382 



O. LOEW. 



these experiments 1 for oats (ripened harvest) i : 1 

 for barley, before flowering, 2 : 1 

 cabbage 2 : 1 

 buckwheat 3 : 1 



If we take the amount of magnesia as the unit we may 

 call the relative amount of lime present the linief actor and 

 express the result thus : The limefactor for buckwheat is 3 ; 

 for cabbage, 2 ; for oats 1. 



If we find the limefactor in a soil 1, the soil does not need 

 liming for a crop of oats, but will need it when buckwheat or 

 onions are to be grown. The beneficial influence of the rotation 

 of crops is partly due to the variations of the limefactor in the 

 soil caused by the growth of different crops. 



Since the limefactor of cereals before flowering is larger 

 than later on after the flowering stage, great benefit might accrue 

 from the application of a highly diluted solution of calcium nitrate 

 to the young plants. The limefactor for various crops may be 

 calculated from the average of many ash analyses ; and thus we 

 find the limefactor by calculation from Wollf's tables of ash 

 analyses, for 



Wheat in the flowering stage. ... 1.4 

 Clover ,, ,, ,, .. 3.2 



Lettuce 2.8 



Sugar cane 1. 05 



But it is safer to determine the limefactor by actual test, 

 since the analysed plants may have taken up more lime than 

 necessary. Many plants will render this surplus partly or 

 wholly innocuous by precipitating it as oxalate. Should plants, 

 however, take up more magnesia than is required from a soil 

 rich in magnesia but poor in lime, the injury cannot be repaired, 

 the harvest will be very unsatisfactory. Such a soil is devoid 

 of natural fertility, even if it be rich in potassa, phosphoric acid 

 and nitrogen compounds. 



One of the beneficial effects of liming is believed to consist 

 in, "unlocking such potassa, as is at the time unavailable for 



1 With onions in water cultures the results were best with the ratio 2 : f", but the 

 results with the ratio 1 : i were nearly the same. These experiments have to be 

 repeated with soilcultures as must also those with soybeans, since Aso's tests relate only 

 to a very early stage. These figures relate as usual in agricultural relations to absolute 

 quantities, not to the number of molecules. 



