H E N R I DE B A K K E R
A N T H R O P O G E N IC S O ILS IN THE N U T H E R L A N D S
Soil S u rvey Institute, W ageningen, The Netherlands IN T R O D U C T IO N
The Netherlands iin well-Jknown for having many soils which are strongly influenced by man. There could be a discussion about the question: When must a soil be considered anthropogenic and when nortnal? In fact, e ve ry soil ploughed and fertilized is changed 'by man and in our country practically all soils are influenced b y man, to a greater or lesser degree.
Even our fe w virgin soils (virgin in the sense of never been ploughed or fertilized) are affected by man. In our humic podzols (compare soil P3 on p. 165 [1]) the black B2h is due to secondary enrichment of humus below the secondary heath vegetation (p. 59 [5]). When seeing the podzol during the excursion of the Polish Society of Soil Science (profile 2, [13]), I agree with Edelman: the striking difference between both soils lies in the organic-matter content (0.9°/o tatal С in the A x of the Polish soil, against 4.2%> in the Dutch podzol, and 0.5°/o in the B H against 4,2°/o in the B 2h of the Dutch soil). This must be caused by the man-induced heath vegetation on the Dutch sandy soils: this herb vegetation raised the organic-m atter content considerably compared with the original forest vegetation.
In our agricultural soils ploughing and heavy application of fe r tili zers (in 1977 430X10« kg N, 92X106 kg P 20 5 and 114X106 kg K 20 on 2 m illion ha of arable, grass and horticultural land) are considered to be “norm al” , 4 anthropogenic m odifying soil form ing factors. Even if podzols have been changed into neutral and fertile soils, such soils are considered normal, because most of our podzols are reclaim ed and are being lim ed and fertilized. Perhaps part of these soils fit already in the class of gle b y k u ltu ro zie m n e [7].
H ow ever, in the Dutch Soil Survey Institute soils are on ly consi-^ dered man-made when they are raised considerably by the addition of mineral m aterial by some agricultural practice. Such soils are called “thick earth soils” in our classification system when having an
anthro-pogenic A l horizon (coded as Aan) thicker than 50 cm ([4] numbers 9, 18, 51 and 52 in the determination key). Soils with thinner anthropo genic topsoils are classified as intergrading subgroups between the thick earth soils and the buried soils
Distribution of plaggen soils in northwestern Europa
The most well-kn'own example of this kind of soil is the so-called plaggen, soil, which w ill be discussed below and has been shown in a poster session during the meeting of the Polish Society of Soil Science in 1979 in Lublin.
N A M E A N D C L A S S IF IC A T IO N
transla-ted into Polish: gleb a d a rn io w a , but with a com pletely d ifferen t con cept and d ifferen t soil form ing process than in the Dutch soil.
The name is derived from the Dutch w ord p lag (Eng. turf or sod, French gazon or m otte, Ger. P la g g e, Sode or R a s e n, Russ. Д ёРН ); iît means the upper part (fe w cm) of grassland or waste land, the latter means in the Netherlands practically heath land, carrying a G e n isto p ilo s a e -C a llu n e t u m , in which Calluna vulgaris (heath) is dominant.
In the Dutch system o f soil classification [4] it is an enk earth soil (enk being a field name fo r old arable land in the sandy district of the Netherlands); in the system of the Federal Republic of Germ any it is a P la g g e n e sch [8]. On the soil map of Belgium, scale 1 : 20 000 these soils are called P la g g e n b o d e n s. Although other countries do not have these special kind of soils, thick man-made soils are named in England and W ales man-made humus soils [1]; in France sol d ’apport a n th ro p i- que [2]; in the U S A P laggep t {12]; in Poland it must be h ortisole po- h ielico w e, however the accumulation horizon is not similar tot that of black earth soils [7]; in the system of the German Democratic Republic [6] ; there is no class fo r such soils, although there are some plaggen soils on the boundary of both Germanies (personal communication Prof. Dr. G. Haase).
