Fundamentally Speaking

USDA September Soybean Yield Estimate

Joel Karlin
By  Joel Karlin , DTN Contributing Analyst

Though the USDA September crop production 2014 U.S. soybean estimate of 46.6 bushels per acre (bpa) was very close to the trade estimate, there have been a number of questions as to how that figure was arrived at.

Specifically, a graphic called Soybean Objective Yield Region shows the pods per an 18 square foot plot vs the implied pod weights for the objective 11 states (10 in Sep report as Arkansas not included).

What is interesting is that the USDA September soybean yield estimate was based on the highest implied soybean pod weight ever at 0.320 grams per pod.

Curiously, the USDA also used a very low 1,650 pods per 18 square foot plot with only 2012 (1435 pods) and 2013 (1571 pods) lower.

P[L1] D[0x0] M[300x250] OOP[F] ADUNIT[] T[]

The ten year average is closer to 1709 and the high water mark appears to be the 1894 pods seen in 2010.

We do note that the 2012 and 2013 pod weights were higher than all years except this one suggesting that there is an inverse relation between pod weights and the number of pods per area.

Still, the low number of pods contained in the September report seems at odds with not only the very good weather conditions seen this summer but runs contrary to field observations from many crop scouts.

This graphic shows the number of soybean pods per an 18 square foot plot for the ten objective states used for the September report, the number of pods as a percent of the September 2004-2013 average, and the ten year average percent change in the number of pods from the September to the final crop report for each of the top ten states.

Only three states, IL, MO, and SD had a larger number of pods in this report than for the ten year average while all states with the exception of OH see pod numbers increase from the September to the final report in January.

Were the USDA to use the ten year average pods per 18 square foot area and the same pod weight then the 2014 yield would project to 48.3 bpa.

Just using the average percent increase in pod numbers from the September to final report for each state would project final soybean yields to 48.0 bpa.

(KA)

P[] D[728x170] M[320x75] OOP[F] ADUNIT[] T[]
P[L2] D[728x90] M[320x50] OOP[F] ADUNIT[] T[]

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