52 RATIONAL FRUIT CULTURE. 



supplies have hitherto come from Germany, potash is now very 

 expensive. Fortunately, there is a large amount in wood 

 ashes, so all hedge chippings, prunings, and other garden 

 refuse that will not readily decay should be carefully collected 

 and burned, and the ashes distributed over the ground where 

 potash is most wanted. 



ARTIFICIALS THAT SHOULD .\OT BE MIXED. 

 In connection with the use of artificial fertilisers, there 

 is one point which should be mentioned. Certain of them 

 should not be mixed with certain others. The combinations 

 to be avoided are — basic slag and sulphate of ammonia, basic 

 slag and superphosphate, superphosphate and nitrate of soda. 

 It is not likely that basic slag would be mixed with sulphate 

 of ammonia, because the former ought to be applied in autumn 

 or winter, and the latter in spring or early summer; but if 

 they are, they will react chemically on one another, with the 

 result that the valuable nitrogen will escape into the air in 

 the form of uiiimoniacal gas. If basic slag is mixed with 

 superphosphate, the soluble phosphate in (he latter is converted 

 into an insoluble form, and is rendered useless as a plant-food. 

 It is still worse to mix superphosphate and nitrate of soda, 

 for the nitrogen not only escapes, but also does so as nitric-acid 

 gas, which is deadly to animal and vegetable life. 



LIMi: AS \ KERTILISINC; A(;i:\T. 



Reference has been made to lime as a disintegrating agent 

 for clay, and as a neutraliser of sour soil. Though not a ferti- 

 liser itself, it is a fertilising' agent, for il hastens the decom- 

 position of organic matter. It may, Iherefore, be used with 

 advantage on clay or heavy loam oeeasionally — say, once in 

 seven years — at the rale of fil'ty biisliels to the aere. If it 

 is used too often the land may be rendered sterile by being 

 completely cleared of its orf^'unie matter dp humus. Hence 

 .sandy soils are better withotil lima. 



