaria splendida).
  5. Rhode grass. (Chloris gayana).

Legumes.

 Common name                                botanical name.

  1. Kenya white clovers. (Trifolium repers).
  2. Louisiana white clovers. (Trifolium semipilosum).
  3. Subterranean clover. (Trifolium subtervianeum.).
  4. (Medicago sativa).

FORAGE CROPS.

Medium altitude pastures.

Pastures found at an altitude between 1500-2500M above the sea level. Favours beef, goats, sheep and dairy farming.

Examples.

Grasses.

Common name                       botanical name.

  1. Rhode grass. (Chloris gayana c.v,Mbarara) 2. Nandi Setaria. (Setaria sphacelata c.v.Nandi)
  2. Star grass. (Cynodon dactylon).
  3. Makueni guinea.                 (Panicum maximum c.v.Makueni).
  4. Congo signal. (Branchiaria yuziziensis).
  5. Malava guinea. (Panicum coloratum).
  6. Giant Setaria. (Setaria splendida).
  7. Guatemala grass.                   (Trypsacum   laxum).

Legumes.

Common name                       botanical name.

  1. (Medicago sativa).
  2. Silver leaf Desmodium. (Desmodium uncinatum).
  3. Green leaf Desmodium. (Desmodium intortum).
  4. (Macroptilium atropurpureum).
  5. (Stylosanthes guiyanensis).

Low altitude pastures.

Found in marginal areas below 1500M above the sea level. Characterised by natural pastures Examples.

Grasses.

Common name                       botanical name.

  1. .African fox tail. (Cenchrus ciliaris).
  2. Maasai love grass.  (Eragrostis superba).
  3. Likoni guinea. (Panicum maximum c.v.Likoni).
  4. Makarikari grass. (Panicum coloratum).
  5. Red oat grass. (Themada triandra).
  6. Hyparrhenia (thatch grass). (Hyparrhenia rufa).
  7. Giant star grass. (Cynodon plectostadyus).
  8. (Bothriochloa insulpta).
  9. Para grass. (Branchiaria mutica).
  10. (Andropogon spp).
  11. (Cymbopogon afranandus).
  12. (Digitaria decumbeus).

Legumes.

Common name                       botanical name.

  1. (Stycosanthes searbra).
  2. (Glycine weghtii).
  3. (Cenrosema pubescens).

FORAGE CROPS.

Other pasture crops, Weed grasses.

Common name                       botanical name.

  1. Couch grass.         (Digitaria scalarum).
  2. Nut sedges. (Cyprus spp).
  3. (Sporobolus spp).

Fodder shrubs.

Common name                       botanical name.

  1.   (Leucaenia leucocephala).
  2. (Atriples spp).

Pasture establishment.

Pastures can be established by use of:

  • Seeds
  • Rhyzomes
  • Splits.
  1. a) Selection of planting materials.

Should be:

  • Adapted to the prevailing environmental conditions.
  • Fast growing in order to give a good ground cover which helps to control soil erosion.
  • A variety able to give high herbage yield per unit area.
  1. Land preparation.

Land should be ploughed and harrowed to a fine tilth. All perennial weeds should be removed at this stage.

  1. Planting materials.

Most are established from seeds. Permanent pastures are established vegetatively due to seed production problem.

  1. Seed rates.

Pasture grasses require a seed rate of 1.5 to 2.0kgs /ha of PGS (pure germinating seeds)

  1. Fertilizer application at planting time.
  • Requires phosphorus for proper root development and establishment.
  • SSP (20% P2O5 and 12%S) at the rate of 200kg/ha for grasses and legumes mixtures because of its sulphur content.
  • For pure grasses a compound fertiliser such as NPK 20:20:0 or 23:23:0 ensures rapid establishment due to presence of starter nitrogen.
  1. Legume seed inoculation.

Addition of effective Rhizobia to leguminous seeds before planting to promote nitrogen fixation.

Involves coating of seeds with the mixture (source of nutrient).

Some Rhizobia are naturally found in soil at pH of5.5-8.5, with adequate calcium phosphorus and potassium and rainfall.

Crop.  Rhizobium species.

 

 

Lucerne.

Rhizobium melioti.
 

Clovers.

Rhizobium trifoli.
 

Beans.

Rhizobium phaseoli.

FORAGE CROPS.

  1. Sowing

Methods of sowing.

