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Wheat grain quality as related to climate: Evaluation and model development
Abstract
Wheat grain quality variations, induced by the environment, cause difficulties for the wheat processing industry. To better understand the cause of this variation, an irrigation experiment was conducted to study the climatic effects on wheat grain quality, to develop and validate a soil water balance-evapotranspiration model and a canopy temperature model, and finally to develop a climatic model for predicting wheat grain quality. Field experiments were conducted with eight different water treatments in a randomized complete block design during 1993 and 1994 wheat growing seasons. Pertinent climatic, biological and edaphic variables were monitored through the season. A modified soil water balance-evapotranspiration model which describes the processes of crop evapotranspiration, soil evaporation, and the hydrological balance of root zone, was validated using measured soilwater content data. The simulated and observed soil water content in the root zone compared well for all water treatments ranging from no irrigation to full irrigation. A canopy temperature model applicable to fully developed wheat canopies was developed based on water movement in the soil-plant-atmosphere continuum. This model allows the estimation of canopy temperature changes within a day. The simulated and observed canopy temperature were compared well for both treatments under drought and under irrigation. Both estimates of evapotranspiration and canopy temperature from the model can be used to predict wheat grain quality. A wheat grain quality model similar to the multiplicative yield model was developed based on experimentally determined sensitivity to evapotranspiration in three growth stages as determined from periodical soil water content measurement. A non-linear regression approach was used to describe the curvilinear relationship between loaf volume and evapotranspiration. The magnitude of the sensitivity indices $\rm(\lambda\sb{j})$ for different growth stages allows the model to quantify the influence of evapotranspiration on loaf volume. The heading to milking and milking to maturity had larger $\lambda$ values. The model derived from 1993 data showed promise by predicting loaf volume in 1994. However, further model refinement will require collection of experimental results from multiple years and multiple sites.
Subject Area
Agronomy|Botany
Recommended Citation
Xu, Meng, "Wheat grain quality as related to climate: Evaluation and model development" (1996). ETD collection for University of Nebraska-Lincoln. AAI9637085.
https://digitalcommons.unl.edu/dissertations/AAI9637085