Scientific Agriculture. 



146 



[August, 1911. 



The grain and particularly the straw 

 of the wheat grown after vetches and 

 crimson clover are much richer in 

 nitrogen than the corresponding grain 

 and straw following the non-leguminous 

 crops, pointing to a greater amount of 

 nitrogen in the soil available for the 

 former crops. 



Speaking generally, the results are 

 what might have been expected from 

 the known power of the leguminous 

 crops to gather nitrogen from the 

 atmosphere, but until the experiments 

 have been repeated for a somewhat 

 longer period of time it will be impossi- 

 ble to determine with any accuracy 

 whether there has been any accumulation 

 of nitrogen in the soil of the plots grow- 

 ing mustard and rape, though these 

 crops are themselves incapable of 

 fixing any nitrogen. One might expect 

 that the soil bacteria, particularly the 

 Azotobacter, would increase the nitrogen 

 compounds of the soil when supplied 

 with the carbonaceous matter which the 

 green plant has drawn from the atmo- 

 sphere. The Azotobacter organism which 

 is present in Rothamsted as in most 

 cultivated soils, is capable of effecting 

 considerable fixation of nitrogen ; but 

 in order to do this it must be supplied 

 with organic matter, by the oxidation of 

 which it derives the energy necessary to 

 bring the nitrogen into combination. 

 Although it has been possible in the 

 laboratory to raise the proportion of 

 nitrogen in the soil by merely adding 

 organic matter containing nitrogen, 

 and thus giving the Azotobacter material 

 to work upon, the evidence that this 

 process goes on in the field is still very 

 scanty. Samples of soil, however, taken 

 from this Rothamsted field at the 

 beginning of the experiment have been 

 preserved, and further analyses after 

 a few more green crops have been 

 ploughed in may be expected to throw 

 more light upon this question. 



If the Rothamsted results, that 

 vetches and crimson clover form good 

 preparations for wheat because of the 

 nitrogen they accumulate, are only in 

 accord with what might have been 

 expected, there still remains the entirely 

 contradictory result at Woburn to 

 explain. Dr. Voelcker has indicated that 

 at Woburn the question is probably one 

 of water supply ; though the vetch crop 

 does contain about twice as much 

 nitrogen as the mustard which is turned 

 in, it seems to leave the land in a drier 

 and more open condition, and this on the 

 light Woburn soil seems more to affect 

 the crop than the extra nitrogen. It 

 would, however, be unsafe to conclude 

 that either the amount of nitrogen 



brought in by the two crops, or the 

 effects upon the physical conditions of 

 water supply of the soil are the only 

 factors concerned. The process of decay 

 which the two materials have to go 

 through before the nitrogen they con- 

 tain can be available for the wheat crop 

 are veiy complex, and are likely to be 

 different in two such contrasting soils 

 as the cool, close Rothamsted land and 

 the drier and warmer Woburn soil, and 

 one is quite ignorant of the possible 

 influence of the intermediate products 

 upon the growing plant. It should be 

 remembered that the opinions of practi- 

 cal men as to whether vetches form a 

 good preparation for wheat are abso- 

 lutely contradictory in different parts 

 of the country. Some men have found 

 that vetches are always followed by a 

 good crop of wheat, while others hold 

 that the result is invariably poor. It 

 is interesting to find that this divergence 

 of opinion on the part of experienced 

 men is illustrated so distinctly by the 

 contradictory results at Rothamsted 

 and Woburn ; evidently here is material 

 for a study of the causes in operation to 

 bring about such different results both 

 experimentally and in farm practice. 

 From the practical point of view the 

 Rothamsted results would seem to show 

 that on strong land the farmer will do 

 better to sow vetches or crimson clover 

 for green manuring than one of the 

 non-leguminous crops. 



THE PRACTICE OP ECONOMY 

 ON ESTATES. 



(Prom the Agricultural News, Vol. X., 

 No. 231, March 4, 1911.) 



In the present days of serious competi- 

 tion and low prices, a full recognition 

 is being given to the importance of 

 effecting the major economies on 

 estates. The nature of these is well 

 recognized, and they have become part 

 of the natural routine in the work of 

 the estate. There are others, however, 

 whose existence is not obvious, which 

 are the outcome of careful thought and 

 consideration, in the light of what may 

 be termed more purely formal know- 

 ledge. The purpose of this article is to 

 indicate briefly the nature of some of 

 these economies. 



A larger proportion of the expendi- 

 ture of an estate than is commonly 

 recognized consists in the continual 

 replacement of small articles. Where 

 no inventory is made of such articles, 

 and where the lists, even if they exist, 

 are not checked every few months, 

 losses are occasioned through careless 



