48 BOARD OF AGRICULTURE. [Jan. 



practical conclusion that cultivation, or the stirring of the 

 upper layers of the soil, breaks capillary connections with 

 the evaporating surface, and thus retards the loss of water 

 and conserves the water for crops, which, as I have already 

 shown, require a really enormous supply, and whose yield is 

 dependent very largely on this supply. Cultivation is a 

 mulch, and it conserves water, as our above figures show, 

 and this is important to remember, much more in a drought 

 than at other times. 



Capillary action is exerted inversely in proportion to the 

 diameter of the tubes or pores, and is stopped at once by a 

 crack or space which interrupts the continuity of the capillary 

 tubes or pores. Hence, in soil, the rate and distance of the 

 action is regulated by the size of the pores in the soil and 

 their abundance, and is checked by any loss of continuity. 

 When water stagnates in the soil the earth particles are 

 liable to come into close contact, the soil may become, if 

 trampled, puddled, as we say, and hence the water of the 

 soil may move rapidly towards the surface and disappear as 

 aqueous vapor. This explains, in part, why undrained clay 

 soil in cultivated fields sufiers so severely from wetness in 

 spring and drought in summer ; this ofi*ers valid reason for 

 the usefulness of drainage ; this explains, in part, the appa- 

 rent paradox that drained soil in summer often contains more 

 water in a drought than does like soil that is undrained, a 

 fact which at one, at least, of our experiment stations was 

 considered so unorthodox that it became the subject of 

 experimental trial and ivas demonstrated. In ploughing, the 

 turned soil does not rest in close contact with the under soil 

 until consolidation is effected by rains, etc., and the dis- 

 turbed section gives of its own moisture to the atmosphere 

 and regains but little from the stored water below. In the 

 spring, when water is abundant and evaporation compara- 

 tively slight, no ill effects are perceived In the summer, 

 however, with shallow ploughing, it is often difficult to 

 secure germination of grass seed, or the continued life of the 

 weak seedling, as the water from the disturbed soil is quickly 

 evaporated and little additional supply can reach it by 

 capillarity from the water stored below. The turning under 

 of raw manure by the plough tends to form a strata discon- 