S O IL G E O G R A P H Y
Plaggen soils on ly are found on Pleistocene sandy soils, mostly on eolian sands from the last part o f the Pleistocene, but also on flu vio- glacial sands and pleistocene flu viatile sands. In the landscape they are situated on low ridges amidst hydromorphic soils ([3] p. 49-53) or on the footslope of low hills ([3] p. 43).
These soils are only known from Belgium, the Federal Republic of Germany and the Netherlands. P a p e [9] compiled a map with the distribution of plaggen soils (Figure 1). He estimates that within the shaded area on this map 16% of the sandy soils have a man-made humose topsoil thicker than 50 cm.
The northern boundary on this map is form ed by the holocene marine and peat deposits, the southern boundary is either the loess area or the low hills in Germany. The eastern boundary, however, cannot be explained t y soil or geological conditions. The same land scape continues eastward with predom inantly podzols developed from pleistocene sands. The explanation of the eastern boundary of the plaggen soils may be found in the d ifferen t agricultural practices by the differen t peoples ([3] p. 44).
S O IL S
thick w ith 5 -8 % organic matter, a C-N-ratio of 16-22, p H -K C l 4-5, m ostly a fine sand w ith practically no cla y and 10-20% silt. The buried subsoils are podzols, hydro'morphic (b ielice glejow e) or iron-humuspod- zols (b ie lice ż e la zisto -p ró ch n icz n e), but also w eak ly podzolized soils (comparable with g le b y rdzaw e).
A n extensive discussion about chemical and physical properties of the Aan horizon is given by P a p e {9].
H IS T O R Y A N D G E N E S IS
The soils were reclaimed roughly a thousand years ago and until the introduction of the com mercial fertilizers (round the turn of last century) the existed an agricultural system which caused a v e ry gradual raising of the surface with dark humose material.
This system was a subsistence farming, more or less in equilibrium w ith its environment. The heath lands, however poor, constituted an essential element in this system. They were the source of the heather sods (plaggen) that were used as bedding material in the stables. Th€; heath lands were also used as rough grazing land for sheep, the flock had to spend the nights in the sheepfolds so that the droppings could be
collected.. In these stables also heather sods w ere used as bedding ma terial. The dung-impregnated bedding was used to manure the arable land; the mineral part of this earth-containing manure stayed back as a kind of weathering residue. Consequently the arable fields were raised v e ry gradually, changing the podzol soil into a iplaggen soil. The farmer's were probably unaware of the fact that they w ere raising their soils by manuring them with the plaggen manure.
Based on some assumptions the nineteenth-century Dutch pedolo gist Dr. W.C.H. Staring (1808-1877) calculated that the raising of one metre would require 750 years, and the agricultural historian Slicher van Bath ([10] p. 258) calculated that 3-7 ha of heath land w ere needed to cut plaggen to manure one ha of arable land. Taken also into1 account the area of rough grazing land needed fo r the sheep, in total 10 ha of heath land w ere used to maintain a certain (rather low fo r today’s standards) fe rtility on one ha of arable land.
A fte r the introduction of the industrial fertilizers (70-90 years ago), this system was com pletely abandoned. Today nearly all heath lands are reclaimed, mostly to .grassland, but p artly also to forest.
These n ew ly reclaim ed podzols only change chem ically under the influence of lim ing and fertilizin g, but the old plaggen soils have chan ged from podzols into soils wich are deeply rootable and have a high water-holding capacity due to the thick man-made surface layer.
L IT E R A T U R E
[1] A v e r y В. W.: Soil classification in the Soil S u rvey o f England and Wales. J. S oil Sei. 24, 1973, 324-338.
[2] C PC S : Classification des soils. Commission de P éd ologie et de Cartographie des sols, 1967.
[3] De B a k k e r H.: M a jor soils and soil regions in the Netherlands. Junk/Pudoc, T e Hague/Wageningen, 1979.
{4] De B a k k e r H. and Schelling J.: A system o f soil classification fo r the Netherlands, the higher levels (Dutch, w ith 30 pages English summary). Pudoc, W ageningen 1966.
[5] E d e l m a n C. H.: Forest podzols and heath podzols [Dutch, w ith Eng. Sum m ary]. Boor en Spade 13, 1963, 51-60, Veenman, W ageningen.
