96 Recent Publications on Manures. 



cheap digging were in many situations substituted for ploughing. 

 Deep subsoil-ploughing is very expensive, as some who have 

 had experience in that way allow : it has been rated much lower 

 than digging, but I believe it is from want of calculation. 

 Lately, in the Ayr Advertiser, a field was thought to have been very 

 economically done, which, after the enclosure was well drained, 

 had been subsoiled 9 in. deep, and the crowns of the ridges 

 levelled with the spade, at an expense of 3/. 3s. per acre, or 

 nearly 4f</. per fall; which, I believe, could have been dug 

 10 in. deep for that sum, and the ground levelled in the 

 digging. 



Since the above was sent off I have seen the fourteenth number, for 

 January, of Professor Johnston's Lectures on Agricultural Chemistry, in which 

 there is an Appendix of Experiments for 1841, which may be had separately, at 

 the price of 3d, by any who have not an opportunity of getting the Lectures 

 themselves, which are increasing in interest as they progress, and ought to be 

 in the hands of all interested in the cultivation of the soil. The principal 

 part of the experiments are those of Mr. Fleming of Barrochan, the gentleman 

 alluded to in a former part of this essay ; who, from his chemical knowledge, 

 and the great variety of soils on his estate, joined to his spirited method of 

 conducting the experiments, is likely to be the means of eliciting much in- 

 formation on these subjects. Some of the results are entirely different from 

 former ones, as also from others in the same appendix, and point out the 

 necessity of reiterated experiments in different situations and on a larger 

 scale, before the action of these saline manures can be properly understood. In 

 portioning off small pieces of land for experiment, it ought to be kept in view, 

 that there is generally much difference in the quality of the ground even in 

 the same park. I have seen in a quarter of potatoes the heads of the drills 

 not to produce half the crop with the same quantity of manure, and the same 

 also occurs often in the middle or bottom of the row. High ridges of stony 

 ochry-coloured gravel will occur at one place, while another portion will be of 

 a heavy stiff clay ; and, again, another of a deep fine loam, which, to the depth 

 of 2 ft., may be all put through a sieve : all these different qualities exist in 

 the soil at present managed by myself in the nursery, and greater variety 

 than this is often to be met with. I have seen pieces of a park where the 

 potatoes, though better manured than the rest of the field, did not yield the 

 same bulk of produce as the seed, while, within a few yards the crop was 

 good. Such varieties exist more or less in all soils; and different soils are 

 also more suitable for some seasons than others, and the same with manures. 

 On all these accounts we should draw our inferences with caution, and not 

 blind ourselves by becoming prejudiced to any opinions, till long and firmly 

 established. 



At Roselle, neither common salt (muriate of soda, or chloride of sodium) nor 

 sulphate of soda was found to do any good, while at Barrochan the common 

 salt applied to a crop of wheat, at the rate of 160 lb. per acre (the same as 

 the nitrate), produced a much greater increase than the nitrate of soda ; 

 about one third part more on the crop, and three times more of increase, as 

 compared with the undressed portion of the field. It produced, however, 

 less than one twentieth part more of produce, as compared with the nitrate of 

 soda and rape-dust mixed, and only one seventh part more of increase. The 

 common salt and lime mixed, at the rate of 28 lb. of salt and 80 bushels of 

 lime to the acre, produced only about one twelfth part more of produce as 

 compared with the undressed portion. These experiments were made on por- 

 tions of one eighth of an acre, or twenty falls ; how far they might have 



