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Carbon Balance Model for May 10, 2012

Posted: May 10, 2012

The carbon balance model for the Penn State Fruit Research and Extension Center in Biglerville indicates that May 9th was essentially a neutral day, with neither a large carbon surplus nor a deficit. Cool temperatures and increased sunlight on May 10th are initiating what is forecasted to be a 3 day period of projected surpluses.
Dr. Jim Schupp, Penn State Fruit Research and Extension Center Pomologist and Station Director

Apple trees would be rather insensitive to new sprays of chemical thinners during this time. Given the forecast, the model projects a strong carbon deficit on Sunday and Monday, May 13th and 14th. These deficits are driven mainly by forecasted cloud cover that would reduce photosynthesis, hence low carbon supply. These deficits would diminish if sunnier conditions prevailed.

Date Carbon Supply Total Demand Carbon Balance
5/2/2012 23.56 53.47 -29.91
5/3/2012 82.39 62.17 20.21
5/4/2012 63.00 75.28 -12.28
5/5/2012 75.06 82.42 -7.37
5/6/2012 6.87 90.13 -83.26
5/7/2012 6.53 81.60 -75.07
5/8/2012 1.17 68.98 -67.80
5/9/2012 52.86 49.99 2.87
5/10/2012 95.68 54.84 40.83
5/11/2012 113.30 64.28 49.02
5/12/2012 104.36 67.10 37.25
5/13/2012 18.65 74.86 -56.21
5/14/2012 15.27 84.22 -68.95
5/15/2012 75.11 52.40 22.72

5/10 through 5/15 values are predicted, based on Intellicast.com forecast. Please keep in mind that this model is only as good as the information provided by the forecast.

Carbon balance values that are bold are below the threshold of -40 grams of carbon. Expect trees to be quite sensitive to thinning chemistries during these periods, especially if they occur for a few days.

A severe deficit was observed from May 6th to 8th. Work by Ross Byers, formerly of Virginia Tech, suggests that 3 to 4 days of heavy cloud cover can lead to natural thinning.

 

Contact Information

James Schupp
  • Professor of Pomology
Email:
Phone: 717-677-6116