424 THE SMALL GRAINS 



nate the seed and grow the crop until it is high enough to 

 shade the ground at the second irrigation. It is after- 

 ward irrigated again when the spikes are just appearing, 

 and sometimes again when the spikes are filling, making 

 3 or 4 irrigations in all. 



Winter grain, if well started in the fall, develops much 

 earlier and faster in the spring than spring grain. There- 

 fore the winter and spring moisture are usually enough to 

 bring it to the stage when the spikes are in the boot. One 

 or 2 irrigations are then sufficient to make the crop, the 

 second irrigation, if any, being given at the time of 

 filling the spikes. < 



454. Time of irrigating spring grain. It is natural 

 to suppose that applications of water will be most effec- 

 tive if made just at the time of occurrence of the impor- 

 tant stages of growth of the plant. These, after the time 

 the crop begins to need water, are chiefly three, joint- 

 ing, heading or flowering, and ripening, but they may be 

 further divided into substages of jointing, booting, head- 

 ing, flowering, soft dough, hard dough, and ripening. The 

 question is, at which of these stages are irrigations most 

 needed, and how many of them should there be. 



Welch (1914, pp. 13-17) studied this subject, and 

 determined in 3 years' experiments that water applied 

 to spring wheat, in southern Idaho, is most effective in 3 

 irrigations given at the jointing, booting, and soft-dough 

 stages. The plat not irrigated, and the one irrigated at 

 the jointing stage, produced grain so shriveled that it 

 was unfit for milling ; while 1 irrigation at the jointing 

 stage made a greater yield than 1 at the heading stage, 

 but the grain resulting from the latter was much superior 

 in quality. The second and third best yields, which 

 were nearly the same, were made by 2 irrigations, at the 