  • Direct sowing. S Under sowing.
  • Over sowing.
  1. Direct sowing.

Establishment of pasture crops in a clean seedbed where no other crops are growing.

Seeds are mixed with fertiliser and broadcasted and then slightly covered 3mm deep.

  1. Under sowing.

Establishment of a pasture under a cover crop usually maize. Maize is planted, weeding is done 2-3 weeks after onset of rains then pasture seeds are broadcasted. Maize is harvested early to expose the pasture seedlings to sunlight.

  1. Over sowing.

Establishment of a pasture in an existing grass pasture.

The growth of the existing pastures is suppressed by:

  • Burning
  • Slashing
  • Hard/heavy grazing with light soil disturbance.

SSP at a rate of 200kg-400kg/ha is applied. Pasture grass is then kept short until the legume pasture is well established.

MANAGEMENT OF PASTURES.

Weeding.

Effects of weed on pastures.

  • Weeds reduce life span of the pastures.
  • Weeds compete with footage crops for nutrients, sunlight and moisture.
  • Weeds reduce quality and herbage yield.
  • Some may result in livestock poisoning such as Datura stramonium.
  • Weeds interferes with forage fertilisation.

Effective weed control measures.

  • Timely land preparation.

Ensures clean seedbed with less subsequent weed problem.

  • Slashing

Eliminates broad leaved weeds before flowering stage preventing formation of seeds.

Application of selective herbicides.

Such as 2,4-D against broad leaved weeds on pure stand pastures.

  • Uprooting of weeds.

Effective where weeds are scattered.

Top dressing.

Reasons for top dressing.

  • To add (replenish) soil nutrients and ensure proper nutrient balance.
  • To improve the nutritive value of the crop.
  • To increase herbage yield.
  • To correct or amend both physical and chemical properties such as oils structure and water holding capacity.
  • To enable the soil microorganisms to break down organic residues into available nutrients.

Rate of application should be related to the nutrients uptake by the forage crop.

  • Topping

Removal of the stemmy fibrous material left over after a period of pastuer grazing.

This stimulates fresh growth.

Done through slashing, mowing and burning.

  • Re-seeding/gapping.

Done when the grass or legume is partially denuded to an extent of refilling the gaps.

  • Controlled grazing.

Some pasture crops are seriously affected by heavy grazing. Grazing should be controlled through paddocking, tethering and strip grazing.

FORAGE CROPS.

Pest control.

The most serious pest is mole. They make underground tunnels destroying roots of pasture crops hence killing them.

Control.

  • Trapping
  • Use of rodenticides.
  • Biological control such as cats.

PASTURE UTILISATION.

Forage quality.

There is gradual decline in quality components and digestibility with age.

Digestibility decline because of the increase in crude fibre content.

Frequency of defoliation.

Defoliation.

Grazing in pastures and cutting for feed in fodder crops.

Intensity of defoliation.

Refers to how often forage stand is grazed or cut for feed.

Effects of very early defoliation. (Less than four weeks).

  • The forage has very high moisture content of about 90%.
  • It has very high protein content on weight basis.
  • Has very low DM content hence low DM yield.
  • Has very low crude protein yield.
  • It has high DM digestibility but low digestible nutrients.
  • Frequent early defoliation leads to a gradual weakening of the stand, followed by empty patches and weed invasion.

Effects of late defoliation. (More than ten weeks). 

  • It has high DM hence high DM yield.
  • It has high cellulose content hence it is woody and fibrous.
  • It has high lignin, cutin, tannin and silica content that are indigestible.
  • Has low crude protein content.
  • Has low leaf: stem ratio.
  • Has low DM digestibility.

Reasons why paddocking is necessary.

  • To control grazing and ensure sufficient re-growth before grazing is resumed.
  • To ensure better forage utilisation and less wastage through trampling, fouling and selective grazing.
  • To facilitate conservation of excess pastures in form of hay or standing forage.
  • To maintain a favourable grass-legume balance in case of mixed stand.

Carrying capacity and stocking rate.

Carrying capacity.

Ability of forage stand to maintain a particular number of livestock units per unit area.

Stocking rate.

Number of animals (LU) maintained per unit area of land.

Ways of increasing the carrying capacity.

Intensive management practices such as:

  • Use of fertilizers/ manure.
  • Use of supplementary roughages.

