258 DRY-FARMING 
clothing, and shelter has become more clearly under- 
stood, more attention has been given to the valuatica 
of commercial products on the basis of quality as well 
as of quantity. Sugar beets, for instance, are bought 
by the sugar factories under a guarantee of a mini- 
mum sugar content; and many factories of Hurope 
vary the price paid according to the sugar contained 
by the beets. The millers, especially in certain parts 
of the country where wheat has deteriorated, dis- 
tinguish carefully between the flour-producing quali- 
ties of wheats from various sections and fix the price 
accordingly. Even in the household, information 
concerning the real nutritive value of various foods is 
being sought eagerly, and foods known to possess the 
highest value in the maintenance of life are displacing, 
even at a higher cost, the inferior products. The 
quality valuation is, in fact, being extended as 
rapidly as the growth of knowledge will permit'to the 
chief food materials of commerce. As this practice 
becomes fixed the dry-farmer will be able to command 
the best market prices for his products, for it is un- 
doubtedly true that from the point of view of quality, 
dry-farm food products may be placed safely in com- 
petition with any farm products on the markets of the 
world. 
Proportion of plant parts 
It need hardly be said, after the discussions in the 
preceding chapters, that the nature of plant growth 