{6] E h w a l d E., L i e b e r o t h I. und S c h w a n e c k e W.: Zur System atik der Böden der Deutschen Dem okratischen Republik besonders in H inblick auf die Bodenkartierung. Sitzungsber. Band 15, H e ft 18, B erlin 1966.
[7] System atyka G leb Polski. 1974, Pol. T ow . Gleb. W arszawa.
[8] M ü c k e n h a u s e n E. in Zusam m enarbeit m it Blume H. P., H einrich F. und M ü ller S.: Entstehung, Eigenschaften und System atik der Böden der Bundesrepublik Deutschland. 2 A u flage, D L G -V erla g, Fran kfu rt am M ain 1977. [9] P a p e J. C.: Plaggensoils in the Netherlands. Geoderm a 4, 1970, 229-255. [10] Polskie T o w a rzystw o G leboznaw cze: P ięcio języczn y Słow nik Gleboznaw czy.
W arszaw a 1976.
[11] S l i c h e r v a n B a t h , В.: The agrarian history of western Europe, A. D. 500-1850 (translated from Dutch by O live Ordishe). London 1963.
[12] SSS: S oil taxonom y, a basic system o f soil classification fo r m aking and interpretin g soil survey. S oil Conserv. Serv., U S D A Handbook 436, W ashing ton, D.C., 1975.
[13] T u r s k i R.: Soils o f the Lu blin region, excursion guide. Lu blin 1979.
X . ДЕ Б А К К Е Р А Н Т Р О П О Г Е Н Н Ы Е П О Ч В Ы В Г О Л Л А Н Д И И Институт почвоведения в Вагенинген (Голлан ди я) Р е з ю м е М ногие почвы в Голлан ди и сильно преобразованы человеком, преж де все го в химическом отношении, однако ли ш ь искуственно насыпные (наносные) почвы зачисляю тся к антропогенным. Н аилучш им примером таких почв я в л я ю тся дерновые почвы (plagen soils) выступаю щ ие в ю ж но-западной Европе (рис. 1) на подзолах образованных из песчаны х плейстоценовых отлож ений. Поверхностны й их слой тёмной окраски имеет мощность свыше 50 см и содер ж ит 5—8% органического вещества. Его создавали постепенно в течении многих столетий при использовании почвенного материала с примесью удобрений. У д о брение бы ло получено из дернины бросовых зем ель (вересковы х пустош ей) с прибавкой песка. Подсчитывается, что для удобрения 1 га угодий нуж но бы ло 10 га бросовых земель. Такая система бы ла заброшена, когда в конце минувше го столетия появились минеральны е удобрения. В настоящее время больш инство бросовы х зем ель вновь обращ ается в зелёвы е угодия и леса.
H. D E B A K K E R
G L E B Y A N T R O P O G E N IC Z N E W H O L A N D II Instytut G leboznaw stw a w W ageningen (H olandia)
S t r e s z c z e n i e
W iele gleb w H olandii zostało silnie przekształconych przez człow ieka, przede wszystkim pod w zględem chemicznym, jednak tylko gleby sztucznie naniesione uznaje się za antropogeniczne. N ajlepszym przykładem tych gleb są gleb y dar niow e (plaggen soils) w ystępujące w południowo-zachodniej Europie (rys. 1) na bielicach w ytw orzon ych z piaszczystych osadów plejstoceńskich. W ierzchnia ciem na w arstw a ma miąższość p ow yżej 60 cm i zaw iera 5-8% substancji organicznej. - Tw orzon a ona była stopniowo przez w iele stuleci przy użyciu m ateriału gleb o w ego z domieszką naw ozów . N a w óz był otrzym yw an y z darni pochodzącej z n ie użytków (w rzosow isk) z dodatkiem piasku. Obliczono, że do użytkow ania 1 ha gruntów uprawnych potrzebne było 10 ha nieużytków . System ten został zanie chany w momencie pojaw ienia się w końcu ubiegłego stulecia naw ozów sztucz nych. Obecnie większość nieużytków zamienia się ponownie na użytki zielone X lasy.
D r Henr i de Bakker Soil Su r v e y Institute Wageni ngen, The Netherl ands