A dairy animal consumes 2.5kg dry matter for every 100kg body weight per day, the amount consumed by a jersey weighing 400kg live weight would be:

2.5X450/1000 X365/1000= 3.65 tonnes DM.

Grass. DM yield  T/ha/year Carrying capacity (L.U/ha.
Napier. 25-30. 5-7.0
Rhodes (Mbarara). 10.9-15.2. 2.5-3.5.
Nandi Setaria. 11.4-13.9 2.5-3.0.
Makueni grass. 9.9-15.9. 2.5-3.5.
Star grass. 5.3-9.1. 1.3-2.0.
Kikuyu grass. 4.3-14.3. 1.0-3.0

Effects of over stocking.

  • Insufficient regrowth period for the forage hence has effects similar to those of early defoliation.
  • Overgrazing and loss of soil cover leading to soil erosion.
  • Invasion of undesirable plant species especially weeds and shrubs.

Intensity of defoliation.

This is the preparation of herbage removed through grazing and that of the residual forage.

In fodder crops it refers to the ratio of the forage cut to what is left.

Pastures should be grazed until 70% of the aerial herbage is eaten up or 5cm stubble for short grasses and 10-15cm for taller grasses.

GRAZING SYSTEMS.

  • Rotational grazing systems.
  • Continuous grazing system.

1) Rotational grazing.

Refers to allowing livestock to feed on a part of pasture for a period down to a certain level before they are moved to the next.

Advantages of rotational grazing.

  1. Livestock make maximum use of pastures.
  2. Reduces the build-up of pest and diseases.
  3. Animal waste is distributed evenly in all fields or paddocks.
  4. Pasture area is given time to regrow before it is grazed on again.
  5. Excess pasture can be harvested for conservation.
  6. It is possible to apply fertiliser in portion of the pastures which are not in use. Reseeding and weeding can also be done.

FORAGE CROPS.

Methods used to achieve rotational grazing.

  1. Paddocking

Paddock. Fenced portion of a pasture in which animals are restricted for grazing.

Water troughs are placed between two paddocks so that animals can drink water from either paddock.

  1. Strip grazing.

Done by allowing livestock to graze on restricted portions of pasture at a time then moving them to the next. Done very high quality pastures.

It is expensive because it involves establishing an electric fences.

  1. Tethering

Involves tying an animal to a post with a rope such that it feed within a restricted area.

  • Continuous grazing.

Pastures are not allowed any resting period.

It may result in overgrazing if the stocking rate is not controlled.

  • Zero grazing. (stall feeding)

Practice of rearing animals in a permanent feeding enclosure known as stall.

Advantages.

  • There is quick accumulation of manure.
  • Animals make use of feeds without wastage.
  • Animals produce high yields due to less wastage of energy.
  • It is easy to control diseases and parasites.
  • Requires little land.
  • Allows higher stocking rate.

Disadvantages.

  • High initial capital is required.
  • High management skills are needed.
  • Need a lot of labour.
  • Diseases can be easily spread.

FODDER CROPS.

Forage crops which are grown, allowed to mature, then cut and given to livestock as feed.

Livestock do not graze directly on them as they easily degenerate.

1) NAPIER GRASS. (Pennisetum purpureum).

Varieties.

  • French Cameroon.
  • Bana grass.

French Cameroon.

Has thin stems and is not very hairy.

 Bana grass.

Hairy type with thick stems.

ECOLOGICAL REQUIREMENTS.

  1. Soil

Does well in a variety of soils within high and medium altitude zones.

  1. Rainfall

Requires a minimum of 750mm of rainfall per year. Should be well distributed throughout the year.

  1. Altitude and temperatures.

Does well in temperatures ranging from 24 degree to 29 degrees Celsius. Does well at an altitude of 2100M above the seal level.

ESTABLISHMENT AND MANAGEMENT. 

Land preparation.

Land is prepared early during the dry season. Vegetation is cleared and all stumps are removed.

Primary cultivation is then carried out removing all perennial weeds. The land is then harrowed to produce a medium tilth.

Furrows are made at a spacing of 90-100cm or holes at a spacing of 90-100cm between rows and 50cm between plants.

7-10 tonnes of well decomposed manure is then applied in the soil.

Planting

The materials should come from healthy and mature mother plants.

Stem cuttings or splits are used.

Stem cuttings should have 2-3 nodes. Planting should be done at the onset of the rains.

