No. 4.] CATCH-CROPS. 325 



there would be no essential increase in this element as a 

 result of green-manuring. 



This has been very strikingly shown by Julius Kiihn. 

 Kiilm's experiments were carried out in 1891 in Halle, 

 Germany. The soil was a good medium loam. It had pro- 

 duced wheat in 1890. After the wheat was harvested a 

 mixture of 194 pounds of peas, 44 pounds of vetch and 35 

 pounds of yellow lupine seed per acre was sown. The 

 resulting crop was ploughed under the last of October and 

 rye was sown. The quantity of green material ploughed in 

 amounted to 8,650 pounds per acre. This supplied about 50 

 pounds of nitrogen. In the spring of 1892 the field was sown 

 to barley, and also an adjoining field, not green-manured. 

 The crops were practically equal under the two methods 

 of treatment. In this case, then, green-manuring produced 

 no appreciable benefit. Kiihn estimated that the crop 

 ploughed in would have been worth for feeding about thir- 

 teen dollars per acre. 



On the other hand, the same experimenter found that on a 

 sandy loam soil green-manuring with field peas sown in the 

 rye stubble after harvesting increased the crop of barley the 

 following year to the same extent as an application of about 

 175 pounds of nitrate of soda. In the latter case green- 

 manuring paid, while in the first it was attended with loss. 



Numerous experiments in the United States, a few of which 

 will be noticed later, established beyond a doubt the possible 

 benefits of green-manuring upon the lighter and poorer soils. 

 It is important to point out, indeed, I have already, in what 

 has been said concerning eating one's cake and having: it too, 

 called attention to the fact, that even when the catch-crop is 

 fed the manurial value of its stubble and roots may be con- 

 siderable. Especially is this true concerning the legumes 

 (clover-like plants). 



A great deal of work to determine the manurial value of 

 the stubble of different crops has been carried out at the 

 Storr's School Experiment Station, Connecticut. Some of 

 the leading results of Professor Wood's investigations are 

 shown in the following table : — 



