The hops in Kent are usually planted in October or November, the plants being 6 ft. apart each way, thus giving 1210 hills or plant-centres per acre. Some planters still grow potatoes or mangels between the rows the first year, as the plants do not bear much until the second year; but this is considered to be a mistake, as it encourages wire-worm and exhausts the ground. Many planters pole hop plants the first year with a single short pole, and stretch coco-nut-fibre string from pole to pole, and grow many hops in the first season. Much of the hop land is ploughed between the rows, as labour is scarce, and the spaces between are dug afterwards. It is far better to dig hop land if possible, the tool used being the Kent spud. The cost of digging an acre ranges from 18s. to 21s. Hop land is ploughed or dug between November and March. After this the plants are “dressed,” which means that all the old bine ends are cut off with a sharp curved hop-knife, and the plant centres kept level with the ground.
Manuring.—Manure is applied in the winter, and dug or ploughed in. London manure from stables is used to an enormous extent. It comes by barge or rail, and is brought from the wharves and stations by traction engines; it costs from 7s. 6d. to 9s. per load. Rags, fur waste, sprats, wool waste and shoddy are also put on in the winter. In the summer, rape dust, guano, nitrate of soda and various patent hop manures are chopped in with the Canterbury hoe. Fish guano or desiccated fish is largely used; it is very stimulating and more lasting than some of the other forcing manures.
The recent investigations into the subject of hop-manuring made by Dr Bernard Dyer and Mr F. W. E. Shrivell, at Golden Green, near Tonbridge, Kent, are of interest. In the 1901 report[1] it was stated that the object in view was to ascertain how far nitrate of soda, in the presence of an abundant supply of phosphates and potash, is capable of being advantageously used as a source of nitrogenous food for hops. An idea long persisted among hop-growers that nitrate of soda was an unsafe manure for hops, being likely to produce rank growth of bine at the expense of quality and even quantity of hops. During recent years, however, owing very largely to the results of these experiments, and of corresponding experiments based upon these, which have been carried out abroad, hop farmers have much more freely availed themselves of the aid of this useful manure; and there is little doubt that the distrust of nitrate of soda as a hop manure which has existed in the past has been largely due to the fact that nitrate of soda, like many other nitrogenous manures, has often been misused (1) by being applied without a sufficient quantity of phosphates and potash, or (2) by being applied too abundantly, or (3) by being applied too late in the season, with the result of unduly delaying the ripening period. On most of the experimental plots nitrate of soda (in conjunction with phosphates and potash) has been used as the sole source of nitrogen; but it is, of course, not be to supposed that any hop-grower would use year after year, as is the case on some of the plots, nothing but phosphates, potash and nitrate of soda. Miscellaneous feeding is probably good for plants as well as for animals, and there is a large variety of nitrogenous manures at the disposal of the hop-farmer, to say nothing of what, in its place, is one of the most valuable of all manures, namely, home-made dung. These experiments were begun in 1894 with a new garden of young Fuggle’s hops. A series of experimental plots was marked out, each plot being one-sixth of an acre in area. The plots run parallel with one another, there being four rows of hills in each. The climate of the district is very dry.
Weight of Kiln-dried Fuggle’s Hops per Acre.
| Plot. | Annual Manuring per Acre. | 1896 | 1897 | 1898 | 1899 | 1900 | Average of 5 Years. |
| Cwt. | Cwt. | Cwt. | Cwt. | Cwt. | Cwt. | ||
| A | Phosphates and potash | 1312 | 712 | 814 | 2014 | 8 | 1112 |
| B | Phosphates, potash and 2 cwt. nitrate of soda | 1612 | 914 | 1014 | 2214 | 934 | 1312 |
| C | Phosphates, potash and 4 cwt. nitrate of soda | 1612 | 12 | 1212 | 23 | 11 | 15 |
| D | Phosphates, potash and 6 cwt. nitrate of soda | 1514 | 13 | 13 | 2212 | 1012 | 1434 |
| E | Phosphates, potash and 8 cwt. nitrate of soda | 15 | 1312 | 1514 | 2312 | 11 | 1512 |
| F | Phosphates, potash and 10 cwt. nitrate of soda | 15 | 13 | 15 | 2412 | 1012 | 1534 |
| X | 30 loads (about 15 tons) London dung | 13 | 8 | 934 | 2412 | 1034 | 1334 |
The table given above shows the annual yield of hops per acre on each plot, and also the average for each plot over the five years 1896–1900.
