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A guide to this issue
A GUIDE TO THIS ISSUE
INTRODUCTION A l a r g e p a r t of this i s s u e of " G e o d e r m a " c o n s i s t s of c o n t r i b u t i o n s f r o m f e l l o w - w o r k e r s of the N e t h e r l a n d s Soil S u r v e y Institute. The e d i t o r i a l b o a r d of " G e o d e r m a " has g e n e r o u s l y p l a c e d a g r e a t deal space at our d i s p o s a l to m a r k the fact that t h i s y e a r the I n s t i t u t e is c e l e b r a t i n g the twenty-fifth y e a r of its e x i s t e n c e . The Soil S u r v e y Institute and its staff a r e v e r y a p p r e c i a t i v e of this g e s t u r e .
DEVELOPMENT OF SOIL SURVEY IN THE NETHERLANDS The f i r s t a c t i v i t i e s in the f i e l d of s o i l s u r v e y in The N e t h e r l a n d s date f r o m the m i d d l e of the nineteenth century. As long ago as 1856 a t r e a t i s e w r i t t e n by Dr. W.C.H. S t a r i n g , g e o l o g i s t and a g r o n o m i s t , was published under the title of "De Bodem van N e d e r l a n d " (The Soil of The N e t h e r l a n d s " ) . A c c o m p a n y i n g this was a s o i l map, s c a l e l : 2 0 0 , 0 0 0 , w h i c h is undoubtedly one of the o l d e s t in the world. S t a r i n g ' s work sank into oblivion and it w a s not until about 1930 that any f u r t h e r a c t i v i t y in this f i e l d d e v e l o p e d in The N e t h e r l a n d s . Around that t i m e Dr. W.A.J. Oosting conducted d e t a i l e d s o i l s u r v e y s in the n e i g b o u r hood of Wageningen, w h e r e he was a t t a c h e d to the A g r i c u l t u r a l U n i v e r s i t y . It was only a f t e r the death of Oosting in 1942 that Prof. Dr. C.H. E d e l m a n (1903-1964) s u c c e e d e d in putting the s o i l s u r v e y in The N e t h e r lands on a solid b a s i s and in winning r e c o g n i t i o n of the soil s u r v e y a s an autonomous b r a n c h of s o i l s c i e n c e . It is to E d e l m a n ' s g r e a t m e r i t that he l a i d the b a s i s for the p h y s i o g r a p h i c school in s o i l s c i e n c e . He d e v e l o p e d t o g e t h e r w i t h h i s pupils - a s y s t e m of c l a s s i f i c a t i o n and a method of m a p ping in which the accent w a s p l a c e d on the connection between the p h y s i o g r a p h i c e l e m e n t s of the e a r t h ' s s u r f a c e in t h e i r mutual r e l a t i o n s h i p (i.e. the l a n d s c a p e ) and the s o i l conditions. T h e s e e l e m e n t s of the l a n d s c a p e a r e s p e c i f i e d f u r t h e r in m o d e r n s o i l c a r t o g r a p h y and defined as " s o i l l a n d scape bodies". The l a n d s c a p e a p p r o a c h to the soil, a s it was conceived by E d e l m a n , has left i t s m a r k on the d e v e l o p m e n t of s o i l s u r v e y i n g in The N e t h e r l a n d s , and on the consequent soil i n v e s t i g a t i o n . It w a s b e c a u s e of t h i s that in the e a r l y y e a r s the i n v e s t i g a t i o n into g e o g e n e s i s and the s o i l p a t t e r n p a r t i c u l a r l y occupied the c e n t r e of i n t e r e s t . Even though pedogenetic f a c t o r s and p r o c e s s e s have taken on a m o r e i m p o r t a n t r o l e in the p e d o l o g i c a l way of thinking in r e c e n t y e a r s , which h a s i t s r e p e r c u s s i o n s in the N e t h e r l a n d s s y s t e m of s o i l c l a s s i f i c a t i o n , t h e r e a r e s t i l l a s p e c t s of g e o g e n e s i s to be found at v a r i o u s l e v e l s of that s y s t e m . As a b a s i s f o r the technique of soil s u r v e y i n g , E d e l m a n ' s p h y s i o g r a p h i c method has r e t a i n e d all i t s o r i g i n a l significance. T h e r e i s a c l e a r connection between the i m p o r t a n t position o c c u p i e d -
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by g e o g e n e s i s in the N e t h e r l a n d s s o i l s u r v e y , and the g r e a t i n t e r e s t taken by the soil s u r v e y o r s in the geology of the u p p e r l a y e r s of the e a r t h . B e c a u s e the knowledge of t h e s e l a y e r s was i n s u f f i c i e n t , the soil s c i e n t i s t s had to u n d e r t a k e this i n v e s t i g a t i o n t h e m s e l v e s . E d e l m a n and his p u p i l s p r o v i d e d a s u b s t a n t i a l c o n t r i b u t i o n t o w a r d s the d e v e l o p m e n t of the Q u a r t e r nary geology, and to the revival of this science in The Netherlands and bordering countries. Soil surveying was for Edelman more than an inventory of pedological data. He always considered the interpretation of those data for agricultural and non-agricultural use to be a vital extension of soil surveying. He propagated these ideas in many publications, in speeches and in his lectures. It is probably because of this practical approach that the soil survey has been fully accepted as a method of soil investigation in The Netherlands. On the 21st August 1945 this led to the founding of the Soil Survey Institute, under the jurisdiction of the Ministry of Agriculture, Fisheries and Food, and Edelman became the first director of the Institute. Since that time soil mapping has assumed extensive proportions in The Netherlands, partly because its practical application has always been considered its most important fact. During the last 25 years, more or less detailed soil surveys have been carried out in many areas of The Netherlands. Most of these surveys very clearly serve the purpose of application, especially in rural reconstruction works (e.g. reallotment), and for regional rural and municipal planning. The revenue earned from these surveys, which are carried out on commission from other bodies, constitutes approximately 25% of the Institute's budget. Apart from this, a number of soil maps of the entire country have been produced. At the 4th International Congress of Soil Science held in Amsterdam in 1950, Edelman and his pupils presented to the soil scientists of the world a specimen of a soil map according to the physiographic system, in the form of a Provisional Soil Map ~ scale 1:400,000. Edelman himself wrote the explanatory book "Soils of the Netherlands" (NorthHolland, Amsterdam). This map was followed by one on the scale of 1:200,000, which was published in 1960. The increasing demand for pedological data throughout the country led to the Minister of Agriculture and Fisheries commissioning the survey and publication of a soil map of The Netherlands, scale 1:50,000, of which 22 of the II0 sheets with explanatory text have now appeared. A great many and a great variety of investigations are needed to support soil surveying and the application of soil maps. The result of research by other institutes must be made applicable for our work, and apart from that, independent research is also carried out within our own institute.
