430 EXPERIMENT STATION RECORD. (Vol.38 



first of a series of investigations of field practices in Minnesota to ascertain any 

 laclf of uniformity in motiiods of worlj. 



" In a study of conifietition between rod rows of small grains grown 1 ft. 

 apart there was some effect on the yield of border rows of the same variety 

 due to lieight of adjacent rows of barley, winter wheat, and, in one of two 

 tests, an indication of such effect in oats. The results were variable in dif- 

 ferent plats, such variation being due possibly to the environmental condi- 

 tions. There was no apparent effect of height of adjacent rows on the yield 

 of border rows of the same variety in spring wheat. The yield of adjacent 

 rows appeared to be of some importance in barley tests and in the farm crops 

 spring-wlieat tests. Correlations obtained for other tests indicated consider- 

 aljle soil heterogeneity. The effect of tlie height of adjacent rows for the barley 

 plant breeding tests was unquestionable. The effects of tlie height of adjacent 

 rows were sufficient to often cause diiferences of 4 or 5 bu. per acre in the 

 yield of border rows of the same variety of barley. Tlie comparison of yield 

 variability of border and central rows of check plats of barley, oats, spring, and 

 winter wlieat was further evidence of the competitive effect of rod rows of 

 small grains when grown 1 ft. apart. In nearly all tests the border rows proved 

 to be more variable in yield than the central rows. 



" In nearly all tests three replications as compared witli a single plat reduced 

 error by from 25 to 50 per cent. 



" In a study of replications for rod rows of small grains considerable varia- 

 bility was shown for the different tests. In general three or four replications 

 seem to be about as accurate a method as the use of any number below nine. 

 The indications are that from 9 to 12 replications would reduce error due to soil 

 hetorogeneity to a minimum." 



A bibliography of 16 titles is appended. 



Improved technique in preventing access of stray pollen, A. Waller and 

 L. E. Thatcher {Jour. Amer. Soc. Agron., 9 {1917), No. 4, PP- 191-195, pi. 1). — 

 A waxed paper capsule for the prevention of contamination by adventitious 

 pollen and used by the authors in plant breeding work at the Ohio State Uni- 

 versity is described and illustrated. Advantages claimed for this device are 

 as follows : 



The translucent paper capsules hinder very little the normal plant proc- 

 esses and are cheap, light, and durable. No other method known to the 

 authors will protect against pollen thrips or other small insects that inter- 

 fere with pedigreetl cultures. Isolation of the inflorescence in the capsules 

 obviates the necessity of locating the cultures in places unfavorable for the 

 plant and inconvenient for observation. The capsule makes possible the isola- 

 tion of flowers borne on shrubs and trees. The device also protects the develop- 

 ing and ripened fruit. 



[Field crops] work of the San Antonio experiment farm in 1916, C. R. 

 Letteer {U. »S'. Dept. Af/r., Bur. Plant Indus., Work ^an Antonio E.tpt. Farm, 

 1916, pp. 1-16, fi(/s. 3).— This reports the progress of work continued along the 

 same general lines followed in preceding years (E. S. R., 35, p. 827), including 

 meteorological observations in 1916. Seasonal conditions for 191G are noted as 

 in many re.spects very unfavorable for crop production. 



Experiments relating to crop rotation and tillage, and corn and cotton culture 

 and variety tests are described, and results obtained in the main similar to 

 those previously noted. The 1916 yields of corn, cotton, sorghum, and oats 

 for grain were .slightly higher on biennially cropped land than ou land cropped 

 annually, although the diflei-ences in favor of the biennial cropping were not 

 deemed suflicieut to make the practice profitable. 



