234 



On Superphosphate of Lime. 



have undergone the modifications which mixture with the soii 

 will produce. 



The bearing of this subject on the drilling of manures is 

 evident; this mode of application almost presupposes the power 

 of the plant to feed upon the unaltered ingredients of manure ; 

 and although undoubtedly these substances do come into contact 

 with a certain quantity of the soil, it seems to me well worth 

 consideration whether, by carrying out the plan of drilling 

 manures in its fullest sense, we may not be overlooking the fact 

 that we thereby limit the roots of the plant to an area of " pastur- 

 age infinitely smaller than they might advantageously enjoy, 

 and whether a more moderate use of this method and a partial 

 return to the system which should make the Vv^hole soil participate 

 in the benefits of manure is not more consonant both with prac- 

 tical information and scientific truth. 



With regard to superphosphate of lime it may be said, that of 

 all manures it is that which is most wanted near the plant, as its 

 office is mainly to influence the early growth when the area of 

 the roots is small and the distance to which they extend very 

 circumscribed ; this is true, but it does appear that there is some- 

 thing in the turnip that particularly delights in phosphoric acid 

 and its compounds, and I cannot doubt that the same influence 

 which it feels so notably in its early stages will not be entirely 

 lost in its more mature condition, and that a ready supply of this 

 mineral will promote its healthy vegetation at every stage ; under 

 this impression I offer the two following suggestions for experi- 

 ments wdth superphosphate of lime. 



1st. To add the quantity of superphosphate of lime intended 

 for the turnip-crop — or a considerable portion of that 

 quantity — to the farm-yard manure also devoted to that 

 purpose. 



This might be done either by placing it in layers with the 

 manure some time previously, or by dissolving it in a small 

 quantity of water, or the liquid running from the dung, and 

 repeatedly pumping it back again. In this case, of course, no 

 waste of liquid must be allowed. 



2nd. To incorporate the phosphate of lime dissolved in water 

 %vith a considerable quantity of soil, so as to form a kind 

 of compost, which should be turned over once or twice, 

 and exposed to the action of water only to such an extent 

 as to favour the distribution of the soluble phosphate. 

 This compost would subsequently be drilled for turnips. 



I repeat that these are suggestions only for experiment on a 



