Data/hora: 09/06/2024 20:36:18

Biblioteca(s): 	Embrapa Meio Norte / UEP-Parnaíba; Embrapa Soja.	
Data corrente: 	07/01/1994	
Data da última atualização: 	23/09/1994	
Autoria: 	DENMEAD, O. T.; SHAW, R. H.	
Afiliação: 	Iowa State University. Agronomy Department. Agricultural Climatology. Ames, Iowa.	
Título: 	Availability of soil water to plants as affected by soil moisture content and meteorological conditions.	
Ano de publicação: 	1962	
Fonte/Imprenta: 	Agronomy Journal, v.54, n.5, p.385-390, sept./oct. 1962.	
Idioma: 	Inglês	
Conteúdo: 	Dynamic aspects of the availability of soil water to plants are discussed briefly. IT is pointed out that as the soil dries, the actual transpiration rate should fall below the potential rate and that this decline in relative transpiration rate should occur at higher and higher soil mositure contents as the potential  transpiration rate increases. Since the decline in relative transpiration rate results from a loss of turgor in the plant, the soil moisture content at which plants wilt should also increase as the potential transpiration rate increases. Transpiratin rates from corn plants grown in containers in the field were determined under varying conditions of soil water supply and varying potential transpiration rates. For moderate potential transpiration rates (3 to 4 mm. per day), the actual transpiration rate fell below the potential rate when the average soil suction in the root zone was about 2 bars. When the potential transpiration rates were as high as 6 to 7 mm. per day, this decline in relative transpiration rate occurred at about 0.3 bar. When the  potential transpiration rate was only 1.4 mm. per day, the relative transpiration did not decline until about 12 bars. The soil moisture content at which the decline in relative transpiration rate occurred, referred to as the turgor loss point, varied from a volumetric soil moisture content of 23% when  the potential rate was 1.4 mm. per day to 34% when the potential transpiration rate exceeded 6 mm. per day. Measurements of dry matter production suggested that one the soil moisture content was less than the turgor loss point, the plants virtually ceased to assimilate.	
Palavras-Chave: 	Availability; disponibilidade; Estresse hidrico; Plant.	
Thesagro: 	Água; Climatologia; Planta; Solo; Stress.	
Thesaurus Nal: 	climatology; soil; water.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CPAMN-UEPP - (3151-1) - ADD - SP - -- - SP 200/1988 -  - 1988.00200 - DIS
CNPSO - (14536-1) - ADD - SP - -- - 9649 -  - 9649 - DIS