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Our field is looking a bit ragged. The leaves are starting to
senescence or die. Our field is at physiological
maturity (R9), which means
the seeds are as big and heavy as they are going to be and we're just
waiting for harvest. So, if it were to rain, it wouldn't really help
the plants. Now, before we can harvest this field the seeds will have to dry
down or lose moisture that's in them and the stalks will have to dry, too.
The heat and drought have speeded up the plants' maturation process. The leaves are yellowing and drying up. It's been 14 days since we've had a rain and that rain was just a sprinkle. The hottest day so far in August was on August 21st when it reached 106 F. That's hot!
This is the front of an R9 plant. The dried floral parts have stuck to the head the whole summer. The head is starting to dry down to a harvestable moisture content. You know, if you stare at that head long enough, you can almost make out eyes and it starts to look like a space alien! What do you think? Sorry, I've been out in the sun too long.
This is the cross section of the same head. Like most of the heads we've observed lately, this one has the brownish areas indicating head moth larvae activity. There's a little bit of Rhizopus head rot visible, but it doesn't appear to be too bad.
The small, shriveled seeds are from the center of the head, while the
larger seeds are from the outside edge.
This is a seed that is physiologically mature. Notice its color is more
grayish than when we looked at a seed a
At this point in the season we'll start to see things, such as this stem
that has lodged or broken over, that we
We've talked about sunflower heads being too large and this one is a good
example. This plant didn't have other
We thought this was an interesting plant. Notice, it doesn't have a head and its leaves and leaf petioles (stems) are purple. I don't know why the head is missing, but the reason the leaves are purple is because the head is gone. In a healthy plant, sugars that are made in the leaves through the process of photosynthesis are transported and deposited into the seeds, but because this plant's head is gone, there's no place for the sugars to go. So, the leaves are purple.