Stem cuttings should be placed in the furrows or holes in a slanting manner. Two nodes should be covered underground and one node should remain above the ground.

Fertiliser application.

Top dressing with nitrogen and potassium fertiliser is done about 6-8 weeks after planting.

(After first weeding).

Top dressing should be don thereafter after every harvesting to increase the rate of stump regeneration.

Weed control.

  • Weeds lower the yields of nappier grass as a result of competition for nutrients.
  • They also lower the rate of establishment.
  • Thorn apple and Sodom apple e.tc are poisonous to the livestock.

Controlled through cultivation, slashing, uprooting and use of herbicides such as 2.4-D.

FORAGE CROPS.

Defoliation.

Refers to the ratio of forage cut to what is left.

French Cameroon matures in about 3 months (first harvesting.).

Should be cut every 6-8 weeks depending on moisture availability. Cut at 1.2-1.5M high.

Bana grass grows up to 12 months without flowering thus is suitable for use as standing forage.

Utilization

Should be cut at 1.2-1.5M high when proportion of leaves is higher than that of stems.

Stems should be cut 2.5-5.0cm above the soul surface to facilitate faster re-growth.

Use a sharp panga to avoid destroying the stumps.

Excess nappier grass should be conserved as silage. It may also be used as mulching materials.

2) GUATEMALA. (Trypsacum laxum). 

It is a tall, hardy broad-leaved grass.

ECOLOGICAL REQUIREMENTS.

Altitude.

Does well in high altitude. It is affected by extreme coldness in altitude above 2000M above the sea level.

Rainfall.

Requires slightly high amount of rains ranging above 900mm per annum and should be well distributed throughout the year.

ESTABLISHMENT AND MANAGEMENT.

  1. Land preparation.

Land is prepared early before onset of rain. Land is ploughed and then harrowed to a medium tilth removing all perennial weeds.

  1. Planting

Established from stem cuttings or from splits. Seeds can also be used but it takes longer to reach cutting stage. Furrows are made at a spacing of one metre apart and the cuttings or splits are planted 0.5m apart. Planting should be done at onset of rains or where possible irrigation can be done after planting.

  1. Fertiliser application.

Organic manure is incorporated into the soil during land preparation. During planting NPK 20:20:0 is applied at a rate 150kg/ha. Top dressing with Nitrogen fertiliser is done when the grass is 6-8weeks old. Subsequent top dressing should be done after each harvesting and weeding to increase herbage production.

  1. Weed control.

Can resist weeds but the filed should be kept weed free especially before it establish well.

Done by uprooting, cultivation, slashing or by use of selective herbicides.

FORAGE CROPS.

  1. Defoliation

Takes a long time to flower thus can be harvested when it is over 8-12 weeks old.

Utilisation.

It is chopped and fed to livestock as green fodder. Suitable for stall feeding.

Production per unit area.

Yields 12 tonnes per ha of DM per year. Can support 2-3 cows.

3) SORGHUM.  (Sorghum alum).   

There are two main varieties.

  • Columbus grass. (Sorghum alum)
  • Sudan grass. (Sorghum Sudanese).

ECOLOGICAL REQUIREMENTS. 

Rainfall.

Does well in areas with rainfall above 650mm per annum. Should be well distributed throughout the year.

Altitude.

It grows best in altitude below 2100M above the sea level.

Soils.

Grows in a wide range of soils as long as the rainfall is enough and well distributed.

ESTABLISHMENT AND MANAGEMENT.

  1. Land preparation.

Land is done early before the onset of rains during which all perennial weeds are removed.

The field is ploughed and harrowed to a fine tilth.

FORAGE CROPS.

  1. Planting

Established by use of seeds. The seeds are either drilled or broadcasted. NPK 20:20:0 is applied at the rate of 200kg/ha for proper root growth and development.

  1. Fertiliser application.

Top dressing using CAN or ASN at rate of 125kg/ha depending on soil pH.

  1. Weed control

Keep the field weed free especially during the establishment stage. Weed control is done by hand cultivation, slashing or by use of selective herbicides.

Columbus grass lasts in the field for 18 months during which it is harvested severally. Columbus grass should be left to dry for two days to avoid prussic and hydrocyanic acid poisoning found in wet grass. In case of this poisoning, the animal should be dosed with sodium thiosulphate.

Production per unit area.

Yields over 20 tonnes/ha of DM per annum.

