8 BEAN CULTURE 



evaporation. In the spring, then, early and 

 thorough preparation of the seed bed tends to make 

 the seed bed warmer; it diminishes the loss of soil 

 moisture ; it increases the formation of nitrates, thus 

 making the soil richer; it hastens and makes stronger 

 the germination and enables one or more crops of 

 weeds to be destroyed before the crop is up ready 

 for cultivation. Hence there is much to gain and 

 little to lose in thorough preparation of the seed bed 

 before planting. 



Air conditions. — Fortunately those conditions 

 which favor conservation of soil moisture also con- 

 tribute in a general way to favorable aeration of the 

 soil. Cultivating to conserve soil moisture admits 

 light and air both of which are valuable to the plant. 

 Interesting observations are reported by Eberhardt* 

 relative to the efifect of humid air on bean plants. 

 In his experiments he found that humid air in- 

 creased very materially the ipward growth of the 

 bean plants, though the diameter of the stem was 

 diminished. There was a tendency greatly to in- 

 crease the leaf surface and diminish the chlorophyll 

 contained in the leaves, as well as greatly to reduce 

 the root system. On the other hand, dry air 

 checked the growth and development of stems and 

 leaves, increased the diameter of the stem, dimin- 

 ished the leaf surface and greatly increased the 

 number and distribution of the roots. 



Electrical influence on beans. — Experiments in 

 Germany by Prengshein ** showed that the increased 

 production in beans on plats under electrical influ- 

 ence was over 30 per cent. On potatoes the in- 

 fluence was but 7 per cent. F. Paulin*** tells us that 



*Compt Rend Acad Sci, Paris, 131, 1900. 

 "E S R, Vol 16. ***France, 1903. 



