A VISIT T(J liOTHAMSTKl). 257 



Oil the two plots which have heeu treated in that way at 

 Kuthamsted it lias ])een found tliat the jinxhicc ]k-v acre is jvist 

 tlie same as that yielded by the unniaiiured land whieh has been 

 constantly under wheat for thirty-six years, Tliere is, of course, 

 this difference between the two, that whereas in the unnianured 

 acre the whole is under a crop, and that a poor one, in the Lois- 

 Weedon acre the half only is under a crop, ami it is a ^^ood one. 

 In order to estimate the success of the Lois-Weedon method as 

 a means of maintaining the fertility of the soil without the a] ipli- 

 cation of manure, it would be necessary to ])ut the wliole acre 

 under a crop for some time, and compare the procUicc with that 

 of the continuously-cropped unmanurcd plot. 



Other experiments with manured land under bare faUowhaveled 

 the ex]K'rimcnters to the conclusion tliat it is a wasteful ])rocess, 

 and tliat any crop whicli will cover the ground is better than none, 

 and that chietly on account of the power which vegetation has of 

 preventing the rapid loss of nitrogen which occurs on a bare fallow. 



A long series of experiments has also been made with legu- 

 minous crops ; but, owing to accidents of weather and other 

 causes wdiich have not yet been explained, it has not l)een found 

 possible to grow leguminous crops continuously. The land lie- 

 comes " clover sick," and no manurial treatment which has been 

 applied at liothamsted seems to have been of any avail in pre- 

 venting that peculiar condition of soil whicli render it unsuited 

 to the growth of clover or other leguminous crops. The applica- 

 tion of potash salts was the most successful, and it succeeded 

 best when put in at considerable depths ; but, no matter what 

 manure was applied, a permanent crop was never secured. The 

 plants seemed to be peculiarly liable to disease, and usually died 

 off in the winter. It is an extraordinary thing, however, that 

 upon garden soil in the neighbourhood the clover plant thrives 

 year after year, and has been grown continuously for many 

 years. Highly nitrogenous nuinures, as noticed in the grass 

 experiments, have an injurious effect, and yet it is known that 

 leguminous crops contain a large amount of nitrogen. 



Another extraordinary result has been obtained on land which 

 has been cropped with wheat and beans alternately. It is natural 

 to suppose that after a crop of beans, which contain a very large 

 })roportion of nitrogen in their composition, the land would be 

 somewhat exhausted of nitrogen, and incapable of yielding a 

 full crop of wheat ; but, so far from that being the case, it was 

 found in the experiment wdth alternate wdieat and beans that 

 eight crops of wheat thus grown produced nearly as much wheat 

 and took from the soil nearly as much nitrogen as sixteen crops 

 of wheat which were grown consecutively in a neighbouring field. 

 It is evident from the results of the experiments with leguminous 

 crops at Eothamsted that we have very much to learn regarding 



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