Once in a decade agriculture rally

Agricultural commodities have been on a historic rally, with sentiment in several commodities at once-in-a-decade levels. Soybeans Optix's 20 day average is at 79. The last time this occurred was in the 2007-2008 commodities bull market:

Due to the frequency of these signals in 2007-2008, soybeans' short-medium term forward returns were not consistently bearish:

Herein lies the problem with commodities sentiment. Commodities are prone to extreme sentiment from time to time, which means that momentum can overpower sentiment in the short term. Nevertheless, this is not a good long term sign for soybeans.

When soybeans rallied >42% over a 7 month period, it typically fell over the next 6-12 months:

Similarly, Corn Optix's 20 day average is extremely elevated (at 72):

Once again, this was bearish for corn over the next year:

Like momentum in soybeans, corn is experiencing strong momentum:

When corn rallied 35% in a 7 month period, it wasn't a clear short term bearish sign as momentum sometimes defeated sentiment in the short term:

Sugar has also been on a tear of late:

Such strong momentum was not a consistently bearish factor for sugar over the next few months: