1920] SOILS — FERTILIZERS. 21? 



Inoculation of lesmncs with nitragin (Rev. Asoc. Rural Urxtguny, ^8 (1019), 

 Xn. 12. pp. ISl-lHJi). — This report suuiiuarizes the works of others bearing on 

 tlie subject and deals with experience which indicates that nitragin is not appli- 

 cable to all soils, especially those in poor tillli and those rich in nitrogen. It is 

 concluded that tiie proper soil conditions under which nitragin may be effectively 

 used are poverty in nitrogen, sufliciency of other fertility constituents, and 

 moisture, and the soil neither achl nor excessively alkaline. 



The protozoan fauna of the soils of New Jersey, C. U. Fkllers and F. E. 

 Ai.uso.N (i<oil Sci., 9 (1920), Xo. 1, pp. 1-25, ftya. //).— This paper, a contribution 

 from the New Jersey Experiment Stations, presents studies on methods and 

 media for culture and examination, excystation, reproduction, and distribution 

 of the protozoan fauna of a large number of New Jersey soils of varying 

 degrees of fertility and reaction. Most of the soils were sampled at a dei)th of 

 from 1 to 4 in. and examined several times at different seasons with the use 

 of several media. 



Protozoa were found in all the soils exaiinned, the number of species identi- 

 fied from any one soil varying from 2 to 28. Poor sandy acid or forest soils 

 contained the least number of species, while fertile soils, rich in organic matter 

 or with high water-holding capacity, contained the greatest number. Of the 

 104 species identified from New Jersey soils, 51 were ciliates, 35 were flagel- 

 lates, 14 were rhizopods, and 4 were heliozoa. In addition to the protozoa, 10 

 genera of algiv' and 6 of diatoms were identified. Nematodes were common, 

 but rotifers or crustaceans were not encountered. Of the species classed as 

 being abundant in the soil, 17 were ciliates, 6 were flagellates, and 1 a rhizuiM)d. 

 The ciliates outnumbered the flagellates in the number of species identified, 

 but not in actual numbers of organisms in the soil. In point of numbers the 

 rhizopods and heliozoa ranked third and fourth, respectively. No suctoria were 

 encountered. 



It is believed that in normal New Jersey soils protozoa exist mainly in a 

 nontrophic state. Only two soils out of some hundred samples taken all over 

 the State showed the presence of living protozoa on direct examination. In 

 soils which were saturated with water for several hours, or in standing soil 

 water, field ditches, and plow furrows limited numbers of protozoa were usually 

 found. 



The soil microfauna consists principally of 'those small, simple, and hardy 

 protozoa which are able to withstand, by means of encystation or otherwise, 

 such extremes of heat and cold, desiccation, aeration, etc., as are natural to 

 their life in the soil. Practically all the species which were identified from 

 the soil have also been found in the fresh-water lakes, ponds, pools, and streams 

 of the State, but not in the same relative abundance. Some species which 

 are abundant in .soil are rarely encountered in fresh water, and vice versa 

 several of the most comuKm plankton organisms in rhe State are but rarely 

 found in soil. 



A new theory to replace the old " egg and germ " theory of distribution of 

 protozoa in soil is put forth as follows: Some protoza undoubtedly are spread 

 by rain, winds, animals, and other natural forces, but it Is not believed that 

 these means are suflicient to account for the large number of organisms of 

 many species found in all soils. Protozoa become active in soil whenever there 

 Is excessive moisture present for a period of several hours, and such conditions 

 are common during prolonged rains, especially in the rainy seasons, during 

 winter and spring thaws, in soils kept moist from seepage, and in poorly 

 drained lands. E^cj'station takes place followed by a feeding period and con- 

 sequent growth, then reproduction takes place. As conditions become unfavor- 

 able again, encystation begins or death occurs. Since all these processes may 



