Can Plant Roots Change Your Soil?

A recent review article in the publication “Trends in Plant Science” caught my attention and to be honest I have read it several times. The title is, “Building soil sustainability from root-soil interface traits,” and is written by several authors all from wonderful universities or institutes throughout the world. The title tends to overwhelm you until you read the first couple of sentences, “By reversing our thinking of how root-soil interface traits affect the function of the rhizosphere (the area around a root where microbes survive) there is considerable opportunity to restore degraded soils, mitigate greenhouse gases, and enhance biodiversity. Breeding crop varieties with the target of improving soil health and reducing soil degradation will produce better condition for crop growth through more efficient resource use and stress tolerance.”

The authors propose that plants are known to have a huge impact on soil properties, but these plant properties are generally ignored in plant breeding in favor of yield. They say, “with the shift towards reduced tillage and smaller input of both fertilizer and chemicals that a plant’s capacity to alter soil structure and the rhizosphere microbiome will become increasingly important.”

In this article they estimate that under the soil under a small grain crop is 2% roots but 50% rhizosphere and this could be even more with better breeding. The properties of the rhizosphere influence both plant growth and the soil environment and form the place where the plant gets nutrients from the soil. Also, a huge amount of microorganisms’ cycle nutrients and compete against plant pathogens in this rhizosphere.

Wheat Rhizosphere

Breeders’ may now have new tools because Quantitative Trait Loci (QTLs) related to this entire concept of improved rhizosphere and rhizosheath (area around the root and the soil that adheres to the root) have been found, and because they are known, breeders can select for plant varieties with these traits. For example, they have found that different varieties of barley can vary by over 500% in rhizosheath size. A larger rhizosheath means great resistance to stress including drought with a direct benefit to the improvement of soils around the root rhizosheath.

I really appreciate this last paragraph! “A genotype’s capacity to engineer favorable soil properties at the root surface could enhance its fitness under variable field conditions. We have shown evidence that selecting genotypes for favorable root–soil interface traits can also improve yield with minimal metabolic cost. The impact of plant roots on soils has been appreciated for centuries, but it is only now that new emerging technologies are unravelling the mechanistic processes of how plant root traits form the rhizosphere and impact both plants and soils. We are only at the beginning of understanding whether rhizodeposition and root hairs could be selected for more sustainable soils, but the emerging evidence is positive and compelling.”

If this is interesting to you the full article can be accessed here: https://agrilifeorganic.org/wp-content/uploads/2022/06/great-building-soil-sustainability-from-root-soil-interface-traits.pdf

Upcoming Rice Field Days

There are two upcoming Rice Field Days titled “Designing Texas Rice for the Future,” and they feature a lot of information for Texas producers.  As always there will be lots of general information on rice production but specifically there will be a look at the future of rice breeding.  Whether conventional or organic, rice breeding work holds the keys to our future and these researchers are working hard to overcome nutrient deficiencies, disease and insect pressure, yield, and more.

Eagle Lake Field Day, Tuesday, June 28 starting at 4 pm.

Beaumont Field Day, Thursday, July 14 starting at 8 am.

To register, help sponsor, or just more details, please call Brandi Morace, Administrative Coordinator at the Rice Research Center in Beaumont, 409.245.8630.

Peanut Seedling Test Plot

Today (May 20) we finished planting a peanut seedling disease test plot at the Texas A&M AgriLife Research Center in Stephenville. In this test we are looking at 10 different treatments for seedling disease control on untreated peanut seed.

Conventionally (not organic) peanut seed is treated with a fungicide that protects the seed and the young seedling from any of the common fungus diseases found in soil. Seed treatments are really beneficial in situations where the conditions are not very good for germination like cold, wet weather. In an organic system with untreated organic seed, you basically need to wait till the weather is better or maybe you discover some organic treatments you can use when you plant, like in this test. What we are doing is testing some organic seed treatments (applied to the seed before planting), some liquid in-furrow treatments, and some soil incorporated treatments and comparing them with an untreated check (just peanut seed) and a check with a regular conventional fungicide treated seed.

