8S PERIODIC PHENOMENA OF VEGETABLE LIFE. 



elevated fields reaches an angle of 30° to 35°; the soil is thus 

 washed down by rains, and has to be carried back with great 

 labour to the upper parts. At the same time the projection 

 becomes smaller as the inclination increases. This projection is 

 for every 100 square metres (or yards).* 



The loss of cultivation is not indeed, as shown by Corrard, quite 

 so great, f as the pulverisation and exposure of the soil to the 

 atmosphere somewhat increases ; nevertheless it is very perceptible 

 in steeply inclined fields. 



Still more prejudicial to the crops are the great number of 

 grasses and other weeds which grow amongst the corn. They are 

 specially favoured by the humidity of the air and soil. Already 

 at an elevation of 3000 feet, must they be weeded out of Wheat, 

 and at great elevations even from Rye and Barley. The haulms 

 are generally very thinly scattered, and often a half or a whole 

 square foot entirely covered with weeds. Yet a too thick sowing 

 of the corn would also be prejudicial, for the passing snow-storms, 

 which occur at great heights, especially in autumn, would easily 

 lay and break down the haulms where they are too crowded. 



The quality of the grain diminishes also with altitude ; the 

 Cereals grown in elevated spots, even in favourable years, are 

 much lighter and yield less flour. The straw, near the limits of 

 the corn cultivation, is much stronger in proportion to the grain; 

 it amounts to from four to five times the latter in weight, whilst 

 lower down the proportion may be valued at from 40 to 60 parts 

 of grain to 100 of straw in weight. J 



The quantity of produce and quality of the grain in different 

 years corresponds, even in plains, with the variations in tempera- 

 ture during the term of vegetation, although in this case con- 

 siderable aberrations may be occasioned by too much rain or by 

 prolonged droughts according to the nature of the soil ; but in 



* According to Boussingault, Economic rurale. 



f Transactions of the Haarlem Society, vol. xv. p. 308. For larger plants, 

 as trees for instance, which in plains also are placed far apart, the loss of 

 space by inclination is much less than for herbaceous crops. 



+ The different kinds of grain show great differences in this respect, the 

 proportions, according to Boussingault, Economic rurale, are as follows : 

 Wheat 41, Rye 47, Barley 50, Oats 60 to 100 of straw. See also Zierl, On 

 the State of Agriculture in Bavaria, Part 2, 1840, Appendix 3. 



