Tillage 



The operations such as plowing, harrowing, and disking 

 that are used in cultivating the soil in order to make condi- 

 tions more suitable for the growth of crop plants. 



Tiller 



A Shoot arising from the base of a plant as in wheat and 



other grasses. 



Till Plain 



A more or less level land area covered with glacial Till. 



Tilth, Soil 



The physical condition, particularly Structure, of soil with 

 reference to favorableness for growth of crops; characterized 

 by friability, high degree of non-capillary porosity, and stable 

 granular structure. Soil in poor tilth is non-friable, hard, 

 non-aggregated, and difficult to cultivate properly. 



Timberline 



This term usually denotes the upper limit of tree growth 

 in mountains or poleward in latitude, cf. Tree limit. 



Tissue 



A organized, usually compact group of cells that have 

 similar structure and function, e.g., cork tissue in plants, 

 bone tissue in animals. 



Tissue Culture 



The growth in a suitable medium of a portion of tissue 

 separated from a plant or animal body. 



Tolerance 



The capacity of an organism to live under a given set 

 of conditions within its range of Ecological amplitude (q. v.), 

 between the Maximum and the Minimum (q. v.) (the limits 

 of tolerance), cf. Preferendum. 



Topography 



A general term to include characteristics of the ground 



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