RECENT WORK AT THE NETHERLANDS SOIL SURVEY INSTITUTE In this i s s u e , s e v e r a l c o l l e a g u e s f r o m the N e t h e r l a n d s Soil S u r v e y I n s t i t u t e r e v i e w r e c e n t i n v e s t i g a t i o n s which m a y p o s s i b l y be of i n t e r e s t to o t h e r s o c c u p i e d with s i m i l a r p r o b l e m s . Making a soil m a p of the e n t i r e c o u n t r y on a s c a l e of 1:50,000 r e q u i r e s the u s e of a s y s t e m of soil c l a s s i f i c a t i o n . The n u m e r o u s a p p l i c a t i o n s in 160
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civil engineering and land development have f u r t h e r strengthened the need for normalization and the definition of t e r m s and units. This has o c c u r r e d simultaneously with an analogous development in the U.S.A. The m o r p h o m e t r i c tendency in American classification has had a great influence on the Netherlands approach. In developing our national s y s t e m of soil classification the n e c e s s i t y of studying the basic principles of soil survey has become evident, i.e. the study of the fundamental concepts and the objectives of both soil s u r v e y and soil classification. The study and exact formulation of these b a s i c concepts a r e n e c e s s a r y f o r the compilation of new s y s t e m s of soil classification, and for the i m provement of existing systems. Schelling, in his article, gives a s u r v e y of the ideas which have been developed on this subject, connecting up with recent publications by Cline, Knox, Russel, Moore, Beckett and others. Here the question a r i s e s whether soil classification can proceed on the method of trial and e r r o r . More and m o r e the conviction is growing that numerical methods (including n u m e r i c a l taxonomy) can be applied in constructing and testing classification s y s t e m s . Schelling d e s c r i b e s the r e l a tionship between soil genesis, soil classification and soil survey in a coherent system of propositions and conclusions. This approach m a k e s it possible to analyse the vital stages in the development of a classification s y s t e m and to t r a c e the inadequately known links in the system. This puts one in a better position to select f r o m a multitude of problems the most essential projects of r e s e a r c h and enables such p r o b l e m s to be defined in a b e t t e r way. It is apparent from Schelling's paper that the purposes of the c l a s s i f i c a tion and the universe for which the s y s t e m is made, t~ave an important influence on its contents. One of the most obvious purposes of soil c l a s s i f i c a tion is its use in soil surveying. The review of l i t e r a t u r e by De Bakker shows that in the various s y s t e m s of soil classification there is often a lack of an explicit formulation of these purposes. It is also obvious that the purpose is s o m e t i m e s lost sight of in the construction and elaboration of the classification. Testing of classifications on a wide scale is an urgent p r e requisite for the advancement of knowledge in this field. The influence of the universe (i.e. the region for which the c l a s s i f i c a tion has been constructed) on contents and c r i t e r i a is illustrated by De Bakker with s e v e r a l examples taken from the Netherlands classification system. In the classification of m a r i n e clay soils, which cover about 30~ of the surface of The Netherlands, an important c r i t e r i o n is f o r m e d by the variation in c a l c i u m - c a r b o n a t e content within the soil profile. The g r e a t differences which a r e encountered in such soils have always been a motive for r e s e a r c h . Van der Sluijs r e p o r t s on his investigation into the decalcification that can o c c u r under various conditions, such as: during t r a n s p o r t , during silting and after enclosure. The decalcification p r o c e s s is significant for the p r o g r e s s of a number of phenomena in the soil, such as the f o r m a t i o n of cat clay (acid sulphate soils) in sediments that are ripening as a result of enclosure. Because of the great i n t e r e s t being taken all o v e r the world in improving the a g r i c u l t u r a l conditions of many delta a r e a s , this investigation is of m o r e than regional significance. In the densely populated Netherlands man has always had a vast influence on the soil. Thus it is not s u r p r i s i n g that since the v e r y beginning, Geodermal 4 (1970)
