158 Experiments upon Sivedes. 



The surface soil is brashy, thin and poor ; when separated 

 from the limestones which render it apparently lighter, it con- 

 stitutes a stiffish clay-marl, which in wet weather is very tenacious 

 and heavy, and in warm weather dries into hard masses which 

 do not readily fall into powder. The subsoil is a stiff tenacious 

 clay ; the field has been well drained. 



Like most soils in the neighbourhood of Cirencester, it con- 

 tains a considerable quantity of lime. It was also richer in 

 organic matter than most arable soils on our farm. It will be 

 seen likewise, by inspecting the following analysis of this soil, 

 that it contained a good deal of soluble silica and much clay, since 

 the insoluble silicious matters consist almost entirely of clay. 



Composition of Soil of Experimental Field, No. 22, on the Royal Agricultural 

 College Farm, Cirencester. 



Moisture, when analysed 4*72 



Organic matter and water of combination .. .. ll^OS 



Oxides of iron 9'98 



Alumina 6'06 



Carbonate of lime 12"10 



Sulphate of lime '75 



Alkalies and magnesia (determined by loss) .. 1'43 



Soluble silica (soluble in dilute caustic potash) .. 17-93 



Insoluble siliceous matters (chiefly clay) .. .. 36 '00 



100-00 



The experimental field was carefully measured out, and after 

 rejecting the headlands, divided into 12 parts of -^Qth. of an acre 

 each. These plots were arranged side by side in continuous 

 rows of 4 rows each. The different manuring matters were sown 

 by hand, and the seed drilled in on the 21st of June. Two of 

 the experimental plots were left unmanured for the purpose of 

 ascertaining the natural produce of the land, and also whether it 

 was uniform or not. The produce of both unmanured plots suf- 

 ficiently proved the equal agricultural capability of the experi- 

 mental field. Although it was my principal object to ascertain 

 whether or not ammonia could be dispensed with for turnips on 

 this field, and which other manuring constituents produced the 

 most marked effect on this crop, I was anxious to ascertain how 

 far the natural produce could be raised by a good dressing of 

 well-rotten farmyard manure, and therefore applied to one plot 

 farmyard manure at the late of 15 tons per acre. 



In all field experiments, at least one, or better two plots, should 

 be left unmanured ; if possible one plot also should receive a 

 good dressing of farmyard manure. By doing this an insight 

 into the natural condition and agricultural capabilities of the soil 

 may be obtained ; and the results of trials with special manures 

 will be interpreted in a more satisfactory manner than is the case 



