Summer Fallowing and Soil Moisture 153 



new mulch to lessen further evaporation during the 

 fall and winter, and to permit nitrification in the fall to 

 be carried forward, is likely to leave the soil in a much 

 better condition for the next season, both as to moisture 

 and available nitrates, than could be hoped for by the 

 other method. 



It is not only difficult to get a good catch crop in the 

 fall on account of deficient moisture, but there is during 

 the growing season of the sub -humid climate so little 

 moisture that a rapid rate of nitrification in the soil 

 is impossible, and hence all the time which can be had 

 for this purpose is needed in order to have enough 

 nitrates developed for the crop the next year. 



6. Summer Fallowing in Relation to Soil Moisture 



The old practice of summer fallowing, which it has 

 been the fashion for writers on agricultural chemistry 

 to discourage of late years, has really much more of 

 merit in it, as indeed practical experience has proved, 

 than has been recently taught. It is not here intended 

 to convey the idea that there are not soils and climates 

 in which, in the majority of seasons, it would be better 

 not to summer fallow, on account of there being danger 

 of an excessive development of nitrates, which would be 

 lost by drainage ; but there is much to suggest that in 

 rich soils which are usually deficient in soil moisture, 

 as in many sub -hum id sections, there is not mois- 

 ture enough in a single year to develop the requisite 

 amount of plant -food and to mature the crop as well, 

 and hence, that some form of summer fallowing, or 