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s o i l m a p p i n g p r a c t i c e h a s d e v o t e d a g r e a t d e a l of a t t e n t i o n to t h i s m a t t e r . In his P r e s i d e n t i a l A d d r e s s to the 4th I n t e r n a t i o n a l C o n g r e s s of S o i l S c i e n c e in 1950, e n t i t l e d " S o m e u n u s u a l a s p e c t s of s o i l s c i e n c e " , E d e l m a n p o i n t e d out t h e i m p o r t a n c e of t h e s o i l f o r m i n g f a c t o r : man. The h u m a n i n f l u e n c e on s o i l s i s obvious, f o r i n s t a n c e , f r o m the l a r g e a r e a s of s o - c a l l e d p l a g g e n s o i l s ( P l a g g e p t s , P l a g g e n b S d e n ) in The N e t h e r l a n d s and in the b o r d e r i n g a r e a s of B e l g i u m and G e r m a n y . A s the r e s u l t of a m a n u r i n g p r a c t i c e t h a t c a m e into b e i n g in the M i d d l e A g e s , t h e s e p l a g g e n s o i l s have a t h i c k h u m o s e top s o i l (Aan horizon). B e c a u s e of t h i s , t h e c h a r a c t e r i s t i c s and p r o p e r t i e s of t h e s e p l a g g e n s o i l s d i f f e r s t r o n g l y f r o m the p o d s o l s on w h i c h t h e y a r e u s u a l l y f o r m e d . P a p e t h r o w s s o m e light on a n u m b e r of a s p e c t s of t h e s e a n t h r o p i c soils. O v e r l a r g e a r e a s of the l o w - l y i n g and flat N e t h e r l a n d s t h e g r o u n d w a t e r l i e s c l o s e to the s u r f a c e . H e n c e a s o i l m a p of The N e t h e r l a n d s w h i c h d o e s not g i v e an i d e a of the h y d r o l o g i c c o n d i t i o n s i s u n t h i n k a b l e - and u s e l e s s . By e x t r a p o l a t i n g g r o u n d w a t e r d a t a m e a s u r e d o v e r a s e r i e s of y e a r s , and c o r r e l a t i n g s p e c i f i c c h a r a c t e r i s t i c s of the s o i l p r o f i l e with the f l u c t u a t i o n s of the g r o u n d w a t e r t a b l e , it h a s p r o v e d p o s s i b l e to i n d i c a t e the a v e r a g e g r o u n d w a t e r r e g i m e on t h e s o i l m a p in a n u m b e r of w a t e r - t a b l e c l a s s e s . Van H e e s e n d e s c r i b e s the m e t h o d s f o l l o w e d in t h i s p r o c e d u r e . The f l o u r i s h i n g d e v e l o p m e n t of s o i l s u r v e y i n g in The N e t h e r l a n d s i s due a b o v e a l l to the f a c t t h a t the p r a c t i c a l a p p l i c a t i o n of s o i l m a p s h a s a l w a y s b e e n the f o c a l point; s o i l s c i e n t i s t s t h e m s e l v e s a p p r o a c h t h e m a t t e r f r o m t h i s angle. In m a n y c o u n t r i e s the s o i l m a p will be u t i l i z e d in o r d e r to e s t a b l i s h the m o s t a p p r o p r i a t e u s e of the s o i l , on the b a s i s of i t s p r o p e r t i e s . In The N e t h e r l a n d s , with i t s h i g h l y d e v e l o p e d , highly s p e c i a l i z e d a g r i c u l t u r e , i t s e x t r e m e l y d e n s e p o p u l a t i o n and e v e r - i n c r e a s i n g u r b a n i z a t i o n , the f a c t o r s which d e t e r m i n e the l a n d u s e often have l i t t l e to do with the s u i t a b i l i t y of the s o i l i t s e l f . To an i n c r e a s i n g e x t e n t t h i s w i l l a l s o b e the c a s e e l s e w h e r e in the w o r l d . In s i t u a t i o n s of t h i s kind, the e m p h a s i s i s s h i f t e d to the l i m i t a t i o n s t h a t a s o i l p o s s e s s e s f o r a c e r t a i n u s e , and to the c h a n g e s that w i l l h a v e to be m a d e in the s o i l a n d / o r in the h y d r o l o g i c c o n d i t i o n s in o r d e r to m a k e the s o i l s u i t a b l e f o r a c e r t a i n u s e . T h e s u i t a b i l i t y c l a s s i f i c a t i o n of t h e s o i l s f o r v a r i o u s f o r m s of l a n d u s e a r e t h e r e f o r e b e i n g a p p r o a c h e d m o r e and m o r e f r o m the v i e w p o i n t of l i m i t i n g f a c t o r s and the p o s s i b i l i t i e s of e r a d i c a t i n g t h e s e l i m i t a t i o n s t h r o u g h a l t e r a t i o n s in the s o i l p r o f i l e o r t h e h y d r o l o g i c c o n d i t i o n s . H a a n s and W e s t e r v e l d r e v i e w t h i s s u b j e c t , i l l u s t r a t e d with e x a m p l e s t a k e n f r o m p r a c t i c e in The N e t h e r l a n d s . T h i s f o r m of s u i t a b i l i t y c l a s s i f i c a t i o n , which l a y s s t r e s s on the i m p e d i m e n t s in s o i l p r o p e r t i e s and q u a l i t i e s to a c e r t a i n u s e , w i l l h a v e to h a v e a d i s t i n c t l y q u a n t i t a t i v e c h a r a c t e r . The e v e n t u a l a l t e r a t i o n s m u s t a l w a y s be s u b j e c t e d to an e c o n o m i c e v a l u a t i o n . Q u a n t i f i c a t i o n of the s u i t a b i l i t y c l a s s i f i c a t i o n , w h i c h is at p r e s e n t s t i l l m a i n l y d e s c r i p t i v e and q u a l i t a t i v e , i s t h u s a s e l f - e v i d e n t t a s k f o r the s u i t a b i l i t y i n v e s t i g a t i o n s . An i m p o r t a n t a p p l i c a t i o n of s o i l s u r v e y i n g in The N e t h e r l a n d s is in t h e f i e l d of r u r a l d e v e l o p m e n t and r e c o n s t r u c t i o n . Both in i t s p l a n n i n g and e x e c u t i o n , u s e i s m a d e of d e t a i l e d s o i l m a p s , which in the l a s t few y e a r s h a v e c o v e r e d an a r e a of 50,000 to 60,000 h a / y e a r . T h e g r e a t d e n s i t y of p o p u l a t i o n in T h e N e t h e r l a n d s i s c a u s i n g a v a s t e x p a n s i o n of the u r b a n a r e a s and an u r b a n i z a t i o n of the c o u n t r y s i d e . 162
