Why are the soybeans yellow? Why does my corn have tillers?
In these parts of south Perth county, June was much kinder than May. Bill Arthur provides heat unit records to me, which he has been collecting for over 30 years. His temperature data shows that 2014 is a very good example of average with respect to heat. Heat unit accumulation to the end of June is very close to the 30 year average, which for these parts is within an eyelash of 1000 heat units. It is easy to tell this is a typical year because corn is now anywhere from mid-thigh to shoulder and on the fast track to tassel by the end of this month.
Corn planted during the last week of May did not get the full benefit of this heat, but as I have explained before late planted corn makes up the difference by advancing quicker through the vegetative growth stages. The later planted corn is more uniform on average than earlier planted corn which has an additional positive effect on yield for the later planted fields. The 45 mm of rain received in June is half the normal amount, but still more than adequate to sustain early growth. Life is good.
There has been some chatter this week about applying nitrogen to soybeans. I have witnessed before the effects of nitrogen availability on early growth. It can be quite dramatic. This picture is from 2010.
However, this is not what caused the yellow beans in the photo.
The field has a history of soybean production. Nodulation was excellent as shown above. There is a rotation difference, with wheat being the previous crop on the left and corn on the right. It looks like the beans on the left would be at least 10% better than the beans on the right. However, at the end of the day the yield difference was negligible. The ugly ducklings still produced 55 bushels.
Another type of yellow was also on display last week. A lot of IP soybeans are grown around here and they had to be resprayed for weed control. The result was lots of scorched soybeans.
The true challenge of trying to manipulate the soybean plant at this time of year is recovering the dollars spent. Weed control dollars are always a wise choice. Fungicides? Yes, 2-3 bushels is the expected response and that more than covers expenses. Supplemental N? Not a clear cut answer. We need 2-3 bushels to pay for the added expense. My experience trying to boost soybeans with fertilizer in early July has produced more failure than success. I am still open to suggestions.
Corn tillers are also prevalent this time of year. Perfectly normal and usually not a reason for concern.
The presence of tillers can indicate you could have possibly bumped your plant population by another 2-3000 per acre because the plants are telling you they are not stressed at all. Genetics sometimes come into play because a hybrid can be predisposed to producing more tillers than average, but this is rare.