4) KALES.  (Brassica spp).

Ecological requirement.

Kales require high altitude with annual rainfall exceeding 100mm. grow well in loam and clay soils with reasonable.

ESTABLISHMENT AND MANAGEMENT.

They are established through seeds. Seeds are planted in nurseries six weeks before the rains.

Land is cleared, ploughed and harrowed to a medium tilth. Holes are dug at a spacing of 1.0MX0.3M. Transplanting is done at onset of rains.DSP is applied t the rate of 150kg/ha during transplanting.

Utilisation. 

Leafy stems are cut, chopped and fed to livestock.

Should be fed to milking cows together with dry roughages because they are very succulent.

Should be given to milking cows after milking to avoid tainting the milk.

FORAGE CROPS.

Production by unit area.

Produce 35-50tones/ha per year.

5) EDIBLE CANNA. (Canna edulis).  

Fodder crop with broad shinny leaves.

Ecological requirements. 

Requires high rainfall areas at an altitude of 15500-2000M above the sea level.

Establishment and management.

The land is cleared, ploughed and then harrowed. Holes are dug at a spacing of 1MX1M. Farmyard manure is mixed thoroughly in the holes before planting. Underground rhizomes are planted at the onset of rains. Early weeding is done. Cultivation, uprooting, slashing and by use of suitable herbicides. Top dressing is done four weeks after transplanting at the rate of 100kg nitrogen/ha. CAN is used for acidic soils while ASN for alkaline soils.

Utilisation.

Cut and feed to livestock when fresh.

Production per unit area.

100 tonnes DM/ha/ year.

6) MARIGOLDS/SUGAR BEETS. (Beta vulgaris). 

Root fodder crop.

Ecological requirements. 

Do well at high altitude areas with annual rainfall exceeding 100mm. grows well in well drained soils.

Establishment and management. 

Established through seed. Seeds are planted in nurseries 6 weeks before onset of rainfall.

Land is cleared, ploughed and then harrowed to a medium tilth. Holes are dug at a spacing of 1MX0.3M. Transplanting is done at onset of rain.DSP at a rate of 150kg/ha is applied at transplanting. Top dressing is done using CAN or ASN depending on soil pH at a rate of 100kg nitrogen/ha.

Utilisation. 

Used for feeding livestock during season at the rate of 22-27kg/cow/day. They are chopped into small pieces to prevent chocking. Should be wilted before being fed to livestock to prevent poisoning by oxalic content.

Production per unit area.

Produces between 30-40kg/ha under good management.

7) KENYA WHITE CLOVER. (Trifolium semipilosum)  

Low forage legume which grows to a height of 30cm. has slender spreading stems which produce roots and underground rhizomes.

Ecological requirements.

Grows in high altitude areas 2500-3000M above the sea level.in lower region it is restricted to the moist regions. Grows in a wide range of soils, preferably well drained with a pH of 5.5.

ESTABLISHMENT AND MANAGEMENT.

Has good seedling qualities and establishment from seed is easy where rainfall is sufficient.seeds are mixed with a Nitro-culture and broadcasted in moist soils. Established clover can do well over sown with other pastures.

Over sowing.

Clovers can be over sown with Nandi Setaria and Rhodes grass. It should be inoculated with the correct bacteria before sowing.

Inoculation. 

Addition of effective bacteria to the clover seeds before planting to promote the Nitrogen fixation especially when grown in mixed stand.

Fertiliser application.

Applicable to already existing grass pasture. Application of phosphatic fertiliser is advisable.

Utilisation.

Do not withstand heavy grazing. It is recommended to harvest the forage crop and take it to the animals.

FORAGE CROPS.

8) LUCERNE. (Medicago sativa). 

Leguminous crop also known as alfalfa. Common variety is the hunter river.

Ecological requirements.

Does well in high altitude areas. Requires well drained soils with a pH of 5.5 and above.

ESTABLISHMENT AND MANAGEMENT. 

Established through seed. The land is cleared, ploughed and then harrowed to a fine tilth. The seeds are then inoculated. A sticker lime gypsum pelleting is necessary if the soil or fertiliser to be used is acidic. Peat-based rhizobia can be bought for this purpose. Seeds are broadcasted at the rate of 5-10kgs/ha. If seeds are drilled in rows, the spacing should be 3050cm between the rows. DSP is applied at planting at a rate of 125kg/ha. Early weeding is done within the first month of establishment.

