NIGERIA CASSAVA GROWERS' ASSOCIATION.
CASSAVA AS A CROP
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CASSAVA: A BASIC FOOD OF AFRICA

 

 

Cassava, Manihot escullenta crantz was introduced into Africa from South America in the sixteenth century and rapidly spread throughout  the continent. Today, cassava is the second most important food in the African diet. It is a crop that contributes significantly to the diets of over 800 million People. Cassava is commonly termed as a subsistence crop. A subsistence crop is often a ‘’poor people’’ Crop , which survive under adverse condition and can be depended upon to produce some food when other crops have failed. Most cassava, particular in Africa, is produced for human consumption and is consumed near where it is grown. Cassava is a major source of calories for roughly two out of every five Africans.

Manihot Esculenta Cranz is a perennial woody shrub of the Euphorbiacae family. It is grown principally for its swollen roots and its leaves are consumed us vegetable in some parts of Africa. Fresh cassava contains varying amounts of cyanide which must be removed by processing before the cassava is consumed. The roots are from 25-30 percent starch, the leaves, which is not so significant as a source of calories but contains significant amount of protein and other nutrients. Cassava is adapted to the zone within latitude 30 degree north and south of the equator, at elevations of not more than 2000 meters above sea level, in temperatures ranging from 18°c to 25°c; to rainfall of 50 – 5000 millimeters annually; and to poor soils with a pH from 4 to 9 

 

            Cassava, traditionally, is produced on small-scale family farm, The roots are processed and prepared as a subsistence crop for home consumption and for sale in village markets and shipment to urban centers.  Cassava roots normally cannot be stored for more than three days after harvest and must, therefore, be processed within that time. Over the past 30 –50 years, small-holders in Nigeria have increased the production of cassava as a cash crop, primarily for urban market, It can be said that cassava is no longer produced for home consumption alone but also for commercial production for urban consumers, livestock feed and industrial use can be described as the cassava transformation being conceived by NCGA and other organizations that were involved informing this cassava farmers apex association.

 

  Cassava provides a more reliable source of food during drought, locust attack and the” hungry season” Cassava is now regarded as “poverty fighter” It has many advantages of other crops. Cassava can be planted at anytime of the year as long as there is enough moisture at planting for rooting to commence. Cassava easily adapts to soils on which many other crops fails and can be easily propagated by stem cuttings. Cassava has a relatively high yield and is a low-cost source of calories. It can produce more carbohydrates per hectare than any other food staple and can be harvested as required.

 

                      CASSAVA.

CASSAVA STEMS
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PLANTING MATERIALS

               CULTIVATION OF CASSAVA

Cassava is planted on mounds or ridges to enhance soil aeration if the soil is poorly drained soils, but in wall drained soils, cassava is grown on flat seed bed, it has this as an advantage over other food crop except rice. The size of the mound or the ridge varies with respect to soil drainage conditions. Cassava is planted in staggered form, almost at random, when it is on flat seed –bed. Mounds, too are often made is staggered formation. When planting is ridges, however, cassava is usually planted in rows

This could be either vertical or upright planting., flat or horizontal . In case of upright , 2/3 of the cutting should be buried in the soil. In case of slanting position, the angle – 30 – 40 and 2/3 buried. It can be completely buried  horizontally. Vertical and upright leads to deeper establishment of roots, vertical planting may lead to higher desication.

 

Horizontal planting allows for more efficient use of fertilizers than vertical easier harvesting, less damage to roots when harvesting. Flat planting gives many root system which is not good for plants cultivated for root tuber, but good for forage. Vertical planting lead to roots clustering i.e Bunching up of roots. Horizontal planting system causes apical dominance, many shoots occur and root spreads longer than vertical planting flat planting lead to more root formation.

 

 

 

Planting Material.

 

Cassava is vegetatively propagated from stem cuttings. Stem  cuttings are usually got from grown cassava or harvested ones, farmers’ fields’ neighbors and sometimes cassava marketing middle men. Some farmers produce stem cuttings for commercial purpose. It is advisable for farmers who plant cassava as cash crop to plant healthy-looking cuttings from plants not older than 12months. Biomas productions is higher on the forest zone than in the Savannah zone, cassava  stem cuttings are in large quantity for planting in the forest zone. But fall short in supply in the Savannah Zone. The multiplication rate of cassava planting material is low in comparison with that of crops, such as grains, which are propagated by seed. Cassava stem cuttings  are briskly, higher  perishable, and dry up within a few days after they have been harvested.

