Farming and Gardening
for Health or Disease
(The Soil and Health)
by Sir Albert Howard C.I.E., M.A.
Appendix C
The Utilization of Municipal Wastes
in South Africa
by J. P. J. van Vuren, M.Sc. (Agric.)
Professional Officer (Extension) and Co-ordinating Officer, Municipal Compost Scheme
LITTLE was it realized in August 1939, when the first sod was turned for the excavation of an experimental compost pit somewhere on the boundary of the Ficksburg town commonage, that history was being made. Had this been known at the time, the criticism and prejudice which had to be faced and fought for so many months to come would then have mattered even less than they did.
Up to that time hardly anybody in the country had shown any practical interest in the conversion of otherwise useless and obnoxious products such as garbage, night soil, etc., from urban areas. My own knowledge of this subject was limited to a mere study of the results obtained overseas by men like Howard, Wad, Watson, Jackson, and others. I felt thoroughly convinced, however, that this method could be successfully employed in South Africa if only one municipality could be persuaded to co-operate in the initial experiment or demonstration.
About the time referred to above the author was transferred to Ficksburg in the Orange Free State, a small town with a population of scarcely 3,000 Europeans and situated on the border of the Basutoland Native Territory. On my arrival in my new sphere of activity the matter was discussed with the local health inspector, who at once declared himself willing to co-operate in the laying down of an experiment.
At first a small-scale trial was conducted, well away from the public eye and almost in secret. No funds were available. Ordinary trenches 12 x 8 x 2 feet deep, were dug in the soil and old pieces of scrap corrugated iron were cut, perforated, and used over drainage channels in the floor of the pit. Dry refuse straight from the tipping wagons was dumped in the pit and levelled into a layer about fifteen inches deep. On the top of this came night soil, followed up with refuse and so on until in about three days' time the pit was filled. Right from the outset problems and numerous difficulties were encountered. Owing to poor drainage and the absence of aeration facilities the contents of the pit became a cold, sloppy, reeking mass. Consequently none of the labourers, whose customary task it was to dig trenches for the usual burial of night soil, could be persuaded to do the necessary turning over of the contents -- and they could hardly be blamed for refusing. The sides of the pit caved in during subsequent rains and myriads of flies issued from the sodden mass. Fortunately very few outsiders knew at that time what was happening, otherwise our experiment might have ended in court.
However, where there's a will there's a way. Our mistakes were gradually rectified and one after the other our problems disappeared until the stage was reached when an invitation to certain members of the Council could be risked. Their visit had the desired effect and a small sum of money was granted for the erection of proper brick and cement installations. In these new pits, erected according to Watson's Tollygunge plans as described by Sir Albert Howard in his pamphlet, The Manufacture of Humus from the Wastes of the Town and the Village, excellent results were quickly obtained. Temperatures started to climb to surprisingly high levels. Fly- breeding was prevented by these high temperatures and within four weeks the final product was a dark crumbly mass with no unpleasant odour and without any trace of its original constituents.
At this stage the local authority became convinced of the practicability of the composting process and it at once decided that this 'modern' method of urban refuse disposal should receive more sympathy and support. It was consequently decided that a more convenient site should be selected and the scheme extended to include at least fifteen pits instead of only two as was the case up to that time. The ultimate site selected was situated only half the distance from town of that where night soil had been regularly buried for over fifty years, the period of Ficksburg's actual existence. The Council at once realized that a considerable saving on transport would result quite apart from the fact that the final product might be sold, thereby increasing the revenue of the town and consequently reducing the cost of refuse disposal.
Based on the valuable experience gained during the experimental stage of the scheme, the new pits were built accordingly. Certain modifications were introduced and these included the following: an increase in the number of cross channels in the floor from two to seven; vertical side walls instead of sloping ones; an increase in the length and width of the pits and also in the gradient from one end of the pit to the other, the latter to facilitate the handling and distribution of night soil. In addition a shed was erected to protect the final product against wind and weather.
