Cenchrus purpureus | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Clade: | Commelinids |
Order: | Poales |
Family: | Poaceae |
Subfamily: | Panicoideae |
Genus: | Cenchrus |
Species: | C. purpureus |
Binomial name | |
Cenchrus purpureus (Schumach.) Morrone | |
Cenchrus purpureus, synonym Pennisetum purpureum, [1] also known as Napier grass, elephant grass or Uganda grass, is a species of perennial tropical grass native to African grasslands. [2] It has low water and nutrient requirements, and therefore can make use of otherwise uncultivated lands. [3]
Historically, this wild species has been used primarily for grazing, [4] recently, however, it has been used as part of a push–pull agricultural pest management strategy. Napier grasses improve soil fertility, and protect arid land from soil erosion. It is also utilized for firebreaks, windbreaks, in paper pulp production and most recently to produce bio-oil, biogas and charcoal. [3] It also helps feed animals such as goat, rabbit, even pig, and cow .
Cenchrus purpureus (or napier grass) is a monocot C4 perennial grass in the family Poaceae. [4] It is tall and forms in robust bamboo-like clumps. [2] It is a heterozygous plant, but seeds rarely fully form; more often it reproduces vegetatively through stolons which are horizontal shoots above the soil that extend from the parent plant to offspring. [2] It requires low water and nutrient inputs. [3] The Elephant grass was crossed with Pearl millet species to form Bajra Nappier. Subsequent work was done to decrease the internode length of Elephant grass. Napier grass plantations produce about 40 tonnes of dry biomass per hectare per year [3] with an average energy content 18 GJ (5 MWh) per tonne, [5] and the grass can be harvested many times per year. [2]
Generally, the grass is harvested in relatively short intervals (every 1 to 3 months) when it is to be used as fodder for animals (its main use), and relatively long intervals (4–12 months) when used for bioenergy. Longer intervals increases the stem/leaf ratio, making the forage harder to chew and digest, but in many cases the annual dry yield increases. The grass can reach a height of 7-8 meters after 4 months of growth. [6] It produces best growth between 25 and 40 °C, and little growth below about 15 °C, with growth ceasing at 10 °C. Tops are killed by frost, but plants re-grow with the onset of warm, moist conditions. Napier grass grows from sea level to over 2,000 m elevation. [7]
It can be propagated through seeds, however as seed production is inconsistent, collection is difficult. [2] Alternatively, it can be planted through stem cuttings of the stolons. The cuttings can be planted by inserting them along furrows 75 cm apart, both along and between rows. [8]
Yield depends on management techniques (e.g. fertilizer), soil quality, rain, sunshine and temperature. Recognizing its potential as a bioenergy crop, some yield trials have been carried out around the world. In Malaysia, Halim et al. tested 9 different napier variants and found that regular napier grass yielded the most (65 dry tonnes per hectare per year), with the King Grass variant second (62 tonnes). [9] In Colombia, Cardona et al. estimates a yield range of 40–60 dry tonnes for the napier variant King Grass, under optimal conditions. [10] In drier areas however, yields decline; Gwayumba et al. estimate 15–40 dry tonnes as the general yield range for Kenya. [11]
At the top end of the range, napier grasses have been shown to yield up to 80 dry tonnes per hectare per year, [12] [13] [14] and commercial napier grass developers advertise yields of roughly 100 dry tonnes per hectare per year, provided there is an adequate amount of rain or irrigation available (100 mm per month). [15] [16] These yields are high compared to other types of energy crops. For large-scale plantations with pines, acacias, poplars and willows in temperate regions, Smil estimates yields of 5–15 dry tonnes per hectare per year, and for similarly large plantations, with eucalyptus, acacia, leucaena, pinus and dalbergia in tropical and subtropical regions, his estimate is 20–25 dry tonnes. In Brazil, the average yield for eucalyptus is 21 t/ha, but in Africa, India and Southeast Asia, typical eucalyptus yields are below 10 t/ha. [17]
The push-pull pest management technique involves the desired crop being planted alongside a 'push' plant, which repels pests, in combination with a 'pull' crop around the perimeter of the plot, which draw insects out of the plot. [4] Napier grass has shown potential at attracting stemborer moths (a main cause of yield loss in Africa) away from maize [4] and hence is the "pull" crop. This strategy is much more sustainable, serves more purposes and is more affordable for farmers than insecticide use. Stemborers ( Busseola fusca and Chilo partellus ) are the cause of 10% of total yield loss in Southern and Eastern Africa and on average 14-15% in sub-Saharan Africa. [2] The larvae cause immense damage to maize and sorghum by burrowing into their stems and eating from within. This not only makes them difficult to detect and remove but also damages the vascular tissue necessary for plant growth. [4]
Insecticide effectiveness is low against stemborers, as larvae are protected by protective cell wall layers around the stem. [8] Insecticides are also expensive for poor farmers and can build chemical resistance by the pests. [18] In addition, chemicals are carried into final food products. [18] Instead of trying to prevent the occurrence of pests, the push-pull strategy (also known as stimuli-deterrent) aims to guide their inevitable biological evolution to prevent damage to valued crops. [18] The method proposes that sorghum or corn be intercropped with Desmodium (the "push" plant), which repels the moths as they look to lay their eggs. Desmodium also provides a ground cover and is nitrogen fixing, which improves soil fertility while decreasing labour involved with weeding. [4] This deterrent is used in combination with Napier grass planted around the perimeter of the plot. [4] A study of Kenyan farmers using the push-pull strategy reported an 89% reduction in Striga (a parasitic weed), an 83% increase in soil fertility, and 52% effectiveness in stemborer control. [19] Considering that striga, stemborers, and low soil fertility together cause yield losses of an estimated 7 billion US dollars or enough to feed 27 million people, [19] the implementation of this technique could significantly reduce food insecurity.