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More and m o r e land is being withdrawn f r o m a g r i c u l t u r e for the extension of residential and industrial a r e a s and the facilities that accompany them, such as sports fields, green belts, wooded parks and other r e c r e a t i o n a l elements. It is in the western part of The Netherlands, where this expansion is most vigorous, that the soil by nature is highly unsuited to this f o r m of land use. It consists largely of wet c l a y - o n - p e a t soils. The r e c o n s t r u c t i o n of such a r e a s , at present predominantly agricultural, r e q u i r e s e n o r m o u s excavations, partly in connection with the intended dredging of sand at a depth of 10-15 m. There is thus a great demand for soil maps, p a r t i c u l a r l y in the form of derivative and interpretative maps, and for data which may concern, for instance, the behaviour of displaced m a t e r i a l and its suitability for afforestation. The development of this type of interpretation is still in its initial stage and is for the g r e a t e r part empiric. The intensive co-operation among all experts employed in this field, however, opens up great perspectives. Alongside investigations aimed directly at soil surveying o r the application of soil maps, the Soil Survey Institute is also engaged in m o r e fundamental soil r e s e a r c h , with clay mineralogy and micropedology occupying an important place. In m i c r o m o r p h o l o g i c r e s e a r c h of r e c e n t y e a r s , t h e r e has been a good deal of attention given to the t r a n s f e r and regrouping of soil components, whereby both natural and anthropic p r o c e s s e s appear to play a role. The translocation of clay, which leads to the forming of an agrillic horizon, is a well-known example that has also been studied in detail elsewhere in the world. Along with this, it appears that many other f o r m s of regrouping occur, a number of which a r e important for m o d e r n agricultural practice: the consequences of deep plowing, compactions caused by vibration of heavy machinery, slaking of m a t e r i a l in the p l o w - l a y e r (Ap) under the influence of n o r m a l tillage, etc. Jongerius p r e s e n t s in his paper a classification of the regrouping phenomena, which can be divided into three c l a s s e s : pedoturbations, pedocompactions and concentrations. On the basis of this classification, two phenomena a r e f u r t h e r analysed: "knip" soils and slaking soils. Micromorphology can also be helpful in solving p r o b l e m s in the classification of red tropical soils, partly in connection with the weathering stage of the soil material. Bennema (who worked for many y e a r s in t r o p i c a l South America), L e m o s and J o n g e r i u s contribute towards the solution of this exceedingly complicated m a t t e r , about which so much disparity of insight still exists. This work can be seen as one of the facets of the Soil Survey I n s t i t u t e ' s efforts for the benefit of developing countries. Since the establishment of the Institute, m e m b e r s of the staff have been engaged, for either brief or m o r e lengthy periods, in c a r r y i n g out soil studies connected with p r o j e c t s of land r e c l a m a t i o n and improvement, drainage and i r r i g a t i o n in those countries. Many people f r o m developing countries have been guests of the Institute in o r d e r to specialize in the technique of soil surveying. This has ultimately led to the establishment of the International C o u r s e on Soil Science at Wageningen. In this issue of " G e o d e r m a " only a few aspects of the activities of the Netherlands Soil Survey Institute have been discussed. The choice of subjects was mainly decided by the i n t e r e s t that might exist elsewhere in the r e s u l t s of s e v e r a l special objects of investigation. The g r e a t e r part of the Geoderma, 4 (1970)
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I n s t i t u t e ' s work c o n s i s t s of c a r r y i n g out s o i l s u r v e y s and c o m p i l i n g d e r i v a t i v e m a p s to aid an e x t e n s i v e v a r i e t y of a p p l i c a t i o n s . T h i s " e v e r y d a y " work could only be m e n t i o n e d i n p a s s i n g . In all the r e s e a r c h u n d e r t a k e n by the I n s t i t u t e , it is the a p p l i c a b i l i t y , in and t h r o u g h the soil s u r v e y , that is c o n s t a n t l y at the f o r e f r o n t . The a p p l i c a b i l i t y of soil data - a s r e p r e s e n t e d on a soil m a p - to b e n e f i t a g r i c u l t u r a l and n o n - a g r i c u l t u r a l l a n d u s e , is and a l w a y s will be the m a i n t a s k of The N e t h e r l a n d s Soil S u r v e y I n s t i t u t e . F.W.G. PIJLS (Director, The Netherlands Soil Survey Institute, Wageningen)
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INTRODUCTION A l a r g e p a r t of this i s s u e of " G e o d e r m a " c o n s i s t s of c o n t r i b u t i o n s f r o m f e l l o w - w o r k e r s of the N e t h e r l a n d s Soil S u r v e y Institute. The e d i t o r i a l b o a r d of " G e o d e r m a " has g e n e r o u s l y p l a c e d a g r e a t deal space at our d i s p o s a l to m a r k the fact that t h i s y e a r the I n s t i t u t e is c e l e b r a t i n g the twenty-fifth y e a r of its e x i s t e n c e . The Soil S u r v e y Institute and its staff a r e v e r y a p p r e c i a t i v e of this g e s t u r e .
