The Enset growing area encompasses the majority of the mid-to highlands of the Southwest quarter of Ethiopia (Figure 1). Enset is an important staple or co-staple food for about 7-10 million of Ethiopia's 56 million people. Knowledge of the contribution of Enset to the food intake of these people is important because foods derived from Enset are protein-poor but contribute large amounts of energy requirements of the peoples of these food insecure, intensively farmed areas.
Incremental increases in the Enset and root crop production were utilized for several years (1989-92) by the FAO/WFP Crop and Food Supply Assessment Missions to estimate overall Enset and root crop production and the relationship of this production to the overall food balance sheet for the country. However, it was evident that considerable confusion existed on the potential per hectare yield of Enset with yields ranging from 4, 5 and even up to 10Mt/hectare. As a reasonable method of estimating Enset yields did not exist, the 1994 FAO/WFP Crop and Food Supply Assessment Mission decided that `misleading data could be more damaging than no data at all' and that Enset and root crop production should not be included in the food balance equation `until a formula for its estimation could be derived'. Also, including the reported Enset and root crop production for the Southern Region (2,747,000 Mt-Cereal Equivalent) into the calculation would have created the impression, at least on paper, that Ethiopia was a surplus producing country. This would have endangered numerous communities which were just beginning to recover from drought, famine, civil disturbance, overpopulation and land shortage and in fact remain vulnerable to food insecurity.
Problems in production estimates
Enset production varies greatly from plot to plot and area to area and yields are extremely difficult to estimate for a number of different reasons:
1. Variations in reported yield per plant range from 12-42 kg.
2. Variations in time to maturity/harvest are normally 4-8 years but can be as long as 10 to 15 years.
3. Variations in plant spacing, due to both transplanting and intermittent harvesting, make the calculation of number of plants per hectare impossible to standardize.
4. Estimates of Enset hectarage are confusing, having gone from 137,000 hectares in the Southern Region in 1993 to 300,000 in the same area in 1994. However, if this increase were actually an increase in new plantings then there would be no immediate increase in actual food production as Enset takes 4-8 years to mature.
5. Enset is a flexible-harvest crop in that households have the option to utilize it at any time after maturity - i.e. a mature Enset plant becomes a mini household food security system available for harvesting and processing immediately or it can be `held in reserve' for another 5 to 10 years and it continues to grow and mature.
6. Villagization by the former government is thought to have discouraged extensive planting of the multi-year crop whereas now households are returning to their land and expanding their plantation.
Previous studies and research into per plant and per hectare yields
Yield per hectare is equally difficult to estimate because of both plant spacing and the great flexibility individual households have in when and how much they harvest in any given year. In 1993, for example, average Enset production was estimated at 206 qt/ha but varied from 117 qt/ha in Oromia region to a high of 1000 qt/ha in Gedeo Zone of the Southern region. For the 1994 production estimate, Gedeo Zone reported 100 qt/ha while Sidamo Zone reported 240 qt/ha up from the previous year of 82 qt/ha.
From the reported yields per plant, Kefale and Sandford[1] calculate that, depending upon spacing and age at the time of harvest, yields could range from 66 to 230 qt/ha (39-137qt-Cereal equivalent). Pijls et al,[2] in a study of 60 households in Gurage Zone, found an average family size of 6.1 consumed 46 plants per year each yielding 34 kg/plant for an estimated production of 95 qt/ha. Yeshi[3] used the average of 6 reported plant yields, i.e. 27 kg/plant and assumed 1/4 of the hectarage would be mature plants for harvest spaced at 2 meters X 2.5 meters to calculate 108 qt/ha. Finally, Hiebsch[4] used two theoretical models and several transplanting schemes to calculate yield per hectare. In the first model he proposed that the yield of a plant is divided by the time-space that it occupied in the course of its existence. In the other system when a plantation is assumed to be in equilibrium, the total annual yield is divided by total area. Hypothetical yields of 44.8 to 86.6 qt/ha/yr were given.
