Agricultural Chemistry — Turnips, 



523 



season, and a number of plants nearly identical with that under 

 mineral manures only. Ag-ain, by mineral supply alone, to which, 

 indeed, as we have seen, may be attributed an influence upon the 

 growth of the plant apart from that which can be traceable to 

 the mere provision of crop-material, we have as many tons of 

 produce as the unmanured plot gives cwts., a weight of bulb more 

 than ten times as great, and a number of healthy plants nearly 

 double. By the side of the farm-yard dung, however, which we 

 presume to contain a sufficiency of all the constituents of a large 

 t;rop of turnips, (though, excepting under the influence of con- 

 tinuity of rain and a relatively low temperature, not calculated to 

 develop the most healthy conditions of growth,) we find that the 

 purely mineral manuring, with a number of plants per acre 

 almost identical, shows a formation of bulb within an equal 

 period of time little more than two-thirds as great. We shall 

 presently see that the largest weight of bulb formed in a given 

 time is not to be taken as affording an unconditional index to the 

 value or promise of the crop ; but in the instances now cited it 

 may, in a pre-eminent degree, be quoted as such; for we know 

 that whilst the plants under minerals only had, when weighed, 

 arrived at their full growth^ those having farm-yard dung had 

 still vitalitv and resources. 



Before tracing any further the probable source of the superiority 

 of farm-yard over the purely mineral manures, we will refer to 

 some other of the points which our arrangement of manuring 

 elucidates. In the two former years it was observed that, w^here- 

 ever either ammoniacal salts or rape-cake were drilled with the 

 seed, a great depreciation and irregularity in the number of 

 plants per acre resulted ; and it may have appeared to some of 

 our readers that we have, without sufficient ground, referred the 

 deficiency of plants to the manner of applying these organic 

 manures ; and that, omitting the indications of the actual acreage 

 results, our reasonings are fallacious. The following summary of 

 the number of plants obtained, when ammoniacal salts and rape- 

 cake are sown broadcast and ploughed in, and of that resulting 

 from the use of mineral manures alone, will show how highly 

 important it is not only to select a manure such as the plant 

 requires, but so to apply it as to ensure a beneficial rather than 

 an injurious result. 



The uniformity under the various classes of manures in this 

 season, as compared with others, is very striking ; though, as 

 before, the mineral manure gives somewhat the higher number. 

 The coincidence throughout the entire series of about 90 different 

 combinations of manures (see Division 4 of Table) is such that, 

 for the first time, the acreage amount of produce maybe taken as 

 a somewhat true measure of the value of the manures. The drilled 



