Page:Notes on five years' experiments on hop manuring conducted at Golden Green, Hadlow, Tonbridge.djvu/21

19 in case a season should turn out to be wet, I should say that, on a soil otherwise liberally manured, 4 cwt. of nitrate per acre would be a thoroughly safe dressing. In the case of neither dung nor any other nitrogenous fertilisers having been recently applied, I see no reason for anticipating that, even in a wet season, 6 cwt. of nitrate of soda per acre would be otherwise than a safe dose.

As to the time of application, the present opinion of Mr. Shrivell and myself is that April or May is the latest time at which nitrate should be applied, and we are inclined to prefer April to May. The quantity used should be applied in separate dressings of not more than 2 cwt. per acre at each time, put on at intervals of a month. Where the quantity of nitrate used is large, and constitutes the whole of the nitrogenous manure employed, the first dressing may, on fairly deep and retentive soils, be given as early as January; or, if the quantity used is smaller, say in February; while February will in most cases probably be early enough for the first dressing in the case of lighter soils. The condition of the soil, and the degree and distribution of rainfall during both the previous autumn and the winter, as well as in the spring itself, produce such varying conditions that it is almost impossible to frame generally applicable rules.

It has been generally supposed that nitrate of soda is a manure which should be reserved for use during the latter period of the growth of the bine. Now the summer months, when the growth of the bine is most active, are the months in which natural nitrification is at work in the soil, converting soil nitrogen and the nitrogen of dung, guano, fish, rape dust, shoddy, or other fertilisers into nitrates, and placing this nitrogen at the disposal of the plant; and it appears