Page:Notes on five years' experiments on hop manuring conducted at Golden Green, Hadlow, Tonbridge.djvu/22

20, therefore, to suppose that nitrate of soda itself will be more grateful to the hops at the earlier stages of their growth, before the products of natural nitrification become abundant. If we can get at any rate a considerable proportion of our nitrate of soda well incorporated with the soil by the time the bine begins its active and rapid growth, we may be helping to lay the foundation of a good crop better than if we delay the application of the nitrate until those months when the soil is actively producing nitrates from other sources. This policy would appear especially to hold good after a wet autumn and winter, which would have had the effect of washing away the residual nitrates unutilised by the previous crop.

In concluding this report I would once again emphasise the necessity, whether dung is used or not, and whatever form of nitrogenous manure is employed, of also using an abundance of phosphates. On soils containing plenty of lime, no better or cheaper phosphatic manure can be used than superphosphate, of which 8 cwt. per acre per annum makes a fair dressing. But if the soil is not decidedly calcareous—that is to say, if it does not effervesce when it is stirred up with some diluted hydrochloric (muriatic) acid—basic slag, bone dust, or guano should be used as a source of phosphates, at the rate of not less than | ton per acre. On medium soils which, without being distinctly calcareous, nevertheless contain a just appreciable proportion of carbonate of lime, it is probably a good plan to use the latter class of manures alternately with superphosphate. But it is wise policy to use phosphates in some form or other every year in every hop garden. They are inexpensive, and without them neither dung, nitrate of soda, ammonia salts, nor organic manures can be expected to