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The first conference of Istro, at Uppsala, Sweden, 1955
Soil & Tillage Research, 5 (1985) 105--115 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
105
T H E F I R S T C O N F E R E N C E O F I S T R O , A T U P P S A L A , S W E D E N , 1955
C. VAN OUWERKERK Secretary-General of the International Soil Tillage Research Organization (ISTRO), Institute for Soil Fertility, P.O. Box 30003, 9750 RA Haren Gn (The Netherlands)
ABSTRACT Van Ouwerkerk, C., 1985. The first Conference of ISTRO, at Uppsala, Sweden, 1955. Soil Tillage Res., 5: 105--115. The main part of the paper is an English translation of a Swedish review (Johansson, 1955), which may be regarded as the Proceedings of the very first international soil tillage conference which was held in 1955 at Uppsala, Sweden. Later on, this conference was recognized as the 1st Conference of the International Soil Tillage Research Organization (ISTRO). The review deals with tillage problems as presented by the diverse terrain and climate of the British Isles, field trials with ploughing and shallow cultivation in the Federal Republic of Germany, soil cultivation and soil conservation in the U.S.A., and some aspects of different systems of ploughing in Sweden. In the discussion following the lectures, the advantages of the then newly introduced one-way plough are stressed.
INTRODUCTION T h e I n t e r n a t i o n a l Soil Tillage Research O r g a n i z a t i o n ( I S T R O ) was f o u n ded in 1 9 7 3 during the sixth o f a series o f i n t e r n a t i o n a l soil tillage conferences, which had started in 1 9 5 5 at Uppsala, Sweden. To do justice to t h e historical d e v e l o p m e n t , and in h o n o u r o f the organizers o f the early c o n f e r e n c e s , the 1 9 5 5 c o n f e r e n c e is r e c o g n i z e d as the first C o n f e r e n c e of ISTRO. The h i s t o r y o f the first 7 C o n f e r e n c e s o f I S T R O has been reviewed, t h o u g h very briefly, in the first issue o f Soil & Tillage Research (Van Ouwerkerk and M a n t e n , 1980). An a c c o u n t o f the 8th C o n f e r e n c e (StuttgartH o h e n h e i m , Federal R e p u b l i c o f G e r m a n y , 1 9 7 9 ) and o f the 9th C o n f e r e n c e (Osijek, Yugoslavia, 1 9 8 2 ) was given in Soil & Tillage Research (Vol. 1: 8 3 - - 8 4 and Vol. 2: 3 9 5 - - 4 0 1 ) . C o n f e r e n c e s 2--9 were covered b y Proceedings or, at least, the integral t e x t or summaries o f the lectures were published. The p a p e r b y H. Kuipers in this issue o f Soil & Tillage Research c o n t a i n s a list o f these p u b l i c a t i o n s (Kuipers, 1985). H o w e v e r , until n o w the h i s t o r y o f the very first C o n f e r e n c e o f I S T R O has r e m a i n e d m o r e or less a m y s t e r y because it seemed t h a t no Proceedings were p r o d u c e d . In 1 9 7 8 a tip o f the veil was lifted w h e n Dr. L. Henriksson (Uppsala, 0167-1987/85/$03.30
© 1985 Elsevier Science Publishers B.V.
106
Sweden) traced the programme of that memorable "very small meeting, half a day during the World Ploughing Contest here at Kungs~ingen". The programme was published in ISTRO-INFO No. 3 (April, 1978), pp. 8--9 but, because it deserves to be more widely known, it is republished in the following sections. PROGRAMME
14.00 Greeting address by Prof. G. Torstensson Lectures: Prof. Dr. H. Frese, Germany: The influence of soil, climate and type of farming on the type of ploughs Mr. S.J. Wright, M.A., England: Tillage problems as presented by the diverse terrain and climate of the British Isles 15.45 Pause 16.00 The film "P15jningens utfSrande" (Ploughing). Short introduction by Agronom, M.S. Karl-,~ke Svensson Lectures: Dipl. Landw. W. Feuerlein, Germany: Field trials with plough, disc harrow, rotary cultivator and harrow Mr. Alf Larsen, U.S.A.: Soil cultivation and soil conservation Agronom Nils M. Nilsson, Sweden: Some aspects of different systems of ploughing
Fig. 1. Prof. emer. G. Torstensson, Honorary Member of ISTRO. ( P h o t o taken in 1984.)
