Atf. /.] OF TURNIPS. 9 



this way the whole energy of the salt being expended where it is required, the 

 greatest possible effect will be produced. 



III. I have already stated the reasons which lead me to anticipate highly be- 

 neficial effects to vegetation from the use of sulphate of soda ; I would suggest, 

 therefore, a trial of this salt on the turnips also, at the same rate of 1 cwt. per 

 acre, and applied in the way above recommended for the nitrate of soda. Of 

 course the intelligent farmer will vary the proportions and mode of application 

 of these substances, as his leisure or convenience permit, or as his better judg- 

 ment may suggest to him. 



The entire series of experiments on turnips, above suggested, may be repre- 

 sented as follows, adding two plots for different proportions of the nitrate and 

 sulphate of soda : 



Some of these experiments most of you may easily try. Those with the 

 burned bones and horn shavings, which in this part of the country are less easy 

 to be obtained, it is not to be expected that inany of you will think of undertak- 

 ing. I hope, however, that they will not be lost sight of by those who possess fa- 

 cilities for obtaining them in sufficient quantity to make a satisfactory experiment. 



In many parts of the United States, gypsum is the universal fertilizer for 

 every crop, and among the rest it is said to l3enefit turnips. The same opinion 

 is entertained in Germany. I am not aware how far, in what way, or with 

 what results, it has been applied to the turnip crop in this country. A simple 

 mode of testing its efficacy, however, would be to strew it over the plants when 

 in the rough leaf, on part of a field, the whole of which had been already ma- 

 nured in the ordinary way with fold-yard manure. The difference of produce 

 would thus show its efficacy, in the given circumstances ; and the experiment 

 could be made effectually at the cost of a single cwt. of gypsum. 



I have not included rape dust among the trials above suggested, though it is 

 undoubtedly, under certain modes of management, a beneficial manure both to 

 corn and turnip crops. There is also a diversity of opinion as to the cause of 

 its fertilizing action, as well as a manifest difference in the effect of different 

 samples of the dust on the same soil. Though, therefore, certain experiments 

 which I may on a future occasion suggest, would undoubtedly throw light on 

 the cause of the good qualities of this manure, yet as its action (taking different 

 samples) is not constant on the same soil, results obtained with it cannot pos- 

 sess the same importance, either theoretical or practical, as those which are ob- 

 served to follow from the use of bones and of saline substances, the composi- 

 tion of which is nearly invariable. 



Many farmers, however, are in the habit of constantly using rape dust. If 

 any of these could conveniently make experiments on the effect of different sam- 

 ples of the cake, from different kinds of seed, and from different oil mills, and 

 would accurately note the results, they would perform an important service in 

 preparing the way for that clear explanation of the cause of its fertilizing action, 

 which is at present wanted,* and which experiment alone can discover to us. 



* Its good effects are generally attributed to the oil which is left in the seed, and its vary, 

 ing action to the ditferent quantities of oil left in it by different crushers. I doubt, however, 

 if the oil ought to be considered as more than a secondary cause of its beneficial action. 