In 1993, FAO consultant Evans[5] attempted to formulate a pilot method of Enset surveying by determining average plant yield by age and region. The 163 plants harvested and processed averaged 30.8 kg but standard deviation of plants within the same age-region averaged 9.3 kg. Although area of the plantation and other socio-economic data was taken, the consultant was unable to establish either a figure to use for per plant yield or a method for determining hectarage for assessment of production.
Definition of Terms
Amicho - the fleshy inner portion of the Enset corm which may be cooked and eaten separately, tasting similar to potato.
Bulla - the small amount of water-insoluble starchy product that may be separated from Kocho during processing by squeezing and decanting the liquid. It is eaten as porridge.
Clone or variety - a distinct type or grouping of plants within a species separable from other types by some form of heritable trait, be it visual, chemical or other. New plants of clones are usually reproduced asexually, i.e. without utilizing flowering and seed production.
Corm - an enlarged fleshy structure at the base of the plant which is used to make Amicho, which can be added to the Kocho or from which new shoots emerge following destruction of the dominant shoot.
Cereal equivalent (CE) - conversion of the yield or weight value of a food to account for the water and energy content, measured in the proportion of standard 3,500 calories/kg equivalents of cereals. Enset and root crop foods, being high in water, are adjusted by the following factors to give Cereal equivalent (CE).
Kocho .54 Cassava .44
Bulla .57 Yam .18
White Potato .21 Taro .32
Sweet Potato .32
Jump- the package of Kocho or Bulla ready for transport and marketing , usually wrapped with dried leaf sheaths.
Kocho - the pulp of the Enset pseudostem derived by scraping the individual pieces and excluding the fibrous remains. Bulla may or may not be extracted and the Amicho may or may not be included. The raw mash is chopped and fermented and it is this product, at 50% moisture, that is being assessed. When steam baked, the flat-bread is also called Kocho.
Multi-year crop- a crop which takes several years to mature or flower as opposed to perennial crops which bear fruit or seeds each year or annual crops which are replanted and harvested annually.
Pseudostem - the `tree trunk' formed by the bases of the leaves or leaf sheaths adhering to one another in concentric fashion
Sucker or Seedling- a new plant shoot that develops at the base of the leaf, in the case of Enset, at the juncture of the pseudostem and the corm, more properly called a sucker since it is not developed from a seed.
Methods of the present study
As Enset is an important source of calories for 15 to 20% of Ethiopia's population but production is extremely difficult to measure, it was thought that there should be further study into possible procedures or methodologies for measuring production. Since plantation systems, age of harvest and household food needs vary tremendously over the Enset growing area, the authors decided to use average household utilization (consumption and sale) as the parameter to measure production. This would eliminate age, spacing, average plant yield and hectarage variables from the assessment and more accurately reflect annual the household food economy and its relationship to the annual crop production scenario. The assessment consisted of two parts: first, creation of a linear regression model of the relationship of plant size to yield; second, surveying average household Enset use, by wereda, which was then multiplied by number of households in the wereda.
Forming the Regression Model of Plant Size in Relation to Yield
Welayita Argicultural Development Unit[6] data indicated a positive relationship between measurements of plant pseudostem girth and height with plant Kocho yield. Assuming an 80% correlation between these parameters and choosing the 90% confidence interval for the standard error of an estimate, 67 plants, sampled over a range of sizes, it was assessed that these indicators would be sufficient to construct the model. Sixty five samples were taken at random throughout the Enset growing area by asking the household whether they had Enset under fermentation from a single plant. The total Enset products were weighed and sampled for moisture content and the size of the plant from which it came was measured.
Individual plant yields varied from 114.7 kg (298 cm circumference X 303 cm high plant) down to 3 kg (a 58 cm X 93 cm plant). Correlation of yield with circumference was 87% and with the pseudostem height the correlation was 83%. both the variance for linear regression and the coefficients for circumference and height were highly significant in predicting plant yield. The derived model
PLANT YIELD = -36.5 + .23 X CIRCUMFERENCE (cm) + .19 X HEIGHT (cm)
was sufficient to account for 82% of the observed variation in plant yield and was used to construct a predictive yield graph (Figure 2) and table (Table 1) for calculating expected yield of any size plants being utilized by the household.