107
Recently, Prof. emer. G. Torstensson (Fig. 1), Honorary Member of ISTRO and initiator of the 1st Conference, found a review in his archives, which may well be considered to be the Proceedings of the 1st Conference of ISTRO (Johansson, 1955). Because of its historical value, and as a tribute towards Prof. Torstensson, the text of this review was integrally translated and is printed below. The number of people who attended the 1st Conference is u n k n o w n but, as Prof. Torstensson put it "Many more attended than we expected". SOIL TILLAGE CONFERENCE AT U L T U N A a
In connection with the recently-held World Ploughing Championships at Kungs~ingens G~rd near Uppsala, the head of the Department of Soil Management and Soil Fertility of the Royal College of Agriculture, Prof. G. Torstensson, had called an international conference on soil tillage problems. The first lecture should have been held by the well-known tillage expert Prof. H. Frese, Germany. However, at the last m o m e n t he was unable to attend the conference. Therefore, the first speaker was Mr. S.J. Wright, agricultural expert with Ford Motor Co., Ltd., Dagenham, England who spoke about ploughing in relation to climate and soils in the British Empire. As an introduction to his lecture, which was based on 25 years of experience with tillage problems in England and other countries, the speaker said that, although horses and their performance are admirable, any work which cannot be done with the tractor must be abolished. For all tillage operations, the cardinal question is: should it serve to get rid of the water in the soil or should it conserve it? This is not only a question of total annual precipitation, but also a question of distribution of the precipitation throughout the year, and of other climatic factors. This varies strongly within the Empire. In Great Britain farmers often have to contend with a dozen really dry days per year. Because of the humid air and the mild winters stubble, plant remains and weeds have to be carefully ploughed down; otherwise the fields would start to green up immediately. In the prairie region of Canada, there are probably only a dozen really wet days per year, and there the stubble should not be ploughed down too deeply, in view of the risk of ploughing it up the following year unchanged. There, it is preferred to leave stubble and plant remains on the surface as a protection against wind erosion. Primarily, the effect of soil tillage depends on the influence of nature, of sun, wind, rain and frost. A wet and dense furrow-slice is difficult to manage. No matter how we try, the result will only be worse, but after a single night of frost the seedbed can be prepared with one single pass aThe original Figs. 2 and 3 (rotary cultivator and mounted alternate plough, respectively) have been omitted.
108 with the harrow. Therefore, the farmer's task is to give nature the best conditions for its work. Uniform, stiff, narrow furrow-slices have been the model for British ploughmen. Such furrow-slices absorb least of the winter precipitation and frost penetrates easily. In spring, they dry quickly. Narrow lands have facilitated the discharge of surface water. This way of ploughing requires great care and expert knowledge and this has become the ideal for the champions' performance in this field. In Great Britain, the outbreak of the war in 1939 forced an increase in the area of arable land. Areas which had been under grass for hundreds of years were ploughed up. There was a lack of experienced ploughmen. Often, the fields were hilly and the result was saddening. Part of the furrow-slices was not turned, whereas another part probably repeatedly rolled down-hill. The disc harrow saved the situation. It cut the furrow-slices, packed them and levelled the worst parts. Despite everything good yields were obtained. The war did away with much routine work. The farmers then became dependent on import of American ploughs, and also ploughs with a better functioning mouldboard were introduced. The practice is now to perform post-harvest cultivation in a u t u m n and to delay ploughing until after New Year. Since drainage has been improved and often has been complemented with tile drains, the discharge of surface water is no longer as essential as it used to be. For autumn-sown crops and for spring ploughing stiff furrow-slices are not required, because seedbed preparation is carried out relatively shortly after ploughing. As a consequence, in Great Britain about 90% of the ploughmen use the semi-digger type of plough body. Ploughing depth has increased, sometimes up to 12". The m o u n t e d plough gains ground, despite the disadvantages of being not so obedient and being more difficult to adjust. However, the advantages prevail. Good ploughing still is the mark of a skilled farmer. The disc harrow is still there, but now it is used predominantly for post-harvest cultivation and for packing of the furrow-slices when grassland is ploughed up. It would of course be ideal to have a tillage operation which would prepare the seedbed in one pass, but it seems impossible to obtain a soil structure which is as stable as the one which is formed by nature.
Field experiments with plough, harrow, rotary cultivator and cultivator Dipl. Landw. W. Feuerlein, head of the tillage research at Ulm in Germany and vice-president of the WPO (World Ploughing Organization} reported the results of field experiments with different tillage methods. A series of experiments on subsoil loosening has demonstrated that different crops respond very differently to deep tillage. Some crops respond favourably to subsoil loosening, whereas other crops require a more compact subsoil. The results of this series of experiments are shown in Fig. 2. Red clover, which is not included in the diagram, usually responded negatively to subsoil loosening.
109 ~n
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L 4numberof exp 7 5 7 "g' 7 /.5 4 2O 8 ]star signif. ~ yield differen-l-y-1 star signif. yield increase~E"__.~ ces nonsignif.r'Q<] yield decrease
Fig. 2. D i a g r a m o f t h e r e s u l t s o f a s u b s o i l i n g e x p e r i m e n t year's effect of subsoil loosening. TABLE
I
Comparison
of ploughing and shallow cultivation Yield after ploughing (kg ha-')
Crop
Experiments Winter
near Ulm, 1947--1954.
wheat
R e l a t i v e y i e l d (%) a f t e r t i l l a g e w i t h : Harrow
Disc harrow
Rotary cultivator
Cultivator
on soils with natural satisfactory air-filled porosity 2720
--
--
112
2440
--
--
111
--
2960
--
--
123
----
2709
116
117
--
4175
113
104
120
3768
109
.
