Stridulation 



The making of shrill sounds by certain insects such as 

 crickets by rubbing one organ against another. 



Strip Cropping 



The growing of crops in narrow fields or strips so that 

 wind and water erosion is reduced or prevented, cf. Buffer 

 strips. 



Strip Survey 



The use of continuous narrow strips as sampling units, 

 especially in forestry. 



Strobilus (Strobile) 



A cluster of Sporophylls; the cone of conifers in which 

 seeds or pollen grains are produced. 



Structure 



(1) An expression of the composition, abundance, spac- 

 ing, and other attributes of plants in a community, cf. 

 Layering, Life-form. (2) The composition of a population 

 with reference to age-classes, or to some other criterion. (3) 

 See Soil structure. 



Struggle for Existence 



Refers to the processes used by an organism to maintain 

 life and to reproduce, especially in an unfavorable environ- 

 ment or where Competition (q. v.) is severe, cf. Natural 

 selection. 



Stubble 



The lower parts of plants that remain after the tops have 

 been removed in harvesting operations; may also be applied 

 to the parts left ungrazed on range or pasture. 



Stubble Crop 



(1) A crop that is produced from Stubble of the previous 

 season. (2) A crop sowed in the grain Stubble after the grain 



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