Crop cultivation forms the largest activity pack of most people in Africa who are engaged in agriculture, which is the backbone of most African economies and livelihoods.
Cultivating crops and ensuring that they grow up to harvest of satisfactory yields is an activity or yearning of many African farmers. Since time immemorial, farmers have known that good yields can only be achieved if there is sufficient crop protection.
According to Patrick Byakagaba, an agricultural technician in Uganda, there are three main ways through which farmers protect or can protect their crops. “We have chemical protection, biological control and cultural practices which are used by most African farmers. Under chemical protection, we use chemicals to fight pests and to boost the nutrients for crops to grow. You can also engage in biological control where for example you use an insect to control (eat) pests that harm your crops,” Byakagaba says.
Under cultural protection, Byakagaba says farmers use weeding (removing weeds where pests survive or can hide or which compete for nutrients from the soil with the crops.
Farmers also use spacing (closer or wider spacing) depending on the type of crop to control the ability of pesticides to harm the crops.
“Some farmers use protected seeds which are not infested with pesticides, while others ensure that they use the right equipment like hoes (which are not infested with pests) in order to protect their crops. Some farmers use planting depth to protect crops from particular pests like ensuring grounds, maize or rice is planted deep enough to ensure they are not spotted and eaten by birds, chicken and related pests,” Byakagaba says.
Kworora Munaabi, a farmer from Rwampara in Mbarara, western Uganda for example says they still first soak seeds of crops like maize, put them in a sack or polythene bags until the seeds start to germinate after about two day and then they plant. This helps the seeds to grow very first before the pests in the soil can affect them. “To protect cereals especially from birds, we still use effigies to deceive the birds that there are human beings guarding the crops in the garden,” Kworora says.
Under chemical control, insecticides are used to kill pathogens (diseases causing organisms), by killing or failing the pest or host of the pest. For example while the coffee fungus (causing coffee wilt) affects the coffee directly and will need to be sprayed directly, some pests hide and grow in weeds from where they attack crops at the ‘opportune’ (for pests) moment.
Some farmers use fertilizers to protect their crops. Some fertilizers make the crops grow very fast and beat the pest/pathogen on the time it would normally have affected the crop. Using fertilizers is a popular way through which many farmers protect their crops because the fertilizers boost the soil nutrition’s for crops to grow and resists pests.
Byakagaba says farmers use a range of organic and inorganic fertilizers, where organic fertilizers provide the soil with chemical from plant and or animal materials, while inorganic fertilizers provide the soil with manufactures chemicals.
Many farmers use organic (manure) from plant and animal materials that are decomposed and put in the soil to offer crops more nutrients and better protection form pests. Some farmers use farmyard manure from excreta of animals while others use green manure from decomposed plant materials or both decomposed plant and animal materials to provide the soil with chemicals from living organisms.
This ensures proper nutrition has long been flaunted as one of the keys to a long and healthy life. Interestingly, that’s as true of plants, trees and flowers as it is of people.
Increasingly, many farmers are using inorganic fertilizers which provide manufactured chemicals to boost soil nutrients for crops.
According to Conway Lum, a Canadian Certified Agricultural Technician, the key cornerstones of good plant nutrition are nitrogen (N), phosphorus (P) and potassium (K). Fertilizer packaging typically indicates N-P-K percentages: e.g., 10-6-6 contains 10 per cent nitrogen, 6 per cent phosphorus and 6 per cent potassium. Each of these nutrients has a special function:
Nitrogen: Promotes leafy growth and green colour; organic sources are blood meal, fishmeal
Phosphorus: Aids root health and seed development; organic sources are bone meal, rock phosphates
Potassium: For strong stems and roots, proper water balance and disease resistance; organic sources are kelp and wood ash.
In addition to these macronutrients (which also include sulphur, magnesium and calcium), many fertilizers contain a variety of micronutrients (iron, manganese, boron, zinc, copper, molybdenum, chlorine, nickel, sodium, cobalt and silicon) that are also essential for healthy plant growth and development.
Lum agrees with Byakagaba that organics tend to be more environmentally friendly than chemical fertilizers and are less likely to pollute any nearby water sources.
They are also less likely to burn plants and they improve overall soil condition and feed micro-organisms,” Lum says.
However, organic fertilizers are slower-acting, more bulky, and in some cases inclined to cost more than chemical fertilizers. And if you are doing agriculture as a business, then you need first acting crop enhancers that also provide you a certainty of crop protection.
The advantages of chemical (inorganic) fertilizers are that they usually pack more of a nutrient punch, work faster and cost less especially for large-scale farmers. Unfortunately, chemical fertilizers burn plants more easily than the organic products.