3000
131
.
3872
--
. .
94
--
97
. .
. .
.
103
....
Spring wheat
2070
113
--
--
--
Oats
2856
103
--
--
--
Barley
2610
98
--
--
--
161
--
--
Sugar beet
11840
--
Experiments on soils with unsatisfactory air-filled porosity Winter wheat 2860 -91 -3760 -77 --
Spring wheat Sugar beet
---
3720
--
--
86
--
4400
--
--
73
--
4600
92
82
--
--
3228
93
84
--
--
90
--
--
52160
--
First
110
The results of these subsoiling experiments gave rise to the question whether those crops that respond negatively to subsoil loosening, would n o t be also adversely influenced by the loosening effect of ploughing. A series of experiments to compare tillage with plough, harrow, disc harrow, rotary cultivator and cultivator, was carried out, the results of which are presented in Table I. Obviously, the results vary. However, the experiments can be divided into two groups according to soil physical properties. One group consists of "active" soils, which build up a good structure of their own. This group consists mainly of clay soils, the other group of "passive" soils, forming crusts and often having a compacted subsoil. Further, it appears that, on average, shallow tillage is better than ploughing for the first group, but worse for the second group. For cereals, the soil should have an airfilled porosity of 10--20%. A higher or a lower value results in a lower yield. In the first group of soils, which already naturally has a sufficient air-filled porosity, ploughing causes it to become too large, whereas in the second group ploughing increases the too low pore space to the optimum range. Table II gives a comparison of total pore space and air-filled porosity at different depths in both types of soil after ploughing and after harrowing or disc harrowing, and the relative yields in both cases. Thus, on soils of the first group (with a satisfactory air-filled porosity) it may be advantageous to prepare the seedbed for winter wheat without ploughing, unless ploughing is necessary for weed control, incorporation of manure, etc. On lighter soils, with an insufficient air-filled porosity, however, omitting ploughing results in a considerable yield decrease. TABLE II Pore space and relative yield on 2 soil types after ploughing and after shallow cultivation Soil type Soil with a natural satisfactory Soil with unsatisfactory air-filled porosity (clay) air-filled porosity (eolian deposit) Depth (crn) 8--12
Depth (cm) 14--18
22--26
10--15
22--26
30--35
Total pore space (%, v/v) Ploughing 55.0 Shallow cultivation 46.9
57.5 43.3
43.6 40.6
57.7 45.6
45.9 40.6
44.1 42.4
Air-filled porosity (%, v/v) Ploughing 24.7 Shallow cultiva*Aon 15.3
24.6 11.6
11.9 7.9
13.7 7.0
7.9 6.0
9.1 7.0
Relative yield (%)
Ploughing Shallow cultivation
87 100
136 100
111
Current soil tillage problems in the U.S.A. Mr. Alf Larsen, MN, U.S.A., member of the Board of WPO and vicepresident of the Soil Conservation Society of America, gave an objective account, spiced with good American humour, of current soil tillage problems in the U.S.A., as observed from the viewpoint of the practical farmer. For the American farmer, soil tillage has two objectives: the preparation of a seedbed and weed control. In many cases, intensive cropping, often accompanied by a too intensive tillage, has led to untenable situations. In large areas, soil erosion and measures to prevent it have become the all-important problem. Terracing of the fields and planting different crops in succession are important measures to control erosion. By now, contour ploughing, i.e., ploughing along the contours, is rather c o m m o n and at the World Ploughing Contest in Ohio in 1957, this way of ploughing will be included as an option. Mr. Larsen stated that in the domain of soil tillage the Americans could learn quite a lot from the Old World. How to keep the soil in good shape after centuries of agriculture, is something the American farmer wants to learn; he now increasingly considers the soil not as a means to earn as much money as quickly as possible, but as a heritage of earlier generations, with the mission to hand it down to coming generations in the same condition.
Some aspects of different systems of ploughing The last lecture was held by agronomist N.M. Nilsson, Uppsala, who explained different systems of ploughing. Since the introduction of the iron plough, the most c o m m o n m e t h o d is ploughing in lands. This method has many disadvantages. Marking the ridges and finishes takes a lot of extra time and it requires great skill to obtain a satisfactory result. On the headlands there is much idle driving. The finishes often cause irregular emergence and development of the crops. Round and round ploughing has been practiced since the end of the 19th century, but only recently has its importance increased. However, this method also requires a considerable number of finishes. Often, it is difficult to start ploughing when the furrows are turned towards the middle of the field {gathering). It tends to impede surface drainage. To get rid of all current problems with c o m m o n ploughing methods, the one-way plough could be the solution. In Sweden, the one-way plough has been used since the end of the 19th century, but for several reasons it did not become popular. However, in a number of other countries this type of plough predominates. In the present-day situation, it is likely that, if suitable types are imported onto the Swedish market, the use of the oneway plough will rapidly increase. Apart from the fact that ridges and finishes will, for the better part, become superfluous, ploughing with the one-way plough is attended with savings with respect to idle driving and the work
1810 9320 2950 14080
7790 9710 1360 18860
24520
1580 22940 --
Towed plough
13930
1420 12510 --
Mounted plough
22600
860 19640 2100
Towed plough
Casting Gathering
9010
860 7270 880
Mounted plough
One-way ploughing
Round and round ploughing
aExtended version (Torstensson and Nilsson, 1955). Field size 250 x 400 m (10 ha). Ploughing with a 2-furrow tractor plough (total width 57 cm). Width of the lands: 32.85 m. Turning radius of the tractor: 4.0 m. Source: Scheibe (1936).
