IPM- Crop Rotations

In Extension, we often talk about integrated pest management, a way to control a pest from various angles. These angles are cultural, mechanical, and biological options for managing pests.  A pest is simply something unwanted in a particular area.  Pests could be plants, insects, or even mammals at times.  The thought process is that there is no one perfect solution to a problem.  Easy come easy go, some would say.  I guess in this case it would be; easy go, easy come back!

A cultural way to break the cycle of many pests is to plan a crop rotation that involves crops from different plant families. Families in the sense of phylogenies or grouping according to similarities.  For instance, the following plants: tomatoes, eggplants, peppers and even potatoes are all in the Solanaceae family.  As you can tell, many of our garden crop favorites share a lot with one another.

One of the biggest mistakes in crop rotations is to rotate between unrelated plants/crops. This is important because pests can share similar crops and over winter in that specific crop residue.  Take for instance the cucumber beetle; this pest will over winter on cucurbit residue and be ready to re-infect that crop, whether it is a cucumber, pumpkin or zucchini.  This bug will also spread bacterial wilt that can cause a loss of an entire crop with a systemic infection.

The cucumber beetle will not damage tomatoes so planting a Solanaceae crop in an area that a Cucurbitaceae was growing would break that pest cycle. Pests can also be fungal.  A fungus called Alternaria tomatophila causes early blight in tomatoes.  The fungus can over winter in certain cultivars of potato and eggplant, both of which are in the Solanaceae family.

A good crop rotation starts with careful planning and can be successful by utilizing crops with complementary planting and harvest dates. A good rotation for May plantings would be to start with sweet corn (Poaceae).  Sweet corn can be harvested around August and into September.  A crop rotation will prevent certain cutworms and corn borers from being problematic in a specific area.  A good follow-up crop in that area would be garlic (Alliaceae) planted in September/October and harvested in July.  Once July comes, planting a legume (Fabaceae) will help remediate the soil and get the soil ready for the following season, hairy vetch for instance.

There are many rotations that work well in a crop rotation system, utilizing soybeans for a food plot can also be done. Just remember to rotate crops that are unrelated and replenish the soil at times.  This can be accomplished through the use of legumes or fertilizers.  A rotation only needs to be more than one crop; two is good, but three is great!  Get your garden plans in place and dig right in.

What, there are three different types of photosynthesis?

As if Photosynthesis was not complicated enough, there are actually different variations of how plants convert CO2 (Carbon dioxide) to C6H12O6 (Carbohydrates).  Plants have various physiologies to adapt to various environments on earth.  Alfalfa for instance can remain persistent and prolific during certain drought episodes due to its deep taproot that can help the plant utilize deep water sources.  In term this causes the Alfalfa legume to be sensitive to poorly drained soils that are not very permeable to surface water.  So the question someone could ask is; do all desert plants have long roots?  The answer is no, but one way desert plants conserve water and grow in a hot and arid climate is by the way they photosynthesize.

The three main types of photosynthesis are C3, C4, and CAM (crassulacean acid metabolism).  In college I had to memorize some of their pathways and mechanisms, but I will highlight what gives one an advantage over another and what types of crops, forages, and weeds have specialized C3 and C4 photosynthesis.  This will tell us why they can do well in certain climates and times of the year and when we can expect certain plants to be more abundant.

Rubisco is the name of the enzyme (protein) that “grabs” the CO2 molecule and puts it into the assembly line that will create the carbohydrates.  It is known as the most abundant protein in the world.  When we examine the quality of feed in our forages, it is rubisco that makes up most of the protein value in the forage analysis.  That is one of the main reasons leaves are desired over stems in hay.

