Burning fields is an old practice that still continues


When I first moved to North Carolina, I was surprised farmers were still allowed to burn wheat fields, especially in places where neighborhoods were close. That was twenty-some years ago. Even in the mid-90s, there was a growing group of people concerned with adding more greenhouse gases into the air.

Burning is a management tool that has merits and under some conditions might be the best treatment for certain places. Ridding fields of noxious weed seed is just one advantage, but to a degree it’s overrated. Weed seed under the insulation of soil is likely unaffected.

Insects are partially controlled, but many lay eggs below the soil surface and they might not be killed. This is especially true when the burn spreads rapidly.

Burning removes the material responsible for holding the soil, so planting soon after the burn is important. Phosphorus is a nutrient that is not lost by burning. It might even be made more available. However, if ash residue is blown away it will be lost.

No knowledgeable person would ever argue that control burning is not an important forest management practice. Keeping levels of readily ignitable fuel at low levels is critical for reducing the number and severity of wildfires. Much of the fire problems in California could have been averted if more of this was done.

This method is not a panacea though. Disadvantages to burning include lowering of long-term natural fertility, increased cost of production, less water retention, greater liability risk and possible health concerns. Farms aren’t as isolated as they once were, so fields are in closer contact to residential areas.

There is somewhat less burning than there once was, as no-till planting has become more popular. Drilling into existing stubble means fewer trips across the field. That saves energy and money.

Yield differences are likely insignificant despite what proponents of each method espouse. I’ve seen data showing increased yields planting into stubble and I’ve seen studies that show no difference.

I’ve also seen inconsistent stands of soybeans, because of differences in stubble density. This probably caused seeds to be sown at different depths. Also, some farmers don’t have no-till equipment, so it’s a moot point to them anyway.

So, if we assume that the practice of burning wheat fields will continue, how can we make it safer? We need to pay attention to the weather. High temperatures, low humidity and high winds are all factors that contribute to fires getting out of control. So is not enough labor to do the job safely.

Paying attention to wind direction is critical. So is keeping the edges of the field clean and free of highly combustible materials. Burning a border against the wind can be a slow process, but it will prevent a raging fire from going where it shouldn’t.

I think burning fields will always be controversial. I further agree that it might not always be the best method for field preparation. This is particularly true as homes continue to encroach on farms, but burning is still a good tool to keep in the toolbox.

 

Ted Manzer teaches agriculture at Northeastern High School.

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Mulching can benefit vegetable gardens too.


Last week I discussed how mulches are used on our landscape beds. Vegetable gardens can also benefit from a good mulching now and then. Often, our goals will determine the type of material used.

In spring, we can speed up the season by using plastic mulches. They act like a greenhouse to warm the soil. Clear plastic warms better than black but it also allows more weeds to grow. A good thing about plastic mulches is that they hold in moisture. A problem is that they don’t allow it to enter in the first place.

Cloth mulches can help in this area. I prefer heavy-duty geotextile cloth. I think it’s worth the investment. This material suppresses weeds and eliminates copious handwork. In a garden situation, it’s usually necessary to remove it after a few years so the soil can be conditioned. Soil compaction between rows eventually becomes a problem.

Organic mulches will eventually turn into compost. Almost any material can be used. Leaves and grass clippings are the most common. When they decompose or weeds begin to be a problem, they can be tilled into the soil to increase organic matter and general soil tilth.

An important thing to remember is not to apply too much at a time. A two-inch layer is ideal. More than that can cause them to mat down and shed water. Also, in the case of dry leaves, they often have a wide carbon to nitrogen ration and additional nitrogen might have to be added. This can be accomplished by adding bagged fertilizer or nitrogen from an organic source like manure.

Sawdust and wood shavings are often used on strawberries. They’re not quite as popular for general vegetable garden use. Plants often become nitrogen deficient during the decomposition process and additional nitrogen must be added to correct it.

Pine straw is another possibility. People are often concerned about lowering the pH of the soil too much, but I think that is overrated. That concern can be overcome by adding a little lime anyway. A little more calcium might just help control blossom end rot on those tomatoes too.

Straw is another material people sometimes use. Like dried leaves and wood shavings, it has a wide carbon to nitrogen ratio. Another problem with straw is that it will contain lots of seed. Sometimes it will look like you planted your garden in wheat. This is not entirely bad. It might be unsightly, but the wheat will not be there forever

Newspaper is another popular organic mulch. Placing it on the garden is a good way to get rid of it. It will eventually decompose and add to the soil. In the meantime, the newspaper will help suppress weeds. The biggest problem I have with it is that it usually dries up and blows everywhere.

