54 CORN CULTURE 



they consume plant food. If our soils were filled with an 

 abundance of available plant food, in sufficient quantity for 

 the growth of both corn and weeds, there would be no need of 

 such a constant warfare against the latter. But our New 

 Hampshire soils do not contain this abundance of available 

 plant food. The necessity for commercial fertilizers is evi- 

 dence enough that our soils do not contain even plant food 

 enough for the growing of corn to maturity. 



Second. Weeds keep sunlight and warmth from the soil. 

 The mulched plot in the preceding experiment was under- 

 yield, not so much because a few weeds grew but principally 

 because of the shade and lack of warmth. Weeds act m the 

 same way; they shade the ground and keep the soil cool. 



Third. Weeds are consumers of water. Insufficient mois- 

 ture in the soil is often the only cause of a small crop. An 

 abundance of water in the soil is necessary for the production 

 of a maximum crop. If there is an insufficient amount of 

 water in the soil the crop will be short; the more weeds in a 

 field the larger the amount of water consumed. 



Eealizing the importance of these facts, the writer thought 

 .it advisable to see if an increased crop would result if witch- 

 grass was kept out by the hand hoe, where the cultivator was 

 unable to do so. 



Two plots were laid off, the same in every respect. The soil 

 was similar to that previously described. On May 9 the plots 

 were planted to corn and were given the same cultivation until 

 June 10. The preliminary cultivation consisted of two har- 

 rowings after the corn was planted and the use of the weeder 

 three times. On June 10 both plots were cultivated with 

 "Planet, Jr." cultivator. Witch-grass was quite prominent at 

 this time. One of the plots was immediately gone over with 

 the hand hoe, not as a cultivator but simply to destroy the 

 grass. On June 21, July 5, and July 20 the same operations 

 were repeated. During the summer the hoed plot was entirely 

 free of witch-grass, but the other plot was matted with it in 

 the rows. The corn was cut and han^ested with the following 

 results: 



