112 



Green Manuring 



[May, 



As an illustration of the value of lupins on light blowy sands 

 the results may be quoted of an experiment carried out in 

 Notts., for particulars of which the author is indebted to the 

 Agricultural Organiser of that countj^. Lupins were sown in 

 May, 1920, and turned under in September, and winter oats 

 >own. The land received no farmyard manure or artificials. 

 The oats after lupins yielded 7 J quarters per acre, while an 

 adjacent control plot on which no lupins had been turned in, 

 yielded only 1J- quarters per acre. This experiment is being 

 extended during the present season. 



Many more results of a similar character to those given above 

 could be quoted, but these suffice to demonstrate broadly the 

 very considerable increase in yield that can be obtained by green 

 manuring. As already pointed out, however, a comparison of 

 the Woburn and Eothamsted results serves to show that, as 

 soon as more detailed and precise information is sought with 

 regard to the best system of green manuring to adopt in any 

 particular district, difficulties and uncertainties are encountered. 

 In fact, if green manuring is to find a much more general 

 adoption in this country than at present, it will be necessnry 

 for careful experiments to be carried out in different districts 

 before the system best adapted to specified conditions of soil, 

 climate, etc., can be definitely laid down. In order to bring 

 out clearly the complexity of the problem, it is desirable to 

 consider at this point, as far as space and the present state of 

 our knowledge permits, the principles underlying the action of 

 green manures, particularly in comparison with farmyard 

 manure. 



(To be concluded.) 



