GROWING ALFALFA SEED. 459 



expense. However, as there is such great variation in the value 

 of different plants, this procedure may be justified at least until 

 strains of known high value for the conditions at hand have been 

 selected and propagated for use on a field scale. 



Row-sown alfalfa fields that have not been properly thinned 

 will not give maximum seed yields on account of the various in- 

 jurious effects of crowding, which have already been discussed. 



If it is impracticable to reduce the stand by hoeing or by use 

 of the ordinary harrow it may be done by cross-disking with a 

 disk harrow. The disks should be so adjusted as to cut out the 

 proper number of plants, which will depend, of course, upon their 

 original thickness in the rows. 



The Right Crop to Leave for Seed. Experiments at Stockton, 

 Kan., show clearly that at that place no crop later than the second 

 will yield returns that will be at all satisfactory. Retarded 

 growth during the dry part of the summer defers ripening until 

 so late in the season that cold nights prevent the maturing of the 

 seed. On the other hand, if the first spring growth is devoted to 

 seed production the flowers are likely to become overmature be- 

 fore the best season for seed development arrives. Frequently 

 also, largely on account of the variation in location of the zero 

 point of growth in the different individuals composing any strain, 

 the first spring growth matures very unevenly. 



For these reasons it is recommended, especially for the Great 

 Plains and the cooler parts of the intermountain area, that the 

 first growth of the second and subsequent years be clipped so 

 early that the time of seed setting will fall in midsummer or 

 slightly later, when favorablfe conditions are likely to obtain. 



The problem as to what crop should be left for seed under the 

 varying conditions of different areas has not yet been fully 

 worked out. It may be well for seed growers to try by simple ex- 

 periments along this line to get definite information on this 

 point. One row may be given an early clipping and then left to 

 go to seed; another a later clipping, while still another may be 

 left for seed after the first crop has been cut for hay, and so on. 

 The temperature and moisture requirements will largely deter- 

 mine the best practice in this regard, but the necessary presence 

 of suitable insects must not be overlooked. 



Harvesting the Seed Crop. The harvesting of alfalfa seed 

 grown in cultivated rows does not differ materially from that in 

 broadcasted fields. With the rows 3 feet apart a mowing ma- 

 chine with a 6-foot cutter bar is necessary if two rows are to be 

 cut in each swath. This arrangement does away with the neces- 

 sity of having an extra man to remove the newly cut bunches 

 from the path of the mower at the next round. A mower with a 



