Fibre crops

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Agave Fibres. I. Morphology, Histology, Length and fineness; Grading Problems
(1936) Nutman, F.J.; East African Agricultural Research Station, Amani, Tanganyika Territory
The paper is in the nature of a progress report on the work done on agaves as fibre producing plants at Amani during the last few years. Agave fibres are of 3 fairly well-defined types: - Mechanical, most strongly developed round the periphery of the leaf; these fibres are of great importance commercially; owing to their shape they seldom divide during manufacture and on their fineness depends the fineness of the sample. Ribbon fibres occur always in association with the conducting tissues though they are present in various sizes in all parts of the leaf except the extreme periphery; they form the longest fibres in the leaf and are important in that they split longitudinally, unlike the mechanical fibres, and therefore their original size does not influence fineness. Xylem fibres are of no commercial importance, being broken up and lost during decortication. Short leaves, whether caused by early cutting or environment, do not produce a markedly finer fibre than long leaves. Fineness of fibre is varietal, in which respect A. amaniensis and A. cantala are much superior to A. sisalana. A. amaniensis possesses a larger amount of short fibres than A. sisalana, but this is offset by the greater length of its leaves. The proportion of mechanical to ribbon fibre in A. amaniensis is twice as great as in A. sisalana. This fact is of technical importance, giving the fibres a different intrinsic make-up and probably affecting spinning behaviour. Methods of mechanical grading to replace the present grading by eye are thoroughly discussed and the defects of the present system pointed out. Nevertheless, expensive grading schemes cannot be put into operation until the consumer gives some indication of the type of fibre required, and so far, this has not been forthcoming.
Suggestions to Managers of Ginneries
(1936) Field, N.; Briggs, P.W.
Before lighting the fire a responsible per seen should make sure that the 1evel 0f water in the boiler is not below the low level mark dangerous and must have immediate. When raising steam from cold slow fire only should be made and a period of time not less than 5 to 6 hours should be allowed to reach full pressure
The Sisal Weevil
(London, UK, Longman, 1936) Harris, W. V.;
This paper amplifies a previous circular [R.A.E., A 23 67] on Scyphophorus acupunctatus, Gyll., attacking sisal (Agave sisalana) in Tanganyika Territory, and embodies the results of the author's observations to date. The most obvious symptom of attack is the presence in the leaves of holes 1 cm. in diameter. These are the result of the weevil boring into the hearts of plants under 2 years old when the young leaves are still unfolded. When the plants are healthy the injury does not develop further, but when growth is not vigourous, the reaction of the tissue around the perforations is not sufficiently active to prevent the entrance of rot-causing organisms. These infect the central shoot, which becomes red and soft, and the plant dies. Large suckers used for planting are more liable to serious injury than bulbils, which are damaged by the weevil penetrating between the bases of the outer leaves into the bulb, or small suckers with newly cut bases, which also attract it. Deep planting and injury to the leaf bases are, however, the primary causes of the death of the plants in many cases, and the weevil is then only a secondary pest. Large healthy sisal plants are sometimes attacked by the adults when the leaves are still more or less part of the heart or central shoot. When cut, the leaves are found to have areas of brown dried-out epidermis about 8 ins. from the base. This causes discoloration of the fibres, but actual damage to them is not considerable. This type of injury is exceptional in that it appears to depend on the population density of the weevils and not on the health of the plants. There is, however, evident varietal susceptibility to weevil injury; Agave amaniensis and Furcraea gigantea (Mauritius hemp) growing in small plots on sisal plantations, particularly near the coast, are severely attacked, and at Amani, 2, 500 to 3, 000 feet higher than the sisal plantations, injury to A. sisalana and A. amaniensis is negligible, damage to A. ingens is more noticeable, while Furcraea gigantea is disfigured by large holes in nearly all the leaves. When eggs are laid in the base of young bulbils or suckers, or in the hole made by the adult weevil in the central shoot of a larger plant, usually only one or two larvae develop, but numbers do so in plants of which the pole has