618 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Soils rich in humus were found to retain more water and larger! 

 amounts of phosphates and of carbon dioxide. 



On exhausted soils fertility cannot be restored by nitrogen alone. 

 Chemical, physical, and bacteriological changes are promoted by the 

 use of farmyard manures, by a clover sod, and by grass crop residues. 

 Cultivation cannot take the place of manures, neither can manures 

 take the place of cultivation. 



In the case of 12 plots cultivated on a rotation of wheat, clover 

 and wheat (2 years), oats, and Indian corn it was found that after 

 10 years 10 of the 12 plots contained more nitrogen than at the; 

 beginning of the period. Nearly 500 lb. of nitrogen was also removed 

 from each acre by these crops during the 10 years. The amount of 

 humus in the soil was also maintained, being 3 per cent, at the begin- 

 ning, and 3*06 at the end of the period. During this time, however, 

 the land was twice manured (farmyard) at the rate of eight tons to the 

 acre. 



As regards potash contents, they were at the beginning 178 and 

 at the end 153 parts in the million of potash soluble in fifth normal 

 nitric acid. There was no material change in the solubility of phos- 

 phate compounds. 



On the other hand under timothy without clover there was a loss 

 (0'017 per. cent.) of nitrogen. Indian corn seems to conserve the 

 nitrogen to a greater extent than roots. All combinations of wheat 

 and clover showed an increase of soil nitrogen. The losses of nitrogen 

 and of humus under 10 years' continuous cropping of wheat, Indian 

 corn, potatos, and mangolds averaged 16 per cent. Lime, alkaline 

 matter, and aeration of the soil assist in producing rapid nitrification. 

 About 1 ton to the acre of organic compounds has been lost annually I 

 on the plots where grains and roots only have been grown. These 

 extracts will be sufficient to show the great practical importance of j 

 this paper.— G. F. S.-E. 



Rubus, Ornamental Varieties of. By Ch. A., A. v. der Heede, j 

 and Hort. (Le Jard., vol. xxiv., No. 555; April 5, 1910; 2 figs.).— j 

 The many kinds of ornamental bramble, which are apt to be neglected, j 

 are enumerated. Among the best are R. fl.agelliformis, with heart- 1 

 shaped leaves and white flowers; H. innominatus , edible, with tri-partite j 

 leaves and clusters of orange-scarlet berries; R. lasiostylus, with red 

 flowers; R. platyphyllos, edible, shrub with annual shoots, white 

 flowers, and big conical purple fruits. These are all hardy, but there ; 

 are also some charming greenhouse varieties, i.e. R. rosaefolius j 

 and its double form, R. r. coronarius, or R. r. florepleno, and R. re- I 

 flexus or R. moluccanus. This last has ivy-shaped leaves, like pale i 

 green velvet with brown veins. — F. A. W. 



Sand Plains in Vermont, Natural Afforestation of. By 



0. D. Howe (Bot. Gaz. vol. xlix. pp. 126-148; with map and 15 figs.; 

 Feb. 1910). — This interesting " study in succession " will repay care- 