Total
Marking out the field and making ridges, etc. Turns during ploughing of the actual field Turns during ploughing of the headlands
Ploughing in lands
Unproductive driving distances ( m ) w i t h different ploughing systems (theoretical calculation )a
TABLE III b~
113
required for marking the lands, the levelling of ridges and finishes, etc. Generally, it is impossible to calculate the difference in idle driving and the extra work involved in different methods of ploughing, but the theoretical calculation of the unproductive driving distances in different methods of ploughing, as shown in Table III, gives a good picture of the relationships. Apparently, ploughing with a m o u n t e d one-way plough is superior in this respect to the other methods.
The one-way plough, the melody of the future After the various lectures, questions were asked of the speakers and problems presented were discussed. Especially the lecture of agronomist Nilsson raised the current question of the more general introduction of the one-way plough in our country. (The one-way plough has a double row of plough bodies, so it can turn the furrow-slice alternately to the right and to the left.) As the lecture of agronomist Nilsson demonstrated, a one-way m o u n t e d plough causes the least idle driving. Prof. Torstensson stated that the more stringent demand for an even development and maturing of the crops, in connection with the more general use of the combineharvester, has made the time ripe for switching over to the one-way plough as much as possible. This would doubtless be the most radical remedy for irregular emergence and maturing, as so often caused by the finishes. The audience generally agreed with him, although it was appreciated that big problems remain. The purchase costs of a plough will increase substantially. There is already a single-furrow one-way plough of satisfactory construction, but to build a two-furrow, one-way, m o u n t e d plough, equipped with a spring release, could give serious problems. As a representative of a firm put it: "The plough is becoming a machine instead of a tool". However, construction is apparently about to begin. The instruction film "Ploughing" was shown, and commented upon by one of the authors of the script of the film, agronomist Karl-/~ke Svensson.
A conference on soil tillage problems should be organized annually The president and chairman of the WPO, J.D. Thomas, U.S.A., addressed a word of warm thanks to the initiator and leader of the conference, Prof. G. Torstensson, for the good work he did. He noted that the conference had been very fruitful and he expressed the hope that the initiative would be repeated, so that this conference would be the introduction to a series of such meetings, organized in connection with the World Ploughing Contest in future years.
114
Fig. 3. Monument at Kungs~ingens G~rd near Uppsala, Sweden, in memory of the Third World Ploughing Contest, 1955. (Photo: B. Gillberg, Uppsala.)
ACKNOWLEDGEMENTS
The author is greatly indebted to Prof. emer. G. Torstensson (Uppsala, Sweden) and to Dr. L. Henriksson (Swedish University of Agricultural Sciences, Department of Soil Sciences, Uppsala, Sweden) for their help in tracing the review by Olle Johansson. The author gratefully acknowledges the help of Mrs. Drs. J.C. TorringaTimmer (Haren Gn, The Netherlands) and of his colleagues Dr. B.J. van Goor and Dr. C.H.E. Werkhoven (Institute for Soil Fertility, Haren Gn, The Netherlands) in translating the review.
REFERENCES Hawkins, J.C., 1962, Tractor Ploughing, 4th Edition. Ministry of Agriculture, Fisheries and Food, Her Majesty's Stationery Office, 56 pp. Johansson, O., 1955. Jordbearbetningskonferens p~i Ultuna (Soil tillage conference at Ultuna). Maskinteknik i Jord och Skog, 9: 404--407. Kuipers, H., 1985. A tillage research analysis based on ISTRO conference proceedings. Soil Tillage Res., 5: 117--128. Scheibe, J., 1936. Untersuchungen iiber die Vorziige und Nachteile des Beet- und KehrpfliJgens (Research on the pro's and con's of ploughing in lands and one-way ploughing). Reichskuratorium fiir Technik in der Landwirtschaft, Berlin, RKTL-Schrift 69.
115
Torstensson, G. and Nilsson, N.M., 1955. Plouging in lands, round and round ploughing and one-way ploughing. In: A. Hall and O. Sandholm (Editors), Third World Ploughing Championship Contest at Uppsala, Sweden, 7--8 October 1955. World Ploughing Organization, Official Souvenir Guide. Jordbrukare-Ungdomens FSrbund, pp. 6369, 58. Van Ouwerkerk, C. and Manten, A.A., 1980. Launching the new international journal "Soil & Tillage Research". Soil Tillage Res., 1: 1--6.
