SOILS AND MANURES 



355 



crumbles them. Applications of manure render them capable 

 of supplying i>lant food. They serve also to assist crops in 

 dry weather in finding root room and moisture ; they enable 

 heavy surface rains to pass away freely ; and as air always 

 follows the retreating moisture, these once useless, worthless 

 subsoils in time become of the most valuable description. 

 There seems to be absolutely no description of subsoil that 

 cannot be made in this way fertile. A most important pro- 

 duct of deep working or trenching ground is that, not only 

 does it tend in winter to keep the soil in which crops may 

 be growing drier than shallow soils do, but is also much 

 warmer. In the summer, when drought so commonly pre- 

 vails, their good working enables the roots of crops to go 

 so much deeper, where the soil is at once cooler and moister, 



Shows a deep or vertical section of deep trenching 

 after the ground has been previously well worked. 

 Both top and bottom spits of 12 inches of soil are 

 thrown out, and the hard bottom soil is forked and 

 broken up 12 inches deep. The entire body of 2 feet 

 of soil from the next trench is thrown out and so on 

 throughout the plot. 



and thus continues productive much longer. Remarkable 

 illustrations of the differences found in crops grown on 

 deeply-worked and shallow-dry soils are often seen on groups 

 of allotments, where the soil is quite of the same nature or 

 texture. In the first case the crops are robust and luxuriant ; 

 in the latter they are poor, soon ceasing to be productive. 



Operations. The process of trenching is simple enough, 

 but should be invariably performed during the winter months, 

 on plots that are for the time uncropped, and have not been 

 deeply worked previously or for several years. In good 

 class gardens the work is done about every third year, but 

 if done in gardens where labour is less abundant it is 

 carried out once in from four to five years. The first effort 

 of the cultivator in trenching where soils have not been so 

 previously treated, is to do so in such a way that the lower or 

 subsoil be not brought to the surface. This is described as 