DEVELOPMENT OF SOIL SURVEY IN THE NETHERLANDS The f i r s t a c t i v i t i e s in the f i e l d of s o i l s u r v e y in The N e t h e r l a n d s date f r o m the m i d d l e of the nineteenth century. As long ago as 1856 a t r e a t i s e w r i t t e n by Dr. W.C.H. S t a r i n g , g e o l o g i s t and a g r o n o m i s t , was published under the title of "De Bodem van N e d e r l a n d " (The Soil of The N e t h e r l a n d s " ) . A c c o m p a n y i n g this was a s o i l map, s c a l e l : 2 0 0 , 0 0 0 , w h i c h is undoubtedly one of the o l d e s t in the world. S t a r i n g ' s work sank into oblivion and it w a s not until about 1930 that any f u r t h e r a c t i v i t y in this f i e l d d e v e l o p e d in The N e t h e r l a n d s . Around that t i m e Dr. W.A.J. Oosting conducted d e t a i l e d s o i l s u r v e y s in the n e i g b o u r hood of Wageningen, w h e r e he was a t t a c h e d to the A g r i c u l t u r a l U n i v e r s i t y . It was only a f t e r the death of Oosting in 1942 that Prof. Dr. C.H. E d e l m a n (1903-1964) s u c c e e d e d in putting the s o i l s u r v e y in The N e t h e r lands on a solid b a s i s and in winning r e c o g n i t i o n of the soil s u r v e y a s an autonomous b r a n c h of s o i l s c i e n c e . It is to E d e l m a n ' s g r e a t m e r i t that he l a i d the b a s i s for the p h y s i o g r a p h i c school in s o i l s c i e n c e . He d e v e l o p e d t o g e t h e r w i t h h i s pupils - a s y s t e m of c l a s s i f i c a t i o n and a method of m a p ping in which the accent w a s p l a c e d on the connection between the p h y s i o g r a p h i c e l e m e n t s of the e a r t h ' s s u r f a c e in t h e i r mutual r e l a t i o n s h i p (i.e. the l a n d s c a p e ) and the s o i l conditions. T h e s e e l e m e n t s of the l a n d s c a p e a r e s p e c i f i e d f u r t h e r in m o d e r n s o i l c a r t o g r a p h y and defined as " s o i l l a n d scape bodies". The l a n d s c a p e a p p r o a c h to the soil, a s it was conceived by E d e l m a n , has left i t s m a r k on the d e v e l o p m e n t of s o i l s u r v e y i n g in The N e t h e r l a n d s , and on the consequent soil i n v e s t i g a t i o n . It w a s b e c a u s e of t h i s that in the e a r l y y e a r s the i n v e s t i g a t i o n into g e o g e n e s i s and the s o i l p a t t e r n p a r t i c u l a r l y occupied the c e n t r e of i n t e r e s t . Even though pedogenetic f a c t o r s and p r o c e s s e s have taken on a m o r e i m p o r t a n t r o l e in the p e d o l o g i c a l way of thinking in r e c e n t y e a r s , which h a s i t s r e p e r c u s s i o n s in the N e t h e r l a n d s s y s t e m of s o i l c l a s s i f i c a t i o n , t h e r e a r e s t i l l a s p e c t s of g e o g e n e s i s to be found at v a r i o u s l e v e l s of that s y s t e m . As a b a s i s f o r the technique of soil s u r v e y i n g , E d e l m a n ' s p h y s i o g r a p h i c method has r e t a i n e d all i t s o r i g i n a l significance. T h e r e i s a c l e a r connection between the i m p o r t a n t position o c c u p i e d -
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by g e o g e n e s i s in the N e t h e r l a n d s s o i l s u r v e y , and the g r e a t i n t e r e s t taken by the soil s u r v e y o r s in the geology of the u p p e r l a y e r s of the e a r t h . B e c a u s e the knowledge of t h e s e l a y e r s was i n s u f f i c i e n t , the soil s c i e n t i s t s had to u n d e r t a k e this i n v e s t i g a t i o n t h e m s e l v e s . E d e l m a n and his p u p i l s p r o v i d e d a s u b s t a n t i a l c o n t r i b u t i o n t o w a r d s the d e v e l o p m e n t of the Q u a r t e r nary geology, and to the revival of this science in The Netherlands and bordering countries. Soil surveying was for Edelman more than an inventory of pedological data. He always considered the interpretation of those data for agricultural and non-agricultural use to be a vital extension of soil surveying. He propagated these ideas in many publications, in speeches and in his lectures. It is probably because of this practical approach that the soil survey has been fully accepted as a method of soil investigation in The Netherlands. On the 21st August 1945 this led to the founding of the Soil Survey Institute, under the jurisdiction of the Ministry of Agriculture, Fisheries and Food, and Edelman became the first director of the Institute. Since that time soil mapping has assumed extensive proportions in The Netherlands, partly because its practical application has always been considered its most important fact. During the last 25 years, more or less detailed soil surveys have been carried out in many areas of The Netherlands. Most of these surveys very clearly serve the purpose of application, especially in rural reconstruction works (e.g. reallotment), and for regional rural and municipal planning. The revenue earned from these surveys, which are carried out on commission from other bodies, constitutes approximately 25% of the Institute's budget. Apart from this, a number of soil maps of the entire country have been produced. At the 4th International Congress of Soil Science held in Amsterdam in 1950, Edelman and his pupils presented to the soil scientists of the world a specimen of a soil map according to the physiographic system, in the form of a Provisional Soil Map ~ scale 1:400,000. Edelman himself wrote the explanatory book "Soils of the Netherlands" (NorthHolland, Amsterdam). This map was followed by one on the scale of 1:200,000, which was published in 1960. The increasing demand for pedological data throughout the country led to the Minister of Agriculture and Fisheries commissioning the survey and publication of a soil map of The Netherlands, scale 1:50,000, of which 22 of the II0 sheets with explanatory text have now appeared. A great many and a great variety of investigations are needed to support soil surveying and the application of soil maps. The result of research by other institutes must be made applicable for our work, and apart from that, independent research is also carried out within our own institute.
