heaping it in parallel ridges a larger surface is exposed 

 to the weathering, particularly to the action of frost 

 during the winter. The effect of frost is to disintegrate 

 the large masses, of soil, and so to render the earth more 

 permeable both to water and to air. By exposure to the 

 atmosphere moreover the decay of organic matter in the 

 soil is promoted, and thereby valuable nutritive matter 

 is rendered soluble and available for plant nutrition. It 

 is, therefore, sometimes recommended, before ridging, to 

 spread any stable manure which is to be incorporated with 

 the soil evenly over the plot. A trough is then dug two 

 spades wide, one spadeful being deposited to the right 

 and the other to the left of the trough. The soil of the 

 latter can also be lifted, and turned, or merely forked over. 

 This operation of ridging should be commenced in the 

 autumn, and can of course only be undertaken on ground 

 that is to remain empty during the winter. 



Further information regarding the nature of soils and 

 manures can be found in the following excellent books : 



E. J. RUSSELL. " Lessons on Soil." Cambridge Nature 

 Study Series, i/-. 



E. T. RUSSELL. a A Student's Book on Soils and Manures." 

 Cambridge Farm Institute Series, igi$, 3/6- 



A. D. HALL. "The Soil." John Murray, London, $!-> 



A. D. HALL. " Fertilizers and Manures." John Murray, 

 London, $/-. 