C3 photosynthesis is the predominant way plants will take in carbon dioxide and produce carbohydrates.  In C3 photosynthesis Rubisco takes the CO2 and it is reduced into carbohydrates all in the same place and time.  By that, I mean in the same cell chloroplast and during the day (sunshine) when the stomata are open and the CO2 is entering the cell and the water is leaving through the same opening.  The issue with this is that it has the greatest water loss and during very high photosynthetic times (July) it becomes stressful for the plant.  Another issue is that oxygen is generated during photosynthesis and the oxygen will inhibit rubisco and slow photosynthesis down when the system is running very fast.  It seems counterintuitive, but the slow down allows the plant to deal with too much light that could cause damage.  Ever notice that cool season grasses do not grow too fast in July and August?  Cool season grasses have a C3 photosynthesis mechanism.

Now let us transition to some of the C4 grasses, also known as “warm season grasses” such as corn, sorghum, crab grass, sugarcane, bermuda grass, and foxtail.  These plants have rubisco in one cell and they have a mechanism of pulling the CO2 in a different cell that is connected by openings between the cells called plasmodesmata connecting the two cells together.  So what happens is that the plant can concentrate its CO2 where the rubisco is located and prevent that oxygen inhibition caused in the C3 mechanism.   These plants don’t have that high sunlight, July inhibition.  In addition to that, the specialization of the cells allows for approximately 40% less water usage per weight of CO2 reduction.  This just means that it is 40% more efficient in water usage on average.  There is always variation among species.  C4 plants can also partially close their stomata to prevent water loss and because they concentrate the CO2 in a different area, the oxygen will not inhibit the rubisco enzyme.  This is one of the major reasons why warm season paddocks are desired in a rotational grazing operation.  It allows for growth during the July and August time period, when the cool season, C3 grasses are inhibited and not actively growing.

Here is the misconception; many dicots (broadleaves) are also C4 plants, it is not just the grasses!  Sedges and many of the Amaranthus species are C4 plants, they seem to be the largest plant families in this C4-broadleaf category.  So Palmer Amaranth and Spiny Amaranth, along with the sedges do great in July and August.  The fact that they are C4 plants could be contributing to this phenomenon. Knowing this allows a farmer to possibly tackle a weed before it takes over a field when a desirable cool season crop could be growing slowly or possibly dormant.  Only 1% of all known plant species have C4 metabolism and even less have CAM metabolism.

Finally there is CAM photosynthesis. CAM is found in desert plants.  What these plants do is open up their stomata at night to allow CO2 in to minimize the water loss during the hot days.  The CO2 is stored in the plant vacuole as malic acid during the night.  When the desert sun comes out, the stomatal openings are closed and the CO2 is “removed” from the malic acid to then be introduced to rubisco and make carbohydrates.  By comparison, CAM is even more water efficient than C4 is.  If C4 is 40% more water efficient, CAM is 83% more efficient as compared to most C3 photosynthetic processes.  Cacti, many succulents, and the pineapple have CAM photosynthetic metabolism.

 

Resources:

  1. Taiz and Zeiger, Plant Physiology Ed. 3
  2. Christin and Edwards, The C4 plant lineages of planet Earth, Journal of Experimental Botany

 

July Blooms

It always feels like July 4th is the peak of summer and when those hot summer days seem to kick off.  In fact the longest day of the year is the summer solstice which falls in late June, and the days gradually get shorter from there.  Many long day flowering plants will flower or “bolt” around this time.  One that I saw most recently was lettuce.  Lettuce is a long day plant that when exposed to darkness for periods of eleven hours or less will flower or bolt.  Unfortunately lettuce was never bred for its flower and the bolting causes chemical changes in the plant and it is accompanied by a bitter taste in the leaves.  I know that read kind of funny.  Even though the plant is called a “long day plant” the transition to flowering is dictated by the shortened period of darkness that comes with the longer days.  So that’s how the long day plants work, they need eleven hours of darkness or less.  So when the days become thirteen hours or longer these plants will start flowering due to the shortened dark periods.

Weeds are also tied to the day lengths and temperatures to transition to flower. There is a reason why allergies fall at certain times of the year.  As stated earlier some long day plants are flowering now.  One of these examples is the Giant Ragweed.

