4 WINTER WHEAT IN WESTERN SOUTH DAKOTA. 



and injury of the roots by the heaving of the soil, and to other causes. 

 The extent of injury differs widely with the different varieties grown 

 and is affected to a less extent by the preparation of the soil and 

 seed and by the time, rate, and method of seeding. 



During the three years in which tests have been conducted at the 

 Bellefourche Experiment Farm,^ situated near Newell, S. Dak., the 

 winterkilling of the best varieties has seldom exceeded 25 per cent, 

 while the average is less than 15 per cent. The stooling of these 

 varieties has been such that the actual loss in bushels has probably 

 been slight. At the present writing (Apr. 1, 1911), the fourth crop 

 has come through the winter apparently in good condition. 



It seems that a field may be greatly injured by winterkilling and 

 yet produce a good yield, especially if the damage is evenly dis- 

 tributed throughout the field. Winterkilhng of over 50 per cent at 

 the Bellefourche Experiment Farm has in some cases been followed 

 by yields of 20 bushels per acre and over. 



The soil of the Bellefourche Experiment Farm is a heavy clay of 

 the Pierre clay formation, commonly known as gumbo. Apparently 

 it does not heave, and this fact has undoubtedly diminished the loss 

 from winterkilling. On the other hand the winters have sometimes 

 been severe and the plats have been so located that they received 

 very little protection from snow. 



THE BLOWING OF THE SOIL. 



Damage from the blowing of the soil in high winds is an important 

 consideration on the dry lands. The danger is greatest on soils con- 

 taining sand or fine gravel and in fields fully exposed to the wind. 

 In the late winter and early spring months, the velocity of the wind 

 is often great enough to carry the soil particles rapidly across the 

 field, cutting off the plants near the ground and exposing the roots 

 to the weather. This condition is especially trying on dry farms, as 

 dry winters are common and the plants and soil are left in a condi- 

 tion most favorable to rapid evaporation. Undoubtedly much of the 

 loss ascribed to winterkilling may be traced to this cause. 



The extent of injury likely to be done is affected by the location of 

 the field, ridges being exposed to and valleys or swales being more or 

 less protected from the full violence of the wind. Consequently 

 fields partly protected are less likely to be damaged than are those 

 fully exposed to the prevailing northwest winds. 



Little progress has been made in devising methods of handling 

 cultivated fields to prevent blowing. The problem is especially dif- 

 ficult for the dry-land farmer, as the fine soil mulcli, which is so 



1 The Bellefourche Experiment Faiin is in charge of the Office of Western Agricultural Extension of 

 the Bureau of Plant Industry. The investigations reported in this cu-cular were conducted in cooperation 

 with that oflic*. 

 [Cir. 79.] 



