Influence of Windbreak-Shelter on Soybean Growth, Canopy Structure, and Light Relations1
- S. N. Ogbuehi and
- J. R. Brandle2
Although changes in canopy morphology of soybeans [Glycine max (L.) Merr.] grown windbreak-sheltered plots have been reported, how these changes affect the canopy light climate has not been evaluated. This information is needed for a better understanding of the mechanisms of shelter influence on soybean production, and for satisfactory models of soybean growth and yield under these conditions. The objectives of the field study reported here were to determine the influence of windbreak-shelter on soybean canopy morphology, canopy light climate, growth, and bean yield. ‘Wayne’ soybeans were grown during the 1978 and 1979 growing seasons under windbreak-sheltered and exposed conditions at the University of Nebraska Field Laboratory, Mead, Nebraska. The soil was a Typic Arguidoll (Sharpsburg silty clay loam).
The sheltered soybeans were characterized by a significantly lower leaf area density and leaf density, and smaller leaf size in the uppermost portions of the canopy in comparison with those grown in exposed plots. Consequently, there was a greater penetration of the incident photosynthetically active radiation to lower canopy strata in sheltered soybeans.
Even though available soil water was similar for the treatments, sheltered soybeans had a more favorable plant water status. This was probably a consequence of lower atmospheric evaporative demand in shelter due to reduced wind-speed. Crop growth and bean yield were significantly increased in shelter obviously because of the better plant water status and canopy light climate. The number of pods per plant, seeds per pod and harvest index were increased in shelter.
Since soybean yield is limited by restriction of light penetration to lower canopy strata, cultivar selection on the basis of this morphological response to shelter should lead to increased soybean production. Models for predicting soybean performance need to accommodate any changes in canopy morphology.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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