From then on practically all night soil and refuse from the urban area was removed to this new site, where it was turned into compost at the rate of about 100 to 150 cubic yards per month. The refuse included, more or less, the following: the contents of garbage bins minus the coarse pieces of unburnt coal and other refractory material which are screened out on arrival at the site; weeds; grasses; hedge clippings; stable manure; papers; rags; abattoir refuse such as paunch contents, portions of the intestines, rejected meat or organs, blood, etc. (horns, hoofs, and bones were also collected but sold directly to bonemeal and fertilizer factories); sawdust; street sweepings, fallen leaves, etc. No longer were these constituents allowed to be dumped somewhere along the approaches of the town where rats and flies could breed unmolested. Instead, they were henceforth carted to one depot and there rendered harmless by being properly composted.
This, briefly, is the history of composting at Ficksburg. It may, however, be stated unhesitatingly that without the undaunted assistance of Mr. H. G. Williams, the Health Inspector at the time, as well as the sympathetic co- operation of the Ficksburg Town Council (through the medium of their energetic and capable Town Clerk), it is doubtful whether the scheme would ever have developed into the great success it is to-day. Without their valuable assistance Ficksburg would just have remained an ordinary Free State town, whereas to-day it is well known, not only in this country but overseas as well, as one of the pioneers in the direction of urban waste utilization.
No sooner were the first articles published in connection with the preliminary experiments at Ficksburg than inquiries started to pour in from various parts of the Union of South Africa, Rhodesia, Belgian Congo, and East Africa. At the same time a host of visitors were received and shown over the scheme at Ficksburg. According to the correspondence received, most of the urban authorities seemed to be faced with the same problems and difficulties of refuse disposal. This process of composting and getting rid of such material sounded to them like an answer to their prayers with the result that they were anxious to obtain details in regard to the process as quickly as possible. It did not then take long for the process to become adopted by various centres in southern Africa.
Owing to the fact that South African soils are generally deficient in phosphates, this country is dependent for her phosphate supplies from overseas. When war broke out, shipping facilities were reserved for the importation of essential war supplies. Imports, as far as this commodity was concerned, dropped to about 50 per cent of the pre-war supplies. At the same time there was an increased demand for food at this stage when farmers could obtain only half the normal requirements of fertilizers. As a result of this shortage all possible avenues of obtaining fertilizing material in the country were explored. Farmers were encouraged to give more attention to neglected manure heaps on their farms and to conserve and use this valuable material more extensively than in the past. In addition, farm composting methods were demonstrated and encouraged. Bat manure and phosphate deposits were explored and in some cases made available to farmers in the crop-producing areas. At the same time a huge trade developed in sheep and goat manure from the Karoo, South Africa's principal small-stock area, ultimately reaching such proportions that it was feared that the supplies would not outlast the war. In spite of the exploitation of all these sources of supply, it was still felt that production might suffer from a shortage of the necessary fertilizer material. It was the imminence of this possibility which caused greater attention to be given to the preparation of urban compost. If vegetable and fruit farmers, it was thought, could be encouraged to use urban compost more extensively, then more of the mineral fertilizers would be available for use in the production of grain crops such as maize and wheat. The possibilities of urban compost fulfilling part of this programme were investigated by a special Departmental Compost Committee on whose advice the Department of Agriculture and Forestry decided to institute an urban compost campaign on a national basis, the author being appointed co-ordinating officer for the scheme for the duration of the war. To assist him, six other officials, stationed throughout the four provinces of the Union, were also designated for this work. The duty of these officers was mainly to visit each urban centre in their respective areas and to encourage the adoption of the composting process.
For the purpose of gaining first-hand knowledge and experience of the process, these regional officers met at Ficksburg in August 1942, immediately after the decision to inaugurate this scheme. Apart from studying the method in its various aspects, these officers in conjunction with the co-ordinating officer drew up a programme of action so as to ensure the co-ordination of advice and policy. This programme included the following:
- The co-ordinating officer was to draw up a specified plan of the pits, as well as a pamphlet describing the Ficksburg composting process in detail, and to issue these to the regional officers for distribution to municipalities in their areas.
- Until such time as the co-ordinating officer was available to accompany each regional officer in turn through his area, these officers were to leave no stone unturned in so far as preliminary propaganda in this connection was concerned. At about this time the annual Municipal Conferences were to be held in the different provinces and they had to be addressed on the subject. Articles were to be written and published in local papers, etc.
