184 



The presence of plenty of lime is essential, and there must also be a 

 sufficient supply of potash and phosphoric acid. 



Results obtained by different investigators respecting the effect of 

 the symbiosis on the character of the plant, especially as regards the 

 production of roots, stems and leaves on the one hand, and of flower 

 and seed on the other, are somewhat conflicting. Both Hellriegel and 

 Nobbe found seed production to be retarded, whilst the yield of straw 

 was increased. Nobbe, therefore considers the action of the bacteria 

 more favourable to the production of fodder, and for green manuring, 

 than for the production of seed. Salfeld thinks that the nature of the 

 soil, and of the season, have a good deal to do with this. Peas grown 

 in peaty soil often ripen very late, and the yield of com was not always 

 satisfactory as compared with the enormous production of stem and 

 leaf, but this is ascribed mainly to the unfavourable weather and other 

 conditions. In the case of lupins, very good seed was obtained on 

 unmanured soil, whilst when heavily manured with potash and phos- 

 phates, the plants did not ripen at all. It is, therefore, proposed that 

 * in growing lupins, or clover for seed, potash and phosphates should 

 be applied sparingly, if at all. In von Feilitzen's experiments with 

 peas, referred to at p. 180, it w^ill be remembered that the gain due to 

 inoculation was chiefly in the production of corn, and that the quality 

 of the com was also improved by inoculation. However, it may be 

 concluded that on the whole it is for fodder, and for green manuring, 

 that soil inoculation will be chiefly employed. 



The practice of green manuring, which has extended a good deal in 

 Germany, will no doubt receive an impetus from the success which the 

 numerous inoculation experiments have met with. Although it would 

 seem especially adapted for improving poor soils, its adoption in 

 ordinary farming will be watched with much interest. In connection 

 with this part of the subject we cannot perhaps, do better than refer 

 to the results of Gr. Dehlinger, of Weilerhof. Dr. Dehlinger, soon 

 after taking possession of a farm near Darmstadt, decided to sell nearly 

 all the cattle, of which a considerable number had been kept, keeping 

 only sufficient to supply his own wants, and to adopt green manuring, 

 supplemented with artificial manures, in the place of stable manure. 

 Several years' experience convinced him that the system is more econo- 

 mical than any other, the cost of nitrogen in pea and vetch manuring 

 being estimated at rather less than a penny per pound, as against about 

 seven-pence in nitrate of soda, and tenpence in stable manure. Dr. 

 Dehlinger also considers the system more unrestrained than whea 

 cattle are kept. Finally, he states that good crops were obtained after 

 green manuring, and that the system is, on the whole very remunera- 

 tive. It should be mentioned that two-thirds of his land is a heavy 

 loam, and the rest a sandy loam. C^). 



With regard to the more frequent growth of such plants as clover 

 and peas, which are liable to sickness, it seems best for the present to 

 keep to the old rules. We, are, as Dr. Salfeld says, still uncertain 

 what the failure of these crops is due to, though Liebscher considers 



14. G. Dehlinger, Viehlose grundiingr^rirtschaft auf schwerem Boden. Berlin, 

 1892. Also Fream, "Farming without live stock," Joum. R. A. S. E., 1891, 



[3],voi..n.,:p.87o.. 



