Water relations and photosynthesis as criteria for adequate irrigation management in 'Tahiti' lime trees

Scientia Agricola

Cláudio Ricardo Da Silva²  Marcos Vinícius Folegatti¹  Tonny José Araújo Da Silva²  José Alves Júnior²  Claudinei Fonseca Souza¹  Rafael Vasconcelos Ribeiro¹ 

[1] ,USP ESALQ Piracicaba SP ,Brasil

关键词: evapotranspiration;    citrus;    lysimeter;    gas exchange;    tensiometer;    evapotrasnpiração;    citros;    lisímetro;    trocas gasosas;    tensiômetro;   

DOI  :  10.1590/S0103-90162005000500001

来源: SciELO

【 摘 要 】

Irrigation scheduling based on soil moisture status is one of the most useful methods because of its practicality and low cost. The effects of available soil water depletion on evapotranspiration (ETc), transpiration (E), leaf water potential at predawn (psiP) and midday (psiM), stomatal conductance (gs) and net CO2 assimilation (A) in lime 'Tahiti' trees (Citrus latifolia) were evaluated to improve irrigation schedule and minimize water use without causing water stress. The trees were spaced 7 ´ 4 m and drip-irrigated by four drippers with the available soil water content (AWC) depleted by suspension of irrigation (40 days). Leaf water potential was measured on a pressure chamber (psiP and psiM) and leaf gas exchange was measured by infrared gas analyzer (E, gs and A). Evapotranspiration was determined with the aid of weighing lysimeter. Water soil content and potential (psiS) were monitored with TDR probes and tensiometers, respectively, installed at 0.3, 0.6 and 0.9 m depths. Meteorological variables were monitored with an automatic weather station in the experimental area. The threshold AWC level for the onset of ETc decline was 43%, and 60% for gs, A, E and Y P. Also, psiP was more sensitive to AWC than psiM, and is therefore a better tool for irrigation. When AWC was around 60%, values of psiP and psis were -0.62 MPa and -48.8 kPa, respectively.

【 授权许可】

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