Whether you choose to mulch or clean till your garden is a personal decision. Adding organic matter is always a good thing, but some folks prefer to incorporate it immediately and not leave the material on the surface. Enjoy your garden either way.

 

Ted Manzer teaches agriculture at Northeastern High School.

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How do we decide about landscape mulching?


Most people spread a layer of mulch around their landscape beds. Some even mulch vegetable gardens. With so many types to choose from, it’s often a confusing situation.

The main reasons we mulch are to conserve water, suppress weeds and just make the area look neat. Almost anything can suffice as a mulch. However, some fit certain situations better than others.

Some mulches are organic. Anything organic will eventually decompose. This can be a good thing or a bad thing, and the rate of decomposition varies greatly. Inorganic mulches generally don’t break down, but they often can get hot. This can be a problem around plants.

Hardwood bark mulch is probably one of the most popular organic mulches out there. Its greatest advantage is its availability. It decomposes faster than most types, but that can be an advantage, especially on sandy soils.

When this mulch breaks down it improves soil structure. That will help with both drainage and water holding capacity. More organic matter also means soils hold nutrients better. Decomposing hardwood mulch is usually not quite as acidic as pine mulch is. Again, this can be an advantage or a disadvantage.

A disadvantage of both types is that they need to be applied more often than most types. Many people like pine straw because it lasts longer and stays put nicely. It is also acid forming, so if that’s not a problem this might be a good choice. Pine bark nuggets can be attractive, but they are often displaced by heavy rains.

Decomposed sawdust or wood shavings are often used as mulching material. They have a problem in that they must be broken down by microorganisms. These bacteria and fungi require nitrogen fertilizer to break these materials down because these materials have a wide carbon to nitrogen ratio.

If this fertilizer is not added, these microbes will extract it from the soil. Consequently, nutrient levels in the soil can be greatly diminished. I recommend fertilizing and composting these materials before they are used.

Hay and straw are occasionally used, but they can contain weed seeds. They generally aren’t very attractive either, especially after a few rainy days.

Sometimes folks like to use weed barrier cloth on their plantings. This helps suppress weeds. It also makes the mulch last longer. Some folks also like to use the colored mulches as they maintain their appearance better.

Inorganic mulches are often the choice around areas where cleanliness and low maintenance the main goals. Crushed stone, river gravel, marble chips, volcanic rock and rubber mulch are just a few of the possible choices.

None are very conducive to plant health. They absorb heat and provide no nutrients or improvements to soils with poor drainage. They also won’t slow water movement on sandy soils.

Rubber mulch is a relatively new phenomenon. It’s often used on playgrounds because it provides protection from injuries due to falls. It does absorb heat and children might be more subject to burns than they would if people used organic mulches.

Mulching planting beds is important, regardless of the type used. Without some type of protection, soil erosion is bound to occur. We don’t need more sediment in our storm drains, nor do we need it in our waterways. Furthermore, planting beds simply don’t look attractive unless they have some type of finishing material on them.

 

Ted Manzer teaches agriculture at Northeastern High School.

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Controversy about GMO crops never seems to go away


We’re all familiar with the term GMO, and many have already made up their minds about these crops. Unfortunately, most people don’t really know how they were developed or how they are different from any other commodity.

That doesn’t stop opinions from forming. To be honest, genetically modifying food and other crops has been around since farming began. Farmers have always selectively bred crops and livestock.

Most plants considered GMO are ones that have been modified by a process other than simple selection and breeding. The results are organisms that contain genetic material from different species. We call these transgenic organisms.

Decades ago, scientists found that a bacteria species called Bacillus thuringiensis (Bt) produced a chemical that was toxic to most caterpillars. It was and is still used as a pesticide to kill these plant pests.

In the mid-1990s, the gene from this bacterium was inserted into corn DNA and the result was a plant that was resistant to European corn borer and other related pests. The corn plants were able to produce the same chemical that the Bt bacteria did. They needed no additional pesticide to control the caterpillars. Yield and quality increased.

Additionally, no traces of Bt related chemicals were present in any part of the plant other than the foliage. This meant fewer pesticides were necessary to produce corn, and if only the grain were used, no chemical would be consumed.

About the same time, scientists stumbled upon another bacterium that contained a gene resistant to the effects of the chemical glyphosate (Round-up). This gene was incorporated into soybean plants and Round-up Ready Soybeans were born. The soybean plants can break down the pesticide and not the other way around.