105
T H E F I R S T C O N F E R E N C E O F I S T R O , A T U P P S A L A , S W E D E N , 1955
C. VAN OUWERKERK Secretary-General of the International Soil Tillage Research Organization (ISTRO), Institute for Soil Fertility, P.O. Box 30003, 9750 RA Haren Gn (The Netherlands)
ABSTRACT Van Ouwerkerk, C., 1985. The first Conference of ISTRO, at Uppsala, Sweden, 1955. Soil Tillage Res., 5: 105--115. The main part of the paper is an English translation of a Swedish review (Johansson, 1955), which may be regarded as the Proceedings of the very first international soil tillage conference which was held in 1955 at Uppsala, Sweden. Later on, this conference was recognized as the 1st Conference of the International Soil Tillage Research Organization (ISTRO). The review deals with tillage problems as presented by the diverse terrain and climate of the British Isles, field trials with ploughing and shallow cultivation in the Federal Republic of Germany, soil cultivation and soil conservation in the U.S.A., and some aspects of different systems of ploughing in Sweden. In the discussion following the lectures, the advantages of the then newly introduced one-way plough are stressed.
INTRODUCTION T h e I n t e r n a t i o n a l Soil Tillage Research O r g a n i z a t i o n ( I S T R O ) was f o u n ded in 1 9 7 3 during the sixth o f a series o f i n t e r n a t i o n a l soil tillage conferences, which had started in 1 9 5 5 at Uppsala, Sweden. To do justice to t h e historical d e v e l o p m e n t , and in h o n o u r o f the organizers o f the early c o n f e r e n c e s , the 1 9 5 5 c o n f e r e n c e is r e c o g n i z e d as the first C o n f e r e n c e of ISTRO. The h i s t o r y o f the first 7 C o n f e r e n c e s o f I S T R O has been reviewed, t h o u g h very briefly, in the first issue o f Soil & Tillage Research (Van Ouwerkerk and M a n t e n , 1980). An a c c o u n t o f the 8th C o n f e r e n c e (StuttgartH o h e n h e i m , Federal R e p u b l i c o f G e r m a n y , 1 9 7 9 ) and o f the 9th C o n f e r e n c e (Osijek, Yugoslavia, 1 9 8 2 ) was given in Soil & Tillage Research (Vol. 1: 8 3 - - 8 4 and Vol. 2: 3 9 5 - - 4 0 1 ) . C o n f e r e n c e s 2--9 were covered b y Proceedings or, at least, the integral t e x t or summaries o f the lectures were published. The p a p e r b y H. Kuipers in this issue o f Soil & Tillage Research c o n t a i n s a list o f these p u b l i c a t i o n s (Kuipers, 1985). H o w e v e r , until n o w the h i s t o r y o f the very first C o n f e r e n c e o f I S T R O has r e m a i n e d m o r e or less a m y s t e r y because it seemed t h a t no Proceedings were p r o d u c e d . In 1 9 7 8 a tip o f the veil was lifted w h e n Dr. L. Henriksson (Uppsala, 0167-1987/85/$03.30
© 1985 Elsevier Science Publishers B.V.
106
Sweden) traced the programme of that memorable "very small meeting, half a day during the World Ploughing Contest here at Kungs~ingen". The programme was published in ISTRO-INFO No. 3 (April, 1978), pp. 8--9 but, because it deserves to be more widely known, it is republished in the following sections. PROGRAMME
14.00 Greeting address by Prof. G. Torstensson Lectures: Prof. Dr. H. Frese, Germany: The influence of soil, climate and type of farming on the type of ploughs Mr. S.J. Wright, M.A., England: Tillage problems as presented by the diverse terrain and climate of the British Isles 15.45 Pause 16.00 The film "P15jningens utfSrande" (Ploughing). Short introduction by Agronom, M.S. Karl-,~ke Svensson Lectures: Dipl. Landw. W. Feuerlein, Germany: Field trials with plough, disc harrow, rotary cultivator and harrow Mr. Alf Larsen, U.S.A.: Soil cultivation and soil conservation Agronom Nils M. Nilsson, Sweden: Some aspects of different systems of ploughing
Fig. 1. Prof. emer. G. Torstensson, Honorary Member of ISTRO. ( P h o t o taken in 1984.)
