34 AXXl'AL RHPORTS OF DKPAItTM KXT OF ACRICTTLTrnK. 



out tliese lonp and costly investijjjntions to develop better rotations 

 are wholl}' inadequate. 



EFFECT OF DAYLIGHT OX PLANT GROWTH. 



A strikinf^ and important discovery, made recently by the depart- 

 ment, is that plants are remarkably sensitive to chanjjes in the dura- 

 tion of the daylight period, even when all other factors are kept 

 constant. It now seems probable that all regular periodic changes 

 in plants, such as time of blooming, fall of the leaf, the resting 

 period, etc., are naturally regulated by the duration of daily light. 

 This discovery explains many plant reactions that have long puzzled 

 investigators, such as the totally different behavior of a plant in 

 widely different latitudes. Thus, by regulating the length of daily 

 illumination, violets can be made everblooming and poinsettias can 

 be forced to bloom in midsummer. The discovery undoubtedly will 

 be of much value in greenhouse culture, and furnishes the explana- 

 tion of a number of plant reactions that occur in the field. Here- 

 after, it must be taken into account in all accurate experimentation 

 with plants. 



IMPROVED TYPES OF L.IYE STOCK. 



The breeding and development of improA^ed types of animals offers 

 possibilities at least equal to those involved in the breeding and selec- 

 tion of better crop plants. The campaign now under way for " Better 

 Sires — Better Stock " is producing excellent results. Its purpose is 

 to bring about the elimination of scrub stock from our herds, thus 

 increasing their producing capacity. It costs as much to raise a 

 poor animal as it does a good one, and more to keep it, so that better 

 live stock makes for increased production and greater profits. The 

 improvement which can be made in a herd with a pure-bred male is 

 startling. If a pure-bred sire is kept throughout, the first genera- 

 tion would be one-half pure blood, the second three-fourths, the third 

 seven-eighths, the fourth fifteen-sixteenths, and the fifth thirty-one 

 thirty-seconds, or practically pure bred. 



A concrete example of the importance pf quality may readily be 

 estimated from the slaughter records of animals. In converting 

 cattle into beef, for example, the present 'average dressing percentage 

 is 53^. Poor breeding, without doubt, is a prime cause of this low 

 percentage. Suppose our efforts to improve cattle should, within 

 a reasonable time, raise the general dressing average only 1^ per 

 cent — that is, to 55 per cent — what would be the resulting increase in 

 beef? On the basis of a total annual production of 7,000,000,000 

 pounds, which is the average dressed-beef production for the last two 

 years, the increase would be 200,000,000 pounds a year. This is far 

 from being a negligible quantity ; in fact, it just equals our average 



