Agricultural Experiments.

Oamaru Mail, Volume XVII, Issue 5204, 10 February 1892, Page 4

Agricultural Experiments.

(Home Correspondent of the New Zealand Herald.) Sir John Lawes has issued the annual report of his multifarious experiments, bringing the records up to the end of 1890. Some of them were commenced as long ago as 1843. The results of those relating to permanent pasture are given for the twenty-two years ended with 1875, for the fourteen years ended with 1879, and for 1880 alone. Let us take those for the fourteen years, as giving the latest averages. On two plots never manured since the experiments commenced the average yield of hay per acre, for two cuttings per annum, was 28cwt. Where superphosphate of lime alone was applied at the rate of 3|cwt per acre per annum there was no increase, and 4001b of ammonia salts (half sulphate and half muriate) gave only a trifling increase of hay, whereas 2751b of nitrate of soda brought the average yield up to 40cwt. Where an expensive dressing of sulphates of potash, soda, and magnesia, with 3£ cwt of superphosphate, was given the yield rose to 52icwt. But a better result in proportion to cost was that of 49 cwt as the fourteen years' anuual average result from the application of 3271b of nitrace of potash and 3|cwt of superphosphate. The greatest average yield of all was 86£cwt, but this was dearly bought at the cost of an enormous dressing per annum of 5001b of sulphate of potash, 1001b of sulphate of soda, 1001b of sulphate of magnesia, 3icwt of superphosphate, 6001b of ammonia salts, and 5001b of silicate of soda. In another field, where experiments on barley had been tried for 48 years, the averages for 38 years are given. The averages for two plots never manured during that period of continuous growth of barley was slightly over 17i- bushels an acre. An annual dressing of 3|cwt of superphosphate per acre alone increased the yield to 21| bushels, and 2751b of nitrate of soda alone to 32f bushels ; but when those two quantities of superphosphate and nitrate of soda were combined the yield rose to 45J bushels —the best result in proportion to cost of manuring obtained of any of the numerous plots. Smaller quantities, it must be borne in mind, would have given equally good results under a rotation of cropping, instead of where barley has been grown every year for a very long period ; and this remark applies to all the experiments on corn. The greatest yield of all was from the annual application of 14 tons of farmyard manure, namely, 49 bushels; but the cost was more than double that of the superphosphate and nitrate of soda, and, therefore, did not pay nearly as well. Yet, as the extra yield over that of the unmanured plots was fully 31 bushels an acre, the value, at 4s a bushel, would be L 6 4s an acre, while the manure and spreading would be valued at about L 3 15s or L 4. Ammonia salts did not give as good results as nitrate of soda. In the experiments with wheat the average annual yield during 38 years of continuous cropping was 13§ bushels an acre where no manure was applied in the whole period. This was raised to 34 bushels by the anuual application of 14 tons of farmyard manure, yielding but a small profit at current prices for wheat, but paying well when wheat was over 40s a quarter all round—the present average is 36s 7d. The most costly of all the mixtures of artificial manure produced no more than 3(J ; ' r bushels ; but only a bushel less was obtained from the use of 2751b of nitrate of soda, Sicwt of superphosphate, 2001b of sulphate of potash, and 1001b each of sulphate of soda and magnesia. It is unfortunate that there was no trial of nitrate of soda and superphosphate without the three other manures, which may possibly have been superfluous.