- By this time there was at least one centre in each of the six areas where the process had been adopted already. At such centres regional officers were to organize two-day short courses for representatives of neighbouring towns. On these occasions practical demonstrations and lectures were to be given so as to make such representatives as thoroughly conversant with the process as possible.
- Radio talks and articles for the daily press were to be drawn up or circularized.
- Certain aspects of the process warranted further investigation and in particular the co-ordinating officer was to be responsible for the carrying out of this work at Ficksburg.
This, briefly, was the programme drawn up at the Ficksburg Conference in August 1942, and within six months practically the whole of the Union with its 300 municipalities and health boards was covered. It was soon found that almost all centres were confronted with the same difficulties and problems. Literally mountains of 'waste' were encountered at many places. These had accumulated over many years in some cases and it was not uncommon to see, lying in sight of these huge dumps, lands where the soil had been worn down to a condition of total impoverishment. That this has been and is still going on in many centres of the Union even to-day is incontrovertible proof of the naked truth of the late Professor King's words, 'Man is the most extravagant accelerator of waste the world has ever endured.' Fortunately South Africa is a country of vast open spaces, otherwise dumping sites might have become so limited that many of these dumps of fertility would have had to disappear in clouds of smoke, instead of still being there to-day in a state in which their fertility is still partly recoverable if only urban authorities can be persuaded to render such material marketable in the form of refuse-dump screenings and compost. These 'humus mines' as Sir Albert Howard calls them, are in many instances ready for immediate use on the land and could contribute materially to a reduction in the existing shortage of fertilizers.
After two years since the inauguration of the compost scheme, the position in regard to its adoption in South Africa is as follows: (p. 253)
In the various provinces the following towns and cities have adopted the urban composting process:
Northern Transvaal: Nylstroom, Potgietersrust, Pietersburg, Messina, Hercules, Zeerust, and Pretoria (Indore compost).
Southern Transvaal: Potchefstroom, Klerksdorp, Ermelo, Brakpan, Heidelberg, Volksrust, Boksburg, Randfontein, Lichtenburg, Alberton and Johannesburg, Roodepoort, Maraisburg (Indore compost).
Orange Free State: Ficksburg, Ladybrand, Clocolan, Bethlehem, Harrismith, Vrede, Reitz, Heilbron, Parys, Kroonstad, Kopjes and Bloemfontein, Kimberley (Indore compost).
Natal:Matatiele, Glencoe, Stanger, Dannhauser, Vryheid, Howick, Margate, Darnall, Bergville and Durban, Pietermaritzburg (Indore compost).
Karoo and Eastern Cape Province: Aliwal North, Elliot, Fort Beaufort, Graaff-Reinet, Kirkwood, Kingwilliamstown, Prince Albert, Queenstown, Umtata, Walmer, Cradock, Dordrecht, Oudtshoorn, Uitenhage, Humansdorp and Beaufort West (Indore compost).
Western Cape Province: George, Parow, Goodwood, Wolseley, Stellenbosch, Mossel Bay, Bellville, Swellendam, Vredenburg, Heidelburg, Robertson, Tulbagh, Capetown, Rivier-Zonder-End, Franschhoek, Ceres, Worcester, Clanwilliam, Wellington, Porterville, Caledon and Malmesbury.
|
Area
|
Schemes in
|
Average Annual Production in Cubic Yards
|
Total Production to date in Cubic Yards
|
|
Production
|
Course of Construction
|
| Northern Transvaal |
7
|
2
|
5,000
|
6,300
|
| Southern Transvaal |
12
|
1
|
13,500
|
18,600
|
| Orange Free State |
13
|
1
|
13,250
|
19,250
|
| Natal |
11
|
7
|
12,000
|
15,500
|
| Karoo and Eastern Cape Province |
16
|
6
|
5,600
|
12,100
|
| Western Cape Province |
22
|
6
|
21,000
|
27,000
|
|
Total
|
81
|
20
|
70,350
|
98,750
|
The main reasons why the remaining centres in the Union have not yet adopted the composting scheme are briefly the following:
- Lack of sufficient capital to construct the necessary pits. The cost of constructing such pits varies from place to place, depending on the cost of material and labour, but anything from £15 to £20 per pit can be taken as an average. Villages and some of the small towns, looking at the matter more from a financial point of view, felt that the output might be so small that it would not warrant the expense.