Variance in the parameters measured and the resulting yield could have been reduced had plants within the same size class been selected from the same clone and environment and then processed by the same household methodology. However, some level of accuracy was forfeited in order to make the model valid across all plant architectures and ages, across all environments and husbandry practices and across all household processing variations. However, one of the factors that could change the model might be if plant measurements were taken while the Enset was under moisture stress. Although the assessment was made rather late in the season, future assessments should be done following the rainy season when plant/water relationships are stable.
Assessment of Household and Wereda Enset Production
Yeshi4 suggested that surveys be conducted using a nested design i.e. a percent of households within each Peasant Association, a percent of PA's within each wereda and a percent of weredas within each zone. However, due to the large variability among weredas, all 74 weredas considered by MoA experts to be major Enset producers were surveyed. One hundred random households within each wereda were surveyed to form the wereda average household Enset production. This was multiplied by the reported number of households within the wereda or in some cases, within the Enset producing PA's of the wereda.
The average numbers of plants, production/plant, production/household, production/wereda, production/ hectare and hectares of Enset from the survey are given in Table 2. Fifty-eight weredas responded with completed survey forms. In order to at least have an indication of overall production, production in the other weredas was calculated using the average household production of adjacent weredas times households in that wereda.
The average number of plants harvested per household per year varied from below 12 plants in a few weredas to more than 100 in several. If 50-60 plants are needed to fulfill a major staple food requirement, then obviously those harvesting the lower number must be supplementing the Enset foods with other food items and those harvesting the higher number are either surplus producers or could be utilizing smaller plants.
Wereda per plant yields averaged 19.7 to 84.6 kg with an overall average of 44.2 kg at 50% moisture. This compares to farmers' opinions that the average yields are 25 kg and researchers' reports of 12 to 42 kg at unspecified moisture levels.
Annual household production of Kocho varied from around 1 quintal in low producing areas to more than 90 quintals in 3 weredas. Average annual household production varied from 5-15 quintals in subsistence producing weredas to 35-70 quintals in surplus producing weredas.
Assessed total annual Kocho production from 80 weredas and 7 special weredas amounted to 4,381,903 MT (metric tonnes) of which 3,704,698 MT is from the Southern Region and 667,205 MT is from the Oromia Region. This compares to 5,422,935 MT reported by the Ministry of Agriculture of which 5,008,515 MT was estimated to be produced in the Southern Region and 414,420 in the Oromia Region. The previous production figure accepted by the FAO-MOA for crop assessment in 1995 was 2,482,574 MT but was derived by deduction and did not include production in Oromia Region.
With the derivation of a formula for assessing Enset production, Enset and root crop production should go back into the food equation. Acceptance of the herein assessed production figure would put the country and certainly the Southern Region in a surplus production situation. While Enset products are not easily transported or stored, other grains produced in the Enset growing area are and should be considered in the national food balance. It may be that balance sheets should be regionalized so that surplus and deficit stocks can be balanced according to traditional foods consumed in that region.
The Enset production assessment does not contradict the current food deficit in the areas currently receiving relief aid. In fact the data supports the concept that, even with Enset, the land shortage in some areas has resulted in immature harvesting and does not allow the most efficient production of this of multi-year crop.
Subsequent assessments, whether on individual farms or in entire affected areas, should show whether relief aid enables the household to recover in terms of allowing Enset plants to grow larger thus more productive.
Immature harvest in relation to assessed production, disappearance of intermediate size plants and household food/financial security
Evans (1993) noted a 60% loss and Kefale and Sandford (1991) recorded a 51% disappearance in plant numbers in the intermediate size, i.e. prior to mature plant harvest. The latter authors first thought that this could be explained by drought and food shortage causing consumption of immature plants. However, in further studies the farmers thought that disease and transplanting shock was responsible for `early' intermediate plant loss (about 40%) whereas `later' intermediate plant loss was attributed to a combination of wilt disease and early consumption. The latter authors concluded that food shortage was indicated as a major factor in immature harvest even though in their study the `very rich' farmers also `lost' 17% of their intermediate size plants.
