Juue, 190S.1 HUMUS IX N. H. SOILS. 1 '•'•"» 



The clay soils contain the most humus and the sandy loam 

 the least, which is in accordance with the principles of humus 

 formation, since moisture and lack of air favors the transform- 

 ation of vegetable matter into humus and the preservation of the 

 latter, as shown in peat beds, while the drier, more open char- 

 acter of the sand}' loam admits air freely to oxidize and destroy 

 the humus. 



The clay loams are not quite midway between the sandy loam 

 and the clay, since they average 2.56 per cent of humus for all. 



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 3.30 per cent. 



From these results it is reasonable to infer that the soils of 

 our old grass fields seldom contain more than 3 per cent of humus 

 on the uplands, but may contain 4.50 per cent on our low 

 meadows. Hilgard^ says: "In ordinary cultivated lands it 

 rarely exceeds five per cent, and very commonly falls below three 

 per cent, even in the humid regions." 



This is sufficient to show that our soils are not so worn out 

 as is often claimed, but compare favorably with other sections. 

 The average for ]\Iinnesota- soils has been found to be 3.66 per 

 cent and in North Dakota^ to be 4.77. per cent. 



The Value of Humus. 



The effects of humus on soils are both physical and chemical. 

 Its physical effects are due in part to its remarkably porous 

 structure which not only lightens the texture of soils but also 

 increases the absorptive power of soils for water and the plant 

 food dissolved in it. Compounds formed between humus and 

 lime, iron and some other elements have strong cementing prop- 

 erties and hence improve the crumb structure of soils, rendering 

 them more friable. The chemical effects on the soil are in part 



1 " Soils," E. W. Hilgard, p. 133. ' Bull. 65. Minn. Agr. Exp. Sta. 



> Bull. 35, No. Dak. Agr. Exp. .Sta. 