- Lack of sufficient quantities of raw materials, especially dry refuse, to absorb the liquids contained in the night soil. In some parts of the country, where the rainfall is low and poorly distributed, the vegetation is naturally scanty. This creates a real problem which cannot be disregarded. At the same time, the climate and type of farming in these areas are such that there is hardly a demand for compost, which means that this product would have to be exported to distant localities, thus raising the cost and leaving only a very small margin of profit, if any at all.
- The decision of the Department of Labour that urban composting schemes should fall under the Factory Act. The application of this Act meant that the provisions of certain clauses applicable to modern, well- equipped factories had to be complied with. Although it was added in the proclamation that exemptions in certain respects could be granted, many centres did not see their way clear to adopt the process under such conditions.
- Uncertainty in regard to the demand for the final product. This question was asked in practically every instance and the fact that the Department was not prepared to guarantee either a price or a constant demand for the product made the scheme less attractive. There is, of course, always the possibility that the demand may decline after the war when supplies of artificial fertilizers will again be available. It is nevertheless felt that as the supplies of Karoo manure are being exhausted since the restriction of the importation of artificials, compost may take its place as a worthy substitute.
- The mercenary attitude of many local bodies. In many cases town councillors were interested in the project only because they regarded it as a potential gold mine. When it was explained to them that they should at most hope for an appreciable reduction on the cost of night soil and garbage disposal, the scheme lost its attractiveness. Many of the municipal compost works are charging excessive prices in an endeavour to show clear profits. In their balance-sheets the costs of disposal under the old system are usually ignored and the national service that is being rendered by making compost is entirely lost sight of.
Whatever the arguments are, one is forced to the conclusion that finance is the major consideration and that unless the venture can be proved to be a sound financial undertaking all the advantages attached to the adoption of such a process, from a sanitary, hygienic, anti-waste, or health point of view, seem to count for very little. Fortunately there are exceptions where urban authorities look upon the composting process as something that has come to stay whether the demand for the product remains what it is to-day or not. In this they find a substitute for a costly sewage scheme, for which they may never hope to raise enough funds. Many of them have already come to the conclusion that most of their disposal problems can be solved in a sanitary, hygienic, and profitable way by the adoption of the urban composting process, provided it is carried out under properly trained supervision.
- Lack of interest. This was found to be due either to ignorance or wrong interpretation. In coastal towns and cities sanitary disposal problems are 'solved' by way of dumping the material recklessly into the sea. To a certain extent, however, an exception was found in the case of Durban, one of the biggest coastal centres. Here the Director of Parks and Gardens has set a worthy example to other similar centres by producing about 1,000 tons of compost annually from organic refuse on the true Indore principle, instead of allowing such materials to be passed through the city's incinerators.
The same lack of interest was encountered in large inland centres with properly equipped sewage disposal schemes. Their objections were in many instances well grounded as the adoption of a composting scheme would have meant the carting of raw materials over considerable distances to the site of the actual disposal works, thus making the scheme not only unpractical but also uneconomical. Fortunately in such centres compost is nevertheless made according to the true Indore method by Directors of Parks and Gardens, but usually on a scale only large enough for their own demands. The rest of the valuable refuse constituent usually finds its way to incinerators where it disappears in smoke instead of being conserved and used on the land.
- Fear of disease dissemination. In certain areas, especially the subtropical parts of Natal, local as well as medical authorities were afraid that amoebic dysentery might be spread by the use of the final product as a fertilizer. The Union Department of Public Health, however, expressed itself quite definitely on this point by issuing the following statement at the time: 'There is no likelihood of the matured compost, used as a fertilizer, acting as a medium for the dissemination of infective material of amoebic dysentery and parasitic worms, provided the process of composting has been carried out in accordance with the instructions issued by the Department of Agriculture and Forestry, where temperatures of 150° to 160° F. are attained in the pits for two to three weeks.' Although this statement, issued by responsible authorities, sounded convincing enough to most urban bodies, some diehards were nevertheless still encountered. The irony of it all is that some of these very same ardent objectors and critics will no doubt cheerfully buy and eat, without any objection or discrimination, vegetables raised by Indians in the sub-tropical parts on soils fertilized with crude and most probably amoebic dysentery-infested night soil.