107
Recently, Prof. emer. G. Torstensson (Fig. 1), Honorary Member of ISTRO and initiator of the 1st Conference, found a review in his archives, which may well be considered to be the Proceedings of the 1st Conference of ISTRO (Johansson, 1955). Because of its historical value, and as a tribute towards Prof. Torstensson, the text of this review was integrally translated and is printed below. The number of people who attended the 1st Conference is u n k n o w n but, as Prof. Torstensson put it "Many more attended than we expected". SOIL TILLAGE CONFERENCE AT U L T U N A a
In connection with the recently-held World Ploughing Championships at Kungs~ingens G~rd near Uppsala, the head of the Department of Soil Management and Soil Fertility of the Royal College of Agriculture, Prof. G. Torstensson, had called an international conference on soil tillage problems. The first lecture should have been held by the well-known tillage expert Prof. H. Frese, Germany. However, at the last m o m e n t he was unable to attend the conference. Therefore, the first speaker was Mr. S.J. Wright, agricultural expert with Ford Motor Co., Ltd., Dagenham, England who spoke about ploughing in relation to climate and soils in the British Empire. As an introduction to his lecture, which was based on 25 years of experience with tillage problems in England and other countries, the speaker said that, although horses and their performance are admirable, any work which cannot be done with the tractor must be abolished. For all tillage operations, the cardinal question is: should it serve to get rid of the water in the soil or should it conserve it? This is not only a question of total annual precipitation, but also a question of distribution of the precipitation throughout the year, and of other climatic factors. This varies strongly within the Empire. In Great Britain farmers often have to contend with a dozen really dry days per year. Because of the humid air and the mild winters stubble, plant remains and weeds have to be carefully ploughed down; otherwise the fields would start to green up immediately. In the prairie region of Canada, there are probably only a dozen really wet days per year, and there the stubble should not be ploughed down too deeply, in view of the risk of ploughing it up the following year unchanged. There, it is preferred to leave stubble and plant remains on the surface as a protection against wind erosion. Primarily, the effect of soil tillage depends on the influence of nature, of sun, wind, rain and frost. A wet and dense furrow-slice is difficult to manage. No matter how we try, the result will only be worse, but after a single night of frost the seedbed can be prepared with one single pass aThe original Figs. 2 and 3 (rotary cultivator and mounted alternate plough, respectively) have been omitted.
108 with the harrow. Therefore, the farmer's task is to give nature the best conditions for its work. Uniform, stiff, narrow furrow-slices have been the model for British ploughmen. Such furrow-slices absorb least of the winter precipitation and frost penetrates easily. In spring, they dry quickly. Narrow lands have facilitated the discharge of surface water. This way of ploughing requires great care and expert knowledge and this has become the ideal for the champions' performance in this field. In Great Britain, the outbreak of the war in 1939 forced an increase in the area of arable land. Areas which had been under grass for hundreds of years were ploughed up. There was a lack of experienced ploughmen. Often, the fields were hilly and the result was saddening. Part of the furrow-slices was not turned, whereas another part probably repeatedly rolled down-hill. The disc harrow saved the situation. It cut the furrow-slices, packed them and levelled the worst parts. Despite everything good yields were obtained. The war did away with much routine work. The farmers then became dependent on import of American ploughs, and also ploughs with a better functioning mouldboard were introduced. The practice is now to perform post-harvest cultivation in a u t u m n and to delay ploughing until after New Year. Since drainage has been improved and often has been complemented with tile drains, the discharge of surface water is no longer as essential as it used to be. For autumn-sown crops and for spring ploughing stiff furrow-slices are not required, because seedbed preparation is carried out relatively shortly after ploughing. As a consequence, in Great Britain about 90% of the ploughmen use the semi-digger type of plough body. Ploughing depth has increased, sometimes up to 12". The m o u n t e d plough gains ground, despite the disadvantages of being not so obedient and being more difficult to adjust. However, the advantages prevail. Good ploughing still is the mark of a skilled farmer. The disc harrow is still there, but now it is used predominantly for post-harvest cultivation and for packing of the furrow-slices when grassland is ploughed up. It would of course be ideal to have a tillage operation which would prepare the seedbed in one pass, but it seems impossible to obtain a soil structure which is as stable as the one which is formed by nature.
Field experiments with plough, harrow, rotary cultivator and cultivator Dipl. Landw. W. Feuerlein, head of the tillage research at Ulm in Germany and vice-president of the WPO (World Ploughing Organization} reported the results of field experiments with different tillage methods. A series of experiments on subsoil loosening has demonstrated that different crops respond very differently to deep tillage. Some crops respond favourably to subsoil loosening, whereas other crops require a more compact subsoil. The results of this series of experiments are shown in Fig. 2. Red clover, which is not included in the diagram, usually responded negatively to subsoil loosening.
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Fig. 2. D i a g r a m o f t h e r e s u l t s o f a s u b s o i l i n g e x p e r i m e n t year's effect of subsoil loosening. TABLE
I
Comparison
of ploughing and shallow cultivation Yield after ploughing (kg ha-')
Crop
Experiments Winter
near Ulm, 1947--1954.
wheat
R e l a t i v e y i e l d (%) a f t e r t i l l a g e w i t h : Harrow
Disc harrow
Rotary cultivator
Cultivator
on soils with natural satisfactory air-filled porosity 2720
--
--
112
2440
--
--
111
--
2960
--
--
123
----
2709
116
117
--
4175
113
104
120
3768
109
.
3000
131
.
