Our season of extremes continue. This past week we experienced extreme temperature differences, as temperatures at one point as low as 33 degrees but daytime highs reached 90 degrees in Northwest Iowa.  This past weekend also brought another rain event – or two – to the area. Top soil moisture is 80% adequate, and subsoil moisture is 79% adequate.

Although last week’s early frost nipped immature crops, 76% of Iowa’s corn and 74% of our state’s soybean crop are in good to excellent condition. Click here to see how crops are faring by region across Latham’s six-state marketing footprint.

Above-average temperatures and frequent rains continued this week. At Latham headquarters in North Central Iowa, about 7 inches of rain has fallen during the past 9 days. Some parts of the state could use a break from the wet weather, however, the crop remains in very good condition. Iowa Secretary of Agriculture Bill Northey, today on KILJ Radio, reports that 76% of corn and 73% of the state’s soybeans crop is in good to excellent condition.

Diseases like Sudden Death Syndrome continue to surface. Keep a watch on stalk rots, which can help prioritize fields for the upcoming harvest. Scouting reports will also be helpful as you select seed now for next year’s crop. Click here for regional crop updates in the territories we cover.

Ever since the cicadas began to sing in mass, folks have been predicting when the first frost will hit. More than one Midwest farmer is worried about how frost will impact late developing corn.  While it may give us something to talk about, the first frost is beyond our control.

“Worry is not preparation,” so let’s instead channel our energies into preparing for harvest.  Make a pre-harvest check list to ensure you’re ready, regardless of when harvest begins.  To preserve maximum yield, you may need to harvest at higher moisture levels this fall.  In addition to having combines and other equipment in tip-top condition, it’s important that drying facilities are clean and ready for use.

You can also prepare now by prioritizing corn fields for harvest.  Fields under stress from either too much water this spring or a lack of rain this summer will warrant special harvest considerations.  Closely watch those fields that show nitrogen deficiencies as the potential for stalk rot increases when nitrogen leaches.  Plants need enough nitrogen to fill the kernels plus maintain plant health.

Check stalk strength by pinching the lower internodes on the plant and feel for weakness.  The root mass can affect the plant’s ability to stand up against late-season winds.  Late-season heat may also affect the ear shank.  If the shank gets weak from heat, it usually kinks or has a sharp bend.  A high-yielding hybrid may also cannibalize itself to maximize yield.  To check for these issues, walk into a field and shake the plants.  Watch to see if ears fall.

Roots can be more of an issue than stalks in a wet spring like we experienced.  Saturated soils limit the growth of root hairs and brace roots, making the total root mass much smaller.  If those plants grow close to full size, that puts a lot of stress on the plant later in the year –either it may not have the ability to take up enough nutrients or the plants may lodge if there is a late-season wind or wind and rain event.

Plan for the worst and hope for the best, as the old saying goes.  With so many consecutive days of excessively high temperatures, it’s hard to imagine it being cool enough frost anytime soon.  Hopefully mild temperatures are on their way – and will last well into October.  If the weather should take a turn for the worse, however, at least you won’t be caught off guard.

Rainfall slowed harvest last week, but no one is complaining.  Ninety-five percent of the corn crop has already been harvested and soils statewide desperately need moisture.  As a result of the recent rainfall, topsoil moisture levels have improved to 31% very short, 38% short, 29% adequate, and 2% surplus.  Subsoil moisture improved and is now rated 60% very short, 34% short, 6% adequate, and 0% surplus.

Subsoil moisture is the first indication of next year’s crop, says Iowa State Extension Climatologist Elwynn Taylor.  We’re still facing dry conditions, and there’s a 22% chance that next year’s growing conditions will be as bad those we faced in 2012.

The good news is there’s a 60% chance that conditions will be better in spring 2013.  Autumn rainfalls can go a long ways toward replenishing soil moistures.  Taylor says 1 inch of rain equates to more soil storage in the fall and spring versus in the summer because (1) not as much moisture is being lost to warm soils and evaporation; and (2) no moisture is being taken up by growing plants.

Another reason why fall rains “goes further” is there are fewer drying winds.  For example, the drying rate for April 15 was 0.2 inches and .14 of an inch for Oct 15.  It took 5 days to dry 1 inch of water in April and 7 days in October.

Rainfall over a longer period of time, which allows the moisture to soak into the ground, is more advantageous than a hard rainfall that runs off the surface.  It takes 2 inches of soaking rain to replace the moisture in one foot of soil, although this varies slightly depending on soil type.  During the 2012 growing season, roots used the water down to 8 or even 10 feet in some places, so now we need 16 to 20 inches of soaking rain to replace those water levels.  Fortunately, the rainfall we’ve received over the past two weeks have been gentle rains for the most part.  We assume 70% of the rain soaks in, so 10 to 12 inches of rain over a long period could conceivably recharge 5 feet of soil.

Thanks to Taylor’s insights, we’re singing the praises of autumn rain.  We’re also doing the rain dance because we’re still facing dry conditions here.  Hopefully, we’ll be singing the rain sometime soon!