150 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 



the nutrition of plants. The absorptive power of the soil 

 explains, therefore, why the crops obtained from manured 

 fields are rather in proportion to the nutritive substances 

 supphed in the manui-e, than to the store of these elements 

 originally present in the soil. 



The operation of manurmg agents, severally or jomtly 

 applied, is even more marked upon soils which are poorer 

 in nutritive substances than the field at Schleissheim above 

 mentioned. 



The following results were obtained on a field broken 

 up for the purpose, which had not been touched by the 

 plough for fifteen years, and had served as pasture for 

 sheep. The entire surface -layer of the ground at 

 Schleissheim is 6 niches deep at most ; below this there is 

 no more soil, but a bed of rubble stones, which might be 

 compared to a sieve with meshes an inch wide, through 

 which the water runs freely ; the crop obtained from the 

 unmanured portion will give some idea of its sterility. 

 Another portion was manured with superphosphate of 

 lime ; the quantity used per hectare (=2| acres) was 525 

 kilogrammes ( = 10 cwt.) of phosphorite decomposed by 

 sulphmic acid, containing 193 kilogrammes of phosphoric 

 acid, or 420 kilogrammes ( = 8 cwt.) of phosphate of hme. 



Crop of winter-rye in 1858 at Schleissheim, per hec- 

 tare : — 