RECENT WORK AT THE NETHERLANDS SOIL SURVEY INSTITUTE In this i s s u e , s e v e r a l c o l l e a g u e s f r o m the N e t h e r l a n d s Soil S u r v e y I n s t i t u t e r e v i e w r e c e n t i n v e s t i g a t i o n s which m a y p o s s i b l y be of i n t e r e s t to o t h e r s o c c u p i e d with s i m i l a r p r o b l e m s . Making a soil m a p of the e n t i r e c o u n t r y on a s c a l e of 1:50,000 r e q u i r e s the u s e of a s y s t e m of soil c l a s s i f i c a t i o n . The n u m e r o u s a p p l i c a t i o n s in 160
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civil engineering and land development have f u r t h e r strengthened the need for normalization and the definition of t e r m s and units. This has o c c u r r e d simultaneously with an analogous development in the U.S.A. The m o r p h o m e t r i c tendency in American classification has had a great influence on the Netherlands approach. In developing our national s y s t e m of soil classification the n e c e s s i t y of studying the basic principles of soil survey has become evident, i.e. the study of the fundamental concepts and the objectives of both soil s u r v e y and soil classification. The study and exact formulation of these b a s i c concepts a r e n e c e s s a r y f o r the compilation of new s y s t e m s of soil classification, and for the i m provement of existing systems. Schelling, in his article, gives a s u r v e y of the ideas which have been developed on this subject, connecting up with recent publications by Cline, Knox, Russel, Moore, Beckett and others. Here the question a r i s e s whether soil classification can proceed on the method of trial and e r r o r . More and m o r e the conviction is growing that numerical methods (including n u m e r i c a l taxonomy) can be applied in constructing and testing classification s y s t e m s . Schelling d e s c r i b e s the r e l a tionship between soil genesis, soil classification and soil survey in a coherent system of propositions and conclusions. This approach m a k e s it possible to analyse the vital stages in the development of a classification s y s t e m and to t r a c e the inadequately known links in the system. This puts one in a better position to select f r o m a multitude of problems the most essential projects of r e s e a r c h and enables such p r o b l e m s to be defined in a b e t t e r way. It is apparent from Schelling's paper that the purposes of the c l a s s i f i c a tion and the universe for which the s y s t e m is made, t~ave an important influence on its contents. One of the most obvious purposes of soil c l a s s i f i c a tion is its use in soil surveying. The review of l i t e r a t u r e by De Bakker shows that in the various s y s t e m s of soil classification there is often a lack of an explicit formulation of these purposes. It is also obvious that the purpose is s o m e t i m e s lost sight of in the construction and elaboration of the classification. Testing of classifications on a wide scale is an urgent p r e requisite for the advancement of knowledge in this field. The influence of the universe (i.e. the region for which the c l a s s i f i c a tion has been constructed) on contents and c r i t e r i a is illustrated by De Bakker with s e v e r a l examples taken from the Netherlands classification system. In the classification of m a r i n e clay soils, which cover about 30~ of the surface of The Netherlands, an important c r i t e r i o n is f o r m e d by the variation in c a l c i u m - c a r b o n a t e content within the soil profile. The g r e a t differences which a r e encountered in such soils have always been a motive for r e s e a r c h . Van der Sluijs r e p o r t s on his investigation into the decalcification that can o c c u r under various conditions, such as: during t r a n s p o r t , during silting and after enclosure. The decalcification p r o c e s s is significant for the p r o g r e s s of a number of phenomena in the soil, such as the f o r m a t i o n of cat clay (acid sulphate soils) in sediments that are ripening as a result of enclosure. Because of the great i n t e r e s t being taken all o v e r the world in improving the a g r i c u l t u r a l conditions of many delta a r e a s , this investigation is of m o r e than regional significance. In the densely populated Netherlands man has always had a vast influence on the soil. Thus it is not s u r p r i s i n g that since the v e r y beginning, Geodermal 4 (1970)
