218 Muuariitij fur Haij 



if in the alternate year a light dressing of "artificials" including nitrate 

 of soda be given. 



2. A complete mixture of "artificials," including nitrate of soda, 

 has given good average crops, but not equal to those given by a biennial 

 application of dung. 



3. For the soil and otlier conditions of Garforth nitrate of soda 

 is distinctly better for the hay crop than sulphate of ammonia. Tliis 

 is doubtless largely associated with the poverty of the soil in calcium 

 carbonate. 



4. The different manurings have effected marked and characteristic 

 changes in the botanical composition of the herbage. In particular the 

 continued use of ammonium salts has led to serious deterioration. 



5. There are now differences also in the chemical composition 

 of the herbage, which probablv represent substantial differences in 

 feeding value. For equal weights, the hay grown with ilung appears 

 to have a lower feeding value than that grown with a good nii.xture 

 of "artificials." 



6. The composition of the ash of the hay does not reflect the 

 character of the manuring, except with regard to potash. 



7. Substantial changes in the power of the soil to sup])ly plant 

 food have taken place as a result of the manuring. The most marked 

 effect is the removal of carbonate of lime by the prolonged use of 

 ammonium salts. 



8. The effects — direct and indirect — of the manuring u])()n the 

 soil have led to marked differences in bacterial activity. In some 

 cases the reduction in biological activity is so great that dead grasses 

 accumulate and form a mat on the soil so thick that the penetration 

 of water to the lower layers is seriously impeded. 



9. In comparing the ammonia-producing powers of soils it is 

 desirable that estimations of ammonia ])roduced be made at relatively 

 shoit intervals, say every twelve hours, since the rale of production 

 in the earlier stages is a more characteristic index of the activity of 

 the soil than the total output after prolonged incubation. 



[Received April Wth. 1915.) 



