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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Publications at this Location » Publication #317051
Title: Time lag characteristics of sap flow in seed-maize and their implications for modeling transpiration in an arid region of Northwest China

Author
item BO, XIAODONG - China Agricultural University
item DU, TAISHENG - China Agricultural University
item DING, RISHENG - China Agricultural University
item KANG, SHAOZHONG - China Agricultural University
item Comas, Louise

Submitted to: Journal of Arid Land
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2017
Publication Date: 6/30/2017
Citation: Bo, X., Du, T., Ding, R., Kang, S., Comas, L.H. 2017. Time lag characteristics of sap flow in seed-maize and their implications for modeling transpiration in an arid region of Northwest China. Journal of Arid Land. 10.1007/S40333-017-0024-4.
DOI: https://doi.org/10.1007/S40333-017-0024-4

Interpretive Summary: Plant capacity for water storage leads to time lags between stem sap flow measured at the base of the plant and transpiration in diverse woody plants but several questions have remained. These questions include: do lags also occur in herbaceous plants, what factors affect lags, and how should the phenomena be modelled. A field experiment was conducted in an arid region of northwest China to examine sap flow lags in maize. We found sap flow lags equal to those of woody plants, which suggests that maize plants have substantial capacity for water storage. Sap flow mainly tracked solar radiation. Sap flow lags were affected by the stage of plant development, potentially due to developmental changes in storage tissues. Seed-maize stem sap flow was estimated using the transfer function model (ARIMAX) and common multivariate regression model (MR). The results showed that the ARIMAX model outperformed the MR model. This data advances our understanding of environmental controls on transpiration and mathematical approaches for quantifying it.

Technical Abstract: Plant capacity for water storage leads to time lags between basal stem sap flow and transpiration in diverse woody plants but several questions have remained. It is unclear if capacitance also leads to basal sap flow lags in herbaceous plants, what factors might affect potential lags for these plants, and how best to model the phenomena. A field experiment was conducted in an arid region of northwest China to examine sap flow lags in seed-maize. Cross-correlation analysis was used to estimate time lags between stem sap flow and environmental factors on short- and long-term scales. We found sap flow lags on par with those of woody plants with changes in seed-maize stem sap flow significantly lagging behind changes of solar radiation (Rs) but preceding changes of vapor pressure deficit of the air (VPDair). Sap flow lags were significantly affected by plant growth stage, potentially due to developmental changes in capacitance tissues and/or xylem during ontogenesis. Changes in daily stored water use corresponded to changes sap flow lags behind Rs. Sap flow lags were longer for one genotype than for another with no difference in stored water use between the genotypes. Our results also showed that soil water content affected time lags between stem sap flow and VPDair in both genotypes but only affected time lags between stem sap flow and Rs in one genotype. Seed-maize stem sap flow was empirically estimated using the transfer function model (ARIMAX) and common multivariate regression model (MR). The results showed that the ARIMAX model outperformed the MR model in prediction of seed-maize stem sap flow. Goodness of fit indicators also implied that the estimated values of ARIMAX could fit the measured data well. The time series approach would be helpful in improving the accuracy of estimation for crop canopy transpiration.