Utilisation.

Fed to livestock as hay since freshly harvested Lucerne can cause bloat. Fed in small quantities mixed with grass hay to lactating cows.

Production per unit area.

Produces 7-11 tonnes/ha with a CP of 17-20%.

FORAGE CROPS.

9) DESMODIUM.

Climbing perennial herb with slender stems and trifoliate leaves. Fixes its own nitrogen thus does not need any nitrogenous fertiliser.

Varieties.

  • Green leaf Desmodium. (Desmodium intortum).
  • Silver leaf Desmodium. (Desmodium unicinatum).

Ecological requirements.

Does well in tropical climate conditions. Grows at an altitude of between 1200M-1800M above the sea level.

ESTABLISHMENT AND MANAGEMENT. 

  1. Land preparation.

Should be done before the rains and all perennial weeds removed. Should be ploughed and harrowed to a fine tilth.

  1. Planting

Established through seeds. The pods contains 1-3 seeds. When interplanted with nappier grass, the Desmodium seeds should be inoculated at planting. Seed rate is 1kg/ha.

  1. Weed control.

Seedbed should be kept weed-free. Done through cultivation, uprooting or use of selective herbicides.

  1. Fertiliser application.

Phosphatic fertiliser is applied at planting time at the rate of 125kg/ha. Does not need top dressing because it fixes its own nitrogen.

Utilisation.

Should not be cut too short. About 25cm ground cover should be left. Fodder may be cut and fed to livestock together with dry forage such as hay. Should be wilted before feeding the livestock.it is eaten less by sheep possibly because it is somewhat aromatic.

10) AGROFORESTRY TREES/BUSHES USED AS FODDER CROPS.

There are several species of shrubs or trees used as fodder crops. Include: Leucaenia, Calliandra, Atriplex and Sesbania.

Ecological requirements.

Leucaenia leucocephala is suited to warm high rainfall of up to 1500mm.

Calliandra calothyrsus is suited to high altitude areas.

ESTABLISHMENT AND MANAGEMENT.

Established through seeds. Seeds are first planted in a nursery bed. Seedlings are transplanted at the onset of rains. Spacing depends on the crop with which it is intercropped with. Seedlings are cared for through weeding, fertiliser application and protection from animals as the farmer tends to the main crop.

Utilisation.

The leaves and branches are cut and given to the animals directly. First cutting should not be done until they are 3-4M high. Shrubs are cut back at 0.5M above the ground once per year and at the begging of the rains. This encourages faster regeneration. Green seed pods produced are removed and fed to the animals. They have many other benefits.

FORAGE CONSERVATION. 

Reasons for conserving forage.

  • To distribute available forage for stock throughout the year.
  • To provide feed for the dry season.
  • To ensure better and full utilisation of available land.
  • On a large-scale, conserved forage can be sold, for example baled hay.

FORAGE CROPS.

METHODS OF CONSERVATION.

  1. Hay

Dried forage, mainly applicable to pasture grasses and legumes for example Rhodes grass or Desmodium.

  1. Silage

Anaerobically fermented forage mainly applicable to succulent fodder such as nappier grass, maize and sorghum.

  1. Standing forage.

Growing forage set aside for dry season feed, applicable to both pastuer and fodder.

HAY MAKING.

Hay refers to forage which has been dehydrated (dried) to about 15-20% moisture content or less. Should be cut when about 50% of the plants have flowered. Cutting should be done when at least three days of continuous sunshine is expected.

Steps in making hay.

  • The crop is cut when 50% of the pants have flowered.
  • After cutting. The crop is spread out evenly on the ground to dry for 2-3 days depending on the environmental temperatures. Should be dried under controlled conditions in order to retain its nutritive value and the original crop colour.
  • The hay is windrowed and the gathered or baled.
  • The hay bales are then stored in a shed out of reach by rain water and sunshine.

Rapid drying is recommended to ensure high quality hay. Slow drying results in oxidation of soluble carbohydrates hence poor quality. Prolonged exposure to the sun results in the breakdown of chlorophyll and carotene. This is evident by bleaching of hay. Rain spoils hay and when occasional showers are expected, the forage may be dried on tripods.

 Factors determining quality of hay.

  • Forage species used.
  • Stage of harvesting hence the leaf: stem ratio.
  • Length of the drying period.
  • Weather conditions during the drying process.
  • Condition of the storage structure.

