158 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Larix olgensis — sp. n. By A. Henry (Gard. Chron. Feb. 27, 1915, p. 109 ; 



2 figs.). — Diagnosis and description of a Larch from Eastern Siberia, likely to 

 thrive high up in mountain districts of this country. — E. A. B. 



Legume Inoculation. By Martin J. Prucha (U.S.A. Exp. Stn., Cornell, 

 Cir. 15 ; March 191 3). — The author demonstrates the value of pure cultures 

 for inoculating the land, when growing a new type of legume, e.g. cowpea, in 

 a particular district. 



Some attempts at cross inoculating by nodules from clovers to grow cowpeas 

 failed in practice. — C. P. C. 



Lilies in 1914. By A. Grove (Gard. Chron. Jan. 9, 1915, pp. 13-15 ; 



3 figs.). — Interesting notes on newer species and hybrids, with figures of L. 

 Bolanderi, L. pardalinum x Parryi, and the bulb of L. Martagon x medeoloides , 

 showing the intermediate character of the bulb scales. — E. A. B. 



Lime Magnesia Ratio as Influenced by Concentration. By P. L. Gile. 



(U.S.A. Exp. Stn., Porto Rico, Bull. 12 ; 4 illus.). — The ratio of lime to 

 magnesia is shown to be of not so great an importance, as far as the rice crop is 

 concerned, as the balancing of lime and magnesia with all the other nutrient 

 salts, or it may explained that the toxicity of an excess of lime or magnesia 

 is not due so much to an unfavourable ratio between these two salts as to 

 an unfavourable proportion between the particular salt in excess and all the 

 others present ; hence the mere addition of lime in a soil containing an excess 

 of magnesia would not of necessity check the latter's toxicity, but the bringing up 

 of all the salts relatively to the one in excess would materially help. — C. P. C. 



Lime Requirements of Certain Soils. By H. B. Hutchinson and K. MacLennan 

 (Jour. Agr. Sci. vol. vii. part 1, pp. 75-105, March 1915 ; pi. and figs.). — The 

 addition of calcium carbonate (i.e. chalk, limestone, marl, &c.) merely corrects 

 the soil reaction. Calcium oxide (quicklime or caustic lime) not only does this, 

 but in addition, if applied in sufficient amount, produces certain effects classed 

 under the head of partial sterilization. Failure to recognize this double effect of 

 caustic lime has led in the past to a misinterpretation of experimental results. 



In order to determine the right amount of quicklime to apply to the 

 five different soils which were subjected to examination, definite weights of 

 soil were taken and, after being moistened, were treated with different amounts 

 of quicklime ranging from 1 to 2*0 per cent, of the weight of air-dried soil. At a 

 certain critical point, different for the different soils, the soil was found to be 

 distinctly alkaline, and from 5 to 10 c.c.s of decinormal acid were required to 

 neutralize the whole filtrate. The different amounts of quicklime required to 

 reach this critical point ranged from -3 to 1 per cent, of the soil taken, and it 

 was further found that the critical point also marked the following : — (i.) inhibition 

 of nitrification, (ii.) destruction of the larger protozoa, (iii.) maximum growth of 

 plants subjected to pot experiments, (iv.) flocculation point. For the soils exa- 

 mined, therefore, the above range of dressings (which correspond to a range of 

 3 tons to 9 tons to the acre) are the heaviest which should be applied. 



To determine whether a soil is acid and therefore requires a dressing of lime 

 it is not sufficient to determine whether or not the soil contains carbonate of 

 lime, since a number of normal soils have been recorded which are neutral and 

 yet contain no carbonate of lime. The authors review the numerous methods 

 which have been adopted by different investigators for the determination of soil 

 acidity, and reject them all as being inferior to the calcium bicarbonate method 

 which they have devised. By treating an excess of carbonate of lime suspended 

 in water with carbon dioxide generated by means of " sparklets " or otherwise 

 a solution of the bicarbonate is obtained which after filtration can be diluted 

 to approximately ~- Q strength. A known weight of the soil to be examined is 

 shaken for three hours with this solution, and at the end of the period the amount 

 of unabsorbed alkali is determined by standard acid solution in the usual manner. 

 Soils showing a positive lime requirement by this method have been found to 

 respond distinctly to the application of carbonate of lime by increased ammonia 

 and nitrate production in laboratory experiments, and by greater plant growth 

 in pot culture and field work. — /. E. W. E. H. 



Loblolly Pine in Delaware, Maryland, and Virginia, Forest Manage- 

 ment of. By W. D. Sterrett (U.S.A. Dep. Agr., Bull. 11; January 23, 1914). — 

 Loblolly pine is easily the leading tree for forest management in those portions 



