ROTATION OF CROPS. 211 



manures together for each course, about 6800 lb. With the 

 mineral manure alone, therefore, there was about twice as 

 much, and with the mineral and nitrogenous manures together, 

 considerably more than twice as much, as without manure. 

 Compared with these amounts of clover reckoned as hay, the 

 seven bean crops (corn and straw together) gave an average 

 of about 1700 lb. without manure, of nearly 2400 lb. with 

 mineral manure alone, and about 3200 lb. with the mineral 

 and nitrogenous manures together. 



Not only, therefore, was the average produce of the bean 

 crop very much less than that of the clover, but in point of 

 fact it was only in one year, 1862, that anything like a really 

 good crop of beans was obtained. It may be added, though 

 the point will be further illustrated presently, that the crops 

 of the four years of clover contained, even without manure, 

 about as much nitrogen as, and with each of the two manures 

 considerably more than, those of the seven years of beans. 

 In fact, the average produce of the bean crop, and of nitrogen Nitrogen 

 in it, was very much less than in the case of the clover. in lf9 umes 

 Nevertheless, even the average yield of nitrogen was much 

 more in the beans than in either of the cereals with which 

 they were grown in alternation. Thus, without manure, the 

 four clover crops gave an average of 60.2 lb. of nitrogen per 

 acre, and the seven bean crops 34.9 lb. ; but over the eleven 

 courses the barley gave an average of only 28.0 lb., and the 

 wheat of only 31.7 lb. With mineral manure alone, the 

 average yield of nitrogen was, in the clover 119.2 lb., in the 

 beans 49.2 lb., in the barley only 27.7 lb., and in the wheat 

 only 39.3 lb. Lastly, with mineral and nitrogenous manure 

 together, the clover gave an average yield of nitrogen of 134.6 

 lb., the beans of 64.1 lb., the barley 41.2 lb., and the wheat 

 43.5 lb. There can, indeed, be no doubt, that the leguminous Legumin- 

 crops, and especially the clover, growing on land in the same ouscro P s 

 condition, and similarly manured, have the power of taking nitrogen. 

 up much more nitrogen over a given area from some source, 

 than the cereals with which they are interpolated ; and that 

 the beneficial effects of the growth of such crops in rotation 

 with the cereals are intimately connected with this capability. 



Before passing from the results in Table 58 it may be Legumin- 

 observed that, both with mineral manure alone, and with °^ r t ^, s 

 mineral and nitrogenous manure together, there is rather more consump- 

 produce, both of the clover and of the bean crop, where the tlon . °f 



TOOLS 071 



roots had been fed upon the land, than where they had been land. 

 carted off ; that is the higher the condition of the land. Thus, 

 then, the effects of the treatment of the first crop of the course 

 — the roots — on the produce of the third or leguminous crop 

 are clearly shown. 