Glyphosate is a chemical that is non-selective. That means it kills all plants hit by the spray. This herbicide has many desirable traits. It has low toxicity to mammals, it doesn’t persist in the environment for very long, and it doesn’t get absorbed by plant roots.

Reducing the amounts of pesticide necessary to produce crops is a major goal of GMO research. Furthermore, EPA regulates all transgenic crops, so they undergo substantial testing before new ones can be released. Developing chemicals that decompose quickly makes producing crops safer, too.

The upside to GMO technology is high. However, there are potential environmental problems that could result. Back in 1989 scientists took a gene from a Chinook salmon and an ocean pout, which has the ability to eat and metabolize food at extremely low temperatures. They inserted this into an Atlantic salmon.  Atlantic and Chinook salmon are close relatives but won’t cross naturally. Ocean pouts are totally unrelated. The result was a growth rate that was close to four times faster.

This sounds great, but what if that cross was introduced into wild populations somehow? Other species might be put at a disadvantage and natural balance of ecosystems could be disrupted. I realize wild Atlantic salmon populations aren’t what they once were, but this could be like the dilemma of the resident Canada geese.

We also could generate superweeds if any cultivated GMO species crossed with wild ones. For example, if GMO sunflowers were developed and they crossed with wild types, it could be a problem.

GMO technology has great potential for solving world hunger, but scientific ethical standards are critical. Short-term thirst for money can destroy great science.

 

Ted Manzer teaches agriculture at Northeastern High School.

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Jimsonweed is another poisonous plant in the potato family


Last week I wrote about angel trumpet, an ornamental plant in the potato family. Jimsonweed (Datura stramonium) is a very close relative and a weedy plant some people think is attractive enough to be used that way. In fact, numerous nurseries sell it.

It has similar looking flowers to angel trumpet, but they are smaller. Plants can achieve heights of five feet and have large pointed edged leaves. Most varieties used ornamentally are much shorter.

Spiny seed pods look like horse chestnuts and can contain 500 or more bean-shaped black seeds. Each plant produces numerous pods. When these pods dry and split, seeds can be thrown ten feet or more. Seed production is part of the reason this plant is a noxious weed.

Jimsonweed is an annual plant, so producing seeds is crucial for its invasiveness. To make matters worse, seeds can remain dormant in the soil for decades without losing viability. Also, plants occasionally will be perennial in our zone 8 climate, so that’s another reason they are a great concern in the southern US.

A further reason we dread jimsonweed is that it is extremely toxic. All parts of the plant are poisonous. That’s a big problem when children spot them since foliage, flowers and seed pods are so intriguing. Additionally, plants have a bad and well-deserved reputation for misuse.

Another name for jimsonweed is devil’s snare, because of its toxicity. Several alkaloids including atropine are present in significant amounts. Atropine is a strong nerve agent, and misuse often means death.

This is a compound that should only be administered by professionals in known quantities. Concentration in plants can vary tremendously, so this is not a plant to play doctor with.

Jimsonweed also is a concern in wheat and soybean fields, as seeds could wind up mixed with the crop seed. Even small amounts mixed in livestock feed can be problematic, so controlling it is essential. Identifying the seed is a skill that farmers should develop, especially if they grow crops for seed.

Most livestock generally avoid eating jimsonweed plants in pastures, but when pasture growth is limited, they sometimes are forced to consume it. If plants wind up in hay, the likelihood animals might eat some is even greater.

In a vegetable or flower garden, jimsonweed can be controlled by cultivation. The only concern is ridding the area of it before plants go to seed. That shouldn’t be too difficult as the plant is so conspicuous.

On a large scale, controlling this weed chemically is the only way. Many herbicides effective against broadleaf plants can be used to kill jimsonweed. Pre-emergent chemicals are also a good choice, especially in field crops like soybeans, wheat and corn.

This is a plant I often contemplated writing about since it is so common. I was always hesitant, because of my concern about people experimenting with it.

Toxicity among individual plant specimens varies tremendously, and that makes jimsonweed especially dangerous if consumed by any manner. Avoid even touching this plant without washing your hands afterward. I’m serious.

Young jimsonweed plant

 

Ted Manzer teaches agriculture at Northeastern High School.

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Angel trumpets love the summer heat


 

We’ve had some beastly hot weather recently, and many landscape plants are suffering. One that isn’t is angel trumpet (Brugmansia sp.), a member of the potato family.

Angel trumpet plants grow to the size of a large shrub, but in our climate, they die to the

ground each year. Still, once they begin growing in spring it doesn’t take them long to achieve heights of ten feet or more. In warmer climates, angel trumpets don’t die to the ground and can grow to be 30 feet tall.

