1018 . THE COMPLETE GRAZIER. BOOK xt. 



supplies a small quantity of salt, more in the neighbourhood of the 

 sea than in inland districts, which, perhaps, accounts for the fact that 

 near the coast the application of salt rarely produces much effect. On 

 the whole, it is scarcely likely that the manurial action of salt is due to 

 its direct feeding value, but rather that its good efforts are secondary, 

 being due either to solvent and " physical " action on the soil, or to some 

 regulating influence in the direction of the checking of overgrowth. For 

 instance, the fact that a more healthy crop of wheat is often obtained by 

 top-dressing with a mixture of nitrate of soda and salt than where nitrate 

 only is used has been attributed by some to the influence of the salt 

 in tending to retard or check growth, so that the plant does not grow 

 too suddenly or too rankly when fed with the nitrate. 



The crops for which salt has been found most beneficial are mangel 

 and cabbage, and in numerous experiments it has greatly increased the 

 yield of mangel at a trifling expense. Salt is also largely used as a 

 preventive to attacks of wire-worm. Some growers of potatoes, on land 

 subject to wire-worm, sow about 3 cwt. per acre of salt in the drills. 

 Next to these purposes, its chief manurial utility is for grain crops, 

 mixed, as just mentioned, with nitrate of soda. 



On some soils the use of a very moderate quantity of salt " pans " 

 the land, which, of course, is disadvantageous. But this very fact 

 shows that salt, either by attracting moisture, or by some other 

 property, influences the physical condition of the soil to an extent that 

 may readily be understood to affect crops for good or ill, quite apart 

 from any possible action of feeding them, or of preparing food for them. 



GYPSUM, OR SULPHATE OF LIME. This is a manure which is useful, 

 as a rule, only on soils poor in lime, and for most purposes it is better 

 to apply lime itself than gypsum. Sulphate of lime is a constituent of 

 superphosphate and dissolved bones, and is therefore applied to the 

 land whenever these manures are used. The crops on which gypsum 

 tells more readily than on others are the leguminous crops, such as 

 clover, beans, and peas. 



CHAPTER III. 



ON THE GENERAL APPLICATION OF ARTIFICIAL MANURES. 



AS a rule, soluble and rapidly acting manures are best applied in the 

 spring, and slowly acting ones like bones, fish-guano, shoddy, 

 rape-dust, &c., in the autumn. Nitrate of soda should never be 

 applied till it is actually required by the plant, as it is not held by the 



