1905.] Manurial Requirements of Swedes. 159 



average increase per acre in each year, are shown in the follow- 

 ing table. The experiments were carried out on thirteen farms 

 in 1904, and on twenty-six farms in 1903 : — 



No. of 

 Plot. 



Amount 



Sulphate 

 of 



Ammonia. 



of Manure 



Super- 

 phosphate. 



per acre. 



Sulphate 



of 

 Potash. 



Cost per 

 acre. 



Average 

 per 



increase 

 acre. 













1903. 



1904. 





lb. 



lb. 



lb. 



s. d. 



Tons. 



Tons. 



I and 5 















(no manure) 















2. 



51 



250 



40 



16 9 



2 -9 



4-2 



3- 



102 



500 



80 



33 6 



4-8 



6-5 



4- 



204 



1,000 



160 



67 0 



7-1 



9-8 



6. 





500 



80 



22 0 



4-0 



s '°s 



7; 



102 





80 



18 6 



1-9 





8. 



I02 



500 





26 6 



5-2 



4'4 



The results obtained in both years show that on the majority 

 of soils it is not possible to obtain remunerative yields of swedes 

 without the addition of phosphatic manures. There are, how- 

 ever, soils here and there in chalk districts which do not respond 

 very much to phosphatic manures. In these experiments the 

 omission of potash diminished the yield of roots in four cases 

 only. This was found to be the case more especially on the 

 stiffish red soils with flints overlying the upper chalk. The 

 average yield of the unmanured plots was 13J tons per acre. 



One of the most striking visible results was the influence which 

 the amount of manure had on the regularity of the crop. Where 

 the plots were unmanured there were large numbers of gaps in the 

 rows, whereas missed plants were rare on the heavily-manured 

 areas. There is no doubt that the presence of easily available 

 manure close to the germinating seed or young plant assists the 

 plant to become established. Moreover, the plants on the un- 

 manured plots were invariably very much more attacked by 

 gall-weevil than those on the manured plots. 



Experiments on the manuring of swedes and turnips were 

 also conducted by the Armstrong College at six centres in the 

 county of Durham. Here also phosphates were found generally 

 to be of the greatest importance, though on certain soils nitro- 



