By Maurice Rangoma Star grass (cynodon dactylon), Bermuda grass or couch grass is a creeping perennial grass mainly having stolons and rhizomes. It can be a serious weed where it is not cultivated especially in the arable farming or pastures.
It is usually unsuitable for crop/pasture rotation but a valuable permanent pasture which can resist animal trampling.
It grows tall if not grazed and become stemmy and coarse therefore unpalatable having very high fibre content. To keep high palatability the grass should be grazed closely before they attain maturity. If grazing is not possible mowing should be done.
About 90% of the grass grows where livestock congregate i.e. in watering points, paddock areas, and under trees therefore the grass can grow anywhere provided the temperatures and soil conditions are suitable. The grass can withstand intense drought but requires fairly fertile soil. In Kenya it grows in all marginal areas to high potential areas.
The grass should not be mixed with legumes. Establishment is by stem cuttings at about 400 kg/ha which is broadcasted. Cuttings should be about 1½ to 3 cm in length. machinery should be rolled after broadcasting or alternatively animals should be allowed to trample on it.
By Maurice Rangoma African fox tail (cenchrus ciliaris) or Buffel grass is a perennial grass that forms spreading tufts. There are three varieties i.e. the short, medium and the tall type. The height of growth ranges from 35cm, 75cm and 100cm respectively. The grass is strong, large and deeply rooted therefore can withstand considerable amount of drought.
The grass is very palatable; it can be cultivated for hay production but its nutritive value is not high. Although it can withstand drought the grass is a low producer.
The grass is grown in marginal areas with rainfall of about 300 – 700 mm/yr. it can grow in soils with moderate to low fertility. However the soils should not be waterlogged. The grass is established from seeds stored at least 1½ to 2 years before planting to break dormancy.
The seeds are small so a well prepared fine seedbed is needed. The seeding rate is 1 – 2 kg/ha and seeds should be covered in a carrier (sand or sawdust) if planting is mechanical.
By Maurice Rangoma There are several methods of pasture establishment but the most common are:
Broadcasting (by hand or machine) or seed drilling
Manual broadcasting can be done on small scale where the area is small. Machines are used where the land is extensive. Fertilizer spreaders can be used to help in broadcasting. Make sure the fertilizer spreader is clean without fertilizer in it to avoid injuring the seeds.
After broadcasting, seeds should be lightly covered with soil. Covering can be done either by dragging tree branches behind a tractor or use of Cambridge rollers in areas not prone to erosion.
Tandem or zigzag harrows tend to cover deeper and therefore used to cover deeper seeds. Homemade harrows like old rolls of barbed wire are also used.
Seeding using seed drill is usually the best because the seeds are covered naturally. Always have a carrier when using seed drill. Hairy seeds do not flow well in drill and therefore should be mixed with moist saw dust before drilling.
Oversowing is the improvement of an existing pasture by seeding the poor one with an improved pasture. The older grass should be mowed or grazed before seeding to improve germination. Older grass can also be burnt although this is not recommended because it can interfere with the soil fauna and flora.
Pasture is established under companion crops such as maize wheat, oat or barley. The aim is to reduce the number of operations to be undertaken. For example, in a 3 year lay one year will be for establishment and the next 2 years for production. But in undersowing all the 3 years are productive.
However this method is popular in temperate countries but not in Kenya. But if Africa is considered Kenya and Nigeria are leading.
The pastures are sown when for example maize is knee high and after second weeding. It is important to make sure there is no competition from weeds.
Some grasses do not produce viable seeds therefore establishment through vegetative means i.e. vegetative cuttings or root cuttings. Examples of such grasses are nappier grass, Kikuyu grass and Star grass.
Always include at least 2 nodes with viable auxiliary buds and root primordial. Root cuttings or sett should have 3 – 5 “stems”. Vegetative and root cuttings are sensitive to dry weather conditions therefore should not be planted in dry periods and only in rainy periods.
Strip off excess leaves because they dehydrate the vegetative parts rapidly.
New upcoming crop should be in a weed-free place, protected against various pests (insects and diseases) therefore spray the plants occasionally against these. Weeding can be done through slashing or through use of herbicides. Slashing is tricky because unless weeds are taller it won’t work. Spraying will depend on the weed type. Broad leaved weeds are easy to control through selective herbicides.
By Maurice Rangoma One of the challenges facing many smallholder dairy farmers is the failure to satisfy the mineral requirement of their animals. Some producers have relied on natural licks known by local names as mwonyo in Eastern Kenya or kuoyo in Nyanza as sources of minerals for their animals. Natural lick is cheap being sold at about Ksh 40 a gorogoro (2 kg container) in many parts of the country. Farmers believe that the natural licks improve digestion, provide essential minerals to animals, increases milk production and have medicinal value to animals.
