25, the percentage found in genuine Peruvian guano; and that it yielded not quite 3 per cent. of ammonia, instead of 16 per cent., which is the average percentage in good guano. Adding together the worthless matters in this feathery compound-for it was nothing else but a mixture of a yellow sandy loam with a little Peruvian guano and plenty of guano-bird feathers-we have no less than 75 per cent. of useless materials, and only 25 per cent. of fertilising constituents. On inquiry, I find that the" feather manure was sold as Peruvian guano, at 147. a ton, by a Mr. Weekes, of Bromyard, Herefordshire. Its real value cannot be put higher than 27. 10s. or 37. at the most. AUGUSTUS VOELCKER. VII.-Field Experiments on Mangolds. By Dr. AUGUSTUS VOELCKER. In laying down a manuring scheme for root-crops, I had mainly in view to ascertain, by direct experiments, what influence potash exerts on mangolds and swedes when grown on light land, and, if possible, to find out in what combinations, with other fertilising matters, potash should be employed in a rootmanure intended for light land in order to produce the most beneficial effect. For field experiments on root-crops one-twentieth of an acre is a convenient and sufficiently large size for each plot. Each experimental one-twentieth of an acre piece should be divided, if possible, in such a manner that it will be occupied by 4 rows of plants. In the following experiments this plan was adopted, and the field divided into 11 plots of one-twentieth of an acre each, which, as regards manure, were treated as follows: Plot 1 Was left unmanured. 2 Mineral superphosphate.. 164 lbs., or at the rate of 3 cwts. per acre. 3 and In this scheme, it will be seen, provision is made for testing the effects of potash in conjunction with mineral superphosphate, and also for ascertaining what the effect is likely to be if to the mixture of potash salts and superphosphate a small quantity of sulphate of ammonia or of nitrate of soda is added. In previous years I applied potash salts alone to a variety of crops; but having found that, in most cases, potash salts without any other fertilising agents did not do much good, whereas in conjunction with superphosphate their application to light land had a most beneficial effect, I omitted from the present scheme potash salts to be tried by themselves. In order to make the experiments comparable with ordinary farm practice, one plot was reserved for a full dressing of rotten dung, and another received half a dressing of dung and a very moderate dressing of mineral superphosphate. Two plots were left unmanured; one right through the middle of the experimental plots, and the other at one end. A third unmanured plot was left at the other end of the experimental field; but as the weighings of the produce on this plot gave quite an abnormal result, no furthur reference need be made to it. The foregoing manuring experiments were tried last season on mangolds by my friends Mr. R. Campbell Ellis, at Iver Moor, near Uxbridge, Middlesex, and Messrs. J. Coleman and J. Hull, Escrick Park, near York, and I have now the pleasure briefly to communicate to the readers of this Journal the results of these experiments. Field Experiments on Mangolds made by Mr. R. Campbell Ellis, at Iver Moor, near Uxbridge, Middlesex. The mangold seed was sown on the 27th April on the flat. The different artificial manures were sown with some ashes, to secure their uniform distribution on the land, and harrowed in. The seed came up well, and a regular plant was obtained on all the plots. The roots were taken up on the 2nd November, 1869, topped, tailed, and weighed, when the following results were obtained : Results of Experiments on Mangolds at Iver Moor, near Uxbridge. The rest of the field (5 acres) was manured with 5 cwts. of Proctor and Ryland's mangold-wurzel manure, and yielded on an average 28 tons of mangolds per acre. On looking over the results of the preceding experiments, several points are likely to arrest the reader's attention : 1. The land, although light, appears to have been in a good agricultural condition; for the unmanured plots yielded at the rate of 21 tons 15 cwts., and 23 tons, or on an average 22 tons 7 cwts. of mangolds; or, in round numbers, 22 tons. 2. Mineral superphosphate applied at the rate of 3 cwts. per acre gave but the slight increase of 1 ton 2 cwts. over the average yield of the two unmanured plots. 3. The addition of 2 cwts. of potash salts to 3 cwts. of superphosphate had a good effect; for it produced an increase of nearly 3 tons, or nearly 2 tons more than mineral superphosphate alone. 4. The mixture of 3 cwts. of mineral superphosphate and 1 cwt. of guano, practically speaking, had the same effect as 3 cwts. of superphosphate and 2 cwts, of potash salts. 5. 3 cwts. of Peruvian guano yielded an increase of 5 tons per acre, and appears to have had a better effect than either a full dressing of farmyard manure or half a dressing and 1 cwt. of superphosphate. 6. Lastly, it will be noticed that the addition of a small quantity of nitrogen to the mixture of mineral superphosphate and potash salts produced a considerable increase. On Plot 7 we have the same quantity of superphosphate and potash salts as on Plot 3, with the addition of 1 cwt. of sulphate of ammonia per acre, and the effect of this addition of sulphate of ammonia was to raise the produce to 30 tons 10 cwts. in round numbers, or to give 5 tons more than the superphosphate and potash salts without ammonia. Practically speaking, the same effect which the sulphate of ammonia produced in conjunction with potash and superphosphate was obtained on Plot 9, on which the nitrogen was applied in the shape of nitric acid instead of that of ammonia; for both the Plots, No. 7 and No. 9, the addition of nitrogen to available phosphates and potash has proved very beneficial to the mangold crop, producing an average increase of 8 tons in round numbers. Experiments on Mangolds at Escrick Park, near York, in 1869. The mangolds were sown on 11th May, 1869, on a barley stubble in 1868. The soil of the experimental field was of a light sandy character, and, though naturally poor, it was in a good agricultural condition, as the produce from the unmanured plot showed. The mangold crop was taken up, topped, tailed, and weighed, on the 11th November, 1869, when the following results were obtained : Results of Experiments on Mangolds at Escrick Park, near York, 1869. Plots of % of Experiments on Mangolds at Escrick Park (continued). Manure per Acre. Produce per Plot of Produce per Acre. and The preceding tabulated results exhibit several points of interest, on which a few observations may be offered : 1. In the first place, it will be seen that the two unmanured portions of the experimental field yielded a fair crop of mangolds. One of these plots produced 22 tons per acre, and the other 21 tons; or, on an average, the unmanured plots produced 21 tons of mangolds per acre. The difference in the weights of the crops on Plot 1 and Plot 6 is not greater than can be expected in field experiments. The experimental field thus was tolerably uniform in character and well adapted for the trials. 2. Mineral superphosphate alone gave only an increase of 1 tons, and thus appears not to be the kind of manure which ought to be employed for mangolds on light land. 3. The addition of 2 cwts. of salts of potash to 3 cwts. of mineral superphosphate proved very successful, inasmuch as it raised the produce to 29 tons, and gave an increase of 7 tons over the average yield of the unmanured portions of the field. 4. In these experiments, the addition of 2 cwts. of salts of potash had a better effect than the addition to superphosphate of 1 cwt. of Peruvian guano, or than 3 cwts. of Peruvian guano alone. 5. Peruvian guano alone answered better than mineral superphosphate applied by itself, but did not appear to be the best artificial manure that can be used on light land for mangolds. |