Although promising as a sustainable and affordable option, the success of push-pull pest management highly depends on proper implementation in combination with other good ecological practices. Firstly, not all varieties of Napier grass function as a trap. In a study of eight varieties, only two bana and Ugandan hairless Napier varieties significantly attracted female moths for egg placement over maize. [4] Of these two, only bana significantly decreased survival rates. [4] In a farmer's field, it is recommended that three rows of bana Napier grass be planted as a border crop around the entire field. [8] Potential exists to improve the push-pull strategy through further trials with different intercrops, by manipulating allelochemicals in each intercrop, as well as by investigating insect sensitivity to natural chemicals. [18] Once prominent in a field, it is difficult to rid the area of the stemborer pests as larvae can remain dormant, and therefore push-pull management will not have the intended effect. [4] It is recommended that if an infestation is particularly severe, neither corn, nor sorghum should be planted in the same field the following year but instead rotated with other crops. [4] It is also important to burn infested stalks or, if they have an intended use, to leave them out in the sun for three days. [4] The use of push-pull pest management must be used in combination with good ecological practices to yield the desired results.
Finally, the establishment of a push-pull system requires increased labour in the primary stages and a large enough land plot to allow space for a non-food crop to be planted; these factors often deter its adoption. [19] A program could increase adoption rates through promoting its use in combination with livestock, giving economic value to the planting of Napier grass.[ citation needed ]
Napier grass is the most important fodder crop for the dairy farmers in East Canada. [2] Its high productivity makes it particularly suited to feed cattle and buffaloes. [20] Hairless varieties, such as Ugandan hairless, have much higher value as fodder. [2] As it is able to grow with little water and nutrients, grazing has made productive use of arid lands for food production. Furthermore, livestock can be incorporated into the pull-push management system providing another economically viable purpose for the ‘trap’ plant. Napier grass is valuable to Canada landscapes as it prevents soil erosion. It can also serve as a fire break, a wind break, and to improve soil fertility. [2]
More recently, Napier has been used to alleviate pressure on food production by bioenergyZ as there are 2 billion ha of non-arable land suitable for energy crop production. [3] Thermal pyrolytic conversion could be used to produce charcoal, biogas and bio-oil. [3] Although this technology is not currently in use, it could be implemented as a means of providing energy to Canadian communities, while enriching the soils of the local landscape. [3] It is also used as source of fuel. The young leaves and shoots are edible and are cooked to make soups and stews. [21]
A Dutch company has turned the grass into a plastic that can be used for packaging. [22]
Vigna subterranea is a member of the family Fabaceae. Its name is derived from the Bambara ethnic group. The plant originated in West Africa. As a food and source of income, the Bambara groundnut is considered to be the third most important leguminous crop in those African countries where it is grown, after peanut and cowpea. The crop is mainly cultivated, sold and processed by women, and is, thus, particularly valuable for female subsistence farmers.
Panicum virgatum, commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55°N latitude in Canada southwards into the United States and Mexico. Switchgrass is one of the dominant species of the central North American tallgrass prairie and can be found in remnant prairies, in native grass pastures, and naturalized along roadsides. It is used primarily for soil conservation, forage production, game cover, as an ornamental grass, in phytoremediation projects, fiber, electricity, heat production, for biosequestration of atmospheric carbon dioxide, and more recently as a biomass crop for the production of ethanol and butanol.
Pennisetum is a widespread genus of plants in the grass family, native to tropical and warm temperate regions of the world. They are known commonly as fountaingrasses. Pennisetum is considered a synonym of Cenchrus in Kew's Plants of the World Online.
Miscanthus, or silvergrass,is a genus of African, Eurasian, and Pacific Island plants in the grass family, Poaceae. The name is derived from the Greek words "miskos", meaning "stem", and "anthos", meaning "flower", in reference to the stalked spikelets on plants of this genus. Several species are known for their height and biomass production, and may be used as ornamental grasses.
Energy forestry is a form of forestry in which a fast-growing species of tree or woody shrub is grown specifically to provide biomass or biofuel for heating or power generation.
