Plants in the service of man
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Abbiv, Daniel. 1990. Plants in the service of man. Spore 27. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/45281
Daniel ABBIW is a Ghanaian botanist and Curator of the University of Ghana Herbarium at Legon. He worked at the Forest Herbarium in Kumasi before taking up his present post in 1972. He is presently working on a book entitled 'Traditional Plants of...
Daniel ABBIW is a Ghanaian botanist and Curator of the University of Ghana Herbarium at Legon. He worked at the Forest Herbarium in Kumasi before taking up his present post in 1972. He is presently working on a book entitled 'Traditional Plants of West Africa' and has recently published another, 'Useful Plants of Ghana'. Forests provide the greatest diversity of plant life yet they continue to be felled and burned and, once gone, are seldom replaced. All the plants (and the animals that depend on them) are lost. To prosper, modern nations need roads, houses and airports; factories, mines and hydro-electric dams; also cropland and pasture. But can we truly prosper If we lose all the plant life In our forests and retain only the handful of species that we cultivate as agricultural crops? Since prehistoric times man (or more often woman!) has used plants for various purposes and will continue to do so as long as life continues on this planet. Even in an age of substitute man-made materials, plants and plant products are still in great demand. The living world depends on plant life. Plants purify the air we breathe and serve as food for both man and beast; they are a source of fuel for cooking, lighting and heating and they provide materials for building and construction. They can yield sweet juices to drink and potions and medicines to cure diseases. Many crops provide our industries with much-needed raw materials. We use wood for construction, fuel and household furnishings. The forest houses and protects game, stabilizes the environment and prevents soil erosion. Even noxious weeds may be utilized to advantage as manure. There is hardly any aspect of human activity which does not depend on, or require the use of a plant or plant material, in one way or another. Some of these potential sources have probably not yet been realized, while others are regrettably under used. Indeed what is known about the use of plants is probably but a miniscule portion of what there is to know. How then can forest and cropland co-exist on a sustained basis? The main loss of forest undoubtedly is to agriculture. When land is cleared and the debris burned it is argued that the ash fertilizes and improves the soil. However, it is not only the trees that are burnt, but with them all the humus that has taken years to accumulate. Humus sustains the soil, and crops need it for their proper growth and development. The fire also destroys all organisms such as earthworms, whose activities help to aerate and turn over the soil. This slash and burn agriculture has a very ancient history but it works best where there are extensive forest and small populations so that the interval between clearing can be at least seven to fifteen years to allow the soil to regain lost nutrients. Now that populations are so much larger and increasing rapidly, more forest has to be cut more frequently to provide the land for extra cultivation. An area of cleared forest that is not burned will support crops over many more years than the one which has been burned because the humus remains. Also cultivation can be sustained if crops with different nutrient requirements are grown in sequence. Nitrogen-fixing leguminous plants grown in the sequence will also add nutrient, while crop residues returned to the soil as mulch or compost will sustain organic matter and make soils cooler and more retentive of water. The greatest benefit of such a sustainable cropping system is that it takes the pressure off the remaining forest. There is no great difficulty in implementing such systems of sustainable agriculture, and simultaneously maintaining remaining forests. It is a matter of informing and educating the great mass of traditional cultivators on the benefit of different systems. Demonstration plots are very obvious evidence of the yields that can be achieved on a sustainable basis from rotational cropping on unburned land and farmers will see for themselves the benefits of being able to remain on the same land without exhausting it and without the need to expend a great deal of effort on clearing fresh land. Farmers are also sensitive to the benefits of forest in terms of protecting steep slopes and, given the option, they will avoid cultivating hillsides. There then remains the opportunity for cultivators to access the forest for timber, fruit and other products that it has always provided, complementing the food and cash crops on the lower land. It is often not appreciated that farmers are pushed by circumstances into cutting forest against their better judgment. Given the right encouragement and assistance, farmers could become guardians of our diverse botanical heritage rather than its destroyer. The entire dependence of mankind on plants and plant products makes them vital to our survival and is the basis for our continued existence. Our survival and continued existence in turn depend on the efficiency with which mankind, with all the resources and technology available, harnesses, develops and utilizes plants and plant products. The views expressed are those of the author and do not necessarily reflect those of CTA.