19-22.] 



( i ree \ Manuring. 



1 1 1 



experiment was then repeated on the same land. The results 

 were as follows : — 



Yield of WJieat after Green Manure*, RothanistetJ, Lit 1 1 Hobs Field 



{St if clayey loam); woo. iu / ; . 



After vetches, grown with mineral manures ... 39*7 34*4 



,, crimson clover ., „ ... 32*5 !0 S 



„ rape „ „ ... 21*3 20-8 



„ mustard „ „ ... 299 19'G 



For comparison : — 

 Wheat on Broadbalk Field, complete minerals 



only 11*5 10*0 



„ „ ,, ,, farmyard manure 



(14 tons per acre) ... 33*7 279 



Again there were no control plants on Little Hoos Field, 

 but the figures for Broadbalk Field afford a rough basis for 

 comparison. Apart from the obviously beneficial effect of 

 green manures on winter wheat, which is clearly brought out 

 by the above Woburn and Kothamsted results, it will be noticed 

 that the relative values of leguminous and non-leguminous 

 crops, such as vetches and mustard respectively, come out 

 very differently in the two sets of experiments. This is a 

 striking instance of the danger of applying the results obtained 

 in one district on a certain type of soil, to another with an 

 entirely different soil. This difference is further discussed later. 

 Both of the sets of experiments quoted above referred to 

 summer-grown green manures for winter wheat. Trials were 

 started by the writer at the Eoyal Horticultural Society's 

 gardens at Wisley in 1919 in which green crops were sown 

 in August for digging in late in the autumn or early the next 

 spring, as a preparation for white turnips. Some of the result- 

 for 1919-20 are shown below* : — 



Green Manuring Experiment at Wistefa W19-20. (Light sandy soil). 







Yield of Turnip Roots 







offer (iru ,i crop. 



< Tree /i crop. 



Tons per acre. _ j 



Tons per acre. Per cent, of control 



A. Green crop turned undU 



i in Spring. 



Plot. 



Crimson clover 





10-5 239 



Vetches 



86 



9*7 220 



Red clover ... 



3-9 



1»3 206 



Rye.* ... 



8-4 



8-6 • 195 



Rape 



93 



6-4 145 



Control 



2-2 (weeds) 



4-4 100 



//. Green crop turned undei 



• in . lutumn. 





Rye 



2-9 



6-3 162 



Oats 



3*6 



6*3 102 



Mustard 



5*6 



5*9 151 



Vetch 



4 3 



5*5 141 



Control 



o s (weeds) 



B-9 100 



* These results will shortly he published in full in the Journal of the Royal 

 Horticultural Society . 



