124 



THE GARDEN AND FIELD. 



August, 1913 



Maize. 



The original home of maize is 

 now quite certainly known to have 

 been in Central Mexico, and hence 

 it is the onlv one of our cereals 

 that is indigenous to the New 

 World. It has been so long and 

 so thoroughly domesticated that 

 no truly wild varieties are known. 

 In geographical ramge and elastici- 

 ty of habit it probably surpasses 

 every Vather cultivated plant. From 

 its original tropical home it has 

 spread to the tem.perate as ' well 

 as the tropical regions of . the 

 world. Introduced into Kurope 

 soon after the conquest of Mexico, 

 it finds a genial home only in the 

 warm valleys of the south and 

 central portions of that contin- 

 ent ; it is exten.sively grown in 

 Africa, and in India it thrives 

 everywhere throughout the ' hill 

 country ; it appears to llourish as 

 well in the temperate as the tro- 

 pical regions, and at altitudes of 

 from sea-le\el to 7,000 feet or 

 more. Maize is, however, as it 

 has always been ■, and will nmdoubt- 

 edly remain, a distinctive and 

 characteristic American i)roduct. It 

 is cultivated from Ca,nada to Pa- 

 tagonia, Over 7,o<xi miles of lati- 

 tude. It has been known to ripen 

 as far north as 63 degrees, and has 

 been found a profitablei crop in 

 latitude 51 degrees north. In re- 

 sponse to the multifarious condi- 

 tions which this great range im- 

 poses, countless varieties have been 

 developed, therc^ being more than 

 2(X) in the United States alone. 



— The effects of Climate. — 

 The effects of climate on maize 

 may be appro])riatel\- classified as 

 immediate, intermediaee, and inci- 

 dental. Prof. Storer has tersely 

 said that the prime object of agri- 

 culture is to collect for purposes 

 of human aggrandisement as much 

 as m'av l)e possil)lf of the energy 

 that comes from the sun in form 

 of light and heat. Now the work- 

 ing capacity of sunshine is, ac- 

 cording to Kelvin, one horse- 

 l)ower for every square ifeet of sur- 

 face. Measured by the standards 

 of mechanics, how inellicient and 

 wasteful an engine is our agricul- 

 ture at its best. The atmosi)here 

 is directly the source of 95 per 

 cent, of the m.aterial in the total 

 jilant and of 98 ]x;r cent, of the 

 matter in the grain of maize. The 

 plant is an elai)orate machine that 

 absor1)s and transforms encrgv, 

 utilising solar radiation to digest 

 rarl)oii rlioxide in the leaves and 

 to comliine into vegetable organs 

 jMid tissues the gases of the air 

 with '.the elements supplied b\ tin- 



soil. \\'hen we remember that the 

 amount of energy available, the 

 food supj)ly, and, consequently, the 

 amount of matter stored, all de- 

 pend directly upon meteorological 

 conditions, we realise how over- 

 whelming is the influence of cli- 

 mate. 



— Growth. — 



A grain of maize once matured 

 is as inert as a pebble until heat 

 and moisture are applied ; then a 

 sprout and a rooti appear, each for 

 a separate function, the" one for, 

 absorljing ethereal waves, the other 

 for absorbing water. In addition 

 to heat and moisture, oxygen is 

 absolutely essential to germina- 

 tion, as well as to all subsequent 

 growth. The importance of mois- 

 ture will be appreciated when we 

 recall that water performs at least 

 four distinct offices : first, directly 

 as a food., being united in the 

 leaves with carbon to form the 

 carbo-hydrates ; second, as a sol- 

 vent for the nutritive matters in 

 the soil ; third, as the vehicle 

 which transports the soluble food 

 through the roots and atems to 

 the leaves ; and, finally, as a cool- 

 ing device, since, through evapora- 

 tion, water largel}^ controls the 

 temperature of the plant. The 

 " free water of vegetation," as it 

 is called, or the water of the 

 juices, comprises from 70 to 90 

 per cent, of corn in the fodder 

 stage, while the " combined water 

 of vegetation," or the water, that 

 remains after the plant is air- 

 dried, is 12 per cent, in a kernel 

 of com. 



— Immediate IJffects. — 



The immediate effects of climate 

 wiU be better imderstood bv glanc- 

 ing first at its intermediate effects 

 through the medium of the soil 

 and through the food supply. Cli^ 

 mate originates soil ^ and all the 

 capacities of the earth ^«r tillage, 

 and it is at the same time more 

 than soil or tillage. For in a 

 really "good year" the worst tilled 

 soil returns a more bountiful har- 

 vest than it is possible with all ' 

 our industry to extract from the 

 best tilled soil in a " bad year." 

 The oasis differs from the de.sert 

 onlv in the item of water suuply, 

 and a given cliniate does not re- 

 sult i)rimarilv from the nature of 

 the earth's surface ; on the con- 

 trary, that surface is deter nined 

 almost wholly by climate. 



— The Soil a Reservoir. — 



Primarily, the soil is a reservoir 

 of moisture and plant food ; but 

 hardly secondary is its office as ii 

 vast laboratory, wherein during 

 the warmer seasons countless com- 



plex chemical agencies and num- 

 berless microscopic organisms oper- 

 ate unceasingly. Indeed, the rela- 

 tions of climate to the plant 

 through the medium of the soil 

 are so intimate and vital that no 

 just idea of their importance can 

 be given here. These relations 

 m.av be classed as physical, chemi- 

 cal and biological. 



• — Texture. — 



The physical texture of the) soil 

 determines its conductivity for 

 heat and its content of water and 

 air, both of which in proper pro- 

 portions are essential to the chem- 

 ical and biological functions. More- 

 over, the water content, through 

 its power to absorb, transform 

 and conserve radiant energy, con- 

 trols the temperature of thie soil. 

 Finally, soil temperature is far 

 more effective than the tempera- 

 ture of the air. Heat is well 

 known to accelerate diffusion, so- 

 lution, osmotic action and evapor- 

 ation. Now these physical pro- 

 cesses are preciseh' those that per- 

 form the chief, almost the entire 

 work involved in plant nutrition 

 and growth. Hence, a high soil 

 temjjerature is essential not only 

 i,OT the life of the plant 1 itself, but 

 also for the ventilation and the life 

 of the soil, a healthy soil being 

 very appropriatel}' called a living 

 mass. On an average 40 per cent, 

 of the radiant energy incident to 

 the soil is absorbed, conducted 

 downward, and stored in the form 

 of heat, 60 per cent, being lost to 

 the soil hy reflection, radiation and 

 evap(jration. ^ 



Oxygen is as indispensable to thie 

 chemical life of the soil as it is 

 to animal life. I^oth oxygen and 

 nitrogen are essential to the biolo- 

 gical i)rocesses, and both the 

 chemical and biological activities 

 in the soil are as indispensable to 

 the cro]) as are sunshine and 

 showers. 



— Kight Proportions. — 



The imj^ortance of right propor- 

 tions of water and air in thie soil 

 is further shown by the fact that 

 the i)rocess of decay, whereby or- 

 ganic material is turned into 

 humus and made available to] the 

 ])lant, cannot go on without an 

 abundant sup])lv of oxygen. A soil 

 that contains too much water con- 

 tains too little air. The ferments 

 thrive best at a temperature of 85 

 degrees to 9.5 degrees, and when 

 the soil contains from one-ltalf to 

 one-third the amount of water re- 

 cpiired for saturation. The ulti- 

 mate source of the nitrogen found 

 , in vegetable matter is the air, 



