1917] SOILS — FERTILIZERS. 317 



" Subnormal rainfall during the months of July and August is more fre- 

 quently harmful in the western portion of the belt than in the central and 

 eastern portions, owing to the normally greater amounts received in the latter 

 districts. In general, the yield of cotton is largely affected by the rainfall 

 during the months of July and August, especially the latter, but in the central 

 and eastern portions of the belt temperature and moisture conditions during 

 the early period of growth are of scarcely less importance. The amount of 

 rainfall during the latter part of the growing season, particularly in Septem- 

 ber, is also of special significance, as this largely determines the amount of 

 the top crop, which plays an important part in the total yield." 



Safe date for planting' potatoes {U. S. Dept. Agr., Nat. Weather and Crop 

 Bui. 10 (1917), p. 3). — It is stated that the potato is " a cool weather crop, and 

 the largest yields in the United States are in the northern tier of States and 

 the Rocky Mountain region, where the mean annual temperature is between 

 40 and 50" and where the July temperature does not average over 70° F. 



The planting of early potatoes progresses from south to north in the Eastern 

 States in close correlation with the spring temperature of 45°, and is usually 

 nearly one month earlier than the average date of the last killing frost in the 

 spring. The total number of days from planting to harvesting of early potatoes 

 is about 100 in the Central States; 90 in the Southeastern, North Cenrai, and 

 Pacific Coast States; and 70 to 90 in the Lake States. The planting of the 

 northern commercial crop becomes general about April 11 in the southern por- 

 tion of the States running westward from Virginia to Kansas and extreme 

 western Texas, and then extends northward to slightly later than June 1 in 

 extreme northern Ohio, central Michigan, and central Wisconsin. 



" Taking the length of the growing period and the first killing frost in the fall 

 into consideration, potatoes should be planted by the first of June in the central 

 and upper Missouri Valley and eastern Rocky Mountain slope, and by June 15 

 in most districts from the lower Missouri and upper Mississippi Valley eastward 

 to the Atlantic coast in order to thoroughly mature before the average date of 

 killing frost." 



SOILS— FERTILIZERS. 



Special crop soils [of New York], E. O. Fippin (Cornell Countryman, H 

 (1917), No. 7, pp. 568-571, 598, figs. 2).— The so-called general purpose soils of 

 New York, including the light sandy and gravelly soils, heavy clay, and muck 

 soils are discussed. 



" The most prominent of these three groups of soil is the muck. . . . Through 

 the central part of the State beds of marl commonly occur under the muck. 

 . . . The smaller and deeper areas of muck are generally the safest for crop- 

 ping purposes." 



Peat moors in the coast regions of southern German East Africa, W. 

 Janensch (Arch. Biontol., 3 (19U), No. 3, pp. 263-276, pis. 2, figs. 2).— This is 

 a report on the origin, formation, and physical and chemical composition of 

 peat moor soils of the Lukuledi and Mbenkuru regions of German East Africa. 



Analyses of the ashes and dry substance of samples of the peat from four 

 different localities are reported, showing the potash content to vary from 0.97 

 to 2.91 per cent in the ash and from 0.22 to 1.3 per cent in the dry matter, the 

 phosphoric acid from 0.41 to 1.34 per cent in the ash and from 0.1 to 0.31 in 

 the dry matter, and the organic matter from 55.24 to 76.91 per cent. The nitro- 

 gen content of the organic matter varied from 2.46 to 3.38 per cent. The lime 

 content is considered to be in general relatively lower than that of European 

 peats, being on the average about 9.62 per cent. 