been cut or in dead stumps. The eggs survive only if there is a certain amount of moisture, and the larvae also die if exposed to dry conditions. The egg, larval and pupal stages last 3-4, 28-55 and 19-36 days, respectively; the larvae bore through the central shoot or make irregular tunnels through the tissues till full-grown, and pupate in cocoons made from fibre and leaf debris. Larvae and pupae both develop most rapidly during the rains. The adult female appears to take a minimum period of 25 days after emerging to reach sexual maturity, so that 11 weeks are needed to complete the life-cycle and there is a possibility of 4 generations a year. The length of life of the adults is not known, nor is the reproductive capacity, but 3 females averaged 62 eggs each over a period of 3 months. The general distribution of the weevil is discussed. In Tanganyika it has now been recorded as far west as Lambeni, but the average population is greatest in the coastal belt from Moa to the Pangani River. It is least in the estates at the foot of the Usambara Mountains, where the soil is of a red lateritic type. Here termites are numerous and are active in destroying the sisal stumps. There are indications that relatively dry seasons are also periods of increased activity of the weevils, but a low average rainfall is not in itself conducive to weevil attack. The control measures recommended are similar to those already noticed [loc. cit.]; attempts to render stumps innocuous by pouring a solution of sodium arsenite into holes made in the tops were unsuccessful as the penetration was not sufficient to render the whole stump poisonous.
Notes on Trials of Ramie in Tanganyika Territory
(1937) Eyre, J.C; Department of Agriculture, Tanganyika Territory
Ramie was introduced many years ago into Tanganyika Territory. There are now a number of small acreages in the Tanga and Moshi districts, but the only planting of any size is one of some thirty acres near Pongwe in the Tanga district, and a smaller one on an estate in the Nguu Hills of Handeni. There has been no recent extension of planting in the Tanga area, and the planter who laid down the large area now considers conditions on his estate to be unsuitable for this crop. The variety mainly planted was Boehmeria nivea; B. utilis is only being grown on a very small scale owing to lack of planting material.: There is no very noticeable difference in the response of these two species; B. utilis produces a somewhat longer but proportionately thinner stem. Observations have been made on the crop planted in both good and bad situations. It usually flourishes during the first year or two, providing there is sufficient rain, after which it very rapidly deteriorates. The stems become progressively shorter and thinner, and harden up very much more quickly, while at the same time the number of stems on a given area rapidly increases. Often, however, ramie shows poor growth even in the first year or two, like that on the Sisal Experiment Station at Ngomeni. From observations it appears that to make an economic success of the crop—apart from marketing considerations—it will be necessary to find some means of controlling the increase in the number of stems aridprobably also to manure. The cost of establishing 36 acres in the Tanga district amounted to Sh. 5,323/50, which included the cost of clearing the land of fairly heavy rubber and also of cleaning a part of the area for three years. On another estate the cost of clearing, planting and cultivating up to the time of the first cutting was said to be approximately Sh. 50 an acre. The accuracy of the figures is, however, doubtful. The cost of maintaining a plantation is not available, since both estates have allowed their areas to revert partly to, bush. It is thought, however, that the cost of upkeep, even without manuring, would be high, since the land would have to be clean cultivated and the number of growing stems controlled. No accurate figures of yield are available, since on each occasion that any quantity of material was harvested the area had to be searched for sufficiently long stems and only these were cut. On a good site and under favourable conditions, stems up to six and seven feet high are Obtained in the first year, but in, the third year or when the rainfall is insufficient the average height is not moze than three and a half feet..
The Vegetative and Nitrogen Efficiency of the Cotton Plant in Uganda
(1937) Hosking, H. R.; Department of Agriculture, Uganda Protectorate
During the 1935'36 season a comprehensive trial on cotton was conducted at the Serere Experiment Station in Uganda. The treatments consisted of six varieties combined with four sowing dates and three spacings. The whole trial consisted of 288 sub,plots.
