36 MAIZE 



CHAP. 27. Soil Temperature. — The temperature of the soil has 



much to do with the successful growth of maize and other 

 tropical crops. In cold soils germination and subsequent 

 growth are retarded. Experiments conducted at Pretoria 

 show that whereas maize planted in September and early 

 October usually requires eight clays to appear above ground, 

 that planted at the end of December or early January will 

 sometimes appear in three days ; in each case the seed was 

 well watered daily, so that lack of moisture was not the cause 

 of retarded germination, which may therefore be attributed to 

 low temperature of the soil. 



Maize lands should be well drained, for wet soils are usually 

 cold soils. It is largely on this account that maize germinates 

 badly, and its growth, also, is retarded in water-logged soils. 

 When water stands for any time on the maize lands, the 

 foliage becomes yellow and the plants remain stunted. In 

 cycles of droughty weather there is a tendency to plant the 

 crops in low-lying ground which retains a certain amount of 

 moisture ; but when normal seasons return the crops in these 

 lands suffer. It is better to apply the principles of dry-farming 

 (i.e. good tillage) to the soil (see chap. IX.), in order to con- 

 serve the moisture, than to use undrained land in anticipation 

 of possible drought. 



28. Moisture Requirements. — Maize is, on the whole, a 

 drought-resistant plant, but some breeds suffer more from 

 drought than others, and these should not be chosen for regions 

 where the average rainfall of the period from December to 

 February inclusive is too light for the ordinary breeds. King 

 (1) has found that in Wisconsin the maize plant abstracts from 

 the surrounding soil 270 lbs. of water for each pound of dry 

 matter grown, which is equal to a rainfall of 2-4 inches for 

 each ton, or only about half the amount required (in Wisconsin) 

 by oats and clover. But the maize plant requires a consider- 

 able amount of water at certain stages of growth. 



In Illinois the growth of maize during one week in July 

 has been found equal to 1,300 lbs. of dry matter per acre, 

 which would require 1-5 inches of rainfall, according to King's 

 experiments. At a time of such rapid growth the plant is apt 

 to suffer from drought unless the soil is in the best physical 

 condition {Hunt, l). 