 

Giant Ragweed Giant Ragweed is a summer annual that can grow up to seven feet tall or greater.  Giant ragweed is a monoecious plant, much like corn.  Giant Ragweed produces separate male and female flowers on the same plant.  It flowers in racemes that hold a cluster of small flowers.  The male flowers that produce pollen are on top while the female flowers are located at the base of the raceme.  This is a strategy that many monoecious plants take.  Corn tassels are also the male flowers which are located on top to increase the chances of pollination.

 

Common Burdock is another weed that is flowering now. Common Burdock

The Burdock flower looks a lot like the thistle flower but the plant has a very large broad leaves at the base.  The leaves can grow to be almost 2 feet long and can be over a foot wide.  When this flower is fertilized it produces a bur type fruit that will attach to clothes and hair.

Wild carrot is also flowering at this time; this plant is sometimes known as Queen Anne’s lace.

Wild Carrot

The flowers are white and set up as an umbel.  An umbel is a cluster of flowers that have a single attachment point.  It produces a round flat cluster of flowers that are known to attract butterflies.  I have heard it being referred to as a “helicopter pad” for butterflies…

One of the best ways to identify plants is to do it during flowering times. When a plant flowers will give you a lot of information as to its identity, and many plant keys will require the flower to be utilized in its identification.

Buttercup in Bloom

There is a plant out there in the Ranunculaceae family known as buttercup.  Buttercup can come in many forms whether it is an annual, biennial, or even perennial it can be a major detriment to livestock in pasture fields.  I was in a May stroll a few days ago when I noticed a bright yellow flower with 2-3 lobed leaflets with deep clefts.

Buttercup 3buttercup 2

I did what any good Ag Educator would do and snagged up a good sample (roots, leaves and flowers) to key out on my front porch. On a side note, the best time to key a plant is when it is in bloom so that blooming time is available to you.

I identified it as Ranunculus caricetorum also known as the marsh buttercup.  This plant does well in low woods, swamps, marshes, and poorly drained areas like around water springs.  Buttercup is a toxic plant in pastured areas if animals ingest it fresh.

Buttercup grows aggressively in patches and has a corm base. Corms are essentially compressed bulb like bases that store a lot of food reserves and thus make this plant hard to get rid of through mowing alone.  I will say that mowing and preventing the plant from going to seed will help keep it from spreading however.

Buttercup 4

The toxin that this plant produces is called protoanemonin. This toxin is oil based and found in the fresh plant stem, it causes irritation and blistering of the skin, lining of the mouth and digestive tract.  Fortunately, if buttercup is baled and dried in hay the toxin becomes inert and will not irritate the livestock.  To livestock, the plant is bitter and animals will avoid eating it.  If the plant overtakes a field however it can become a problem if livestock do not have anything else to eat, especially during the summer months of slow forage growth.

Buttercup is sensitive to most broadleaf selective herbicides used in pastures such as 2,4-D and dicamba products. It also grows in clusters so spot-treatments are a good way to get it under control.

OSU/WVU Extension Radio Jan-Feb 2016

OSU/WVU Extension Radio

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1/3/2016: 

Knowns and Unknowns of Oil and Gas from Landowner  Perspective

 

 1/24/2016: Marketing Beef Cattle

 

2/14/2016: Advantages of Crop Diversity in Pasture Fields

 

 2/21/2016: GMOs: Why They are Created and Labeling

 

2/28/2016: Bt and its Variable Uses and Agrobacterium  

Transplanting Into the Home Garden

It is that time of the year when the soil is warming up and people are starting to put in their garden starter plugs that they grew indoors. Starting plants indoors is a great way to get a “head start” on things and be safe from some late frosts that occur in April and May.  When you are transplanting some of these plants, be sure to check the frost tolerance and make sure you put them out during the proper times.

Besides the frost, plants have to acclimate or “harden” from indoor conditions to outdoor conditions. When a plant grows indoors the light conditions can be as much as 40 times less intense than the full sun, and exposure time can be less than half of what it will be outside.  Plants will generally grow thicker leaves and produce more chlorophyll to make better usage of the light energy provided to the plant when they are grown in low light conditions (indoors).  This is actually one reason why lettuce is grown in partial shade.