These dramatic plants are often used as specimen plants as they can attract everyone’s attention with their large and copious flowers. Flowers are as big as a football, and hummingbirds and butterflies love them.

The leaves are large as well. I’ve got a couple pale peach colored specimens at school that stop traffic when they are in full bloom. Every year people ask me what they are. Blossoms are short-lived, and sometimes plants can be covered with blooms one week and then not flower again for a month.

Angel trumpets grow best in full sun, but they also tolerate partial shade. Increasing the shade will reduce blooming and the overall size of the plants.

The fragrant flowers might tempt you to taste them, as flowers of many plants are edible. Don’t even consider it for this one. Angel trumpet is deadly poisonous when ingested.

I’ve read where some people even have reactions to touching the plant, but I have never run into anyone with that affliction. Still, I don’t recommend them in areas where pets might eat them.

If that isn’t a problem, these plants are easy to grow. They tolerate a wide variety of soils, but they perform best in rich moist soils with high organic matter. Heavy mulching is often helpful, especially if winters are harsh.

Plants also respond well to fertilizer. I prefer to use slow-release types as fertilizer burn will rarely occur. I’ve found that fertilizers with a roughly equal ratio of nitrogen phosphorus and potassium seem to work best.

Propagation is simple too. Plants readily root from stem cuttings any time of the year. I usually take cuttings in the fall right before the first hard frost. I clip stems about 12-18 inches long or when they contain about four leaf buds. Rooting hormone is rarely necessary.

In the fall, the whole stem will die in our climate. However, it is very important that plants are not pruned to the ground until they are completely dormant, and all possibilities of Indian summer are gone. If plants begin growing in the fall after pruning, they’re likely to experience winterkill.

Don’t be alarmed if plants are slow to emerge the following spring. They are among the last to show themselves, but like lantana, once they do, they grow like gangbusters. The only major problems they face early in the season are from slugs and snails.

Angel trumpets are dramatic plants. However, they are large and will dominate the space. They also are poisonous to people and pets who try to eat them.

Angel trumpet plant in rapid growth

Ted Manzer teaches agriculture at Northeastern High School.

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Elephant ears make an interesting addition to your garden bed


Elephant ears (Colocasia sp.) are that plant with the huge heart-shaped leaves that look like they belong in a tropical rainforest. That’s probably because they do. They are native to Southeast Asia.

These peace lily and caladium relatives are one of those plants that can be perennial, but usually, it takes some ingenuity to get them to return year after year. Leaves of some types can be over two feet across and three feet long, so they can be quite dramatic.

Most species of that Arum family are tropical, but there are exceptions. Growing up in Maine, I regularly encountered a plant called skunk cabbage. It is an elephant ear relative that is very winter hardy.

Just as there is variation about the hardiness of all Arum family plants, there are considerable differences concerning specific types of elephant ears. Some may be left in the ground with no additional protective mulch and come back year after year.

Dwarf elephant ears are usually less winter hardy than the giant types. These should either be treated as annuals or dug up and stored until spring.

Some people like to plant elephant ears in large pots and bring them inside for the winter. They grow well in a sunny window but require quite a bit of space. They are also easily mutilated by pets, so they might look a little ragged when taken outside in the spring.

If planted directly outdoors, elephant ears grow best in well-drained but moist soils and partial shade to full sun. We are in zone 8, which is at the limit of hardiness for even the giant types.

For those concerned about their plants dying over the winter, I suggest cutting the plants back after a frost and digging up the underground structures. Let the plants dry down before storing and keep them in the garage or another cool dry place for the winter. If this method is used, it is important not to replant them until all danger of frost has passed in the spring.

Most people refer to these fleshy structures as bulbs, but they are corms, much like on gladiolus. Anatomically, these corms more closely resemble the tubers of potatoes than they do bulbs.

By the way, corms of one type are edible and grown for food production throughout their natural range. This is a group of plants referred to as taro, and they are cooked before they can be consumed. People eat cooked taro leaves too.

Young common elephant ear corms may be cooked and eaten by some people, but many suffer mouth irritation as plants contain calcium oxalate. Leaves should not be consumed raw or cooked. In fact, they can be somewhat toxic to pets. Several references refer to elephant ears as being readily consumed, but I suspect many of these are confusing elephant ears with taro. They are very similar looking.

Many folks like to incorporate their landscape with that tropical look. If you are one of those people, elephant ears might be for you.

Elephant ear plant ready for transplanting

Ted Manzer teaches agriculture at Northeastern High School.

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