I hope you have dealt with the heat better than I have. I am not accustomed to it being this hot this early in the year, so I have spent most of my time during the past week indoors where it is air conditioned. I am sure there will be more hot weather to come, but I surely hope it does not continue to get any hotter.

Since I work so closely with farm crops, I am always fascinated about how plants grow. It is interesting to me to see how different things in the environment affect plants and to learn more about the interaction between plants and other factors such as insects, weeds, daylight, drought, and even heat.

You have probably noticed how the heat during the past week has affected plants in your landscape or if you are a farmer, the plants in your fields. It is apparent that most plants are suffering from the heat. If you are inquisitive like me, you might be asking yourself why this happens.

By using soybeans as an example, allow me to share some basic information about how plants react to extremely hot weather. When it gets above 95 degrees outside, many plants, like soybeans, cannot move enough water fast enough from the roots to the leaves to keep up with what is being lost out of the leaves. Moving water through the plant is referred to as translocation, and losing water out of the leaves is referred to as evapotranspiration.

So when temperatures exceed 95 degrees, soybeans will wilt in the heat of the day no matter how much water is available to them. Even if there is plenty of moisture in the soil, they may still wilt.

Soybeans, like many other plants, close their stomates in order to reduce the amount of water that is lost from the leaf. Stomates are tiny pores in the epidermis, or outer layer, that allows air to move in and out of the leaf. This air contains carbon dioxide. When the stomates close, carbon dioxide cannot get into the leaf, so photosynthesis can no longer take place. Photosynthesis is the process used by green plants to use sunlight to change carbon dioxide and water into oxygen, starches, and sugars.

If water is available to the roots of the plants, they will tend to recover quite well when temperatures drop back into the 80s. This is why plants will often start looking normal during the late afternoon as the sun begins to set.

If water is not available to the roots, it will take much longer for the plants to recover. In fact, if there is too little water in the soil, such as happens during extreme droughts, and the daytime temperatures are too high, such as we have seen during the past week, it is very likely that many plants will actually die. Fortunately, soybeans can tolerate much more of this situation than can many other plant species.

The heat affects blooming and plant reproduction as well. Many plants will not produce flowers or its pollen may become sterile during periods of extreme heat and the plant will not be able to produce any seeds. Soybeans are different. If soybeans have not started blooming, there is probably very little long-term effect other than delaying maturity a couple of days. But if soybeans are blooming or are past blooming during extreme weather, they will tend to abort whatever reproductive structure is being developed at the time, such as flowers, pods, or seeds. Then they will start the flowering, blooming, and seeding process all over again when the weather gets better. Very often the question is whether or not they have enough time to put on more flowers and complete the seeding process.

Hopefully, now you understand a little more about how your plants are dealing with this heat. Be kind to them. Give them a drink of water.

I was pleased to read some information in the most recent issue of The Progressive Farmer magazine that our younger generation is now more optimistic about farming. For many years, I had been concerned that the average age of our farmers continued to get older, since fewer and fewer young people were going into farming.

Rising commodity prices make farming a little more financially rewarding. New technology and automation has removed much of the hard work from farming. The greatest challenges remaining are the availability of land, the high cost of equipment, and overall profitability.

About 83 percent of the young people surveyed between the ages of 18 and 35 indicate they are more optimistic about farming than they were five years ago. Of these, 90 percent said they are better off now as compared to only 70 percent in 2000, and 92 percent see themselves remaining in farming for the rest of their lives. In addition, 95 percent would like to see their children become farmers as well.

It is good to know that with a new generation of farmers, we will continue to have an ample supply of food. We might have to figure out how we can do without gasoline because of rising prices. But even though it is getting more expensive, it will be impossible to do without food.

E-mail address: Everett_Davis@ncsu.edu

Mailing Address:
P. O. Box 2280
Lumberton, NC 28359-2280

Phone: 910-671-3276
Fax: 910-671-6278

Date Created 6/10/08