EXERCISE 37 



A FIELD STUDY OF THE DEFICIENCIES OF CORN PLANTS 



Statement. Low yields of corn are not due to a single cause. The deficiencies in the average field 

 of corn are numerous and require wide knowledge of soils and plant life to correct them. 



Object. To determine the influence of the stand and the 

 proportion of barren to fruitful stalks upon the yield of corn ; 

 also the causes of poor stands and of barrenness of stalks. 



Materials. Measuring stick or tape measure ; spring 

 balances ; a bag or bushel basket. 



Directions. Select a row of corn that represents, as 

 nearly as may be ascertained by the eye, the average of 

 the field and measure the distance between the rows. If 

 the rows are 3^ feet apart, a row 125 feet long will be the 

 equivalent of one hundredth of an acre. In any case, 

 measure off a row long enough to be the equivalent of one 

 hundredth of an acre. 



Count the hills in the row ; the number of hills missing ; 

 the number with one stalk, with two stalks, with three 

 stalks, with more than three stalks. Compute the average 

 number of stalks in a hill ; the total number of stalks in 

 the row. Count the number of stalks with one good ear, 

 with two good ears; the number bearing nubbins (ears 

 under five inches in length) ; the number of barren stalks ; 

 the total number of ears; the total weight of ears; the 

 percentage of stalks bearing good ears ; the estimated yield ; 

 and the number of ears to the acre. 



Compute the yield per acre on the basis of a perfect 

 stand and each stalk bearing an ear weighing 12 ounces, 

 and compare the result with the actual increase in yield 

 per acre if each stalk found barren or producing only a 

 nubbin had borne a normal ear. 



Explain some of the causes for poor stands and barrenness 

 and how these defects may be remedied. 



Fill in these data on the form opposite and discuss the 

 results obtained. 



Questions. How could the farmer have increased his 

 yield ? Would the row you have examined be a good place 



Fig. 45. High and low yielding ears 

 The difference in the yielding power of different ears of 

 corn of the same variety is well illustrated by the produc- 

 ing record of the ears shown. These two ears were selected 

 from the same field as good seed and the grains planted 

 side by side and given the same care. The seed from the 

 ear at the left yielded 16 bushels to the acre, and seed 

 from the ear at the right yielded 70 bushels per acre. 

 (Courtesy of the Kansas State Agricultural College) 



for the farmer to obtain seed for the next year's planting ? 

 On the basis of 90 per cent of a perfect stand what would have been the yield of the row you counted? 

 What would have been the yield if each stalk had borne a 12 -ounce ear? Will the ears be as large 

 and the proportion of fruitful stalks as large with a perfect stand as with 80 per cent of a stand? 

 In a very dry season is a thick or a thin stand best and why ? In a wet season which is best and 

 why? On rich land? On poor land? Which when the variety planted is large? When it is small? 



References. Waters, H. J. Essentials of Agriculture, pp. 137, 141. 

 The Cereals in America, pp. 196-197. Orange Judd Company. 



[74] 



Ginn and Company. Hunt, T. F. 