Notwithstanding all these objections and difficulties, which naturally had a hampering effect on a more general adoption of the composting process, the results after two years from the inauguration of the scheme are spectacular and encouraging. From the table given it will be seen that before long this country may have at least 100 urban areas in which this process has been adopted. Although actually only about one-third of the urban centres in the Union are actively engaged in this work, the figures rather tend to give a wrong impression of the true position, since about two-thirds of the total urban population are included in the 100 centres mentioned.
Were it not for the instructional short courses held mainly at Ficksburg, Potchefstroom, Walmer, Fort Beaufort, and Graaff-Reinet, it is doubtful whether the actual position would have been as it is to-day. At these centres the various urban representatives became acquainted with the process in general very much more readily and thoroughly than would have been the case if they had had to be taught by their own experience.
Apart from the above, a very encouraging development has taken place at Darnall in the sugar belt of Natal, where Mr. G. C. Dymond has demonstrated so clearly that the vast quantities of sugar waste could be composted with little difficulty and at small expense to serve the essential purpose of linking up the productivity of soils of the sugar belt with the most important factor in the production of cane or any other crop, namely, yield. The same investigator hopes to prove that it may be possible to prevent the degeneration of varieties by practicing such conservation methods. For many years these mountains of valuable sugar waste were burnt or neglected, or their value as a compost manure overlooked, but now many scientists and planters in the sugar industry have become compost-minded. The author was invited to read a paper on this subject at their recent conference held in Durban in April 1944.
Although the practice of burning trash before the cane is cut and transported to the mills may result in a saving of labour and expense, it is nevertheless an extremely wasteful procedure. The sooner some other and less wasteful method is discovered by means of which the plant could be stripped of its leaves in an economical and practical way, the better for the industry as a whole. By virtue of its high organic matter content cane trash is a very valuable fertilizer material when composted with nitrogenous substances. Even though the resultant manure may not be required on the plantation itself (which in itself is still a debatable question), together with megasse and filter press cake it may form a valuable by-product for any sugar concern if turned into compost and disposed of to fruit or vegetable farmers in the vicinity.
Compost is also manufactured at Durban on the Earpe-Thomas principle, mainly from vegetable leaves, fruit peels, leaves, and similar materials. It is claimed that according to this method the composting process can be completed within thirty-six hours by the inoculation of the material with special bacteria. The cost of production of this type of compost called, Organo, is very high in comparison with that of urban compost, but chemically there is very little difference between the two. A considerable quantity of otherwise wasted organic material is thus finding its way back to the soil, which otherwise would not have been the case.
In addition, some of the larger inland centres are making available considerable quantities of sewage sludge to market gardeners in their vicinity, while the effluent from sewage disposal works is often used for irrigating artificial pastures.
The above is a brief summary of the position as it presents itself to-day in this country. Very much more could undoubtedly still be done in utilizing the enormous quantities of valuable organic materials which are accumulating daily somewhere within the boundaries of urban areas.
As regards the return of the bulk of such materials to the land in the form of properly prepared compost, the question arises whether the State should not step in and either compel the local authority to make compost under supervision or itself undertake the composting of urban refuse material.