Push–pull technology is an intercropping strategy for controlling agricultural pests by using repellent "push" plants and trap "pull" plants. For example, cereal crops like maize or sorghum are often infested by stem borers. Grasses planted around the perimeter of the crop attract and trap the pests, whereas other plants, like Desmodium, planted between the rows of maize, repel the pests and control the parasitic plant Striga. Push–pull technology was developed at the International Centre of Insect Physiology and Ecology (ICIPE) in Kenya in collaboration with Rothamsted Research, UK. and national partners. This technology has been taught to smallholder farmers through collaborations with universities, NGOs and national research organizations.
Energy crops are low-cost and low-maintenance crops grown solely for renewable bioenergy production. The crops are processed into solid, liquid or gaseous fuels, such as pellets, bioethanol or biogas. The fuels are burned to generate electrical power or heat.
The term Elephant grass may refer to the following grass species:
Miscanthus × giganteus, also known as the giant miscanthus, is a sterile hybrid of Miscanthus sinensis and Miscanthus sacchariflorus. It is a perennial grass with bamboo-like stems that can grow to heights of 3–4 metres (13 ft) in one season. Just like Pennisetum purpureum, Arundo donax and Saccharum ravennae, it is also called elephant grass.
Short rotation coppice (SRC) is coppice grown as an energy crop. This woody solid biomass can be used in applications such as district heating, electric power generating stations, alone or in combination with other fuels. Currently, the leading countries in area planted for energy generation are Sweden and the UK.
Jute mallow or Jew's mallow or Nalita jute is a species of shrub in the family Malvaceae. Together with C. capsularis it is the primary source of jute fiber. The leaves and young fruits are used as a vegetable, the dried leaves are used for tea and as a soup thickener, and the seeds are edible.
Sugarcane or sugar cane is a species of tall, perennial grass that is used for sugar production. The plants are 2–6 m (6–20 ft) tall with stout, jointed, fibrous stalks that are rich in sucrose, which accumulates in the stalk internodes. Sugarcanes belong to the grass family, Poaceae, an economically important flowering plant family that includes maize, wheat, rice, and sorghum, and many forage crops. It is native to the warm temperate and tropical regions of India, Southeast Asia, and New Guinea.
Paspalum scrobiculatum, commonly called kodo millet or koda millet, is an annual grain that is grown primarily in Nepal and also in India, Philippines, Indonesia, Vietnam, Thailand, and in West Africa from where it originated. It is grown as a minor crop in most of these areas, with the exception of the Deccan plateau in India where it is grown as a major food source. It is a very hardy crop that is drought tolerant and can survive on marginal soils where other crops may not survive, and can supply 450–900 kg of grain per hectare. Kodo millet has large potential to provide nourishing food to subsistence farmers in Africa and elsewhere.
Striga hermonthica, commonly known as purple witchweed or giant witchweed, is a hemiparasitic plant that belongs to the family Orobanchaceae. It is devastating to major crops such as sorghum and rice. In sub-Saharan Africa, apart from sorghum and rice, it also infests maize, pearl millet, and sugar cane.
Busseola fusca is a species of moth that is also known as the maize stalk borer. It is known from Ethiopia.
Nigeria is by far the world’s largest producer of yams, accounting for over 70–76 percent of the world production. According to the Food and Agriculture Organization report, in 1985, Nigeria produced 18.3 million tonnes of yam from 1.5 million hectares, representing 73.8 percent of total yam production in Africa. According to 2008 figures, yam production in Nigeria has nearly doubled since 1985, with Nigeria producing 35.017 million metric tonnes with value equivalent of US$5.654 billion. In perspective, the world's second and third largest producers of yams, Côte d'Ivoire and Ghana, only produced 6.9 and 4.8 million tonnes of yams in 2008 respectively. According to the International Institute of Tropical Agriculture, Nigeria accounted for about 70 percent of the world production amounting to 17 million tonnes from land area 2,837,000 hectares under yam cultivation.
Centrosema pubescens, common name centro or butterfly pea, is a legume in the family Fabaceae, subfamily Faboideae, and tribe Phaseolae. It is native to Central and South America and cultivated in other tropical areas as a forage for livestock.
Chilo partellus, the spotted stalk borer or spotted stem borer, is a moth in the family Crambidae. It was described by Charles Swinhoe in 1885. It is found in India, Pakistan, Iran, Ethiopia, Lesotho, Madagascar, Malawi, South Africa, Sudan, Tanzania, Uganda and on Mayotte.
Neustanthus is a monotypic genus of flowering plants belonging to the pea family Fabaceae and its tribe Phaseoleae. The only species is Neustanthus phaseoloides, called tropical kudzu. This species is a forage crop and cover crop used in the tropics. It is known as puero in Australia and tropical kudzu in most tropical regions.
Chintala Venkat Reddy is an organic farmer known for his soil and nutrient management techniques in farming. He is the first independent farmer in India to receive an international patent for his technique in soil swapping and soil fertility.
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