28 



On Subsoil-Ploughing. 



that very intelligent farmer, Mr. Black, land-agent to the Earl of 

 Zetland, at Marske, in Cleveland. 



" There is probably no agricultural operation that has been so 

 strongly recommended by some, and so much censured by others, 

 as subsoil-ploughing. Its advocates have represented it as the 

 great iianacea for all soils and situations ; and its introduction, 

 they say, will form a new epoch in agriculture. Believing that 

 neither party have viewed the subject properly in all its bearings, 

 I beg leave humbly to offer a few remarks, first, on the soil that 

 will receive the most permanent improvement from subsoil- 

 ploughing ; and, second, where it can be of no utility. The soil 

 that I believe will receive the most permanent improvement from 

 subsoil-ploughing is one in which silica predominates ; indeed all 

 shallow soils, of the lighter kinds, will be improved by it ; and 

 particularly so if there is any moorland pan, or indurated in- 

 crustations, formed by the weight of the plough going for a num- 

 ber of years at the same depth, or from other causes. If the 

 subsoil is of good quality, and a greater depth of furrow is 

 wished for, the subsoil-plough may be used with advantage ; the 

 percolation of water prepares the subsoil for amalgamation with 

 the surface. Strong clayey land cannot be permanently improved 

 by subsoil-ploughing. Alumina is a tenacious, compact^ adhesive 

 substance ; its parts are in minute divisions, and have great affinity 

 for each other. In September, 1838, I subsoiled two fields of 

 10 acres each, which had been previously drained, and as the 

 nomenclature of soils is not at all intelligible, and has led to much 

 mischief in detailing experiments, I send you the analysis of 300 

 grains of the field since ploughed. 



300 grains consisted of — 



Grains. 



Moisture .61 



Soluble matter, principally vegetable . . 3 

 Lime, in the state of carbonate ... 2 



Peroxide of iron 50 



Alumina 130 



Silica, or fine land . . . . . .20 



Vegetable matter ...... 33 



Loss .... 1 



300 



One of these subsoiled fields produced 35, and the other 27J 

 bushels of wheat per acre ; the field that produced the greatest 

 number of quarters per acre was subsoiled across the drains ; 

 the other parallel with them. I do not attribute this great fall- 



