Some Causes of Unproductiveness in Soils. 127 



illustrate this part of my subject. A correspondent wrote to me 

 last spring from Churchdown, near Gloucester. 



" Sir, — I have this day forwai'ded to you a bottle of earth for 

 analysis. The land has been laid down to permanent pasture 

 five years, the first year or two it grew luxuriant crops, but now 

 it is almost worthless, although it has been dressed with different 

 kinds of compost. With the analysis, please to give me your 

 opinion what sort of manure would be most likely to bring it to 

 a state of fertility." 



On analysis the soil yielded the following results : — 



Moisture 4-04 



Organic matter and water of combination .. .. 11"6G 



Oxides of iron and alumina and phosphoric acid .. in-G7 



Carbonate of hme 10"03 



Magnesia 1'38 



Potash and soda I'Ol 



Insoluble siliceous matter (clay) 55"21 



100-00 



The soil ought to yield good crops, for it contains all the 

 elements of food required by plants. It certainly is not unpro- 

 ductive because it is deficient in any one element of vegetable 

 food, but I believe, because its physical condition is such as not 

 to allow the plants to avail themselves of the food which is 

 unquestionably present in the soil. It contains, it will be seen, 

 a good deal of organic matter, and is a very stiff and retentive 

 soil, difficult to drain. Surface water is removed readily enough 

 by drainage from such land : this is one thing ; but to make it 

 sufficiently porous by draining to allow the water and after it the 

 air to pass through the soil, is quite another matter. The soil 

 appears to have grown luxuriant crops a year or two after 

 it was laid down in permanent grass, and then to have become 

 almost worthless. I can readily understand this, and have no 

 doubt, if the land were again broken up, its previous fertility 

 would be restored without the addition of any manure. Reten- 

 tive clay-soils having a composition like this do not require 

 manure, but must be penetrated by air, which is freely admitted 

 when land is broken up. In the course of a year or two, however, 

 the pores of such land again became closed up ; and in conse- 

 quence of the exclusion of the air, and not for want of mineral 

 food, vegetation becomes languid in growth. 



On land like this it is only waste to apply manures, especially 

 if the season should be dry. Artificials, such as guano or 

 ammoniacal salts, then do positive harm ; and in wet but warm 

 seasons, water itself is the best means of developing, so to speak, 

 the natural resources of the land and encouraging the growth of 