Usually, these reasons may or may not be valid but there are far more efficient ways of improving animal health and performance than by providing natural licks. More importantly, the question the farmer should ordinarily ask is which are the correct minerals that should be given to livestock under certain conditions?
Minerals form a tiny percentage of dry matter intake in livestock and this may be the reason farmers often ignore it in their herd’s nutritional program. As a farmer, you should know that livestock require about 15 important mineral elements. Seven of these are regarded as major essential elements (macro-minerals) because they are required in relatively larger amounts. These are calcium, phosphorus, potassium, sodium, chlorine, sulfur and magnesium. Minor elements (micro-minerals) are required in trace amounts and include iron, iodine, copper, manganese, zinc, cobalt, selenium and chromium. Although these minerals are essential, they are only required in very small quantities. Normally pastures and feeds contain minerals in sufficient amounts to supply the needs of most ruminants. However, specific mineral requirement depend on the age, weight, stage of production, stress and lactation status of the animal among other factors. Also, pasture conditions determine mineral quantities and availability. For example, during drought, calcium and sodium deficiencies are very common. Also calcium and sodium deficiencies occur in diets based on cereal grains.
Potassium amounts in Kenyan forages are quite high and are adequate in meeting the requirements of grazing livestock. Iron concentrations are likewise high because of large quantities in the soil and animals, through direct ingestion of soil or from soil-contaminated herbage supplement their iron supplies thereby averting deficiency. Except for some parts in Central and Rift Valley regions which are deficient, calcium levels in Kenyan pastures are mostly adequate. Major minerals elements that are likely to limit livestock production in Kenya are phosphorous, sodium, copper, cobalt and minor minerals include selenium and zinc.
Phosphorus
Deficiencies in phosphorus are common on red soils. Pasture levels of phosphorous are sufficient to maintain slow maturing and low producing indigenous animals but is inadequate for high producing improved breeds. Low levels of phosphorous in pastures and fodder has causes loss of appetite hence reduced feed intake, retarded growth, interference with regularity of heat hence reproductive rates, lowered milk production and, in extreme cases, depraved appetite or pica.
Sodium
The concentrations of sodium in pastures throughout Kenya are very low particularly in the dry season. Wet season grass may, however, also contain sodium levels that are insufficient in meeting animal requirements. This is because rapid gain in weight by animals during the wet season induces high mineral requirements. Severe symptoms of sodium deficiency have not been reported in Kenya mainly because most farmers feed salt to their animals.
Copper
Copper concentrations in Kenyan pastures are low and a deficiency has been recorded in Rift Valley and parts of Central Kenya. This is especially in soils in which the underlying rock is ash and pumice where copper is usually deficient. Disorders such as stiff gait, rusty coat colour and, in severe cases, fragility of bones in calves have been identified as due to copper deficiency. Copper deficiency is widespread in Kenya and is more pronounced in the dry seasons.
Cobalt
Cobalt is a serious mineral limitation to livestock. It is rare for grasses to contain cobalt in sufficient quantities that meet the demands of grazing animals. Even when grazing is abundant deficiency will lead to chronic starvation or wasting which is often indistinguishable from energy and protein malnutrition. In Kenya, the condition is known as "Nakuruitis" or "Narurasha"i. Cobalt deficiency is common along the Rift Valley and is seasonal in character with symptoms usually appearing after the rains when grazing is plentiful and green. Animals suffering from cobalt deficiency lose appetite and condition, may abort if in calf or may have difficulty to conceive again. The condition affects lactating cows more than any other type of livestock.
Others minerals
Other mineral deficiencies are specific to certain environments and seasonal conditions. They include those of magnesium and selenium. Magnesium deficiency leads to grass tetany, and selenium deficiency leads to white muscle disease. Both conditions require specific treatments.
Presentation
What is the best method of presentation of minerals to livestock? This is important because some farmers have mixed mineral supplements with feeds or water. Although in some circumstances mixing with feeds is allowed, never mix salt or mineral supplements with water. When you mix with feed or water you will be forcing the animal to take more minerals than it requires and limiting feed or water intake. This is even more serious when you mix salt with water for calves. The calf will tend to drink more water causing haemolysis where it develops respiratory problems, urinates blood and might die eventually.
Salt and mineral supplements are presented in various forms depending on the needs of the animal. The most common are mineral blocks and powders. Mineral blocks and powders however do not provide all the minerals that the animals might need. The mineral profile of natural licks is even lower and their composition varies significantly. You should know from the start that cattle hardly ever get enough minerals if you just give them natural licks.