Before proceeding to a brief description of some of the experiments carried out at Ficksburg during the past two years in connection with urban compost, the author would like to give the chemical analysis of some samples, calculated on a dry basis, in the following table:
|
Origin of Sample
|
Percentage
|
|
Loss on Ignition
|
N
|
P2O5
|
K2O
|
| Ficksburg |
34.43
|
1.14
|
1.42
|
1.24
|
| Ficksburg |
44.94
|
1.18
|
0.99
|
1.46
|
| Ficksburg |
39.17
|
1.12
|
1.41
|
1.39
|
| Ficksburg |
46.24
|
1.36
|
1.34
|
1.00
|
| Ficksburg |
47.61
|
1.53
|
1.92
|
1.08
|
| Ficksburg |
49.79
|
1.40
|
1.59
|
1.31
|
| Walmer |
44.37
|
1.54
|
2.76
|
1.10
|
| Volksrust |
30.21
|
0.78
|
1.49
|
1.11
|
| Alberton |
43.64
|
1.62
|
1.46
|
1.93
|
| Bethlehem |
42.30
|
1.58
|
0.90
|
1.19
|
| Bethlehem |
38.03
|
1.41
|
1.11
|
1.31
|
According to these figures and other observations made at Ficksburg, urban areas in the Union of South Africa are annually accumulating: 230 to 240 thousand tons of organic matter; 15.7 to 26.2 million pounds of nitrogen; 5.4 to 9.3 million pounds of potash; and 5.2 to 8.8 million pounds of phosphoric oxide, in the form of human excrete and town refuse. (The urban population is taken at about 3 3 millions for Europeans and non-Europeans.) Of these quantities, at least 50 per cent is lost or destroyed in one way or another with the result that, no matter how thorough the methods of salvaging and conservation, the quantity ultimately returned is only about half. The longer the return of this material to the land is delayed, the greater is the actual loss. The composting of urban refuse, therefore, is not only an essential but also a most urgent duty resting on the shoulders of those responsible.
As far as the process itself is concerned, in any composting scheme there is one dominating factor which must be borne in mind continually and that is temperature. This factor is not only an indication of the success with which the process is being carried out, but also determines the degree to which fly maggots and harmful pathogens may be destroyed. Temperature, therefore, may serve as one of the best indications of the success of a composting process. If it fails to develop, everything goes wrong: if, on the other hand, it develops favourably, we may take it for granted that the process is being carried out properly and successfully.
In the experiments carried out at Ficksburg since the inauguration of the national scheme temperature, therefore, played a major role. In view of the fact that harmful pathogens are destroyed at certain temperature levels if subjected to such temperatures for varying lengths of time, an experiment was carried out to determine average temperature ranges in an urban compost pit, the results being as follows:
|
Temperature Range in Degrees F.
|
Time Expressed as Percentage of Total (30 days) at which Compost Material was Subjected to such Temperature Range
|
|
51-60
|
1.78
|
|
61-70
|
1.11
|
|
71-80
|
2.89
|
|
81-90
|
2.00
|
|
91-100
|
1.77
|
|
101-110
|
2.22
|
|
111-120
|
2.67
|
|
121-130
|
9.55
|
|
131-140
|
24.67
|
|
141-150
|
33.33
|
|
151-160
|
18.00
|
It may at the same time be stated that this experiment was carried out during the winter months when the minimum temperatures were as low as 18 deg. F.
If 125 deg. F. could be regarded as the minimum safety limit (cysts of amoebic dysentery, for example, are destroyed at 122 deg. F. in two minutes) then one may conclude that the material in a compost pit is exposed to temperatures above this limit for 80 per cent of the time and that the possibility is, therefore, exceedingly small of harmful pathogens surviving or being disseminated when subjected to such limits of heat over such long periods.
Temperature has also an important bearing on the extent to which flies will breed in a compost pit. Flies are not only a nuisance but a menace, since they are largely responsible for the spread of certain diseases and epidemics. After a careful study the conclusion was reached that, wherever excessive numbers of flies are encountered at a compost site, this may be taken as an indication that the process is not going properly, the most probable cause being carelessness. Experiments conducted at Ficksburg in this connection have proved that 85 per cent of the maggots present in the compost material during the process can be destroyed by giving the contents a thorough turning. The heat generated as a result of this will be sufficient to destroy them, provided the material containing such maggots is buried in the centre of the pit where, as a rule, the temperature is very much higher than at the bottom or along the sides. Naturally it is impossible to kill all the maggots in this way and some of them will ultimately escape as full-grown flies, but if poisoned bait is put out these may be got rid of as well. In the early stages of the process fly maggots fulfil a rather important duty, since they help to break up lumpy material, thus bringing about better aeration and advancing the process in general. They should, however, be carefully watched and destroyed as soon as their job is done, otherwise they may complete their life cycle and cause endless trouble.
