SOILS FERTILIZERS. 215 



few instances the tests show as high an average as 8.7 per cent. In the first 

 foot it ranged as high as 16 per cent, while in the third foot it was qnite often 

 a negligible quantity." 



Humus in New Hampshire soils, F. W. Morse (New Hampshire Sta. Bui. 

 138, pp. 191-203, figs. 3). — The importance of the functions performed by humus 

 in the soil and methods of maintaining and increasing tlie humus content are 

 discussed, and determinations of the humus content of samples of soils from 

 the station farm and from other places in the State are reported. 



The percentages of humus found in typical soils of the station farm were: 

 Sandy loam 1.81; clay loam (upper slopes) 2.1 to 2..57, averaging 2.31; clay 

 loam (lower slopes) 2.81 to .3.09, averaging 2.93 ; and clay 3..33 to 5.37, averaging 

 4.5. *' Besides these samples of our farm soils, a few lots which were received 

 from time to time from other farms were also analyzed for humus, with the 

 following results : Four loams contained from 2.12 per cent to 2.65 per cent, 

 with an average of 2.32 per cent ; two sandy loams contained 1.52 per cent 

 and 1.57 per cent, respectively, and one dark loam contained 3.3 'per cent." 

 These results show that " there is a fair average proportion of humus in the 

 soils of this State, and they ai'e by no means worn out when compared with 

 the soils of localities noted for fertility." 



Comparisons of the humus in cropped and fallow plats on the station farm 

 show that "continuously tilling the soil on the one hand, or cropping it with 

 haj- for a long term of years on the other hand, are unsuitable methods for 

 handling our soils, since the former way destroys humus rapidly, while the 

 latter does not maintain it at the highest point." 



It is estimated from the analyses reported that the average loss of humus to a 

 depth of 12 in. in a clay soil which had been frequently tilled amounted to 

 28,000 lbs. per acre, and in a loam soil similarly treated 22,000 lbs. per acre 

 annually. 



On the other hand there were " found in three samples of old grass land on 

 the clay soil, which had been cropped with hay for more than 20 years, per- 

 centages of humus ranging from 2.95 to 3.69 and averaging 3.27, while the 

 average of immediately adjoining fields, which had been under tillage for 2 

 years, reseeded and cropped with hay for 3 or 4 years, was 4.5 per cent. The 

 average difference in humus between these two classes of grass laud on the 

 same soil was 1.23 per cent, which, calculated for an acre to the depth of 6 in., 

 would be 18,450 lbs., or over 9 tons per acre. 



" The new fields had of course received a dressing of manure at seeding time, 

 but the difference in humus would be equivalent to organic matter in over 35 

 tons of manure per acre, which is more than is ever applied in the practice of 

 the farm. Therefore a considerable part ef the gain must have come from the 

 decay of the turf, roots, and stubble turned under by the plow. 



" It is apparent that the marked decrease in the yield of hay after 3 or 4 

 years' cropping is due in part to the decrease in humus and its accompanying 

 fertilizing constituents." 



The conclusion therefore seems warranted that " a rotation of crops by com- 

 l)ining periodical rests from tillage, with additions of sod and stubble to the 

 soil, favors the production of humus and promotes its increase." 



Soil deterioration and soil humus, J. L. Hills, C. H. Jones, and C. Cutler 

 (Vcnnont Sta. Bui. 135, pp. l-'i2-m). — In this article an attempt is made to 

 cover causes and remedies with particular reference to the humus content of 

 soil, its benefits, maintenance, and increase. 



"The depletion of the soil humus supply is apt to be a fundamental cause of 

 lowered crop yields. The one-crop system, fallowing, shortage of manure, no 

 green manuring ; the nonuse of legumes or grasses in the rotation ; deforesta- 