3872
--
. .
94
--
97
. .
. .
.
103
....
Spring wheat
2070
113
--
--
--
Oats
2856
103
--
--
--
Barley
2610
98
--
--
--
161
--
--
Sugar beet
11840
--
Experiments on soils with unsatisfactory air-filled porosity Winter wheat 2860 -91 -3760 -77 --
Spring wheat Sugar beet
---
3720
--
--
86
--
4400
--
--
73
--
4600
92
82
--
--
3228
93
84
--
--
90
--
--
52160
--
First
110
The results of these subsoiling experiments gave rise to the question whether those crops that respond negatively to subsoil loosening, would n o t be also adversely influenced by the loosening effect of ploughing. A series of experiments to compare tillage with plough, harrow, disc harrow, rotary cultivator and cultivator, was carried out, the results of which are presented in Table I. Obviously, the results vary. However, the experiments can be divided into two groups according to soil physical properties. One group consists of "active" soils, which build up a good structure of their own. This group consists mainly of clay soils, the other group of "passive" soils, forming crusts and often having a compacted subsoil. Further, it appears that, on average, shallow tillage is better than ploughing for the first group, but worse for the second group. For cereals, the soil should have an airfilled porosity of 10--20%. A higher or a lower value results in a lower yield. In the first group of soils, which already naturally has a sufficient air-filled porosity, ploughing causes it to become too large, whereas in the second group ploughing increases the too low pore space to the optimum range. Table II gives a comparison of total pore space and air-filled porosity at different depths in both types of soil after ploughing and after harrowing or disc harrowing, and the relative yields in both cases. Thus, on soils of the first group (with a satisfactory air-filled porosity) it may be advantageous to prepare the seedbed for winter wheat without ploughing, unless ploughing is necessary for weed control, incorporation of manure, etc. On lighter soils, with an insufficient air-filled porosity, however, omitting ploughing results in a considerable yield decrease. TABLE II Pore space and relative yield on 2 soil types after ploughing and after shallow cultivation Soil type Soil with a natural satisfactory Soil with unsatisfactory air-filled porosity (clay) air-filled porosity (eolian deposit) Depth (crn) 8--12
Depth (cm) 14--18
22--26
10--15
22--26
30--35
Total pore space (%, v/v) Ploughing 55.0 Shallow cultivation 46.9
57.5 43.3
43.6 40.6
57.7 45.6
45.9 40.6
44.1 42.4
Air-filled porosity (%, v/v) Ploughing 24.7 Shallow cultiva*Aon 15.3
24.6 11.6
11.9 7.9
13.7 7.0
7.9 6.0
9.1 7.0
Relative yield (%)
Ploughing Shallow cultivation
87 100
136 100
111
Current soil tillage problems in the U.S.A. Mr. Alf Larsen, MN, U.S.A., member of the Board of WPO and vicepresident of the Soil Conservation Society of America, gave an objective account, spiced with good American humour, of current soil tillage problems in the U.S.A., as observed from the viewpoint of the practical farmer. For the American farmer, soil tillage has two objectives: the preparation of a seedbed and weed control. In many cases, intensive cropping, often accompanied by a too intensive tillage, has led to untenable situations. In large areas, soil erosion and measures to prevent it have become the all-important problem. Terracing of the fields and planting different crops in succession are important measures to control erosion. By now, contour ploughing, i.e., ploughing along the contours, is rather c o m m o n and at the World Ploughing Contest in Ohio in 1957, this way of ploughing will be included as an option. Mr. Larsen stated that in the domain of soil tillage the Americans could learn quite a lot from the Old World. How to keep the soil in good shape after centuries of agriculture, is something the American farmer wants to learn; he now increasingly considers the soil not as a means to earn as much money as quickly as possible, but as a heritage of earlier generations, with the mission to hand it down to coming generations in the same condition.
Some aspects of different systems of ploughing The last lecture was held by agronomist N.M. Nilsson, Uppsala, who explained different systems of ploughing. Since the introduction of the iron plough, the most c o m m o n m e t h o d is ploughing in lands. This method has many disadvantages. Marking the ridges and finishes takes a lot of extra time and it requires great skill to obtain a satisfactory result. On the headlands there is much idle driving. The finishes often cause irregular emergence and development of the crops. Round and round ploughing has been practiced since the end of the 19th century, but only recently has its importance increased. However, this method also requires a considerable number of finishes. Often, it is difficult to start ploughing when the furrows are turned towards the middle of the field {gathering). It tends to impede surface drainage. To get rid of all current problems with c o m m o n ploughing methods, the one-way plough could be the solution. In Sweden, the one-way plough has been used since the end of the 19th century, but for several reasons it did not become popular. However, in a number of other countries this type of plough predominates. In the present-day situation, it is likely that, if suitable types are imported onto the Swedish market, the use of the oneway plough will rapidly increase. Apart from the fact that ridges and finishes will, for the better part, become superfluous, ploughing with the one-way plough is attended with savings with respect to idle driving and the work
1810 9320 2950 14080
7790 9710 1360 18860
24520
1580 22940 --
Towed plough
13930
1420 12510 --
Mounted plough
22600
860 19640 2100
Towed plough
Casting Gathering
9010
860 7270 880
Mounted plough
One-way ploughing
Round and round ploughing
aExtended version (Torstensson and Nilsson, 1955). Field size 250 x 400 m (10 ha). Ploughing with a 2-furrow tractor plough (total width 57 cm). Width of the lands: 32.85 m. Turning radius of the tractor: 4.0 m. Source: Scheibe (1936).