Fertilizers can be solid or soluble. Lum says water-soluble fertilizers are most quickly absorbed by plants. In addition to being absorbed by the plants’ roots, a considerable percentage of nutrients is also absorbed through the leaves. The disadvantage is that there is very little residual effect from this type of feeding, therefore, consistent feeding is required.
“Never apply fertilizer to a plant under water stress (when the soil is completely dry). Water plants with plain water before feeding. This is extremely important when using water-soluble products with very high nitrogen content like a 15-30-15 or 20-20-20.”
Many people agree that tapping these synthetic-and sometimes dangerous-pesticides, herbicides and fertilizers can double farm productivity as evidenced in many African countries, but the chemical fertilizers have also, in some cases, tainted produce and contaminated the ground.
New green agriculture offering better crop protection
According to Beth Karlin in a paper on the second green revolution, the push today is for genetically engineered crops that require less chemical intervention because they are more resistant to the ravages of the environment, pest and weeds.
This is part of the new “green agriculture” spearheaded by Nobel Prize winner of the Green revolution fame, Ryoichi Sasakawa, chairman of the Japan shipbuilding Industry Foundation. This green agriculture has been embraced by many members of the scientist and the agribusiness community.
Working with former American President Jimmy Cater and agronomist Norman Borlaug, the noble prize winning pioneer of the first green revolution, Sasakawa funded the Sasakawa Global 2000 Agricultural Project. Since 1986, the project has helped the farmers of Ghana cultivate 65,000 acres of land, boosting yields by 400% and bringing that country to the verge of food sufficiency. The effort has also help farmers in Sudan, Zambia, Tanzania, Togo and Benin.
When crops do require agricultural enrichments, moreover, the new agriculture taps synthetic pesticides, fungicides and herbicides that can be used more selectively and in much smaller quantities than before. Productivity has also been boosted by the use of scientific management techniques, including better irrigation methods for crop rotation.
At the vanguard of the current green revolution is a generation of robust plants more resistant than their predecessors to heat and cold, drought, a range of pest and crop disease. Some varieties, including the sorghum and maize introduced in Ghana for example, have been produced through the years of scientific breeding. Other plants have been created by the insertion of foreign genes.
France Rhone-Poulenc, for example, is modifying tobacco with a technique known as chemical shielding in which the tobacco receives a gene that makes it resistant to bromoxynil, one of the most commonly used herbicides. Thanks to this technique, says William J.Kilbey, director of Rhone-Poulenc’s ethics and environment group in Lyon, farmers can spray a moderate amount of herbicide on weeds without killing the tabacco plants themselves. In a similar effort, the U.S based Monsanto Agricultural Co. is using biotechnology to produce herbicide-resistant cotton.
Companies also are studying ways to make the herbicides and pesticides themselves safer. Britain’s Imperial Chemical Industries (ICI), for instance, has developed and fine-tuned an insecticide to kill destructive insects while permitting harmless and helpful critters to survive. Dubbed Poromicarb, the insecticide kills the destructive aphid; it does not, however, harm the ladybug, a predator that helps control a range of destructive pest.
Monsanto, meanwhile, has developed a popular herbicide called Roundup, which works by blocking protein production in the encroaching weeds, effectively halting their growth. The herbicides break down once it has completed its job, eliminating the danger of ground and crop contamination. Sandoz has taken a similar approach in developing fungicides to protect cereals, fruit, vines and vegetables from fungal diseases. Alto, one of the company’s newest products, interferes with the growth of organisms that attack small grain plants.
New fertilizers and techniques for their application are being developed as an alternative to spreading vast quantities of fertilizer and the sometimes harmful nitrogen it contains.
West Germany’s BASF has introduced a time release fertilizer called Basammon extra 25. Basammon slowly releases nitrogen through the duration of the growing cycle, so that the plant adsorbs only what it needs when it needs it. Other life forms are barely affected.
But the new environmental products are even more effective when used in combination with scientific farming techniques. Beth Karlin says one effective new irrigation technique has been developed by Italy’s Ferruzzi Group, an international industrial company that operates in the chemical and agribusiness sectors. The method uses a series of underground plastic pipes, which capture water that has mixed with fertilizers and pesticides. The water and chemicals are recycled, reducing the amount of fertilizers and pesticide required and preventing toxic liquid residues from seeping into the ground.
But you and me know how long it will take for such technology to reach the majority of African farmers, and whether it will be affordable for the majority of small scale farmers. After all, insect side use is a must for moistly genetically modified crops, which many African farmers are trying to avoid. In many farming villages, you will still notice presence of age-old techniques such as rotating crops and use of composite manure.