A Study of Methods of Cultivating Sisal in Kenya in Comparison with those used in Tanganyika
(1937) Lock, G.W.; Sisal Experiment Station
The system of cultivating sisal in Kenya does not correspond exactly with that ordinarily followed in Tanganyika and consequently it may be of interest to compare the respective methods of the two principal sisal producing centres in East Africa. Broadly speaking the distinction arises through climatic differences. induced chiefly by a wide disparity in altitude. Over 80 per cent of Kenya sisal exports originate from the highlands above ).000 feet and it is proposed to describe in most detail sisal growing in those parts.
Notes on the Economic Possibilities of Blue Sisal (Agave amaniensis)
(1938) Lock, G.W.; N.D.A., A.I.C.T.A., Tanganyika Territory
The production of blue sisal (Agave amaniensis) is still in the experimental stage and has not yet developed into an economic proposition. Since the discovery in 1929 of a few plants growing in a remote corner of the East African Agricultural Research Station at Amani, lack of planting material has prevented the cultivation of blue sisal on any extensive scale. The position is rapidly changing, for bulbils and suckers are now distributed to estates in larger numbers, so that the area under blue sisal is increasing annually. Within the next few years fibre should be forthcoming in exportable quanties.
The Utilization of Sisal Waste in Java and Sumatra
(1938) den Doop, J.E.A.
On page 5 of the July 1937 issue of this Journal the editor asks for articles on one's experiences in composting of sisal waste. Although the author's experiences in sisal waste utilization are not just parallel with same of Mr. Layzell, it, might be of interest to some readers of. This Journal to communicate them here, especially as they comprise practically the whole history of sisal waste utilization in the Dutch East Indies, i.e. in Java and Sumatra.
Factors Affecting the Attacks of Sucking Insects on Cotton
(1938) Gwynn, A.M.; Department of Agriculture, Uganda Protectorate
It is often convenient to distinguish between insect pests with biting mouthparts (locusts, caterpillars, beetles, etc.) and those with sucking mouth-parts (Thrips, and the many divisions of the Hemiptera, such as Aphids, scales, Capsid bugs, etc.). The cotton crop is attacked by a large variety of pests of both groups, but in the present article attention is confined to the latter. In a sense the biting insects are more straightforward to deal with, since the result of their feeding is usually obvious; the amount of damage done is correspondingly easy to assess, and often their activities are little affected by the health of the plant. On the other hand, with sucking insects it is frequently necessary to do experiments to determine the effect of their feeding; it is usually difficult to assess even roughly the amount of damage they cause, and any estimate of loss is almost bound to be speculative and open to controversy; finally, they may be much influenced by the health of their host plants, so that it is nearly always a matter for argument whether they are doing any damage at all. It is sometimes maintained that the presence of sucking insects is always a symptom of ill-health in a crop, and that any loss incurred is in fact due to the ill-health of the plants, or at least that the only way to reduce insect damage is to improve the health of the plants.'In answer to this it may be said that. while the health of the plant undoubtedly influences the degree of insect attack in many cases, it is by no means the only factor involved; that, even where the degree of insect attack is largely governed by factors operating through their effect on the health of the plant, the pests concerned often cause severe damage to crops which woulo otherwise have produced fair yields in spite of somewhat adverse conditions; and lastly that it is frequently easier to control such pests by direct methods than by treating the plants. It is worth examining the effect of plant health on insect attack in some detail. The first point which arises is whether the health of the plant affects the insects feeding on it as much as is often made out. Often the severity of insect attack may be correlated with poor soil, waterlogging, or other unfavourable factors which would be reflected in yield, even in the absence of insects. Here it seems legitimate to say that the health of the plant does influence the amount of insect attack. On the other hand there are cases where the extent of insect'attack may be correlated with other factors, such as varietal susceptibility, climate, or other ecological circumstances, which may not be connected with the health of the plant. Examples of both sorts are discussed below, under the individual pests. Secondly, it is necessary to distinguish between the effect of climate and weather, and the effect of plant health, on the insect population. It is of course obvious that climate has a profound effect on the health of the plant. At the same time it has an equally great effect on insect population, having a direct influence on the activities of the insects, on their reproduction, on their natural enemies.
