18 DEPOSITS OF PHOSPHATE OF LIME. [bull.4( 
gave a quick though temporary stimulus to the soil, eDablingthe farme 
to obtaiu the greater part of the return for his investment iu the seaso 
following the application of the high priced manure. Very general! 
the fertilizer, guano or compounded material, was applied with th 
seed or dibbled in the soil alongside the young plant, so that it wool 
be immediately available in the first stages of its growth, and, what is 
more important consideration, that it might take less of the substauc 
to give the effect than if it were sown broadcast over the surface o 
mingled with the soil of the whole field. 
In this way a habit has been established in the art of using phos 
phates, as well as in the composition of the material, which, like all con 
mercial habits, is hard to overcome. The question to be determined i 
as to the utility of phosphates with other modes of treatment than thos 
which are applied to the imitation guanos. At present this treatmeu 
requires the commingling of the lime phosphate with a number of costl 
substances. The manufacture can only be advantageously carried o 
at points remote from the districts where the materials are produce 
and remote from the fields where they are used, so that the costs ( 
transportation are great. The problems to be solved by the agriculture 
stations are as follows : 
(1) As to the effect, immediate as well as permanent, arising from th 
application of ground phosphatic rock commingled with other materia} 
on soils used for the production of different crops. 
(2) As to the degree of comminution of the material which is moi 
advantageous. It seems possible that fine pulverizing may take th 
place in a measure of superphosphatizing. 
(3) As to the effect of mingling the powdered rock with ordinal 
barn yard manure, peat, and other similar substances. 
(4) As to the effect of lime phosphate used alone on soils containin 
different mineral constituents, as, for instance, those having consider; 
ble propoitions of lime carbonate and those having but little of tin 
substance. 
(5) As to the proportion of the lime phosphate which it is necessai 
to apply in order to produce different degrees of effect upon the fertilil 
of soils. 
It is desirable that these and other experiments should be tried at 
number of stations in different parts of the country, in order that tl 
needs of various crops may be considered and the effect of the fertili 
ers on different classes of soils ascertained. 
The effeei of a small amount of lime phosphate on the fertility of tl 
soil is clearly great, but so far we do not know with accuracy tl 
amount necessary to produce a given effect. The range in phosphor 
acid contents in the soils of Kentucky, as determined from many hundrt i 
analyses, varies from 0.510 to 0.00 1. 1 In most cases the fitness of tl 
'See report of Dr. Robert Peter iu Repts. Geol. Survey Kentucky, new series, v< 
5, 1878, N. S. Shaler, Director: 
(492) 
