76 CROP PRODUCTION AND SOIL FERTILITY 



(d) The presenct of helpful soil organisms of which there are 

 several kinds; viz., bacteria which cause the formation of the 

 nodules on the roots of legumes; bacteria, molds and fungi which 

 help make plant-food elements available, and are helpful in other 

 ways. Angleworms may also be mentioned in this connection. 



{e) A good supply of available plant-food elements from which 

 crops may secure sufficient nitrogen, phosphorus, potassium, 

 calcium, etc., to permit of good yields. 



(/) The absence of harmful agents in the soil, such as poisons; 

 too much salt, such as alkaU; certain diseases; too much water, etc. 



These factors are further discussed under '^soil fertility," and 

 in the following chapters. 



Good Seed. — It is generally recognized that good seed is a 

 factor of much importance. Poor seed in poor soil means miserable 

 failure. Good seed in poor soil renders just as little, if not less, 

 for labor than poor seed in good soil. But the best combination is 

 good seed in good soil. 



The emphasis put on good seed in agricultural development 

 today leads some to think that this idea is a product of the twen- 

 tieth century. Not so. Early agricultural writings reveal the 

 fact that the value of good seed was much discussed in the old 

 countries himdreds of years ago. The following quotation, taken 

 from a book, '^Way to Get Wealth," by G. Markham, printed in 

 London in 1660, is interesting in this connection: 



"... You shal then take your Seed which would be the finest, cleanest, 

 and best Wheat you can provide, and after the manner of good Husbandry, 

 you shal sow it on the ground very plentifully, not starving the ground for 

 want of Seed (which were a tyrannous penury) nor yet choaking it with too 

 much (which is as lavish a foolery) but givmg it the full due, leave it to the 

 earth and Gods blessing." 



Factors Involved. — In spite of the fact that much has been 

 said and written in this generation ^bout good seed, there 

 are still many who fail to give this factor any serious con- 

 sideration. A high germination test is not the only indica- 

 tion of good seed. There is also involved a selection of size of 

 seed, and for adaptability, purity, disease resistance, high yield 

 and superior quality. 



Size and Weight. — There is a decided advantage in the use of 

 large or heavy seeds over small ones, even though they may be of 

 the same variety and all of high germination test. The Ontario 

 Agricultural College (Canada) produced a seven-year average of 