The Utilization of Sisal Waste in Java And Sumatra-Part 11
(1938) den Doop, J.E.A.; Bandoeng
In the first part of this article the fuel value of sisal waste was discussed extensively and it was further shown that under Java and Sumatra conditions it must in general be more economical to use the sisal waste as manure than as fuel, although possible exceptions were not excluded.
The Root-System of Agave Sisalana in Certain East African Soils
(1939) Glover J.; East African Agricultural Research Station, Amani
The results of root investigations of Agave sisalana in various soils are given. Excavation was carried out by the water method since this was the most suitable for use with only African assistants. A triangular prism with apex at the base of the plant and base about 18 in. wide at 10 or more feet away was excavated mainly by washing and it was found that such a section gave an accurate picture of the root system. The size of the root system of the average 5-year-old sisal plant was shown to be larger in the soils examined than might have been expected from the scanty literature consisting in the main of a few generalizations. The plants examined had many roots over 5 ft. in length, with a maximum radial spread of bearers (i.e. main suberized roots carrying feeders) to at least 10 ft. from the base. The main concentration is usually in the top 24 in. but roots have been found at 6 ft. down, the water-retaining properties of the soil largely influencing the depth of distribution. There is thus considerable root competition, especially in dry soils, under the spacing used in East African planting (8 x31/2 ft.) which is intensified when weeds are allowed to grow. Surface clean weeding only is advocated since deep cultivation injures the sisal roots. Roots grow well on soils with a pH 9.15 to at least pH 4.75. A high concentration of alkali is shown to upset the plant nutrient balance. A badly drained soil is fatal and in certain soils the presence of a water table has caused the death of roots even when a height of 12-18 inches above it.
The Utilization of Sisal Waste in Java and Sumatra-Part IV
(1939) Den Doop, J.E.A.; Bandoeng, Java
After the findings, as described in Part III of this article, the author designed in 1928 a field experiment, S.93, in the old red-soil area with a view to finding out the effect of green manure (Tephrosia candida D.C.), with and without various combinations of artificial manures, on sisal yield. The green manure was planted in 1928, worked into the soil in various ways in 1929, and the sisal was planted thereafter, at the end of the latter year. This experiment, S.93, has been reported upon from the point of view of green manuring in a Dutch journal. 1 Some of the yield data, as relevant to the present subject, are to be found in Table I, together with some other data.
Hand Spinning and Weaving in Nyanza Province, Kenya
(1944) Smith, D. G.
A year ago the crafts of spinning and weaving were very nearly unknown in the Nyanza Province. A little spindling had been taught by one or two public-spirited women in their very limited spare time, but a wheel and a loom were still the" unknown quantity". During a rather hurried tour of the Province early in July, I made a point of finding out how the craft was being received by the Africans. Everywhere it was the same story—" we like this work—we want to learn more". At Mumias I was told the little children make themselves a spindle with a lump of clay on the end of a stick, pick up the waste bits of wool, teach themselves to spin a thread and then take it to the Sisters at the Convent saying" now you see we can spin let us join your class". Other Missions tell me they have had to forbid the girls taking their spindles to class, and that every available moment between other work is given to spindling.
