THE FARMER'S MAGAZINE. 



287 



on a smaller scale in the kitchen garden, only a 

 few hundred yards oil', were conducted with widely 

 different results. Here the soil was in ordinary 

 garden cultivation, and had probably been so for 

 two or three centuries. Early in 1854 (March 29) 

 0^ square yards of soil were sown with red clover. 

 From that time till the end of 1859, fourteen 

 cuttinas have been taken without any re-sowing 

 of seed. In 1856, this little plot was divided into 

 three equal portions : of these. No. 1, has been 

 kept continuously without any manure ; No. 2 

 was manured with gypsum ; and No. 3, with sul- 

 phate of soda, potash, and magnesia, and super- 

 phosphate of lime. The following table shows 

 the amount of produce obtained, cut green; but 

 as the space allotted to each experiment was so 

 very small, the results must not be taken as ab- 

 solutely correct. The product on small isolated 

 experimental plots is almost always very much 

 larger than one large plot; they can, as their 

 authors add, be only looked upon as rough ap- 

 proximations ; but as such they may be trusted as 

 indicating the large amount of clover that has 

 been taken from this garden soil, and as affording 

 some idea of the relative amount of produce under 

 three conditions of manuring. In the following 

 table, the quantities are estimated per acre in tons 

 and cwts., on I. the unmanured plot; If. manured 

 with gypsum apphed May 22, 1856 ; III. manured 



with sulphate of sod 

 applied May 22, 1856 — 



1854, two cuttings ... 



1855, three cuttings .. . . 



1856, two cuttings .... 



1857, three cuttings .. . . 



1858, two cuttings .... 



1859, two cuttings .... 

 Total produce six years 

 Average annual produce 



six years 



Total produce last four 

 years 



Arerage annual produce 

 last four years - 



Total increase by ma- 

 nure last four years. . 



potash, and 



I. 



II. 



magnesia, 

 III. 



10 

 39 

 23 

 27 

 14 

 10 

 125 



20 19 



75 15 



18 18 



25 

 30 

 19 

 14 



91 



29 

 33 

 24 

 17 



104 11 



22 15 I 26 2 

 15 8 ! 28 16 



From the above table we learn that the total 

 amount of clover obtained in six years from the 

 garden soil, without any manure being applied 

 during that period, is nearly 126 tons per acre, 

 equal to about 267^ tons per acre of hay, or nearly 

 4i tons per annum. In four years, the application 

 of gypsum increased the produce of green clover 

 by about 15^ tons, or about 3i tons of hay ; 

 nearly 1 ton per annum during the same period, 

 the use of alkalies and phosphates increased the 

 produce about 2s| tons of green clover, or rather 

 more than 6^ tons of hay, equal to an annual 

 increase of nearly ij tons of hay. It is worthy 

 of remark, add the reporters, that it was in some 

 of the very same seasons in which these heavy 

 crops of clover were obtained from the garden soil, 

 even though grown year after year, and without fresh 

 seed, that we entirely failed to get anything like 

 a moderate crop of clover in the experimental 

 iield, only a few hundred yards distant. The 



failure in the latter case would therefore appear to 

 be connecteil with the conditions of the soil in 

 relation to the plant, rather than to those of the 

 atinosp/iere. 



In reasoning upon the probable caubcs of the 

 clover-sickness, the authors of these experiments 

 evince a wise and cautious spirit, well worthy of 

 searchers after truth in so interesting and so 

 diflicult a field. In alluding to the excrementitious 

 matters which are emitted by the roots of plants, 

 they remark that it is not probable that any mineral 

 constituents which may be thus rejected during 

 the growth of one clover crop, are prejudicial to 

 the growth of a similar crop on the same land 

 for a number of years to come. If the failure of 

 the clover plant when repeated too soon upon the 

 same land be due at all to the excrementitious 

 matters left by the former crop, it is much more 

 probable that the injury is in some way connected 

 with the organic matters which have been rejected. 

 Unfortunately, we are not yet able by the aid of 

 chemistry to distinguish those organic compounds 

 of the soil, which are convertible into the sub- 

 stance of the growing plant, and those which are 

 not so. It would certainly appear that some or- 

 ganic matters of the soil are absorbed by the 

 plant, without being assimilated. We all know 

 how stock avoid the grass growing upon the site 

 of a cow pat ; how eagerly they devour the grass 

 which has been dressed with salt or other saline 

 substances. Then again, as Messrs. Lawes and 

 Gilbert remark, experience teaches us that when a 

 crop of clover is eaten by sheep folded upon the 

 land, animals dislike the growth which immediately 

 succeeds. It might be inferred therefore, that in 

 such a case the plant had taken up from the soil 

 certain matters which it had not finally elaborated. 

 But how then are we to account for the fact, that 

 whilst the clover plant would not grow healthily 

 in the experimental field, we have been able to cut 

 fourteen crops from seed sown six years ago, in 

 a garden only a few hundred yards distant? Are 

 we to suppose simply, that the ultimate constitu- 

 ents required by the clover were more abundantly 

 available to the plant in the garden soil ? or is it 

 that they existed in different states of combina- 

 tion ? According to Mulder, who has investigated 

 the organic compounds of the soil, the vegetable 

 decomposing matters of the soil go through a 

 series of changes before they are converted into 

 carbonic acid. He supposes the intermediate 

 compounds to constitute a series of acids which 

 combine with ammonia, and with fixed bases in 

 soil, forming so many salts. Now if we were to 

 suppose that some plants, clover for example, 

 required for their healthy growth a certain propor- 

 tion of their food to be presented to them in the 

 form of carbon compounds, a form more complex 

 than carbonic acid, and perhaps combined with 

 ammonia, we should then more easily comprehend 

 why it should be necessary for a certain time to 

 intervene before again cultivating certain crops on 

 the same land ; for we could easily understand that 

 this might be requisite for the gradual formation 

 and accumulation of a certain amount of the com- 

 pounds in question. It would very likely lead to 

 useful results if those of my readers who have 



