Leaf Area Development of Corn as Affected by Windbreak Shelter

Abstract

Windbreaks generally have positive effects on crop yield because of improved growing conditions. To quantify these effects, leaf area and vertical leaf area distribution of corn (Zea mays L.; cv. Wilson 2100) were studied with and without windbreak shelter during 1991 and 1992. Simulation models for leaf area estimation were also evaluated for the two years. Leaf area, length, and width were measured for the whole canopy several times during each growing season. Two types of area prediction models were developed and tested: a simple length‐width model using a correction factor (C) and a statistical model. Although the statistical model gave a slightly better overall estimate of leaf area, the simple model was the preferred choice because of its simplicity and better area predictions when leaves were small. Regardless of windbreak shelter or year, values of C were stable. The average C for this corn hybrid was 0.75, which is consistent with other reported values for corn. Windbreaks did not affect total leaf area nor alter the vertical distribution of leaf area for the two years. With or without shelter, the height of maximal leaf area was at 1/2 of the canopy in 1991 and in the lower 1/3 of the canopy in 1992. This downward shift of maximal leaf area was probably due to lower temperatures and more evenly distributed rainfall in 1992 and may have been positive for plant productivity. The variations of windbreak effect on leaf area development with species and environmental conditions indicate the need of similar future studies on other major crops to formulate an effective strategy for windbreak evaluation.