prevents the buds developing into leaves, catkins and nuts, and sometimes destroys a large proportion of the crop.

There is no fear of the disease spreading from nut to blackcurrant bushes, for the mite is of a different species, though difficult to distinguish except by its slightly smaller size. Its life-history has never been accurately determined, but there is little doubt that it is substantially like that of the black-currant mite, except that it probably has two definite migration periods, one from the spring buds in May, and one from the second growth of buds which appear in July and August. It should be mentioned that the observation recorded by some writers that the attack is worst in damp situations, and on bushes much over-shaded by other trees, was not borne out by the present instance. The destruction of badly diseased bushes and the pruning off and burning of twigs badly galled has generally been advised. Hazel and filbert bushes are attacked.

The beetle-mite Oribata orbicularis to which attention was called in the Zoologist's Report for 1901 (Vol. 62, page 270) as apparently injuring lime trees to some extent, has again been sent for identification, this time from apple trees. The developing mites look like clusters of little glossy brown eggs, and are generally observed at the base of a branch, where they seem to cause bare scabs upon the bark. In this situation, on the main trunk, they are pretty easily scrubbed off and destroyed, but on the apple trees they occurred largely on the small twigs, where it is difficult to see what could be done with them. More information with regard to this creature is certainly a desideratum, as much doubt still exists as to the extent to which it is positively injurious.

Zoological Laboratory,
Cambridge.

CECIL WARBURTON.

308

THE WOBURN

EXPERIMENTAL

STATION OF THE ROYAL AGRICULTURAL

SOCIETY OF ENGLAND.

I. FIELD EXPERIMENTS, 1901.

CONTINUOUS GROWING OF WHEAT

CONTINUOUS GROWING OF BARLEY

ROTATION EXPERIMENT (STACKYARD FIELD)

ROTATION EXPERIMENT (LANSOME FIELD)

GREEN-MANURING EXPERIMENT

VARIETIES OF BARLEY; AND KILN-DRYING OF BARLEY
VARIETIES OF OATS .

.

1901

330

330

330

338

346

346

346

349

350

350

353

356

358

359

360

360

360

361

HOME PRODUCE. PURCHASED FOOD (BULLOCK-FEEDING)

ECONOMY OF ROOTS IN SHEEP-FEEDING

III. POT-CULTURE EXPERIMENTS, 1901

THE HILLS EXPERIMENTS

The Influence of Lithium and Potassium Salts on Wheat
The Influence of Lithium and Potassium Salts on Barley

4. ANNUAL CHRYSANTHEMUM (Chrysanthemum segetum)

I. FIELD EXPERIMENTS, 1901.

THE last Volume of the Journal (1901), carried the account of these experiments to the end of the year 1900; the present is a record of the work done during 1901. Inasmuch as the details of the different experiments were very fully dealt with in the last report, their repetition is not now called for, but the statistical results will be set out with brief comment.

Continuous Growing of Wheat.

309

CONTINUOUS GROWING OF WHEAT (STACKYARD FIELD), 1901 (25TH SEASON).

The seed-" Street's Imperial "--was drilled on October 24, 1900, at the rate of nine pecks per acre, mineral manures being applied to the plots at the same time. Farmyard manure-made during the early winter by bullocks in the feeding boxes-was applied to the "dunged" plot (11b) on February 25, 1901, and rape dust to plot 10b on the same date. The top-dressings of nitrogenous salts were given on May 2 and 22, the heavier applications in two lots on these respective dates, and the lighter dressings on the latter date only.

On plot 2a (ammonia salts without lime) there was, as usual, a very poor plant, but now, in addition, signs of failing were seen in the case of plots 8a and 8b, where mineral manures had been used with the heavy dressing of ammonia salts, but without the addition of lime. Improvement was still visible on plot 2b (ammonia salts) as the result of lime applied in December, 1897, there being quite a fair plant.

The season, it will be remembered, was a dry and very early one, so that the crop was reaped much sooner than usual. The wheat was in ear by June 17, and was all cut by August 6. It was threshed on October 30, and the weights obtained are given in Table I., in which is set out also the valuation of the produce.

The general produce was a very low one, being less than that of either 1899 or 1900, for the unmanured plots gave only 7-7 bushels per acre, and mineral manures (plot 4) the same.

Nitrate of soda throughout gave better results than ammonia salts, whether when used alone or with minerals. In part, this may have been due to the drier season, but it was also clear that a general failure of the ammonia salts plots was showing itself. Up to this year the falling off had been only noticed in the case of 2a (ammonia salts alone), but now it appeared in plots 5, 8a, and 8b, more especially in 8a, where the heavy dressing of ammonia salts was applied. Exactly the same results have thus been seen, though somewhat later, in the case of wheat as with barley; the first plots to suffer have been those where no minerals were used, the minerals doubtless prolonging the duration of the plant through supplying a certain amount of lime, potash, &c., as bases, whereas in their absence the lime has been more rapidly (plot 2a) exhausted. That this is the case is shown by the partial restoration of the crop in plot 2b, to which lime was given in December, 1897. Though not since applied, it is still showing its influence (compare 2a and 2b), and though the effect is diminishing, the lime is evidently not all worked out yet. It will be desirable

TABLE I-Continuous Growing of Wheat, 1901 (25th Season).

(Wheat grown year after year on the same land, the manures being
applied every year.)

1 Ammonia salts are equal weights of sulphate of ammonia and muriate of ammonia.

2 Mixed mineral manures are, throughout, 34 cwt. superphosphate of lime, 200 lb. sulphate of

potash, 100 lb. sulphate of soda, 100 lb. sulphate of magnesia per acre.

TABLE II. Continuous Growing of Barley, 1901 (25th Season).

(Barley grown year after year on the same land, the manures being

applied every year.)

Stackyard Field-Produce per acre.

1 Ammonia salts are equal weights of sulphate of ammonia and muriate of ammonia.

2 Mixed mineral manures are, throughout. 34 cwt. superphosphate of lime, 200 lb. sulphate of

potash, 100 lb. sulphate of soda, and 100 lb. sulphate of magnesia per acre.