11)^0] FIELD CROPS. 527 



considerable variety of cn»i).s, is sliown as having brought out that in every tiekl 

 tlie irregularities of thi- sui>stratuin were suflicient to influence the exi)eri- 

 uiental results. 



The coetlicients for water content and for chemical composition of the soil 

 were found to be of about the same order as those determined for croj) yields, 

 and the belii'f is expressed that liie heterogeneity of experimental tieUls in their 

 capacity for crop production is directly due to these and other physi<'al and 

 chemical factors. The existence of signilicant lieterogeneity in fields passed 

 l»y agricultural experts as satisfactorily uniform is regarded as illustrating the 

 ina<le<iuacy of personjil judgment concerning the uniformity in physical char- 

 acters or in crop-producing capacity of fields under consideration for expei-i- 

 mental work. 



[The relation of size, sliapc, and number of replications of plats to prob- 

 able error in field experimentation], J. W. Day (Jour. Amcr. iS'oc. Ayrun., 12 

 {li)20), No. .J. PI). 100-10')).— '^{mVivs of the grain and straw yields of 3,100 

 5-ft. row segments of a wheat plat at the Shelbina tield of the Missmiri Experi- 

 ment Station, made to determine the relation of size, shape, and number of 

 replications of plats to probable error in tield experimentation, are discussed. 

 Detailed notes with standard deviations and coefficients of variability are pre- 

 sented in tabular form. 



Summarizing the results, it is stated that increasing the size of the plat to 

 at least ;o acre or more reduced variation. Single plats, long and narrow in 

 form and extending in the direction of greatest variation, gave more accurate 

 results than tliose of .other shapes, but plats, square or nearly square, were 

 preferable to long, narrow plats with the greatest dimensions in the direction 

 of least variation. Itesults from single plats wei'e usually not sufficiently accu- 

 rate to determine small differences between varieties or fertilizer and cultural 

 treatments. 



The use of a unit of comparison composed of systematically distributed parts 

 gave results nmch less variable than those obtained from an equal area in a 

 single plat. When the number of replications remained constant but the size 

 of the plat was increased, variation was reduced. From the viewpoint of shape, 

 the most effective replicated block was one that was long and narrow with its 

 greatest dimension in the direction of greatest variation. 



The uselcssness of hill selection under conditions where rapid degenera- 

 tion or *' running out " is prevalent, K. Wellington (Proc. Amer. Soc. Hort. 

 Sci., IG {I'.illi), pp. 175-179). — Hill selection experiments at the Minne.sota Ex- 

 periment ii'ation, where potato varieties iiad been degenerating or "running 

 out " very rapidly for many years, are described. It is stated that efforts made 

 to select strains resistant to degeneration ended in total failure. High and 

 low-yielding hills and tubers posses.sing so-called desirable and unilesirable 

 characters f(jllowed the same course, low-yielding hills often giving the better 

 results. 



Annual hay and forage crops, L. II. Waluron and F. W. Cuiustknskn (N. 

 iKik. Agr. Col. Ext. Circ. 37 (1920), pp. 8, fig. i).— Millet, Sudan grass, corn, 

 oats, barley, Canadhm tield peas, sunflowers, sweet clover, rape, and Russian 

 thistle are among the crops considered for use as hay and forage. Brief notes 

 are presented on varieties, culture, yields, and utilization of the crops listed. 



Harvest report [Koseworthy Agricultural College], 1919-20, W. J. 

 CoLKUATCH (Jour. Dcpt. Ayr. So. Aust., 23 (1020), Nos. 8, pp. 659-671; 9, pp. 

 758-755).— This continues work previously noted (E. S. R., 41, p. 639) reporting 

 considerable meteorological and crop data for the season 1919-20. Average acre 

 yields on the college farm for 1919 were as follows : Berseem clover 28.4 tons, 

 silage from wheat, barley, and oats 1.95 tons, wheat 9 bu. 22 lbs., barley 17 bu. 



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