ON THE GROWTH OF LEGUMINOUS CROPS. 15 



It should be further explained that, in the first 5 years, the nitrogen 

 applied to the third plot was in the form of ammonium-salts. The 

 effects were, however, so small and irregular, that the application of 

 nitrogenous manure was then suspended for some years ; indeed for 10 

 years, when, it having been observed that nitrates were more beneficial 

 to Leguminosse than ammonium-salts, sodium-nitrate was applied 

 instead ; in amount supplying 86 Ibs. nitrogen per acre per annum, or 

 nearly twice as much as had been given as ammonium-salts in the earlier 

 years. This application of the nitrate commenced in 1862 ; and with 

 some breaks, owing to severe or wet winters, which prevented the seed 

 being sown, or destroyed the plant, it was continued up to 1878, when 

 the experiments were finally abandoned. 



Referring to the results, a glance at the Table shows that, inde- 

 pendently of fluctuations obviously due to season, there were frequent 

 entire failures, which were also more or less due to season, but which 

 were also dependent partly on the conditions induced in the land by 

 the continuous cropping with this plant ; which, as is the case with 

 most Leguminosse, is very susceptible to parasitic attacks of various 

 kinds, when the conditions of growth are not normal and favourable. 

 Indeed, it is seen that, even when there was not absolute failure, there 

 was a general tendency to decline in yield, and then to recover again, 

 more or less, after a break. This was somewhat marked after a year 

 of Fallow in I860, and the growth of Wheat in 1861 ; after which 

 there was, in 18(52, fair produce, especially on the third plot, where the 

 nitrate was now applied. The land was again Fallow in 1863, and 

 this was again followed by improved growth ; after which there was 

 declining produce for a number of years to 1870 inclusive, and again 

 recovery in 1874, after 3 years of Fallow. This general view of the 

 results is of interest, as fixing attention on the great tendency to 

 failure of this Leguminous crop, when grown year after year on the 

 same land. 



Turning to the effects of the different manures, it will suffice to 

 direct attention to the last three columns of the Table, which record 

 the amounts of total produce, that is corn and straw together, under 

 each of the three conditions as to manuring. 



Disregarding the results of the first year, when the unmanured 

 plot gave relatively high produce, it is seen that, although there are 

 irregularities, there is generally, whether the crops are large or small, 

 a considerable increase of produce by the use of the mineral manure 

 containing potash, but there is comparatively little further increase by the 

 addition of nitrogenous to the mineral manure. Thus, as shown in the 

 bottom division but one of the Table, the average annual total produce, 

 over the 32 years (which however included 7 without any Bean crop) 

 was without manure, 1,389 Ibs., with the mineral manure alone 2,168 

 Ibs., and with the mineral and nitrogenous manure together 2,507 Ibs. 

 That is to say, whilst the mineral manure without nitrogen gave an 

 average annual increase of 779 Ibs., the addition to it of nitrogenous 

 manure only further raised the produce by 339 Ibs. 