By interviewing the female head of houses, the present study discovered that often intermediate size plants were being utilized even though there were plenty of mature plants available for consumption. When questioned about immature harvest, the woman explained that `there isn't enough land to transplant all these to the larger spacing', or `these plants are being crowded and we have to thin them' or the intermediate plants are more sweet and juicy, thus accelerating the fermentation process. But the significant finding of this initial survey was that a woman can harvest as many intermediate size plants as she wants so long as enough large plants remain to keep the man socially and economically comfortable. It is her `Sekret' that she can take small amounts of Kocho to sell in the market for purchase of household necessities.
This immature harvest could substantially add to the overall Enset production figures. Even though small plants yield less, there could be large numbers involved. Hiebsch, who hypothesizes 46 mature plants consumed/household/year, calculates an additional 520 immature plants utilized (after 10% natural loss) amounting to 25% of consumption or an additional 13 qt/ha/yr. It is obvious that if these consumption figures for immature plants are valid throughout the Enset producing areas, immature plants could constitute a significant addition to family food or financial security.
Factors influencing Enset Production
In addition to the above mentioned aspect of food/financial security, Enset has many additional positive and few negative characteristics. Just like un-harvested but mature Enset plants in the plantation are a household food security reserve system, Enset products in the fermentation storage pit are like a `living refrigerator' that allows utilization of a flexible amount at a moments notice. When energy foods are needed by the family, when guests drop in, or to fill the `hungry gap' between annual cereal crops, the Enset supply can easily be tapped anytime during the day, season or year.
Also, the standing plants are a source of financial security that can be sold as needed. As one farmer noted when his neighbor sold 4 large plants to pay hospital bills, `it is easier to replace a 40 birr Enset plant than a 40 Birr shoat'. With the development of a free market economy and urban sales (the Mercato in Addis Ababa sells more than 500- 70 kg Jumps per week), rural commercial producers and middle-men buy standing or processed Enset products (at costs of less than 100 birr/qt) for retail with a sizable margin (100-200%). There is also scope for the expansion of this market.
`De-villagization' and the ability to sell agricultural products on the open market are encouraging return to homesteads and the expansion of land under cultivation. Enset production is favored by land tenure stability and, because of the high density of plants per hectare, land shortage. Although a multi-year crop, land requirements for Enset to provide 50% of the energy requirement of a family of 6 persons could be as low as .005-.01 hectares. Unless production keeps up with demand, cereal prices may continue their upward rise, increasing demand for the 'poor man's' food - i.e Enset products. Also, in addition to fermented products, Enset can been dried, ground and added to other flours to make acceptable breads, injera and starch foods.
Inputs for Enset are low, sustainable and actually build soil productivity. Enset is reproduced by the farmer from suckers emerging at the juncture of the root and shoot following decapitation of the dominant shoot. Although manure is used if available, fertilizer is not needed and soil fertility actually increases in the Enset plantation due to the decomposition of mulches. Also, lack of tillage reduces organic matter decomposition. Although Enset thrives on deep fertile soils, soil degradation is arrested by plant interception of rainfall, lack of erosion, increase of organic matter and improvement of soil structure. Enset could be more intensively intercropped, especially with pulses, than is currently practiced. Enset itself contributes considerable forage to the livestock-cropping system. Surplus forage during the rainy season, whether from Enset or other sources, could be preserved by using the known technology of Enset fermentation.
One of the greatest constraints, both to the local food security and to Enset in general, is the Enset bacterial wilt. Bacterial spread is thought to occur by lack of sanitation on the part of the farmer; its control is recommended by destruction of infected plants and fire-sterilization of knives and cultural tools. Although the bacteria is highly pathogenic (1 ml of exudate from a diseased plant will kill a large plant in 10 days), it does not appear to be highly infectious, i.e. rapidly spreading to other plants and areas. However, development of a transmitting vector would be very devastating since banana is also susceptible to the same bacterial wilt. So far, screening of clones or Enset varieties has not identified sources of genetic resistance but rather levels of susceptibility.
The contribution of other factors to disease occurrence and spread still needs to be explained. These include plant physiological/maturity status, natural means of spread including splashing rainfall, insects and gophers or mole rats, which in themselves are highly destructive.