INCREASE OF CROPS BY USE OF FERTILIZERS 13 



such obvious results on the general appearance of the crop 

 to which the manure has been supplied as do similar appli- 

 cations of nitrogenous manures. The development of grain 

 and root, however, appears to be very intimately connected 

 with the supply of phosphorus. The proportion of grain to 

 straw is generally increased, and the period of ripening 

 shortened. The increased development of seedlings when 

 well supplied with phosphates is very marked. A very 

 striking instance of this result is the increased growth of the 

 young turnip plant after it has received an application of 

 phosphatic manure. As with nitrogen, a sufficient amount 

 of phosphorus is necessary for the complete development 

 of all crops. A very striking result of the application of 

 fertilizers containing phosphorus, is the extent to which 

 root formation is encouraged. As long ago as 1847 Lawes 

 wrote : u Whether or not- superphosphate of lime owes 

 much of its effect to its chemical actions in the soil, it is 

 certainly true that it causes a much enhanced development of 

 the underground collective apparatus of the plant, especially 

 of lateral and fibrous root, distributing a complete network 

 to a considerable distance round the plant, and throwing 

 innumerable mouths to the surface." 



The effect of another phosphatic manure, basic slag, on 

 old land hay, is as striking as the results on grain alluded to 

 by Lawes. At Cockle Park, in Northumberland, the Palace 

 Leas hay field very strikingly demonstrates the effect of 

 continued application of phosphatic manures on the fibrous 

 development of the roots of the grasses and other plants 

 growing in ordinary herbage. Where phosphates are absent 

 the tendency is to develop a thick mat of useless grass, which 

 appears to act as a thatch, keeping rain from penetrating 

 into the soil underneath, so that root development is very 

 feeble. On the other hand, where phosphates are used in 

 large quantities, the roots break up the soil, and convert a 

 very indifferent clay into a fair loam. These results follow 

 from the changed bacterial and fungoid decompositions of 

 organic matter in the soil which are induced by the kind of 

 fertilizers applied to the hay field. Where much acid manure 



