ment of water. Again, the seed-bed should be thoroughly disced until 

 all of the lumps are pulverized in order to make plant food accessible to 

 the roots. Plant food is held in solution and forms a film; or, in other 

 words, clings to each particle of soil. The little delicate root filaments 

 are thrown around these particles of soil and absorb, through the process 

 of osmosis, the food and moisture. If lumps exist, the roots will not 

 penetrate them; hence, the feeding area is restricted just in proportion 

 to the number and density of the lumps in the seed-bed. The seed-bed 

 should also be compact. Compactness is essential to capillary attrac- 

 tion, and it is also necessary in order that the plant roots can receive a 

 firm hold in the soil. 



Air 



Atmospheric oxygen is necessary to plant roots; or, in other words, to 

 soil bacteria, which convert plant food into compounds. If the seed-bed 

 is not deep and thoroughly pulverized, it is not well aerated. If, for any 

 reason, the soil becomes surcharged with water, so that the air spaces 

 between the particles of soil are filled up, the air is driven out and the 

 growth comes to a standstill, and if the clogging continues even for a day 

 or two, the plant will smother. Every farmer has seen this condition 

 where water has stood for twenty-four or forty-eight hours in a wheat 

 field. 



Rotation 



It is well known to every wheat-grower that if he plants that cereal on 

 the same land for a series of years, the production will become less each 

 year, until, finally, he will hardly get his seed back. 



It is thought by some that plant roots throw off a deleterious excreta 

 which is a poison to its own kind, but that the excreta is a food or stimu- 

 lant to plants of a different variety; while others claim that a plant 

 exhausts its specific requirements from the soil to such an extent that 

 there is not enough fertility left to make a crop. Beyond question, both 

 theories have merit in a degree, but certainly the second one is far from 

 being correct, for we know that after wheat has been grown on soil until 

 a crop cannot be produced, the same soil will make a remarkable crop 

 of barley, rye, buckwheat or millet, using practically the same plant 

 food elements, showing that fertility still exists, but for some reason 

 cannot be utilized by the wheat. 



A piece of land which produced two hundred bushels of potatoes per 

 acre the first two years, finally failed to grow twenty bushels after it had 

 been cropped for sixteen years, but did make the seventeenth year 

 seventy-five bushels of oats per acre. Many other like experiments 

 might be given. 



Regardless of theories, however, we know that a scientific rotation 

 always results in an increased yield. Wheat makes its greatest yield 

 when following a legume. It also does well when sown on corn ground. 



