130 Irrigation and Drainage 



percolates and travels downward through such soil with difficulty, 

 makes the growing of a second crop of almost any kind very 

 difficult and uncertain by methods of tillage unaided by irriga- 

 tion. Every one is familiar with the fact of short pastures in 

 midsummer and early fall, and that second crops of hay can be 

 raised only in exceptional seasons, and even then they are seldom 

 heavy. 



The difficulty in these cases is not that less rain falls during 

 the summer and autumn, for the measured amount is actually 

 greater. Neither is it true that they will not grow because it is 

 out of season, for when plenty of water is supplied heavy crops 

 of grass are obtained for the second cutting. As a matter of 

 fact, the summer rains are less effective because they are re- 

 tained so near to the surface as not to come within reach of the 

 roots before they are lost by surface evaporation. 



In our own experiments in irrigating clover, there has been 

 secured for the second crop of clover hay 1.789 tons in 1895, 

 2.035 tons in 1896, and 1.648 tons of hay, containing 15 per cent 

 of water, in 1897, or an average for three years of 1.824 tons per 

 acre. When it is recalled that the average yield of hay per acre 

 for the thirteen states cited is but little more than 1 ton per acre 

 for the first crop, when the rains have their maximum effective- 

 ness, it is plain that without irrigation it is not possible to grow 

 a paying second crop of hay to any extent in either the sub- 

 humid or humid parts of the United States. Further than this, 

 on account of the small effectiveness of summer rains, it is often 

 quite impossible to secure a catch of clover with any of the small 

 grains, while with irrigation the catch would be positively as- 

 sured every year. These are cases in which present methods of 

 tillage can do nothing, but in which irrigation will give certain 

 results. 



The present season we put into the silo 6,552 pounds of 

 clover and volunteer barley, cut from .58 acres of ground upon 

 which had been harvested 45 bushels of barley to the acre. This 

 was rendered possible by irrigating the land, and thus forcing 

 the new seeding of clover after the crop was removed. In this 

 way it was possible to get two good crops in one season from the 



