CROPS AND CROP TILLAGE. 31 



Great Basin, hoAvever, oxperieiioe has shown that much better crops 

 of wheat result when only 3 pecks of wheat or 45 pounds per acre arc 

 sown, while with alfalfa about 8 pounds of seed per acre gives the 

 best results. Some farmers even sow^ 35 pounds of wheat per acre 

 without ai)parently decreasing the yield, and careful experiments 

 have shown that even less than 8 pounds of alfalfa seed per acre will 

 give a good crop if evenly distributed, but uniform distribution is 

 difficult with much less than 8 pounds of seed per acre. The bene- 

 ficial effects of thin seeding are very striking, particularly in the drier 

 years, when a seeding of 75 pounds of wheat results in crop failure, 

 while a seeding of 35 pounds gives a good crop. This apparent 

 anomaly is due to the fact that the heavier seeding results in so large 

 and sudden a demand for soil moisture that the suppl}' Avithin reach 

 is exhausted while the plants are still in the active growing condition 

 and before the seed is formed, while with thin seeding the same 

 amount of soil moisture is sufficient for the plants produced. Both 

 wheat and alfalfa are able to throw out numerous branches from the 

 central stem, so that when moisture conditions are favorable the num- 

 ber of stems actually produced may be nearly as great from thin 

 seeding as from thick seeding. 



THE SUSTAINED PRODUCTIVENESS OF DRY-FARMED SOILS. 



In a system of farming where wheat is grown continuously, that is, 

 not in rotation with other crops, such as is the case on the dry lands 

 of the Great Basin, the question of maintaining the soil fertility is 

 a natural and important one. It is ordinarily assumed that the con- 

 tinuous production of any one crop, and particularly such a crop as 

 w^heat, must rapidly reduce the fertility of the soil. It would seem, 

 how^ever, that with the tillage S3^stem for Avheat, previously described, 

 by which a clean summer fallow is given every second or third year 

 and a large amount of straw is plowed under after each crop, the 

 reduction of fertility is by no means so rapid as it is in some other 

 regions and under some other conditions. 



As a matter of fact, there are fields in some of the older settled 

 valleys in the Great Basin that have been producing wheat every 

 other year for a third of a century w^ithout showing any signs of 

 depleted fertility. (See PI. Ill, fig. 2.) A^Tiile actual comparison is 

 of course impossible, there are reasons for believing that some of 

 these fields are capable of producing better crops now than when 

 first plowed. If this be true, it is important to discover the causes 

 involved and to determine whether this tillage method, if it be found 

 a contributing cause, is capable of wider application w^ith a hope of 

 similar results. It must be kept in mind that in the practice followed 

 on these dry lands, where the grain is headed rather than cut with 



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