It can be propagated from (I) seed  (ii) budding. Seed and budding are restricted in application . They are mainly used in  Research stations. Propagation by seed needs special techniques i.e. incubate and germinate the seeds in sterilized medium to disallow invasion and destruction by micro-organism.

 

BUDDING:- Every bud has the potentially to grow into a new shoot. By budding many of   the buds can be propagated. This is done by removing the buds in the stem and use it as scion on other plant to give a plant each.

Rooting agents may be used to induce the rooting. The common method of propagation in Nigeria and West Africa is cutting. The cutting used must contain at least 3 buds thus the length must be between 9” – 12” or 22.5-30cm and must be 1 – 11/2” thick. It should not be very tender.

 

Cutting must be from a plant that is more than 10 months old for good establishment and yield. Cuttings should not be stored more than 8weeks before planted if longer, they are dead.

 

 

 

Plant Density.

 

Cassava plant density is one the determining factors that determines cassava yield. It is strongly and positively correlated  with the cassava yield. NCGA recommends spacey for cassava to be 1m x1m for its members , which is equivalent  to a plant density of ten thousand stands per hectare. Boot in Nigeria, cassava that is planted for commercial purpose has higher plant density than that which is planted for home consumption.

 

Cassava plant density varies widely, it depends on climatic zone, cassava morphological characteristics such as branching type and leaf shape, soil fertility status, seed-bed type, cropping pattern etc. .Farmers who plant cassava as a cash crop plant at higher plant densities than do farmers who plant the crop as a famine-reserve crop or as a rural food staple.

 

Planting Date

 

There is no definite plantain date for cassava to be planted. Presence of enough moisture to aid the stem in roofing to start is the critical issue. Rainy season starts by February-March and ends by October-November in West Africa, other food crops (most) are planted at the onset of this season except cassava. It can be planted at the beginning of the rainy season to the end of the season. Intercropping also determines planting date. The growth cycle of the associated crop will determine when cassava can be planted.

 

 

 

INTERCROPPING

 

Studies have shown that cassava yield is higher when the crop is grown in mono-culture (20 ton/ha )  than when it is intercropped (14 tons/ha). In Nigeria, cassava farms are intercropped while 40 percent are mono-cropped. Cassava with maize is by far the common, constituting about 50 percent of all cassava-based intercropped fields. Other common combinations are cassava/bean, cassava/banana (or plantain), cassava/rice, cassava/millet (sorghum), cassava/yam and cassava/sweet potato.

 

Shortage of land, shortage of labour are parts of reasons while Intercropping is practised. Others are flexibility of cassava’s planting schedule, its wide interspacing, its slow rate of growth relative to maize, money got from maize is used in weeding cassava and sustenance of farmer and his family, make it suitable for cropping.

 

GERMINATION: Occurs 2 – 3 weeks after planting depending on environmental conditions, the drier the conditions the longer the interval.

 

In the  field of cassava about 5 % will not germinate, therefore supplying should be done immediately.

 

For early maturing varieties, 2 –3 months of planting is very crucial for effective take –off and tuberization.

 

 

WEEDING:

If weeding is not done within 2 –3 months of planting yield loss of up to 45% may occur. This is the critical period because it is the period of tuberization, when the plant does not tolerate competition and stress. Thus the critical period is the early tuberization when fertilizer, adequate water, free of weeds are needed. Normally local farmers weed 2 or 3 times. Some weed only once while some do not  weed at all. This is based on the notion that cassava is very hardy. Weeding alone account for 21 – 40% of total labour input in cassava production.

 

Since the cost of manual weeding is high, tendency, these days is to use chemical such as weedicides, herbicides particularly at the critical period. The recommended herbicides are primextra, Grammouron and Diuron.

 

The above are useful in area where dicot are the predominant weeds but where there are other weeds, the addition of Tricarboxy acid or glyphosate to the above chemical will control the weed. The chemical is applied once before emergence. The only one pre-emergence application will control all the weeds. The early low canopy branching variety suppresses weeds earlier than high growing ones.

 

·                    SPACING :- This depends on the sizes of ridges or rows- The recommended spacing is 1 metre by 1 metre. This gives a plant population of 10,000 stands per hectare.