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s o i l m a p p i n g p r a c t i c e h a s d e v o t e d a g r e a t d e a l of a t t e n t i o n to t h i s m a t t e r . In his P r e s i d e n t i a l A d d r e s s to the 4th I n t e r n a t i o n a l C o n g r e s s of S o i l S c i e n c e in 1950, e n t i t l e d " S o m e u n u s u a l a s p e c t s of s o i l s c i e n c e " , E d e l m a n p o i n t e d out t h e i m p o r t a n c e of t h e s o i l f o r m i n g f a c t o r : man. The h u m a n i n f l u e n c e on s o i l s i s obvious, f o r i n s t a n c e , f r o m the l a r g e a r e a s of s o - c a l l e d p l a g g e n s o i l s ( P l a g g e p t s , P l a g g e n b S d e n ) in The N e t h e r l a n d s and in the b o r d e r i n g a r e a s of B e l g i u m and G e r m a n y . A s the r e s u l t of a m a n u r i n g p r a c t i c e t h a t c a m e into b e i n g in the M i d d l e A g e s , t h e s e p l a g g e n s o i l s have a t h i c k h u m o s e top s o i l (Aan horizon). B e c a u s e of t h i s , t h e c h a r a c t e r i s t i c s and p r o p e r t i e s of t h e s e p l a g g e n s o i l s d i f f e r s t r o n g l y f r o m the p o d s o l s on w h i c h t h e y a r e u s u a l l y f o r m e d . P a p e t h r o w s s o m e light on a n u m b e r of a s p e c t s of t h e s e a n t h r o p i c soils. O v e r l a r g e a r e a s of the l o w - l y i n g and flat N e t h e r l a n d s t h e g r o u n d w a t e r l i e s c l o s e to the s u r f a c e . H e n c e a s o i l m a p of The N e t h e r l a n d s w h i c h d o e s not g i v e an i d e a of the h y d r o l o g i c c o n d i t i o n s i s u n t h i n k a b l e - and u s e l e s s . By e x t r a p o l a t i n g g r o u n d w a t e r d a t a m e a s u r e d o v e r a s e r i e s of y e a r s , and c o r r e l a t i n g s p e c i f i c c h a r a c t e r i s t i c s of the s o i l p r o f i l e with the f l u c t u a t i o n s of the g r o u n d w a t e r t a b l e , it h a s p r o v e d p o s s i b l e to i n d i c a t e the a v e r a g e g r o u n d w a t e r r e g i m e on t h e s o i l m a p in a n u m b e r of w a t e r - t a b l e c l a s s e s . Van H e e s e n d e s c r i b e s the m e t h o d s f o l l o w e d in t h i s p r o c e d u r e . The f l o u r i s h i n g d e v e l o p m e n t of s o i l s u r v e y i n g in The N e t h e r l a n d s i s due a b o v e a l l to the f a c t t h a t the p r a c t i c a l a p p l i c a t i o n of s o i l m a p s h a s a l w a y s b e e n the f o c a l point; s o i l s c i e n t i s t s t h e m s e l v e s a p p r o a c h t h e m a t t e r f r o m t h i s angle. In m a n y c o u n t r i e s the s o i l m a p will be u t i l i z e d in o r d e r to e s t a b l i s h the m o s t a p p r o p r i a t e u s e of the s o i l , on the b a s i s of i t s p r o p e r t i e s . In The N e t h e r l a n d s , with i t s h i g h l y d e v e l o p e d , highly s p e c i a l i z e d a g r i c u l t u r e , i t s e x t r e m e l y d e n s e p o p u l a t i o n and e v e r - i n c r e a s i n g u r b a n i z a t i o n , the f a c t o r s which d e t e r m i n e the l a n d u s e often have l i t t l e to do with the s u i t a b i l i t y of the s o i l i t s e l f . To an i n c r e a s i n g e x t e n t t h i s w i l l a l s o b e the c a s e e l s e w h e r e in the w o r l d . In s i t u a t i o n s of t h i s kind, the e m p h a s i s i s s h i f t e d to the l i m i t a t i o n s t h a t a s o i l p o s s e s s e s f o r a c e r t a i n u s e , and to the c h a n g e s that w i l l h a v e to be m a d e in the s o i l a n d / o r in the h y d r o l o g i c c o n d i t i o n s in o r d e r to m a k e the s o i l s u i t a b l e f o r a c e r t a i n u s e . T h e s u i t a b i l i t y c l a s s i f i c a t i o n of t h e s o i l s f o r v a r i o u s f o r m s of l a n d u s e a r e t h e r e f o r e b e i n g a p p r o a c h e d m o r e and m o r e f r o m the v i e w p o i n t of l i m i t i n g f a c t o r s and the p o s s i b i l i t i e s of e r a d i c a t i n g t h e s e l i m i t a t i o n s t h r o u g h a l t e r a t i o n s in the s o i l p r o f i l e o r t h e h y d r o l o g i c c o n d i t i o n s . H a a n s and W e s t e r v e l d r e v i e w t h i s s u b j e c t , i l l u s t r a t e d with e x a m p l e s t a k e n f r o m p r a c t i c e in The N e t h e r l a n d s . T h i s f o r m of s u i t a b i l i t y c l a s s i f i c a t i o n , which l a y s s t r e s s on the i m p e d i m e n t s in s o i l p r o p e r t i e s and q u a l i t i e s to a c e r t a i n u s e , w i l l h a v e to h a v e a d i s t i n c t l y q u a n t i t a t i v e c h a r a c t e r . The e v e n t u a l a l t e r a t i o n s m u s t a l w a y s be s u b j e c t e d to an e c o n o m i c e v a l u a t i o n . Q u a n t i f i c a t i o n of the s u i t a b i l i t y c l a s s i f i c a t i o n , w h i c h is at p r e s e n t s t i l l m a i n l y d e s c r i p t i v e and q u a l i t a t i v e , i s t h u s a s e l f - e v i d e n t t a s k f o r the s u i t a b i l i t y i n v e s t i g a t i o n s . An i m p o r t a n t a p p l i c a t i o n of s o i l s u r v e y i n g in The N e t h e r l a n d s is in t h e f i e l d of r u r a l d e v e l o p m e n t and r e c o n s t r u c t i o n . Both in i t s p l a n n i n g and e x e c u t i o n , u s e i s m a d e of d e t a i l e d s o i l m a p s , which in the l a s t few y e a r s h a v e c o v e r e d an a r e a of 50,000 to 60,000 h a / y e a r . T h e g r e a t d e n s i t y of p o p u l a t i o n in T h e N e t h e r l a n d s i s c a u s i n g a v a s t e x p a n s i o n of the u r b a n a r e a s and an u r b a n i z a t i o n of the c o u n t r y s i d e . 162
