402 



THE AGRICULTURAL NEWS. 



December 23, 1911 



is taking place; thus the leaves contain propoitionately 

 more ash than the branches, and the latter more ash 

 than the trunk. 



Liebig stated further that it is not likely that 

 a plant, under normal conditions, produces a much 

 greater quantity of any given acid than it reijuires for 

 its existence: it is also to be expected that the amount 

 of alkaline base in a plant wilt always remain the same, 

 no matter in what kind of soil it i.s growing. It was 

 explained by Liebig that any deficiency in regurd to 

 one base would be supplied by the substitution of an 

 equivalentamouiit of another base. It results from this 

 circumstance that, as the weights of the bases vary, the 

 absolute weight of the ash must differ according to the 

 kind of substitution in the compounds which it contains 

 Another conclusion reached by Liebig. which is perti- 

 nent to the matter under discussion, was that, even 

 where plants have been grown in soils containing very 

 different proportions of lime, magnesia and potash, the 

 equivalent amount of these bases, expressed in terms 

 ot oxygen, is the same, within reasonable limits, for 

 similar quantities of wood and of the ash. 



The results of the work of Liebig and others were 

 expressed more clearly by Champion and Pellet, f and 

 their statements virtually corresponded with what has 

 just been put forward. In legard to the interchange- 

 ability of the bases, the author of the paper mentioned 

 at the head of this article agrees that this exists, but 

 draws attention to the presence of limits to the extent 

 to which any one base may be excluded by the substi- 

 tution of one or more that are different. When this 

 critical point is passed, the plant ceases to develop favour- 

 ably; this fact is supported by the work and opinions of 

 Loew in Japan, Bernardini, and May at Washington. 

 Ciaassen has also reached the same conclusion, as the 

 result of investigations with sugar beets, and Pellet has 

 shown that the heart rot of the beet is most ])revalent 

 in soils possessing an undue proportion of potash and 

 a deficiency of magnesia. Further Marchal, of 

 Gembloux, has provi^d that the formation ot nodules 

 on the roots of leguminous plants receives interference 

 from an excess of potash in the soil, and that the 

 development of the ])!ants themselves is adversely alTec 

 ted; so that the ultimate effects are lessened yields, with 

 the minimum fixation of atmospheric nitrogen. Lastly, 

 other investigators have made the observation, in the 

 case of certain plants, that an excess of potash produces 

 decay; and that if some of the potash is replaced by 



+ See r'oHipfe.s liouJus de VAcaddmle ■ I e.i Sciences de Paris, 

 1874, 1876, 1876. 



other bases, as for example magnesia, the plants can 

 be made to revive and resume normal growth. 



Sufficiefi^i tia's been said to indicate that much 

 harm is likely to arise through the absoiption of an 

 undue proportion of potash by plants. The condition 

 may bring ab.5ut large changes in the nature of the 

 crops; and it certainly causes a diminution in the 

 power of planfjS to assimilate nitrogen, so that from 

 a practical point of view a waste takes place of this 

 impoitant and comparatively expensive item of plant 

 food. From the point of view of economy the matter 

 is affected in another way. Next to nitrogen, potash 

 is the most costly element that has to be supplied 

 to plants; thus its supply in excess leads to waste on 

 this account alone. There is the further consideration 

 that the fact of the presence of an undue amount of 

 potiish causes the assimilation of other bases to be defi- 

 cient, and the plant is accordingly deprived of the 

 means by which the important and useful anatomical 

 and physiologicixl changes that are dependent on them 

 may be brought about. 



The conclusions reached in the article under review 

 are that, firstly, since lime, soda and magnesia cost 

 nine-tenths less than potash, practical field experi- 

 ments should be made in order to determine how far 

 these bases may be substituted for potash: secondly 

 that there should be ascertained the best proportions 

 of lime, magnesia and phosphate of lime, for the devel- 

 opment of legumes and all other plants, as well as the 

 extent to which, when these proportions are assured, 

 nitrogen should be added to the soil; thirdly, tor differ- 

 ent soils, the effects on the soil of potash, and of lime 

 and magnesia, should be investigated. 



It is evident that the proper carrying out of such 

 work should do much toward the devising of methods 

 of nianurial treatment that will contribute to the 

 realization of maximum returns with minimum 

 expenditure. 



In tlie Agricultwal News for October 28, lit 11, it was 

 stated that information had been received from the Secretary 

 of State for the Colonies to the effect that arrangements had 

 been made by His Majesty ;s Stationery Office with Mr. T. 

 Fisher Unwin, of Adelphi Terrace, London, W.C., under 

 wbicii Mr. Unwin would act as sole whole.sale agent for the 

 sale of British Official rul)lications ouUside the I'nited Kiag- 

 dom, with depots in certain cities that are mentioned. 



This Depaatment h.as .since been infornieif liy the Secre- 

 tary of State that it i.s not at present found possible to give 

 effect to the. arrangement; and that the nature of any future ■ 

 developments will l)p conuuunicaled. 



