GROWING FIELD CROPS IN SUGAR-BEET DISTRICTS. 5 



Some of the crops studied can be grown without the practice of 

 irrigation in the semiarid climate of Colorado. However, to reach 

 the maximum yield it is necessary to irrigate. There are other crops 

 which can not be grown at a profit except by irrigation. Sugar beets 

 are never grown in this region without irrigation, and cantaloupes and 

 cucumbers are not commercially profitable without it. Beans, po- 

 tatoes, and small grains are grown on both irrigated and nonirrigated 

 lands at a profit, with the average production per acre much greater 

 on the irrigated areas. 



Precipitation and the seasonal distribution of rainfall are much the 

 same for the two valleys. Fortunately, the major portion of the an- 

 nual rainfall occurs during the growing season. There is a some- 

 what heavier rainfall in the months of March, April, and May in the 

 South Platte Valley than at Kocky Ford. (See Table II.) This 

 with the slightly increased temperature of the Rocky Ford district 

 accounts partially for the fact that it is customary there to irrigate 

 immediately after or previous to planting some crops. (Fig. 2.) 



Fig. 2. — Watering sugar-beet seed for germination, showing an example of row irrigation. The furrows 

 must be well made, and careful attention should be given to the running of the water. The furrows 

 are made as the seed is planted. 



The Greeley and Fort Morgan growers do not practice spring irriga- 

 tion, as there is, as a rule, sufficient precipitation or stored moisture 

 in the soil to germinate the seed and start the crops. 



Some rains which fall during July, August, and September do not 

 benefit the crops greatly; in fact, they may do serious damage by 

 forming a heavy crust or by causing the crop to lodge. Many of these 

 rains come in heavy showers, when the run-off is great, and others in 

 light showers which do not penetrate the soil. The average being 

 very low, the evaporation is rapid and excessive. In some years 

 because the winter rains are light, the fields remain dry and hard and 

 are in such poor condition in the spring that unless irrigation is prac- 

 ticed the seed germinates slowly and unevenly. 