In only one year did the very large dressing of 10 cwt. of nitrate of soda per acre afford any better result than was produced by the less heavy dressing of 8 cwt. per acre, and this was in 1899, a season of such abundance and such low prices that it may be regarded as an abnormal season. If the effect of this one season on the average be eliminated, the best results, as regards quantity, were obtained on plot E, receiving 8 cwt. of nitrate of soda per acre. But plot C, with 4 cwt. only of nitrate of soda per acre, has been on the average not more than 12 cwt. per acre behind plot E.
Valuations of the hops made by merchants and factors show that, on the whole, the market quality of the produce is very little affected by manuring. Moreover, chemical investigation of the hops appears to indicate that the brewing quality is not in any constant or definite way influenced by the manuring, except where the quantity of nitrate of soda has amounted to the large dressing of 8 cwt. or more per acre, a quantity which in some seasons would seem to have been prejudicial, although in one season it happened that the highest brewing value appertained to a sample grown with as much as 10 cwt. per acre.
The results of modern investigation show that it is very largely to the presence and proportion of soft resin that hops owe their preservative value, although the quality of hops is by no means wholly dependent on this one feature. The resin percentages on the samples grown on the several plots in 1898, 1899 and 1900 were the following:—
| Plot. | Annual Manuring per Acre. | 1898 | 1899 | 1900 | |||
| Total Resin. | Soft Resin. | Total Resin. | Soft Resin. | Total Resin. | Soft Resin. | ||
| Per Cent. | Per Cent. | Per Cent. | Per Cent. | Per Cent. | Per Cent. | ||
| A | Phosphates and potash | 14.15 | 9.21 | 15.07 | 8.60 | 14.53 | 8.90 |
| B | Phosphates, potash and 2 cwt. nitrate of soda | 14.30 | 9.20 | 16.59 | 8.83 | 15.09 | 8.51 |
| C | Phosphates, potash and 4 cwt. nitrate of soda | 14.06 | 9.04 | 15.87 | 9.27 | 14.46 | 8.16 |
| D | Phosphates, potash and 6 cwt. nitrate of soda | 13.57 | 8.60 | 14.90 | 8.70 | 13.46 | 7.62 |
| E | Phosphates, potash and 8 cwt. nitrate of soda | 14.11 | 8.85 | 14.49 | 8.96 | 13.30 | 7.18 |
| F | Phosphates, potash and 10 cwt. nitrate of soda | 12.21 | 7.91 | 15.47 | 9.41 | 12.77 | 6.77 |
| X | 30 loads (about 15 tons) London dung | 13.93 | 8.66 | 14.92 | 8.80 | 14.78 | 9.07 |
The general results seem to show that the purchase of town dung for hops is not economical, unless under specially favourable terms as to cost of conveyance, and that it should certainly not be relied upon as a sufficient manure. Home-made dung is in quite a different position, as not only is it richer, but it costs nothing for railway carriage. As a source of nitrogenous manure, purchased dung is on the whole too expensive. There is a large variety of other nitrogenous manures in the market besides nitrate of soda, such, for instance as Peruvian and Damaraland guano, sulphate of ammonia, fish guano, dried blood, rape dust, furriers’ refuse, horn shavings, hoof parings, wool dust, shoddy, &c. All of these may in turn be used for helping to maintain a stock of nitrogen in the soil; and the degree to which manures of this kind have been recently applied in any hop garden will influence the grower in deciding as to the quantity of nitrate of soda he should use in conjunction with them, and also to some extent in fixing the date of its application.
Dressings of 8 or 10 cwt. of nitrate of soda per acre, such as are applied annually to plots E and F, would be larger than would be put on where the land has been already dressed with dung or with other nitrogenous manures; and even, in the circumstances under notice, although these plots have on the average beaten the others in weight, the hops in some seasons have been distinctly coarser than those more moderately manured—though in the dry season of 1899 the most heavily dressed plot gave actually the best quality as well as the greatest quantity of produce.
With regard to the application of nitrate of soda in case the season should turn out to be wet, present experience indicates that, on a soil otherwise liberally manured, 4 cwt. of nitrate of soda per acre
- ↑ Six Years’ Experiments on Hop Manuring (London, 1901).
