Growth and yield of snap beans as affected by wind protection and microclimate changes due to shelterbelts and planting dates

摘要

The effects of wind protection on growth and total and marketable yields of snap bean (Phaseolus vulgaris L.) planted at 2-week intervals through the 1994 and 1995 growing seasons were examined. Research was conducted under nonirrigated conditions at the Shelterbelt Research Area, Univ. of Nebraska Agricultural Research and Development Center (ARDC) near Mead. 'Strike' (white-seeded) and 'Rushmore' (dark-seeded) were planted in locations sheltered from wind stress by tree windbreaks (shelterbelts) and in locations exposed to normal winds using a randomized complete-block design with a split-split plot arrangement of treatments. Air temperature, soil temperature, humidity, wind speed, and wind direction were monitored. Detailed microclimate conditions at bean canopy level in sheltered and exposed plots are provided in the text. Wind speed in sheltered areas averaged 36% of open field wind speed in 1994 and 43% of open wind speed in 1995. Soil temperatures were higher in sheltered areas than in exposed areas. Microclimate changes due to shelter had no effect on the percent seedling emergence or number of days to emergence. Plants in shelter had significantly higher total dry weight and leaf area index and greater total internode length than exposed plants. Both total and marketable yields were increased significantly by production under sheltered conditions each year. Planting date and cultivar also had a significant impact on average pod yields. No interactions between shelter and planting date, or shelter and cultivar, were found in either year. The results suggest that wind protection provided by shelterbelts (tree windbreaks) can increase pod yields of snap bean both early and late in the season. This may result in greater profit for the grower due to a tendency for higher prices at these times.