6 



the supply of more potash was attended with no profit. The 

 case is one of far-reaching importance. I shall have illustra- 

 tions to give you presently, showing, on the one hand, the 

 very great effect produced by residues of manure on poor 

 land ; and, on the other, the absence of any effect when the 

 land is already in a condition to produce full crops. When 

 the illustrations are before us we shall have to consider the 

 bearing of these facts on the question of compensation. 



The behaviour of phosphatic manures furnishes us with 

 another class of illustrations. Bones are often a very 

 valuable manure on light and medium soils, but they are 

 almost without effect when applied to heavy land ; while basic 

 slag gives its best results on clay soils. Finely ground mineral 

 phosphates, if not crystalline in their structure, form effective 

 manures on soils containing little lime, while on calcareous 

 soils their value is very small. In this class of illustrations it 

 is not the poverty or richness of the soils in phosphates which 

 determines the result, but the varying power of the soils to 

 render phosphates soluble and available as plant food. The 

 special suitability of basic slag to clay soils is probably due to 

 the excess of lime which it contains. In the case of all the 

 phosphates mentioned their physical condition will also have 

 a considerable influence on their effectiveness ; thus half-inch 

 bone and bone-dust will disappear with very different rapidity 

 in the soil, and will require a different scale of compensation. 

 Facts such as I have just mentioned ought clearly to be 

 taken into account by a skilled referee when deciding what 

 compensation should be given for the use of phosphatic 

 manures. Manures which are unsuitable and ineffective must 

 always be treated as of little value to the incoming tenant. 



The influence of the physical condition of the soil on the 

 effectiveness of manures is far-reaching. All organic manures, 

 such as farmyard manure, sea- weed, green manures, and 

 shoddy, will be of much greater value when applied to a 

 moderately light, well aerated soil, than when applied to one 

 which is naturally consolidated and wet. The saying that on 

 heavy land tillage is of more importance than manure 

 expresses a great truth, which the professional valuer must 

 take into account as well as the farmer. 