Total
Marking out the field and making ridges, etc. Turns during ploughing of the actual field Turns during ploughing of the headlands
Ploughing in lands
Unproductive driving distances ( m ) w i t h different ploughing systems (theoretical calculation )a
TABLE III b~
113
required for marking the lands, the levelling of ridges and finishes, etc. Generally, it is impossible to calculate the difference in idle driving and the extra work involved in different methods of ploughing, but the theoretical calculation of the unproductive driving distances in different methods of ploughing, as shown in Table III, gives a good picture of the relationships. Apparently, ploughing with a m o u n t e d one-way plough is superior in this respect to the other methods.
The one-way plough, the melody of the future After the various lectures, questions were asked of the speakers and problems presented were discussed. Especially the lecture of agronomist Nilsson raised the current question of the more general introduction of the one-way plough in our country. (The one-way plough has a double row of plough bodies, so it can turn the furrow-slice alternately to the right and to the left.) As the lecture of agronomist Nilsson demonstrated, a one-way m o u n t e d plough causes the least idle driving. Prof. Torstensson stated that the more stringent demand for an even development and maturing of the crops, in connection with the more general use of the combineharvester, has made the time ripe for switching over to the one-way plough as much as possible. This would doubtless be the most radical remedy for irregular emergence and maturing, as so often caused by the finishes. The audience generally agreed with him, although it was appreciated that big problems remain. The purchase costs of a plough will increase substantially. There is already a single-furrow one-way plough of satisfactory construction, but to build a two-furrow, one-way, m o u n t e d plough, equipped with a spring release, could give serious problems. As a representative of a firm put it: "The plough is becoming a machine instead of a tool". However, construction is apparently about to begin. The instruction film "Ploughing" was shown, and commented upon by one of the authors of the script of the film, agronomist Karl-/~ke Svensson.
A conference on soil tillage problems should be organized annually The president and chairman of the WPO, J.D. Thomas, U.S.A., addressed a word of warm thanks to the initiator and leader of the conference, Prof. G. Torstensson, for the good work he did. He noted that the conference had been very fruitful and he expressed the hope that the initiative would be repeated, so that this conference would be the introduction to a series of such meetings, organized in connection with the World Ploughing Contest in future years.
114
Fig. 3. Monument at Kungs~ingens G~rd near Uppsala, Sweden, in memory of the Third World Ploughing Contest, 1955. (Photo: B. Gillberg, Uppsala.)
ACKNOWLEDGEMENTS
The author is greatly indebted to Prof. emer. G. Torstensson (Uppsala, Sweden) and to Dr. L. Henriksson (Swedish University of Agricultural Sciences, Department of Soil Sciences, Uppsala, Sweden) for their help in tracing the review by Olle Johansson. The author gratefully acknowledges the help of Mrs. Drs. J.C. TorringaTimmer (Haren Gn, The Netherlands) and of his colleagues Dr. B.J. van Goor and Dr. C.H.E. Werkhoven (Institute for Soil Fertility, Haren Gn, The Netherlands) in translating the review.
REFERENCES Hawkins, J.C., 1962, Tractor Ploughing, 4th Edition. Ministry of Agriculture, Fisheries and Food, Her Majesty's Stationery Office, 56 pp. Johansson, O., 1955. Jordbearbetningskonferens p~i Ultuna (Soil tillage conference at Ultuna). Maskinteknik i Jord och Skog, 9: 404--407. Kuipers, H., 1985. A tillage research analysis based on ISTRO conference proceedings. Soil Tillage Res., 5: 117--128. Scheibe, J., 1936. Untersuchungen iiber die Vorziige und Nachteile des Beet- und KehrpfliJgens (Research on the pro's and con's of ploughing in lands and one-way ploughing). Reichskuratorium fiir Technik in der Landwirtschaft, Berlin, RKTL-Schrift 69.
115
Torstensson, G. and Nilsson, N.M., 1955. Plouging in lands, round and round ploughing and one-way ploughing. In: A. Hall and O. Sandholm (Editors), Third World Ploughing Championship Contest at Uppsala, Sweden, 7--8 October 1955. World Ploughing Organization, Official Souvenir Guide. Jordbrukare-Ungdomens FSrbund, pp. 6369, 58. Van Ouwerkerk, C. and Manten, A.A., 1980. Launching the new international journal "Soil & Tillage Research". Soil Tillage Res., 1: 1--6.