502 



Agricultural Chemistry — Turnips. 



turnip in ag^ricultural quantity should ])e so essentially dependent 

 on artificial supply as our results would show to be the case. 

 There can be no doubt that there is some truth in this current 

 supposition, but there is little doubt that the power of collection 

 from the atmosphere very materially depends upon the quantity 

 and quality of the supply to the soil by manures ; in fact, that 

 upon the judicious and liberal provision of certain constituents by 

 art we must rest our hopes for atmospheric accumulation. 



Having shown, then, that climatic agencies constitute an impor- 

 tant element in the necessary conditions of growth of our culti- 

 vated turnip, and that these are only available when associated with 

 an abundant artificial supply of certain constituents, the question 

 arises — What are the substances which it is essential should thus 

 be provided ? I'his brings us U} the second branch of our subject, 

 namely, the influence of monurvmj upon the growth of the turnip. 



Having discussed in some detail the comparative characters of 

 the first three seasons during which we have been conducting an 

 extensive series of experiments, under very various yet known con- 

 ditions of manuring, we are prepared to consider the results of 

 those experiments ; and it is believed that those of them which 

 were obtained in the three years referred to will amply suffice to 

 indicate the nature of the necessary supply by manure, and also 

 to lead to some interesting^ and important explanations regarding 

 the true office of the turnip in a course of agricultural cropping, 

 and the sources of its economic value. We would again remind 

 our readers that the object of the experiments was not the pro- 

 duction of large crops, but to learn, by the effects of different and 

 known conditions of supply, in what respect and to what extent 

 the plant was dependent upon the resources which must be kept 

 up by the farmer, and \\u\v far hf; uvA\j r(.']y iJ})on the natural yield 

 of the atmosphere; for it is 11k; itfMri u\ :;ourcc of constituents, as 

 well as that of quantity and quality, which should influence our 

 selection of plants and manures under a truly rational and eco- 

 nomic system of agriculture. 



The experiments were commenced in the season of 1843, the 

 early part of which, it will be remembered, was greatly superior 

 to that of 1844, and equal to that of 1845 in suitableness to the 

 growth of the turnip; but in the middle and latter periods it was 

 inferior to either of the two succeeding seasons. The soil was a 

 somewhat heavy loam, not well adapted for turnips ; but as the 

 plant is cultivated on such land with admitted advantage for rota- 

 tion purposes, it was well fitted to answer our special ends. The 

 previous crops since manure had been wheat, clover, wheat ; so 

 that in an agricultural point of view the soil might Ije considered 

 as somewhat e^ihausted, and therefore in a favourable condition 



