No. 1, October, 1920] AGRONOMY 3 



amount of hydrated lime; and the percentage of this grade in the 10-mcsh limestone repre- 

 sented approximately t lie first season's efficiency of the calcium oxi<le equivalent in the lime- 

 stone as compared with that in hydrated lime. During the 5 years following the single appli- 

 cation, the average results were slightly in favor of the hydrated lime — Four crops were grown 

 in each of 5 years on the same plat sections to ascertain their cumulative effect on a single 

 crop of barley grown ovor the entire area in the field, and on lettuce grown in pots. Arranged 

 in a decreasing series, the order of the crops was the same in accordance with their need for 

 lime, and also their cumulative effect in enhancing acid-soil conditions. The order is as 

 follows: Mangels, carrots, alfalfa, and barley. Where the acidity was reduced by liming, 

 the four crops affected a succeeding crop about uniformly. — B. L. Hartwell. 



17. Hartwell, Burt L., and S. C. Damon. The value of sodium when potassium is 

 insufficient. Rhode Island Agric. Exp. Sta. Bull. 177. 29 p. 1919. — Field results are reported 

 for 1905 to 1918, of an experiment which was begun in 1S94 to ascertain the value of sodium 

 as a partial substitute for potassium. Both elements have been applied in carbonates and 

 in chlorids in connection with two different rates of liming. Nitrogen and phosphorus were 

 added liberally and alike to all plats. Sodium was generally useful where there was an 

 insufficiency of potassium. — Some of the benefits arising from the use of sodium in the field 

 are attributable to indirect action; but solution culture indicates that direct beneficial effects 

 were probably obtained also in the field. — B. L. Hartwell. 



18. Hartwell, Burt L. , F. R. Pember, and G. E. Merkle. The influence of crop plants 

 on those which follow. II. Rhode Island Agric. Exp. Sta. Bull. 176. 47 p. 1919.— Five 

 different crop plants were grown for two or three successive years in pots containing the same 

 soil and then followed by a single crop plant. In case of each crop, uniform fertilizer series 

 were maintained with super-optimum nutrients, with optimum nutrients, and with the latter 

 from which potassium, nitrogen and phosphorus were individually omitted. — When onions 

 constituted the single crop, the yields of onions increased after the crops in about the follow- 

 ing order: Buckwheat, mangels, rye, onions, and redtop. Subsequently, when buckwheat 

 was the single crop, its yield increased after the crops arranged about as follows: Redtop, 

 buckwheat, mangels, rye, and onions. The relative effect of the different crops varied some- 

 what, depending upon the fertilizer treatment, but not as much as would be expected gener- 

 ally. — The divergent effect of crops on those which follow seems not to be attributable, at least 

 principally, to differences in the amount of nutrients removed by the crops grown previously; 

 that is, the smallest yield may not occur after the crop which removes the largest amount 

 of even the most-needed nutrients. — The change which a given application of a nutrient causes 

 in its percentage in the crop depends not only upon its own effect on the rate of growth, but 

 also upon the abundance of the other nutrients in relation to the needs of the crop. — So-called 

 soil acidity was affected differently by the several crops, and their influence on succeeding 

 crops was much less pronounced after thorough liming.— B. L. Hartwell. 



19. Hibbard, R. P. Seed potato preparation. Michigan Agric. Exp. Sta. Quart. Bull. 2: 

 176-178. Fig. 5. 1920.— Reports a small experiment on sprouting of seed pieces of various 

 sizes and effect in yield of size of seed pieces. Pieces with but one eye gave 61 per cent 

 sprouting, with 2 or more eyes 100 per cent sprouting. Whole tubers averaging 4.6 ounces 

 gave a yield of 9 per cent more than the yield from seed pieces averaging 1.4 ounces. — E. A. 

 Bessey. 



20. Hodson, Edgar A. Correlations of certain characters in cotton. Arkansas Agric. 

 Exp. Sta. Bull. 169. 16 p. June, 1920.— Correlation coefficients have been worked out for a 

 large number of physical characters of cotton and are reported in this publication. The co- 

 efficients do not indicate as high a correlation in many cases as has popularly been supposed 

 to exist. There is, however, a very consistent negative correlation between per cent of lint 

 and length of lint, a high positive correlation between weight of seed and size of boll, etc. — 

 Edgar A. Hodson. 



