August 4, 1910] 



NATURE 



157 



I'rof. F. E. Weiss contributed the results of observa- 

 tions on the garden Trop.xolum, some plants of vvh'ch 

 bore flowers of different colour at different seasons of the 

 year. These and other cases of differing flower colora- 

 tion, c.jf. in AnagcMis arvcnsis, are under investigation to 

 ascertain to what degree they are hereditary characters, 

 and to which factors the changes are to be attributed. 



Animal pests naturally received considerable attention. 

 Dr. R. .Stewart MacDougall emphasised the importance in 

 dealing with coleopterous enemies of trees of taking 

 .'iccount of the length of life passed in the various stages, 

 whilst in a second paper he dealt with the sheep-maggot 

 fly i^Lucilia sericata) and the problems suggested by its 

 life-history, and announced the first record in this con- 

 nection of Protocalliphoru azurca. Other pests dealt with 

 were the warble-fly of the reindeer, by the president ; a 

 species of Rhabditis injurious to cress, by Mr. G. O. 

 .Sherrard ; the horse bot-tly, by Mr. Collinge ; and the 

 larch saw-fly, by Mr. Mangan. Dr. Maiden dealt with 

 the diseases of bees, and Mr. \V. G. Freeman with the 

 economic importance of the cambium in plants. 



The members Of the association attended the formal 

 opening of the Biological Experimental Laboratories at 

 Fallowfield, when Sir Thomas Elliot, of the Board of 

 .'\griculture, spoke of the harmonious relations now in 

 existence between practice and science, and the w^elcome 

 degree to which the agriculturist is prepared to appreciate 

 the aid of the man of science in attempting to solve difficul- 

 ties. The new .Manchester laboratories owe their origin to 

 such calls for aid, and .Sir Thomas indicated that the 

 Board of .Agriculture would be prepared to assist financially, 

 so far as it could, the local efforts in providing the means 

 for research in economic biologv. W. G. F. 



THE FIRST INTERNATIONAL AGRO- 

 GEOLOGICAL conference:- 



CTO.ME time ago the Royal Hungarian Geological 

 '-^ Institute sent out letters of invitation lo those 

 interested in soils in the various countries of Europe and 

 America asking them to attend an International Conference 

 in Budapest, where some attempt would be made at 

 standardising methods and objects. Some degree of 

 uniformity is urgently needed. " Plus que partout aiileurs," 

 says the secretary in his introduction to the present 

 volume, " il y rfegne une disparity d'id^es, de m^thodes, 

 de proc^d^s, une divergence de vue sur le chemin k prendre 

 et sur le but a atteindre, un chaos dans I'usage des termes 

 scientifiques, des mesures, des figur<5s, des noms et des 

 classifications : divergence qui se manifeste non seulement 

 de pays i pays, de langue a langue, mais aussi entre les 

 ceuvres d'un meme pays et dans la litt^rature d'une meme 

 langue." Some confusion is for a time inevitable in a 

 borderland subject like the present, that joins up with 

 geology, botany, and chemistry, and is closely connected 

 with agriculture ; indeed, even its very name has not yet 

 been settled, for we find the subject of the conference re- 

 ferred to as agrogeology, agricultural geology, pedology, or 

 simply " the science of the soil." 



The results of the conference are now issued in the 

 volume before us. Several of the papers are descriptive of 

 the soils of the countries in which the respective writers 

 are working, among them being accounts of the soils of 

 European and .Asiatic Russia, of Norway, of Rumania, and 

 Bohemia. .As an illustration of the method adopted, Prof. 

 Glinka's account of the Russian soils may be noted. There 

 are six main zones recognisable, running in belts from 

 north-west to south-east, and corresponding fairly com- 

 pletely with the climatic and vegetation zones. The most 

 northerly is the Tundra zone, practically destitute of vegeta- 

 iSon higher than lichens and mosses. The soils have been 

 but little investigated, but appear to be generally acid and 

 rich in partially decomposed oiganic matter. South of this 

 lies the Podzol zone, covered with forest, or in lower lying 

 places with marshes and lakes. The typical podzols may 

 be sands, loams, or clays ;»they are white when dry, acid, 

 generally poor in mineral plant food, but contain a fair 

 amount of organic matter, and they are porous. There is 



1 "Comptes rendus de la premiere Confe'-ence Internationale agrogtSo- 

 logique." Public par I'lnstitut ge'ologique du Royaume de Hongrie. (1909.) 



