350 SOIL PHYSICS AND MANAGEMENT 



inauy cases a considerable portion of the oats are not covered, being 

 in some cases by actual count one-eighth of the amount seeded. 



Plowing the ground before seeding aids in producing an ex- 

 cellent seed bed; however, it will be too loose unless thoroughly 

 firmed. The harrow and cornpacter should be used, and if the 

 soil is well supplied with organic matter so it will not bake it 

 should be rolled after the seeding is done. The disk drill has some 

 advantage over the broadcast seeder for seeding oats, and the fact 

 that it co' 3rs practically all the seed is a decided advantage. Only 

 about two-thirds as much seed will be required as when seeded 

 broadcast. 



Cultivation. Object. The objects to be accomplished in the 

 cultivation of a crop are: first, and primarily, the killing of 

 weeds; second, the conservation of moisture; and, third, aeration. 

 While the conservation of moisture has usually been placed first, 

 recent experiments show that cultivation for the killing of weeds in 

 humid regions is of vastly more importance to the crop than for 

 the conservation of moisture. It is a question whether this may 

 not be true in semi-arid regions as well. Weeds require both 

 moisture and plant food for their growth and are much better for- 

 agers than the cultivated crop. At the Illinois Station (table, page 

 352), as a result of nine years' investigation, corn with weeds de- 

 stroyed by a hoe without producing a mulch gave a yield of 48.9 

 bushels per acre for a nine-year a\ r erage, while for the same time 

 corn in which weeds were allowed to grow produced 7.5 bushels per 

 acre, or 41.4 bushels in favor of preventing the growth of weeds 

 (Figs. 167, 168, 169). In order to determine whether it was the 

 lack of the plant food or the moisture that caused the greater loss, 

 part of each plot in which the weeds were allowed to grow was sup- 

 plied with all the moisture the crop and weeds needed, and as a five- 

 3'ear average the yield was increased 2.5 bushels over the plots where 

 no water was applied. This shows rather conclusively that the 

 greatest loss was caused by depriving the corn of food. 



Value of the Mulch. In this same experiment the plots men- 

 tioned above in which the weeds were kept down with a hoe with- 

 out producing a mulch gave a yield of 48.9 bushels, while the corre- 

 sponding plots which were cultivated gave a yield of 43.3 bushels, or 

 5.6 bushels were lost due to damage by cultivation. Moisture de- 

 terminations in each of these three plots were made and it was 

 found that the amount of moisture in the uncultivated plot actually 

 exceeded that of the cultivated by 0.3 per cent for an eight-year 



