7
The general scheme of experiment is that on one plot phosphates and potash are applied without any nitrogen, while on five other plots the phosphates and potash are supplemented by nitrate of soda in quantities varying from 2 cwt. per acre up to 10 cwt. per acre. The heavier dressings of nitrate are for the most part applied in successive doses of 2 cwt. per acre.
In my article of a year ago I gave a general description of the results of the experiments as far as they had then gone, giving full details of the crops of 1896, 1897, and 1898. I have now to record the results obtained during the past year, 1899, but may first briefly summarise our earlier experiences.
In the first year we did not begin to apply our nitrate until May, a very usual time for top-dressing, and the last dressings went on as late as August. The summer of 1895 was a very dry one, and the greater part of the nitrate failed to produce any effect at all, the crop being from 11 to 13 cwt. of hops per acre, without any consistent difference being shown between any of the differently manured plots. In 1896 we began to apply the nitrate earlier, viz., in February, and finished dressing in June. We got better results, but nitrate in excess of 2 cwt. per acre did no additional good. Two cwt. of nitrate of soda per acre, in conjunction with phosphates and potash, gave 16½ cwt. of hops per acre, as against 13 cwt. per acre grown on the rest of the field with the aid of dung. In 1897 we also applied our first dressing of nitrate in February, but finished dressing at the end of May. The results were far more satisfactory and progressive. In 1898 we applied the first dressing earlier still, viz., in the third week in January, and the last towards the middle of May, and the results were yet more satisfactory.
