226 



THE CEREALS IN AMERICA 



yield of fifty-one bushels as compared with fifty-six bushels on 

 an average of ten adjacent plats when surface planted. 



302. Time of Planting. — The soil should be at least 60° F. 

 at the depth of the seed before maize is planted. But it is not 

 enough to consult the thermometer ; the almanac should also 

 be consulted. A change in the weather may follow even after 

 the temperature of the soil is 60° F. The old Indian sign, 

 which is to plant maize when the leaves of oak trees are as big as 

 a squirrel's ear, is not much at fault. The best date of planting 

 will of course vary largely with the season. The following table 

 gives the best dates as determined at the stations indicated, as 

 well as indicating the period over which the test was made. 



Results from Planting at Different Dates. 



There is fairly good evidence that in the main maize belt 

 there is a period of three to four weeks within which the time 

 of planting does not materially affect the yield. At the Illinois 

 Station, for example, while the best results during an average of 

 eight years were obtained from May nth to May i8th, there was 

 but little difference in yield from May 4th to June ist. Very 

 early planting, however, has been shown to require more cultiva- 

 tion to keep the land free of weeds. On the other hand, it is 

 not wise to delay planting when the conditions are favorable 

 for fear that subsequently climatic conditions may be such as 

 to prevent the planting at the theoretically best time. Where 



