191 1.] Value of Different Crops as Green Manures. 971 



to see if the results obtained on the light dry land at Woburn 

 would hold for the heavier and cooler soil that prevails at 

 Rothamsted. 



At the time the experiments were begun in 1904, this field 

 was in a very poor condition, and more than usually short of 

 organic matter, because it had been farmed for several years 

 without any farmyard manure. No fertilisers were applied, 

 but during 1904, 1905, and 1906, on the four plots rape, 

 crimson clover, vetches, and mustard were sown, and turned 

 in at the end of the summer. The treatment was repeated, 

 because the land was in such poor condition that none of the 

 crops were large, the vetches and mustard growing better than 

 either the crimson clover or the rape. A crop of wheat was 

 taken in 1907, after which, in 1908 and 1909, the green crops 

 were repeated, a second crop of wheat being taken in 19 10. 

 The following table gives the results for the two crops of 

 wheat. 



Table I. — Yield of Wheat per acre after Green Manuring. 

 Little Hoos Field, Rothamsted. 



Previous Green Crop. 



Dressed 

 Grain. 

 Bushels 



Dressed 

 Grain 

 Lb. 



Offal 

 Grain. 

 Lb. 



Total 

 Grain. 

 Lb. 



Straw. 

 Cvvt. 



I907. 



After mustard 



29-9 



1923 



96 



2019 



22*5 



I907. 



rape 



21 3 



1376 



75 



I45 I 



29*6 



I907. 



,, crimson clover 



32-5 



2096 



294 



2390 



36-1 



I907. 



vetches ... 



397 



2542 



2IO 



2752 



39*4 



I9IO. 

 I9IO. 

 I9IO. 

 I91O. 



After mustard ... 

 rape ... 

 crimson clover 

 ,, vetches 



196 

 20 -8 

 308 

 34'4 



1247 

 1327 

 1926 



2144 



34 

 37 

 85 

 127 



I28l 

 i ;,64 

 201 1 

 2271 



15-3 

 i6'3 

 27*0 

 347 



From these figures it will be clear, as, indeed, it was to the 

 eye, that the superiority of the wheat after the leguminous 

 crops of crimson clover and particularly of vetches, is beyond 

 any possible limit of experimental error. During the last 

 year the value of the previous growth of vetches was par- 

 ticularly manifest, as the wheat on this plot possessed a fine 

 colour, very free from blight, and yielded more than any of 

 the manured wheat plots on the experimental ground. A 

 plot in the same field, where the wheat had been manured 

 with cake-fed dung after the preceding crop of barley, only 



3 Z 2 



