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Windbreak shelter and physiological responses of corn
Abstract
Windbreaks have been used extensively to improve crop growing conditions and to enhance crop growth and yield. The effectiveness of a windbreak is represented by the amount of windspeed reduction in the sheltered zone and determines the amount of potential benefit the protected crop will receive. The objectives of the research described in this dissertation were to evaluate the various approaches used to assess windbreak effectiveness in terms of windspeed reduction and crop response to shelter-induced environment. The study was conducted at the University of Nebraska-Lincoln Agricultural Research and Development Center near Mead, Nebraska from 1990 to 1992. Windbreak structure, windspeed reductions, air and soil temperatures, humidity, and soil moisture were monitored. Leaf light and CO$\sb2$ responses; leaf photosynthesis, stomatal conductance, transpiration; and biomass and grain accumulation of corn were measured at various stages of development. Windspeed reduction in shelter was a function of exposed windspeed, windbreak porosity and distance away from the windbreak. When exposed windspeed was below a threshold windspeed, relative windspeed reduction in shelter decreased as the windspeed increased; when windspeed was above the threshold windspeed, relative windspeed reduction was independent of exposed windspeed. The effectiveness of a windbreak also depends on the sensitivity of objects with objects defined as anything needing wind protection. A model was developed to evaluate this effectiveness by considering the critical windspeed for various objects that causes initial damage to the objects. The model was evaluated using measured windspeeds and published data. Leaf light responses were not significantly influenced by windbreaks. Both short term and longer term comparisons suggested that windbreaks did not significantly change chamber-measured leaf photosynthesis, stomatal conductance, transpiration, or water use efficiency. Leaf area, leaf area estimation, and vertical area distribution were not significantly changed by windbreak shelter. Plant biomass and grain accumulation were simulated by a mechanistic model based on radiation use efficiency. The comparison between measured and predicted values for biomass and grain yield showed a good agreement. Windbreaks slightly increased biomass and grain production of corn.
Subject Area
Forestry|Botany|Agronomy
Recommended Citation
Zhang, Hehui, "Windbreak shelter and physiological responses of corn" (1993). ETD collection for University of Nebraska-Lincoln. AAI9410366.
https://digitalcommons.unl.edu/dissertations/AAI9410366