NITRATES OF 



POTASH AND SODA. 



I have noticed on more than one occasion, 

 the advantage of sowing the cubic petre in 

 moist weather. In the dry summer of 1840, 

 the effect of the cubic petre was very inferior 

 to that produced by it on similar land and crops 

 in 1838 and 1839 an effect which entirely 

 supports my conclusions with regard to the 

 inefficacy of all top-dressings in periods of 

 long-continued dry weather. Of this opinion, 

 too, is a very excellent and extensive farmer 

 of Surrey. 



Mr. Hewitt Davis noticed too the effect on 

 some of the clays as well as the sands of Surrey 

 in 1840, that the effect of cubic petre upon 

 young wheats at the rate of 1 cwt. per acre 

 was excellent, not only in producing a t very 

 deep green colour, but in inducing a very con- 

 siderable rankness of growth. But then, in 

 his experience and observations, he has no- 

 ticed that the wheat thus dressed has a stronger 

 tendency to blight than that growing on the 

 adjoining lands. On his farms, however, this 

 rankness of growth is not felt as an evil ; for 

 on all soils, heavy as well as light, he practises 

 an excellent system of thin sowing, the effect 

 of which, as I can attest, is excellent in pro- 

 ducing most abundant crops ; either on the 

 poor, hungry, black gravels and sands of Ad- 

 dington in Surrey, or on the tenacious clays of 



. he never drills more than 5 pecks of 

 seed wheat per acre at intervals of 12 inches. 

 It is true that by this plan the appearance of 

 the wheat during the winter months is not so 

 vigorous as many farmers would at first sight 

 approve ; but the plants gradually get together, 

 stool out very abundantly, have all their ears 

 of a uniform length; the produce is abundant, 

 the sample generally excellent, and rarely sub- 

 ject to blight. 



These valuable experiments of Mr. Davis 

 entirely confirm those which I have been in- 

 duced to make on several occasions, and may, 

 in a great measure, perhaps, serve to explain 

 some of the discordant results of the recent 

 extensive, and, in the majority of instances, 

 successful experiments, with nitrate of soda 

 and saltpetre, as a top-dressing for wheat, bar- 

 ley, and oats. For in a great many instances 

 where the cubic petre has failed to produce 

 advantageous results, the seed has been sown 

 in rather large quantities ; the corn, therefore, 

 by the action of the salt becomes darkly green, 

 grows with great luxuriance is perhaps too 

 thick on the ground ; and the farmer, as a 

 natural consequence, finds that the nitrated 

 corn has a tendency to mildew. In the first 

 number of the second volume of the Journal 

 of the Royal Agricultural Socie.'y of England, there 

 is a mass of valuable information, collected by 

 Mr. Barclay, which illustrates very considera- 

 bly these observations on the advantages of 

 hin sowing; such as the experiments of Mr. 

 Barker, Mr. Hyett, and others. And although 

 I am not prepared to contend that the effects 

 of these two powerful salts will be in all cases 

 the most apparent on thin-sown corn, yet I am 

 much inclined to think that the farmer will find 

 that this is very often indeed the case. 



In most soils there is to be found a certain 

 proportion of carbonate of potash, and in many 

 it exists in sufficient quantity to decompose the 



348 



nitrate of soda, and form nitrate of potash and 

 carbonate of soda. This may, perhaps, serve 

 to account, in some instances, for the varying 

 results obtained in some apparently similar soils 

 from the application of the nitrate of soda, and 

 may be one reason amongst others why moisture 

 is found to be so essentially necessary for the 

 beneficial action of cubic nitre ; for it is a 

 chemical axiom, that to produce any chemical 

 action between two substances, one of them 

 must be in a fluid state, perfectly dry sub- 

 stances hardly ever producing any chemical 

 action on each other. 



Such, then, are the results of the long-con- 

 tinued experiments and observations upon nitre 

 and cubic nitre which I have been able to 

 make, and to suggest to others to re-examine 

 and verify; and such, too, are, I think, the rea- 

 sonable conclusions to be derived from our 

 united experience. 



In pursuing a path so novel, and so exten- 

 sive, it need hardly astonish us that there are 

 yet several sources of error to be avoided, de- 

 ceptive appearances to be scrutinized, and ad- 

 ditional experiments needed, before we can 

 expect to arrive at the knowledge of the best 

 and most economical modes of applying these 

 two valuable nitrates. The soils to which they 

 are best adapted, and the causes of their not 

 always producing even on apparently similar 

 soils the same powerful effects, are amongst 

 the objects of inquiry to which I have alluded 

 in this paper. The advocates, however, of 

 these saline manures have no need to com- 

 plain of the progress which they have made; 

 for admitting that on some soils they have 

 apparently produced but trifling effects, and on 

 other soils hardly any, yet still in the multitude 

 of instances they have amply repaid the farmer 

 for his outlay. There is no other instance, per- 

 haps, of such a rapid introduction of a saline 

 manure into agriculture, as that of the modern, 

 extensive, and increasing use of cubic petre by 

 the farmers of Great Britain ; and if we only 

 pause to remember the difficulties of experi- 

 mental researches like those, exposed, as all 

 examinations of the process of vegetation of 

 necessity are, to innumerable sources of error, 

 we shall find no reason to complain of the suc- 

 cess of its introduction, or of the talent and 

 enterprize with which the farmers of England 

 have conducted their valuable experiments. 



There are many experiments with these two 

 salts to be met with in the agricultural journals 

 of the last few years. 



1. Memorandum of saltpetre, nitrate of soda, 

 and common salt, used as top-dressings in the 

 south-east garden park, of a lightish land, well 

 drained, llth April, 1840, on pasture laid down 

 with grain in 1839: one acre sown with 1 cwL 

 of nitrate of soda, measured and marked as 

 such ; then a piece of one rood, without any 

 dressing; again, one acre sown with 1^ cwt 

 of saltpetre ; next to this half an acre dressed 

 with three-fourths of a cwt. of common salt. 



Result. In little more than a fortnight after 

 this, having had some favourable showers, 

 there was an extraordinary change on the two 

 distinct acres dressed with saltpetre and nitrate 

 of soda, as compared with the rest of the field. 

 The grass continued to grow on these divisions 