Sprinkling salt or molasses improves the palatability of hay.

SILAGE MAKING.

Fodder crop harvested while green and kept succulent by partial fermentation in a silo.

Silo is a structure used for fermenting.

The process of silage making is known as ensiling.

Advantages of silage making.

  • More nutrients are preserved.
  • It has few field losses.
  • It is less dependent on weather conditions.
  • Can be persevered for prolonged periods with minimum loss of nutrients.
  • Once ensiled, there are no storage problems.
  • Can be fed directly without liquid additives.

Disadvantages of silage making.

  • It requires skills and great attention.
  • It is a labour intensive exercise hence expensive.
  • Most farmers cannot spare sufficient forage for ensiling at any one time.
  • It is bulky to store and handle.
  • Must be fed soon after removal.

FORAGE CROPS.

TYPES OF SILOS.

Trench silo.

Rectangular excavation on a slightly sloping ground to ensure proper drainage.

Applicable to small scale farmers.

Soil layer.

Clamp silo.

Constructed above the ground level in form of a trough with slanted sides for ease of compaction. The sides are made of timber walls with gaps between each pair of timber wall where soil is compacted. The floor is cemented.

 Bunker/tower silo.

A bunker silo is made of concrete above the ground and has perpendicular walls suitable for mechanical ensiling.

A tower silo is a tall. Round, metallic structure for mechanical ensiling.

Steps followed in making silage.

  1. The silo is prepared before harvesting the crop.
  2. The crop is cut at the appropriate stage (8-10 weeks for re-growths) and wilted for 612 hours to about 65-75% moisture content.
  3. The crop is chopped up and put into the silo, compacting it every 10-12cm layer.
  4. The silo should be filled as rapidly as possible, preferably in less than two days. The ensiled materials should have a ‘ridge’ appearance when ensiling is complete.
  5. Temperatures in the silo should be checked regularly during the ensiling process. If it is higher than 32.2, water should be added and compaction reduced. If it is below this, compaction should be increased and dry materials or molasses added.
  6. The ensiled materials is covered with polythene sheet or a layer of dry grass to prevent it from water and air.
  7. The silo is covered with a thick layer of soil.
  8. A trench is dug all round the silo to drain off rain water.

Principles of preservation. 

If aerobic respiration occurs during the ensiling process, it utilises the available soluble carbohydrates lowering quality. It must thus be minimised by compaction and rapid filling. Fermentation allows lactic acid bacteria (Lactobacillus spp) to increase rapidly within the first 4 days after silo sealing. Lactic acid bacteria acts on the readily available carbohydrates to produce lactic acid and limited amounts of: acetic, propionic, formic and succinic acid. Lactic acid concentration may reach 8-9% of DM reducing pH from 4 to 2. Low pH inhibits further bacterial growth and preserves the silage.

Use of additives.

Maize and other cereal crops such as wheat, oats and barley do not need additives. They are harvested at the soft dough stage as they have adequate supply of carbohydrates for proper fermentation. Others such as nappier grass have low amounts of carbohydrates thus need use of additives such as:

  • Crushed grains 100kg/ton of silage.
  • Molasses at 20-40kg/ton of silage.

Silage quality.

Poor silage compaction leads to low temperatures that results in excessive production of butyric acid instead of lactic acid.

Characteristics of good silage:

  • Be from high quality forage cut at the proper stage of growth.
  • Have a pH of 4.2 or below.
  • Have 5-9% lactic acid.
  • Be free of moulds and bad odours such as ammonia and butyric acid.
  • Be greenish to yellow, not brown or black.
  • Have a fine texture with no sliminess.

Silage losses.

  1. Surface spoilage.

Up tom 20% loss due to exposure and contact with soil.

  1. Seepage losses.

Extent of the loss increases with increase in herbage moisture and can be up to 50% in very young and succulent forage and the silo is not watertight.

  1. Gaseous losses.

Extended respiration results in loss of carbohydrates in form of CO2 .

Standing forage.

This is deferring cutting a portion of the forage for the dry season feed. However the herbage quality is low.

FORAGE CROPS.

ALL AGRICULTURENOTES FORM 1-4 WITH TOPICAL QUESTIONS & ANSWERS

PRIMARY NOTES, SCHEMES OF WORK AND EXAMINATIONS

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