NO. 2127, VOL. 84] 



either a pan or else a good deal of concretionary matter in 

 the subsoil, the former being usual in the sands, the latter 

 in the loams, and clays. This zone covers an enormous 

 area in Russia and Siberia ; it is not much cultivated, the 

 method adopted usually being to clear a part of the forest, 

 crop for a few years, then leave to run wild again, and 

 move on to some freshly cleared ground ; to the south, 

 however, the agriculture is much more advanced. Through- 

 out this zone the low-lying soils differ somewhat in type 

 by reason of the accumulation of humus and the presence 

 of reduction products such as pyrites, marcasite, and 

 others ; they are more like moorland soils. 



The next zone is the famous black earth or Tschernosiom 

 zone, but in between the two is a transition zone occupy- 

 ing the region of the prehistoric steppes now in forest, 

 so that the original steppe soil has become modified. The 

 calcium carbonate originally present may still be found 

 lower down in the soil, and there is also more food material 

 than in the soils further north ; still, in the main, these 

 soils are of the podzol type. The black earth proper 

 stretches from the Carpathian to the Ural mountains, and 

 thence across to Siberia ; it covers Volhynia in the west 

 and Perm in the east. It is characteriseti by a dark grey 

 or black layer rich in humus and granular in structure, 

 overlying a subsoil rich in calcium carbonate ; this subsoil 

 may originate either from loess, drift clay, or marine 

 deposits. There are no forests, except in the north, as 

 already mentioned, the whole region being steppe country 

 now largely in cultivation producing cereals. Several other 

 tvpes of soil scattered as islands over the zone are described 

 in the paper, but need not concern us here. 



Southwards come the chestnut-coloured soils of laminate, 

 and not granular, structure, where the black humus layer 

 is thinner or absent, although calcium carbonate is found 

 in quantity, as in the soil underlying the black earth. We 

 are now approaching the dry steppes, a pastoral region 

 inhabited by a nomad population. .Alkali soils are not 

 uncommon in this and the lower zones. 



Below this come two others in the semi-desert region, 

 where the rainfall is 8 to 12 inches per annum only, the 

 northern layer being brown and the southern grey or white. 

 Thev have not been much studied as yet. 



We have dwelt at some length on this paper because 

 it illustrates the difficulties in the way of introducing any 

 uniform international system of soil classification. Any 

 attempt to arrange British soils in zones in this way would 

 fail : indeed, in one paper where a very broad system was 

 used, all British soils were classed as of one type. After 

 looking through the descriptions of the soils of the other 

 countries we feel bound to agree with Prof. Hilgard that 

 each region should adopt its own classification. Distinc- 

 tions of colour, he points out, are not of sufficient general 

 significance to form a basis of uniform soil classification, 

 yet in a particular region they may be of vital importance, 

 and would form the only basis useful in practice. Ramann 

 has drawn up a scheme of classification, so also has 

 Sibirtzeff, both admirable so far as they go, yet neither 

 will fit the soils of California. Indeed, the various authors 

 at the conference were looking at the subject from at least 

 two different points of view : some were considering the 

 zones of continental areas, others confined themselves to 

 the soils of small regions. Climate reacts on soil to a 

 marked extent. The soils of arid and of humid regions 

 differ fundamentallv, as Hilgard has shown. To take an 

 illustration from 'Prof. Glinka's paper, the difference 

 between the black earth and the chocolate-coloured or grey 

 soils further south may arise entirely from climatic causes. 

 Over continental areas, therefore, climatic zones will 

 furnish a useful method of grouping soils in the first 

 instance ; but it is not complete, for marked variations 

 occur among the soils in the same zone, necessitating a 

 more detailed classification which would take account of 

 the presence or absence of calcium carbonate, and the 

 " lightness " or " heaviness " of the soil on cultivation. 

 Probably several systems of classification would be found 

 necessary to fit the various climatic regions. _ If the con- 

 ference failed to come to anv agreement on this subject, it 

 at any rate did much useful work in bringing out the 

 inherent difficulties. 



Another matter was dealt with which ought to be cap- 

 able of arrangement. .At present no two countries adopt 