Observations on the Spacing of Sisal
(1946) Lock, G.W.; Sisal Experimental Station, Tanganyika
The early field trials on the Mlingano Sisal Experimental Station showed that of all the factors affecting sisal yields, spacing, in so far as it determined the density of plants, was by far the most important. As the population of plants per unit area increased so did the total tonnage of fibre obtained during the life cycle. A paucity of plants, such as 1,500-2,000 per hectare, only yielded about five to six tons against 30 tons reaped from 10.000 plants per hectare. Intermediate populations likewise yielded according to plant number. The total fibre yield and the longevity of the sisal were closely and positively correlated with plant density. It is not proposed to deal with the results of spacing trials in this article beyond pointing out the profound influence of plant density upon yield. The optimum density will vary according to climatic and soil conditions and no hard and fast rule can be laid down beyond stating that one aim should be to have as many plants as possible without seriously impairing the development of the sisal. Within reason, the more favourable the growth conditions are, the greater the density may be, and, conversely, the poorer the conditions the lower the plant population. The proper approach to determining any spacing for an estate, or section thereof, is first of all to decide how many plants the land will carry satisfactorily. Having reached this decision the actual espacement to be adopted should then be considered. Frequently these two factors are dealt with in the wrong order. For example, should a density of 5,000 plants per hectare be settled upon, then the question whether the spacing should be 2 x 1 m., 2.50 x. 80 m., 4 x 1 m. x. 80 m., or any other variant giving 5,000 plants, should be answered afterwards.
Agricultural Research in the Sudan Gezira
(1956) Maxwell, D.R.C.; Sudan Gezira Board, Wad Medani
In recent years the high quality of the long staple cotton grown in the Sudan Gezira has gained world-wide recognition. As the following survey shows, much of the credit for the success of the Gezira Scheme is due to extensive experiment and research devoted to controlling pests and improving the breeds of plants.
A Feeding Trial with Sisal Waste
(1956/1957) Frank, P.J.
During the past few years the price of sisal fibre has dropped so steeply that the sisal industry is looking for means to increase the financial return from its estates. At present, only 4 percent of the leaf is recovered as fibre, and to improve this extraction rate some estates are using a machine for the secondary removal of fibre, in addition to the preliminary decortication. The material produced after this second removal is known as Sisal waste, and consists mainly of the leaf pulp together with a small amount of fibre.
A Feeding Trial with Sisal Waste
(1957) Frank, P.J.; Veterinary Department Experimental Station, Naivasha, Kenya
During the past few years the price of sisal fibre has dropped so steeply that the sisal industry is looking for means to increase the financial return from its estates. At present, only 4 per cent of the leaf is recovered as fibre, and to improve this extraction rate some estates are using a machine for the secondary removal of fibre, in addition to the preliminary decortication. The material produced after this second removal is known as sisal waste and consists mainly of the pulp together with a small amount of fibre.
Rapid Propagation of Sisal Hybrid No. 11648
(1960/1961) Diekmahns, E.C.; May, W.B.; East African Agriculture and Forestry Research Organization, Kikuyu; Sisal Research Station, Tanganyika
The normal plantation method of propagating sisal vegetative, is by the use of basal suckers or bulbils. Where it is desired to bulk up rapidly one particular plant, such as hybrid No. 11648, the use of single rhizome buds greatly speeds the task of multiplication.
Standard Variety Trials 1964-65 Season (Cotton Research Corporation)
(1964-65) Coffee Research Corporation; Coffee Research Corporation
Corporation staff are invited to send in their comments on the results of the standard, variety trials summarized below and to suggest alternative interpretations of the data. The attention of staff is particularly drawn to 'the proposal made by Professor Bunting at the Summer Meeting: that stations should pool all available information on factors determining yields and this should be checked by a programme of physiological observations.
Masai and Kipsigis Notes on East African Plants: Part II—Domestic Uses of Plants.
(1966) Glover, P.E.; Stewart, J.; Gwynne, M.D. ; E.A.A.F.R.O., Muguga, Kikuyu, Kenya
Part II includes edible plants, dye plants and plants used for string and rope. The list in part III is grouped under disorders. All groups are subdivided according to plant families.

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