Use of Artificial Manures. 



445 



per acre, than to apply n cwt. per acre to 10 acres, and J cwt 

 to the other ten. Or the case may be stated thus : if I cwt. of 

 nitrate of soda applied to an acre can increase the oat crop by 

 5 bushels, 2 cwt. per acre will produce less than io bushels. 



After artificial manure has been applied, it should, if the state 

 of the crop admits of it, be chain-harrowed. If the manure is a 

 soluble one, this operation must be done at once, or much of it 

 may have gone down into the soil, where, of course, it is beyond 

 the reach of further mechanical distribution, but in the case of 

 an insoluble substance, like basic slag, there is not the same need 

 for haste. 



Where possible, manure should be thoroughly incorporated 

 with the soil. This is of greatest importance in the case of 

 insoluble manures, and of those, notably dung, which act to a 

 large extent through the improvement that they effect in the 

 physical condition of the soil. Manifestly there may be no choice 

 but to spread the manure on the surface of the ground and to 

 leave it there, but where it is possible to work it in this should be 

 done. For instance, where artificials are being applied to a corn 

 crop at the time of sowing, they should be put in with the seed 

 so that they may get the benefit of the subsequent harrowing. 



Finally, a word of caution may be given as regards the mixing 

 of artificials. Probably it is now universally known that sulphate 

 of ammonia must not be mixed with any manure holding free 

 lime, notably basrc~s1a"g and precipitated phosphate. The im- 

 mediate result of making such a mixture is the liberation of 

 free ammonia, whose presence in the air can at once be detected 

 by its pungent odour. If it is desired to apply sulphate of 

 ammonia with one of these substances to any particular area 

 of ground, the phosphate should be put on a month or more 

 before the other substance. Sulphate of ammonia may, however, 

 be mixed with the other ordinary manures, such as super- 

 phosphate, dissolved bones, bone meal, kainit, sulphate and 

 muriate of potash, and nitrate of soda. Nitrate of soda should 

 not be mixed with superphosphate, dissolved bones, or dis- 

 solved guano. Not only does such a mixture result in the loss 

 of more or less nitrogen, but the mass is apt to become sticky 

 and difficult to sow, Superphosphate and dissolved bones 

 should not be mixed with basic slag or precipitated phosphate, 



