15 



manures. Bearing these facts in mind, the results given in the table 

 will be seen to be quite consistent. 



The first three columns in the table show, approximately, how 

 the mixed herbage was made up under the four different conditions 

 of manuring. It will be observed that, without manure, and with 

 superphosphate of lime alone, both the proportion and the amount of 

 the different descriptions of herbage are much the same. Plot 8, 

 with a complex mineral manure, including potash the first six years, 

 but excluding it the next fourteen years, gave a considerable increase 

 of both gramineous and leguminous herbage ; whilst plot 7, with a 

 complex mineral manure, including potash every year of the twenty, 

 there is a still further increase of gramineous herbage, but a very 

 much greater proportional increase of leguminous herbage. 



It will be observed how much greater is the increase of gramineous 

 produce by the application of purely mineral manures to this mixed 

 herbage than in tie case of gramineous crops grown separately. It 

 is a question how far this is due to the mineral manures enabling 

 the grasses to form much more stem and seed, that is, the better 

 to mature, which in fact they do ; how far to their favouring more 

 active nitrification in the more highly nitrogenous permanent mixed 

 herbage soil ; or how far to an increased amount of combined nitrogen 

 in a condition available for the grasses in the upper layers of the 

 soil, as the result of the increased growth of the Leguminos89 in the 

 first instance, induced by the potash manure, as in the case of the 

 alternation of clover and barley, and as in the actual course of 

 rotation ? 



To turn to the yield of nitrogen on the different plots of the 

 mixed herbage, it will be seen that the amounts are almost identical 

 without manure, and with superphosphate of lime alone, about 

 33 pounds per acre per annum. On plot 8, where a co/nplex mineral 

 manure, including potash six years, but excluding potash fourteen 

 years, was employed, the amount is raised to 46*3 pounds ; and on 

 plot 7, which received the mixed mineral manure, including potash 

 every year of the twenty, the yield is 55'6 pounds per acre per annum. 

 Further, without manure, and with superphosphate of lime alone, 

 there was a decline in the yield of nitrogen in the later, compared 

 with the earlier years. With the mineral manure, including potash 

 in the first six yea:'S only, there was a much more marked decline. 

 With the miners nanure, including potash every year, there was, 

 on the other hand, even a slight tendency to an increased yield of 

 nitrogen in the later years. 



m 



