372 HANDY-BOOK OF HUSBANDRY. 



cannot usually be predicted, the application of nitrate of soda to 

 wheat is always attended with more or less uncertainty. 



" The case is different when a good crop of clover-hay has been 

 obtained from the land on which wheat is intended to be grown 

 afterward. An enormous quantity of nitrogenous organic matter, 

 as we have seen, is left in the land after the removal of the clover 

 crop ; and these remains gradually decay and furnish ammonia, 

 which at first, and during the colder months of the year, is retained 

 by the well-known absorbing properties which all good wheat-soils 

 possess. In spring, when warmer weather sets in, and the wheat 

 begins to make a push, these ammonia compounds in the soil are 

 by degrees oxidized into nitrates ; and as this change into food, 

 peculiarly favorable to young cereal plants, proceeds slowly but 

 steadily, we have in the soil itself, after clover, a source from which 

 nitrates are continuously produced ; so that it does not much affect 

 the final yield of wheat, whether heavy rains remove some or all 

 of the nitrate present in the soil. The clover-remains thus afford 

 a more continuous source from which nitrates are produced, and 

 greater certainty for a good crop of wheat than when recourse is 

 had to nitrogenous top-dressings in the spring. 



" The remarks respecting the formation of nitrates in soils upon 

 which clover has been grown, it should be stated, do not emanate 

 from mere speculations, but are based on actual observations, 



" I have not only been able to show the existence of nitrates in 

 clover-soils, but have made a number of actual determinations of 

 the amount of nitric acid in different layers of soils on which 

 clover had -been grown ; but as this paper has grown already to 

 greater dimensions than perhaps desirable, I reserve any further 

 remarks on the important subject of nitrification in soils for a 

 future communication. 



" Summary. 



" The following are some of the chief points of interest which 

 I have endeavored fully to develop in the preceding pages : — 



" I. A good crop of clover removes from the soil more potash, 

 phosphoric acid, lime, and other mineral matters, which enter into 

 the composition of the ashes of our cultivated crops, than any other 

 crop usually grown in this country. 



" 2. There is fully three times as much nitrogen in a crop of 

 clover as in the average produce of the grain and straw of wheat 

 per acre. 



" 3. Notwithstanding the large amount of nitrogenous matter 