During periods of excessive rain one cannot rely on the above method alone, namely, that of killing maggots by working over the contents of pits, as the rain tends to cool down the material before the maggots are destroyed. An experiment was therefore conducted with certain chemicals harmless to the process but harmful to the maggots. Two relatively cheap by-products of the Iscor Steel Works were tried out. These were crude naphthalene and interstill residue. The former was used in a fifty-fifty mixture with sand, scattered over the surface of material and lightly worked in, while the latter, emulsified with soap water and used in a 4 per cent strength, was sprayed over the surface of the material in a pit. Both of these chemicals proved effective enough to destroy about 80 to 90 per cent of the maggots during excessively wet periods, when ordinary turning of the contents could not be resorted to. At the same time, these chemicals appeared to have no ill effects on the development of the process itself, judging by temperature observations during the experiment.
For the above two reasons alone it ought to be the aim of every compost producer to obtain as high temperatures as possible in the Compost pits under his supervision. There are certain external influences, however, over which one unfortunately has no control. Such factors are rain and atmospheric temperatures.
During the coldest months of the year a rainfall of 15 to 25 inches had the effect of decreasing the temperature in a compost pit by anything up to 15 deg. F. On the other hand, a fall of less than 1-5 inches had no material effect on the temperature in a compost pit at all, and observations seemed to point to the fact that such precipitations may be expected to promote rather than hamper the process.
Minimum atmospheric temperatures of 16 deg. F. to 18 deg. F. during the winter months caused the temperature in a compost pit to drop only 2 deg. F. This only seems to happen when temperatures fall to 20 deg. F. or lower; above this, it was shown to have no material effect at all on compost temperatures.
Factors which influence the temperature in compost pits and over which definite control can be kept are depth of pit and quantity of night soil added per volume of dry refuse. Experiments proved that a four-foot depth of pit gave rise to about 30 per cent higher temperatures than did a two-foot pit, while a proportion of one gallon of night soil to one cubic foot of dry refuse gave the best results as far as temperatures were concerned. The wider the ratio of the latter, the slower the rise in temperature and naturally the longer the time before the process is completed.
Until such time as further tests are carried out, it may be stated that preliminary experiments seem to indicate that during the ripening process, over a period of six months, urban compost did not undergo any material change chemically, whether stored in the open or under protection. A reduction in volume may, however, have taken place in the meantime.
Urban compost production in South Africa has undoubtedly come to stay. To most of the municipalities in the country who have adopted the process this way of refuse disposal means more than just a possible source of extra revenue or an answer to the call of the Department of Agriculture and Forestry to produce compost in order to relieve the fertilizer shortage in the country. To such centres it means, in the majority of instances, a solution to long-standing sanitary and other disposal problems that called for urgent attention long ago. It offers above all a hygienic, harmless, beneficial, and economic method of disposal of obnoxious collections accumulating in urban areas, where up to now these valuable, though dangerous, materials were merely lying scattered or buried on town commonages as a constant source of nuisance and possible disease infection. Furthermore, a proper composting process renders such materials harmless in a quick and efficient way, and may ultimately result in creating a healthier environment for congested communities.
Cities and towns have for too many centuries been veritable graveyards where, in most instances, only the charred remains of the youth and life of many a soil -- and ultimate civilization -- lie buried and forgotten. It is our duty, as well as our privilege, to ensure that such destructive, almost criminal, practices are no longer allowed to continue. It is sincerely hoped, therefore, that this brief description of what has been done along these lines in South Africa will serve the worthy purpose which Sir Albert Howard intended when he sent me his kind invitation to write this appendix.
If we are 'to endure, if we are to project our history, through four or five thousand years, as the Mongolian nations have done', according to the late Professor King in Farmers of Forty Centuries, 'we must re-orient ourselves; we must square our practices with a conservation of resources, which can make endurance possible'.
Ficksburg,
South Africa.
I9th December 1944.
Next: Appendix D. Farming for Profit on a 750-Acre Farm in Wiltshire with Organic Manures as the Sole Medium of Refertilization
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