Showing posts with label statistics. Show all posts
Showing posts with label statistics. Show all posts

Friday, July 31, 2009

Soybean trend yields from the model

In the post below are the estimated annual yield growth for corn, so here are the numbers for soybeans. All results are expressed in bushels/acre/year from 1986-2008 estimation period, with condition variables and planting progress also used as explanatory variables.
AL 0.35 bu/ac/yr
AR 0.65
GA 0.56
IA 0.54
IL 0.49
IN 0.63
KS 0.39
KY 0.33
LA 0.60
MI 0.44
MN 0.25
MS 0.63
MO 0.49
NE 0.71
NC 0.20
PA 0.35
ND 0.40
OH 0.44
OK ~0
SC ~0
SD 0.40
TN 0.38
WI 0.73

I've found some historical performance graphs from previous years I'll post. I'll also post some old performance relative to USDA, of course USDA predicts out of sample while I'm comparing it to my in-sampe results.

Wednesday, July 29, 2009

Corn trend yields from the model

Calculating simple trend yields is fraught with danger. The selection of the starting or ending year can have significant influence. There are still issues with using conditions to 'correct' for this but in the model I do estimate an underlying annual trend based on the 1986-2008 period. What follows are the estimated annual trend yield improvements for corn out of the model. I'll follow up with soybeans and cotton as I take the opportunity to use this blog to explain the model.
All results are expressed as bushes of corn/acre/year
AL 1.65 bu/ac/year
CO ~0
GA 2.06
IL 2.67
IA 2.74
IN 2.16
KS 1.43
KY 1.93
MI 1.96
MN 2.48
MS 2.75
MO 2.22
NE 1.95
NC 1.16
PA 0.97
OH 2.18
SC ~0
SD 2.84
TN 2.02
TX 1.95
WI 1.83