Low Light vs High

(Plant Physiology 3rd ed.)

Taking this idea a bit deeper (down to the roots); it is important to remember that the water and nutrient uptake is essentially all done through very fine and tender root hairs. When a plant is moved many of these hairs are damaged and water uptake can become insufficient for the plant’s needs.

Seedling

So let’s combine the problems now: A plant is moved to 12 times the sun, with increased chlorophyll and 2 times the light exposure that it is used to.  On top of that the plant cannot get the water to support the increased photosynthesis demand in that direct sunlight.  That could set the plant back, and all the sudden that “head start” might not be so advantages anymore.

 

Some tips from OSU Extension:

  1. Slowly transition the plant from indoors to outdoors by bringing it out for a few hours at a time without damaging the root hairs during the move (keep it in the original container).
  2. Don’t put out frost sensitive plants too early.
  3. Wait for the soil temperatures to warm up nicely (60 degrees or greater).
  4. When transplanting the starter plant, don’t let it get too big and don’t shake off too much soil from the root mass (root hair damage).
  5. Be sure to actively water the plant during the first week especially. This will compensate for the decreased water uptake ability of the plant.
  6. If you are utilizing weed control, make sure the pesticide doesn’t have a long residual period (refer to the label).

These tips will work for both gardening and landscaping; so when you buy a plant from a nursery, ask about the growing conditions. Things like: “Has the plant been growing indoors or outside?”  And “How long has it been out and how much sun is it getting here?”

NOV/DEC 2015 OSU/WVU Extension Radio

OSU/WVU Extension Radio

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11/1/2015: Animal Handling

11/8/2015: Light Quality, Light Intensity, and Light Duration

11/29/2015: Composting and Winter Livestock Feeding

12/06/2015: Kissing Bugs and Other Assassin Bugs

12/13/2015: Types of Christmas Trees and Their Characteristics

12/20/2015: Firewood Laws and Emerald Ash Borer Damage

12/27/2015: Timber Harvesting

SEP/OCT 2015 OSU/WVU Extension Radio

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9/6/2015: Belmont/Ohio County Fair Updates and Fair Biosecurity

9/13/2015: Lawn Care and Herbicide Use

9/27/2015: Forage Management and Forage Quality Terminology

10/18/2015: Stink Bug (Indoors) and Winterizing Roses

 

 

 

AUG 2015 OSU/WVU Extension Radio

Catch us on 1170 WWVA, Sunday mornings at 5:00 AM


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8/2/2015: Brown Marmorated Stink Bug

8/16/2015: Plant Stress and disease in Cucurbits and Local Produce

8/23/2015: Nutrient Management

*Urea is 46% N not 16% (Mistake in above program)

8/30/2015: Hay Making during the AUG Drought

Hay Storage Considerations

OUTDOOR HAY STORAGE

Hay bales stored outdoors that do not form a good protective thatch layer can mold up and the dry matter losses can penetrate deep within the bale.

(OSU Beef Team Newsletter)

  • Forming a Protective Thatch on Your Hay Bales

A thatch forms from oxidation of the exposed outer layer of grasses to sunlight and moisture on the outside of a bale. This layer can be a protective barrier from the elements, protecting the inner contents of the bale.

Factors that INCREASE the probability of thatch formation include:

  1. Uniformity
  2. Density
  3. Fine stemmed grasses
  4. Leafy grasses
  5. Weed-free

Factors that DECREASE the probability of thatch formation include:

  1. Course stemmed grasses
    1. Annual grasses
    2. Weeds
    3. Johnsongrass
    4. Pearl Millet
    5. Sorghum-Sudangrass
  2. Loose bales
  3. Woody stems and weeds
  4. Hollow stems

*If you have re-seeded a right-of-way with a lot of annuals, it would be best to not store that hay too long outdoors if baled. You could feed it right away or store those bales inside. Hay bales from annual grasses are more prone to weathering and will lose quality more rapidly if stored outdoors due to the course and hollow stems in those grasses.