On Subsoil' Ploughing. 



27 



whole difficulty vanishes. One was made in a stiff marly clay, 

 on the new red sandstone formation ; the other on that most tena- 

 cious of soils, the lias clay ; the one was permanently improved ; 

 the other ran together again almost as soon as done. 



It would be but waste of time to give any additional proof of 

 what has already been fully established, viz. — that on some soils 

 the subsoil-plough has been eminently useful ; that on others it 

 has signally failed. The grand desideratum, at present, is the 

 discovery of some test which shall enable us, on the examination 

 of any given soil, to pronounce tolerably confidently that it would 

 be advisable or useless to subsoil it. I feel fully persuaded that 

 the per centage of alumina, or pure clay, in any soil furnishes 

 the required criterion. In the two instances quoted above I pro- 

 cured an analysis of the soils, and found that, in the one on which 

 subsoiling was of no use, the proportion of alumina was twice as 

 great as in the other : this most unexpected result first suggested 

 the rule above stated ; and in all the cases which I have since 

 had an opportunity of examining it has been fully confirmed. 

 A rule of this kind can only be established by numerous experi- 

 ments on various soils ; but if those gentlemen who are anxious 

 to promote agricultural improvement would kindly forward to the 

 Secretary of the Yorkshire Agricultural Society the result of 

 their own experiments with the subsoil-plough, accompanied by 

 either an analysis of the subsoil on which it was tried, or even a 

 specimen of the subsoil for analysis, the question of subsoil- 

 ploughing would very soon be set at rest ; and it would be as 

 easy to point out the soils which would be benefited by it as it is 

 now to distinguish turnip and barley soils from those adapted for 

 wheat and beans. I am aware that chemical analysis has hitherto 

 been unattainable without so much trouble and expense as to put 

 it out of the reach of most practical farmers ; but I am happy to 

 be able to state that Mr. Spence, chemist and druggist. Pave- 

 ment, York, whose chemical attainments are beyond dispute, has 

 kindly offered to furnish an analysis of any soil sent him, on very 

 moderate terms. A list of charges, for a partial or complete 

 analysis, will be found at the end of this article. 



I will now state the steps taken to test the truth of the rule 

 above mentioned ; viz.— that the per centage of alumina ought to 

 guide us in the selection of soils for subsoiling. I wrote to several 

 gentlemen whom I knew to have used the subsoil-plough, and on 

 whose accuracy I could rely, and begged that they would furnish 

 me with some account of their experiments, and send me a speci- 

 men of the subsoil for analysis. I have, wherever practicable, 

 given the account in the words of the writer ; and can only regret 

 that the shortness of the time has prevented my collecting more 

 evidence on the subject. The following Essay was sent me by 