The most practical solution to phosphorus deficiencies is to provide dry lick or block lick formulated from safe phosphorous sources. In some cases it is far more efficient supplement calcium and sodium by adding lime and salt to the feed ration than to allow free access to licks. When added to the ration, animals will consume the additional minerals they need in proportion to the feed they eat. Selenium deficiency is often treated with ‘bullets’ placed in the rumen, or by specially formulated selenium drenches. However, where mineral supplementation is a routine practice in the farm, the best is to present minerals in form of powder.
Toxicity
Overdosing with minerals such as selenium, zinc, manganese, iodine, copper, molybdenum and cobalt can have toxic effects. This problem is usually avoided by having lower levels of these elements in dry licks or blocks. In this case it is always better to treat animals for the specific deficiency.
Examples of mineral supplements
Farmers have a wide range of mineral licks to select for their livestock. Majority of farmers however do not know what the particular premix contain and how suitable they are for their livestock. In many of the brands listed below it is not possible to determine the availability of mineral elements available to the animals. Some of these brands cannot support high milk yield hence the farmer should not risk giving to dairy cows.
By Maurice Rangoma Rhodes grass (chloris gayana) is a leafy perennial grass which grows to 30 to 150 cm in height. Their roots have stolons and therefore spread easily in the field.
The grass is extremely adapted to a wide range of ecological conditions and therefore grows in many parts of the country. It can tolerate a wide range of soils. However it prefers well drained fertile soil and an annual rainfall between 600 and 1100mm. the grass is not suited for very dry areas or excessive moist conditions especially where the soils are not free draining. In Kenya Rhodes grass is common in medium dry lands. If well managed they give good pasture all year round.
Rhodes grass has been used extensively for pasture improvement because its seeds being easily available and being easy to establish and manage. Varieties in Kenya produce large bulk of herbage which are good for grazing and hay making. They are readily eaten by livestock even when they are mature although the nutritive value is very low at old age.
The grass is established at a seeding rate of 4 – 6 Kg per Ha. The seedbed should be fine and compact because the seeds are very small. If the seedbed is rough seeds may land in low levels and may fail to come up after germination. Compaction helps to ascertain that most levels of planting are uniform and seeds do not go far deep.
Fertilizers are required moderately. For example during planting time it may be added at 40 – 60Kg of phosphate fertilizer per hectare. If the soil nitrogen is at reasonable levels then there would be no need for nitrates. However nitrates can be applied during the second year after grazing at 60 – 90 Kg per hectare. Time should be allowed to pass before grazing to avoid nitrogen poisoning of cattle.
Yields on well managed Rhodes grass are around 5 – 8 ton/ha/year after the second year although much higher yields can be obtained. The crude protein (CP) content varies with age and nitrogen level in soil. If well managed about 7 – 11% can be obtained after the eighth week of planting.
Commercial varieties in Kenya are
Elma and boma Rhodes are good for regions with good rainfall while the others are drought tolerant.
| Climate | Grow at altitudes from 600 to 2000 m above sea level. It does well in areas receiving rainfall of more than 250 mm annually and also persists well under drought conditions. |
| Soils | It grows in a wide range of soil conditions but performs best in loamy, fertile soils. It does not do well in alkaline or very acid soils. |
| Site | It is best grown in grazed plots or shut-up for hay making. |
| Preparation | Plough and harrow at least once to make a fne seedbed. Harrow after the weeds have emerged to reduce competition during establishment. Sow immediately after harrowing. |
| Sowing | Sowing it is usually established from seed but root splits can also be used. Te best time to sow where there are two rainy seasons is during the short rains. Where there is one rainy season, plant from early to mid rains. Sow when the soil is loose (dry). Make furrows 25 cm apart using a peg. Drill the seeds in the furrows, at a seed rate of 12 kg per hectare. Cover the seeds lightly, for example by pulling light tree branches over the furrows. |
| Fertilizer | For high productivity, apply nitrogen fertilizers preferably during heavy rains at the rate of 100 kg per hectare. |
| Weeding | Make sure the plot is weed-free during the initial period of establishment. Remove weeds between the rows using a hand hoe. |
| Pests | No diseases of importance but common pests such as army worms may attack the pastures. |
| Harvesting | Start harvesting or grazing soon after flowering. If cutting, cut close to the ground to stimulate spreading. Leave to re-grow again until next flowering. When well managed, Rhodes grass can yield an average of 8 tonmes dry matter per hectare per year. |
| Feeding | Grazing is the most common method of feeding Rhodes grass although some farmers use it for cut-and-carry. Tends to decrease in abundance on over-grazed pasture due to its high palatability. Rhodes grass is very good for hay making. It can also be used for seed production; up to 350 kg seed per hectare can be harvested. |
Page 8 of 8