 

FERTILIZER:- Cassava requires potassium. Potassium (k) must not be lacking. Its deficiency leads to:

 

1.                  Low yield

2.                  High HCN

3.                  % starch is low

 

Before planting therefore, one must be sure that available K is not lacking. This is ensured by perior  soil analysis before planting . In Nigeria however laboratory for soil analysis is not common. Therefore blanket application is given as follow:

 

If pH < 5.0 apply lime, complete fertilizers 10:10:20 should be applied at 2 –3 bags per hectare depending on the soil nutrient status, cost of fertilizers and tubers. Time of application must be before tuberization at a time between 3 – 5 after planting. The reasons for not applying fertilizer immediately after planting is that the shooting does not depend on soil nutrient but on

 

The stored food in the stem. Thus root formation must begin before fertilizer application. Maturation occurs between 12 – 18 months after planting, depending on the variety. Some varieties  can stay in the soil for 18 months without loss.  But the longer its stays in soil, the more fibrous is the root. When grown for starch industry, harvest begins at 15 months because root is at maximum size at that time. Cassava can be grown for forage purposes.

 

CLIMATE AND SOIL CONDITIONS FOR CULTIVATION.

 

TEMPERATURE: Cassava is a warm loving plant. Optimum production is obtained between 77-85 f i.e 25 c-37 c. Thus, it is concentrated between Latitude 30 N$ S of equator. It can not withstand low temperature, efforts to grow it in Europe therefore failed.

 

RAINFALL: Rainfall is essential for growth and it must be well distributed for optimum yield. It can be successfully grown in rainfall range 508mm-2540mm per annum. Over 2540mm, drainage system must be good. It has admirable ability to withstand drought.It does very well  under irrigation.

 

SOIL CONDITION:- Although cassava is less demanding as regards soil conditions, it does well on sandy and loamy soil. It can grow on soils with high clay contents but yield is not optimum. Soil must be deep, rich but could be growth on wide range of soils if other conditions are favourable.  Optimum soil pH range is 5.5-8.5.  In Nigeria, cassava is growth as last crop in a rotation and this accounts for low yield. It is a short day  plant. It produces less tubers when the day length exceed 10-12 hours.

 

                       CASSAVA HARVESTING

 

Most varieties of cassava can be harvested within the first six months of planting or they would have formed edible roots. It will continue to increase in size as the plant continues to grow if it is not harvested. Cassava can be harvested in relation to its stand, which depend on variety, size and location in the field. Some farmers spread over their harvesting period to months and it may be up to 4 years. Cassava farmers can milk their cassava plants, that is they harvest but not all the roots of a plant at one time, only to come back later, sometimes after several weeks or even months, to harvest the remaining roots. This is done as a famine reserve” process.

           

The cassava –harvesting schedule is influenced by the general food supply outlook, market conditions, and labour availability for period of attractive market prices farmers will harvest their cassava early, sometimes before roots attain their maximum bricking. Harvesting their  cassava  is now becoming most labour intensive filed task in Nigeria. Labour difficulty is now shifting from cassava weeding to cassava harvesting because TMS varieties  have boosted yields by 40percents.

           

Mechanization  of the harvesting operation is more urgent than mechanization of any preharvesting  tasks because it will facilitate  the adoption of agronomic measures that can raise cassava yields. In some areas where cassava is planted as a cash crop and where there are  accessible roads, cassava fields  are harvested manually but taken to processing  centers  by motor vehicles. In rural area, most of the roads are so bad that rural dwellers  transport cassava by head- load. Therefore, there needs to be an improved roads to enhance movement of the mechanization equipment to the cassava fields and evacuation of cassava.

 

                            CASSAVA PRODUCTION

 

Labour is the main component of the cost of cassava production but people believe cassava requires low labour inputs for production. Farmers in Nigeria use more hired labour in cassava production, because cassava is commonly grown as a cash crop for urban consumption. Mechanized equipment are available for tillage and land clearing but they are not commonly used in Nigeria in cassava production because available mechanized technologies are not suitable for preparing seed-beds for cassava. It is suitable to make ridges (high) and mounds to enhance drainage and soil aeration because of poorly drained soils we have in Nigeria. Yet mechanized  technologies are not efficient in making ridges and mounds in poorly drained soils.

           

Planting without tillage (ploughing, ridging or mounding ) reduces soil erosion, and maintain soil structure. According to the research done  by 11TA (1992) ,it  was discovered that minimum – tillage method controlled soil erosion and maintained soil structure, it required a chemical herbicide for weed control.  The effect of minimum –tillage on cassava yield revealed that the yield was significantly higher when cassava was planted on ridges, because of better weed control. Weeding was found to account for a large proportion of total labour input, the COSCA study found that weeds constitute a serious problem in cassava production because generally it takes about two to four months before cassava leaves close the canopy and suppress weeds growth.