On the middle plots to which no manurial nitrogen is applied, 

 the yield on Plot 3 (bare fallowed before the wheat) was 9 tons against 

 1 1*8 tons on Plot 4, which carried clover two years before. Thus the 

 roots and stubble of the clover grown in 1906 had left behind 

 sufficient nitrogen gathered from the atmosphere to raise the wheat 

 crop in 1907 by 92*8 per cent., and the Swede crop in 1908 by 317 

 per cent. 



On the wholly unmanured plots 5 and 6. however, the yield of 

 turnips after clover was only 6 - 4 cwt. against 2 1 "6 cwt. on the bare 

 fallowed portion. The reason for this difference between the after 

 effect of clover on Plots 5 and 6, and on Plots 3 and 4, is probably to 

 be found in the fact that the clover of 1906 was followed by a bigger 

 wheat crop in 1907 ; 21 '4 bushels were obtained from Plot 6 as 

 against 1 6-3 bushels from Plot 5. This increased crop caused a 

 greater draught on the phosphoric acid and other minerals in the 

 soil, consequently as the phosphates form the limiting factor for the. 

 Swede crop in the absence of fertilisers of any kind, the yield from 

 Plot 5 is less than that of Plot 6 because of the greater removal of 

 phosphoric acid by the previous wheat crop. The clover crop grown 

 on Plot 6 in 1906 must also have removed phosphoric acid, and the 

 extra nitrogen it left behind annot compensate the Swede crop for 

 the phosphoric acid that is lacking. 



The Little Hoos Field, used for testing the effect of residues of 

 manures, was also in Swedes this year ; there was a regular plant and 

 satisfactory growth. Shoddy and Farmyard manure continue to 

 show large residues, perceptible up to the fourth year after their 

 application, but the superiority of cake-fed dung over dung made 

 from roots and hay only, very marked in the year of application, is 

 small in the succeeding years. 



In the Laboratory a beginning was made of an investigation of 

 the existence and nature of land " sickness," whether plants do not 

 unfit the soil for their continuous growth in some other way than by 

 depleting the plant food or infecting the soil with a specific disease. 

 Different plants have been started in soil, sand, and water respectively, 

 some are grown repeatedly in the same medium, in other cases a 

 rotation is followed. The great heat of June and July was not, how- 

 ever, very favourable for work in pots. A heating apparatus is being 

 put in the glasshouse to enable us to make an earlier beginning in the 

 year, so as to obviate the necessity of starting the second crop so late. 



As part of the same investigation, an examination was also begun 

 of 1 he changes taking place in soil when it is heated to the temperature 

 of boiling water or partially sterilised by treatment with volatile 

 antiseptics such as chloroform. Dr. Russell has been working on the 

 chemical and Dr. Hutchinson on the bacteriological side of the 

 problem ; the usual great increase of crop was seen, heating raised 



