The purpose of all agricultural activities is to produce enough food to feed the population. To the professional farmer, there is a second reason, the production of food on a sustained level for sale and to earn income.To achieve these aims, appropriate factors of crop production (good seeds, variety, land preparation, fertiliser application, weeding, maximum harvest and good storage) and crop yield can therefore be improved through the following ways:
1. Good and timely land preparation: Limited resources (money or planting materials) can cause farmers to start land preparation late or have it poorly done. This eventually affects crop yield. Crop yield can be greatly improved by good land preparation at the right time of the year.
2. Management, use and allocation of input (planting materials, chemical, fertiliser and adequate labour).
a. This involves good selection of seeds, cobs or planting materials that are high yielding and resistant to crop diseases.
b. The proper application of fertilisers (the right type, right measure, right time).
c. Control of pests by application of pesticides and herbicides, instead of manual weeding.
d. Enough farm hands (labour to handle farming activities).
3. Technology (farm equipment): These can improve crop yield because of their efficiency in soil preparation, seeding, chemical application and especially harvesting. With appropriate technology, all crops planted have a chance to survive and yield.
4. Farm management: Crop yield can greatly increase in the hands of a good knowledgeable farm manager. Good knowledge of the crop and experience in the production of a particular crop can maximise production at the end of a farming season.
Causes of food waste
Most crop wastage especially in Nigeria occurs during post-harvest. The causes of waste may be enumerated as follows.
(i) Poor harvesting: A lot of food is wasted in the field during harvest through inefficient machinery, inadequate farm hands or poor methods of harvesting a particular crop.
(ii) Some crops are left in the field (in heaps) causing rot and wastage.
(iii) Poor processing techniques: During processing, some methods are inefficient, e,.g. local threshing of rice; manual pounding of palm fruits and pressing for oil, and peeling of cassava could be done in such a way that a lot of the cassava is chopped off and thrown away as peelings.
(iv) Poor storage: Lack of good storage facilities or inadequate storage capacity (more food-grains that can be stored or sold).
(v) Poor infrastructure: Bad roads isolate farms from their markets and urban population. Most fresh foods are highly perishable and begin to decay and deteriorate in value before they reach the market. The result is dumping the food when it cannot be sold.
(vi) Pests: Especially in stored products, a lot of food is wasted yearly through the damaging effect of insect pests in stores and warehouses.
Methods of preserving and storing food
When a farmer produces food, he aims to be able to consume the food steadily throughout the year, if possible, in the same fresh condition as it was produced or at worst in edible processed and stored condition. Storage of food is also necessary if the farmer produces food in excess of consumption with the objective of selling his food for income.
The following methods are widely used in agriculture or food merchandising, for preservation and storage of food:
1. Traditional crib: This is used at the domestic (subsistence) level, where the scale of operation is small. A crib would be built by an individual family or co-operative group to store food. Cribs are used mainly to store grains (maize, sorghum, millet). Traditional cribs are poorly ventilated and require the crops to be well dried before storage to avoid mould. Capital cost is low.
2. Improved cribs: These are well ventilated, eliminating the mould problem. Husks must be removed because of the high moisture content. Insecticide treatment in dust or spray is necessary to protect the grains against insect attacks.
3. Silos: Silos range from medium scale community built structures to huge national grain reserve storage facilities. Traditional silos are poorly ventilated, require drying of grain in a humid zone and they also require constant inspection to prevent caking of the stored crop. Insect control in silos is good. With good management, silos are effective.
4. Bag stores (Warehouses): These are storehouses for crops in large quantities, stored mainly in bags e.g. cocoa, coffee, kernel, etc. These require initial drying of the crop before bagging and storage. Because of the big space and for valuable produce, it may be necessary to fumigate the warehouse. Food, especially fresh foods, may also be preserved using the following methods:
5. Freezing: It is a process of reducing the temperature of the food below what is suitable for the action of micro-organisms that cause spoilage. Freezing is used for meat, fish, vegetables, milk, butter, etc.
6. Drying: High moisture content is usually the cause of spoilage in foods. Inadequate water (their requirement is small), bacteria, fungi and protozoa thrive and cause the spoilage of food. Drying reduces the moisture content considerably, and preserves the food.
7. Smoking: Mainly for fish and meat. In smoking, the food is also dehydrated by heat application. The food is coated by smoke and some smoke components like phenols which kill micro-organisms and preserve the food.
8. Salting: This prevents the growth of micro-organisms because of the pH which is rendered toe low by the salt for the action of spoilage organisms, e.g. fish, meat and pepper. Salt also dehydrates the micro-organisms, leading to their death.
9. Canning: In this method, food, fish, meat, fruits, etc., are preserved in hermetically sealed cans, after prolonged heat treatment. The cans are tight and keep for long. This is suitable for travellers, soldiers, etc.