vii.] GREEN MANURING 211 



ploughing in the green crop. Mineral manures alone 

 are employed, latterly basic slag and the Stassfurt 

 potash salts ; the lupins accumulate nitrogen from 

 the atmosphere, thus gradually there is built up both 

 humus to bind together the loose sand and make it 

 retentive of moisture, and also a store of nitrogen for 

 the nutrition of succeeding crops. The soil of a field 

 growing lupins every year from 1865 was found in 

 1880 to contain 0-087 per cent, of nitrogen in the 

 surface 8 inches, as compared with 0027 per cent, 

 in an adjoining pasture. By 1891 the proportion of 

 nitrogen had increased to 0-177 per cent, despite the 

 annual removal of the lupin crop and the fact that 

 the manuring had been with phosphates and potash 

 only. It is in reclaiming these heath lands which 

 have not previously been under cultivation, nor, in 

 many cases, carried any leguminous vegetation what- 

 ever, that soil inoculation from land previously cultivated 

 has given successful results. Dr Salfeld of Hanover has 

 recorded several cases of the successful cultivation on a 

 large scale of various leguminous plants, beans, clover, 

 serradella, lupins, only after previous inoculation with 

 soil. The experiments were made on both peaty (moor) 

 and sandy soils, on which, without inoculation, legumin- 

 ous plants made but little growth and developed no 

 nodules. Success followed when about 8 cwt. per acre of 

 soil from a field which had previously carried the crop in 

 question were sown broadcast over the land in April, 

 and harrowed in just before seeding. In one case, over 

 7 tons per acre of green serradella were grown where 

 the land had been treated with 8 cwt. of soil from an 

 old serradella field, whereas the crop failed after germina- 

 tion where no inoculation had been practised. 



