We had a few frosts this week. With record warm temperatures in December, this cold is going to help some of our winter crops claim some chill hours. We’ve also been having plenty of rain as El Nino was predicted. Here are some screen shots of rain, temperatures and chill hours from the Dixie weather station from www.georgiaweather.net. You can see how much lower chill hours are as were last winter this far. The ’12 to ’13 winter was also warm.
Our forage crops look okay and hearing some good reports. We need to watch some of our forage now as cool temperatures are going to come back this weekend and next week. Oats, of course, are more susceptible to the cold damage. Some cattlemen are fertilizing forage after heavy grazing to encourage new growth. Ryegrass is one of our small grains that has 3-way split, with one fertilization through the winter. Everything else we fertilize once at planting and then before spring to encourage more tiller growth. We may want to be careful with management inputs during these upcoming cold hits. Below is the forage recommendation fact sheet from the UGA Soil Test Handbook:
Here are some oats I looked at today. Overall, they look good. Fields are wet and we need to watch for compaction. And we need to watch our grazing. To determine when to pull cows off, we look at the node or joint inside the stem of the plant. This is the growing point, and it feels like a bump or bee bee inside the stem. We don’t want them to graze lower than the growing point. In the picture below the joint is between my thumb and the roots.
I also see a little crown rust showing up. These orange/red pustules on the leaf resemble that of aphid feeding. The rust pustules will rub off on your finger. They are also raised above the leaf.
Crown rust will cut back on yield even in grazing, so we have to graze heavily when rust is seen so we remove the leaf tissue where spores land.
Some crops are not going to appreciate the cold. Thomas County has 2,500 citrus trees in commercial production now – mostly Satsumas. The biggest challenge for citrus north of Florida is cold protection. Certain plants handle cold more than others. Satsumas have the greatest degree of cold hardiness. Bearing satsumas can withstand temperatures as low as 19º to 20ºF without considerable wood damage. (Citrons, lemons and limes, on the contrary, are most easily killed by freezing temperatures – as low as upper 20s.)
I took a picture of these satsumas Tuesday morning. The temperature that morning was 29 degrees. Once temperatures get down to 24 and 25, they will cut on the irrigation as a form of cold protection. Previous cool weather allowed the plants for some cold acclimation. Cold acclimation is very important for citrus. The sudden, hard freezes in November 2014 hurt us so much more, because plants were essentially not ready for the cold. A few nights in the upper 20s is good for our citrus.
Cold damage always takes some time to show up. Lowndes County Agent, Jake Price, gave a good talk on cold damage at the Satsuma meeting this week. There are a few types of cold damage we may see. Sometimes damage occurs on the leaves only. If damage is on the stem, it is worse. If the plant incurs cold damage on the leaves, it may drop those leaves. This is a good sign since the plant has to be alive to drop the leaves. If cold damage occurs and leaves do not drop, this is not good news. Here are some pictures of cold damage. The darker green is cold damage: