that the upper surface is convex in section, caused by the 

 growth of Sphagnum. 



Hogback 



A ridge with a narrow summit and steep slopes. 



Hohenheim System 



A system of grazing followed by resting small pastures 

 or paddocks for short periods in rotation. 



Holarctlc 



Refers to the combined Palearctic (q. v.) and Nearctic 

 (q. v.) regions of the faunal realm Megagea (Arctogea) (q. v.). 



Holard 



A term used occasionally to designate the total water con- 

 tent of the soil. 



Holism 



The doctrine that life hi all its forms and the inorganic 

 environment form an interacting, integrated system, cf. 

 Ecosystem. 



Holocoen 



Equivalent to Ecosystem (q. v.). 



Holocoenotic 



Refers to the joint action and interaction of a numbei 

 of environmental factors upon organisms. 



Holoparasite 



An organism that is wholly parasitic, e.g., wheat rust. 



Holophytic 



Refers to an organism that utilizes light as the primary 

 source of energy, e.g., green plants, purple bacteria, cf. Auto- 

 trophic, Chemotrophic, Heterotrophic, Holozoic. 



Holoplankton 



An organism that is in the Plankton (q. v.) during its 

 entire life-cycle, e.g., Copepod. cf. Meroplankton. 



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