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More and m o r e land is being withdrawn f r o m a g r i c u l t u r e for the extension of residential and industrial a r e a s and the facilities that accompany them, such as sports fields, green belts, wooded parks and other r e c r e a t i o n a l elements. It is in the western part of The Netherlands, where this expansion is most vigorous, that the soil by nature is highly unsuited to this f o r m of land use. It consists largely of wet c l a y - o n - p e a t soils. The r e c o n s t r u c t i o n of such a r e a s , at present predominantly agricultural, r e q u i r e s e n o r m o u s excavations, partly in connection with the intended dredging of sand at a depth of 10-15 m. There is thus a great demand for soil maps, p a r t i c u l a r l y in the form of derivative and interpretative maps, and for data which may concern, for instance, the behaviour of displaced m a t e r i a l and its suitability for afforestation. The development of this type of interpretation is still in its initial stage and is for the g r e a t e r part empiric. The intensive co-operation among all experts employed in this field, however, opens up great perspectives. Alongside investigations aimed directly at soil surveying o r the application of soil maps, the Soil Survey Institute is also engaged in m o r e fundamental soil r e s e a r c h , with clay mineralogy and micropedology occupying an important place. In m i c r o m o r p h o l o g i c r e s e a r c h of r e c e n t y e a r s , t h e r e has been a good deal of attention given to the t r a n s f e r and regrouping of soil components, whereby both natural and anthropic p r o c e s s e s appear to play a role. The translocation of clay, which leads to the forming of an agrillic horizon, is a well-known example that has also been studied in detail elsewhere in the world. Along with this, it appears that many other f o r m s of regrouping occur, a number of which a r e important for m o d e r n agricultural practice: the consequences of deep plowing, compactions caused by vibration of heavy machinery, slaking of m a t e r i a l in the p l o w - l a y e r (Ap) under the influence of n o r m a l tillage, etc. Jongerius p r e s e n t s in his paper a classification of the regrouping phenomena, which can be divided into three c l a s s e s : pedoturbations, pedocompactions and concentrations. On the basis of this classification, two phenomena a r e f u r t h e r analysed: "knip" soils and slaking soils. Micromorphology can also be helpful in solving p r o b l e m s in the classification of red tropical soils, partly in connection with the weathering stage of the soil material. Bennema (who worked for many y e a r s in t r o p i c a l South America), L e m o s and J o n g e r i u s contribute towards the solution of this exceedingly complicated m a t t e r , about which so much disparity of insight still exists. This work can be seen as one of the facets of the Soil Survey I n s t i t u t e ' s efforts for the benefit of developing countries. Since the establishment of the Institute, m e m b e r s of the staff have been engaged, for either brief or m o r e lengthy periods, in c a r r y i n g out soil studies connected with p r o j e c t s of land r e c l a m a t i o n and improvement, drainage and i r r i g a t i o n in those countries. Many people f r o m developing countries have been guests of the Institute in o r d e r to specialize in the technique of soil surveying. This has ultimately led to the establishment of the International C o u r s e on Soil Science at Wageningen. In this issue of " G e o d e r m a " only a few aspects of the activities of the Netherlands Soil Survey Institute have been discussed. The choice of subjects was mainly decided by the i n t e r e s t that might exist elsewhere in the r e s u l t s of s e v e r a l special objects of investigation. The g r e a t e r part of the Geoderma, 4 (1970)
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I n s t i t u t e ' s work c o n s i s t s of c a r r y i n g out s o i l s u r v e y s and c o m p i l i n g d e r i v a t i v e m a p s to aid an e x t e n s i v e v a r i e t y of a p p l i c a t i o n s . T h i s " e v e r y d a y " work could only be m e n t i o n e d i n p a s s i n g . In all the r e s e a r c h u n d e r t a k e n by the I n s t i t u t e , it is the a p p l i c a b i l i t y , in and t h r o u g h the soil s u r v e y , that is c o n s t a n t l y at the f o r e f r o n t . The a p p l i c a b i l i t y of soil data - a s r e p r e s e n t e d on a soil m a p - to b e n e f i t a g r i c u l t u r a l and n o n - a g r i c u l t u r a l l a n d u s e , is and a l w a y s will be the m a i n t a s k of The N e t h e r l a n d s Soil S u r v e y I n s t i t u t e . F.W.G. PIJLS (Director, The Netherlands Soil Survey Institute, Wageningen)
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