Over the course of the next several weeks we will be evaluating the germination percentage for each of the 400 seed planted in each treatment, how quickly they grow, and the stage of plant at each week. Below are the products used and the treatment method: IF = in-furrow, seed is a seed treatment sprayed on to wet and then dried, incorporate into beds before planting.

CompanyProductMethod
1Ecological LaboratoriesQuantum-EXP 1IF
2Summit AgroAviv 20 oz/100 gallon wet and drySeed
3Summit AgroAviv 20 oz/acIF
4Certis BiologicalsDouble Nickel 8 oz/acIF
5Certis BiologicalsDouble Nickel 16 oz/acIF
6American Plant FoodSigma 5-3-2 1000 lb/acincorporate
7Untreated Check
8Corteva AgriscienceBexfond 14 oz/acIF
9ValentEndoprime 2 oz/acIF
10Treated Check

Scale on Pecan?

It is not fun to write about a problem that has not been a problem! This picture was taken by David Schwegman in his orchard north of Georgetown. He showed me pictures of scale on some limbs he took earlier in the year when I spoke at the San Saba Pecan Field Day. Since then, he has more pictures and according to his email he is now seeing the immature “crawlers” as the young scale insects hatch and begin moving to a new location on the limb. I thought this was obscure scale, but others think it may be lecanium scale.

This might not be such a worry except that David is finding it more and more. Also, I am getting reports from other orchard owners finding scale on pecan limbs in their orchards. So, is this becoming a problem for pecan growers? Maybe, or maybe this is just one of those isolated issues that we occasionally see. Either way it is important to be scouting, especially when trees are bare (winter), and the scale is easy to see.

Organic treatments are dormant oils in winter, when there are no leaves, or now with Certis Biologicals Des-X or Sil-Matrix, Marrone Bio’s Venerate or Grandevo, and/or possibly some of the botanical organic oils (cinnamon, garlic, thyme, etc.). Be sure to spray a limb or two in the afternoon heat first before treating the whole orchard with anything that has an oil or soap base. Shouldn’t take more than 30 minutes to see if it affects the green leaves in the heat!

Budding and Grafting Pecans, What Is It?

Figure 1. A “graft” where a new variety is “grafted” or added to the established tree in an orchard.

Most people don’t have a clue what budding, or grafting is or if they do, don’t know why we do it! I can sure understand this since most of the reproduction in the world on the human side is not asexual it is sexual.

Wow! How did we go from budding and grafting to SEX? Well in budding and grafting we bypass the typical crossing of a male and a female to produce offspring by using either “budding or grafting” a portion of the plant we want (a new pecan variety) onto the same type of plant (an old pecan variety).

For instance, in pecan trees the nut that is produced can be planted by a squirrel and grow up into a big, beautiful pecan tree but the nuts on that tree may not resemble the planted nut at all. This is because the nut planted was produced by sexual means. The male pollen (figure 2) was produced on another tree, and it floated on the wind and fell on the pecan tree nutlet (figure 3) of another tree. Once on the flower parts of the nutlet, the male pollen and female nutlet mate and the resulting fruit (pecan nut) now has the genetics of the male crossed with the female to produce a new “child.” As any parent knows our children are not exactly like us! In nature this natural crossing produces what we know as native pecans in the wild or possibly an improved pecan variety if the cross was intended or made by someone to produce a named variety. This crossing process to produce new varieties is not easy!

Figure 2. male catkins that produce pollen

Figure 3. Small nutlets that receive pollen on tip ends with the flower

Now in budding and grafting we bypass this uncertainty by taking a bud or a piece of graftwood with buds from a tree we like and then transfer these buds onto a pecan tree that possibly produces poor quality nuts. This is an asexual method which will eventually produce exactly the pecan nuts we want. This is also used on all our fruit trees as well as our nut trees. Basically, we can use either buds or grafts depending on the tree type, personal preference or tree size. Most nurseries growing small trees use single buds in a method we call “budding” and in established orchards we typically use “grafting” which is placing a small limb with several buds onto a tree limb or even the main trunk as in figure 1.

Having said all this there are still many people who grow pecans, but very few that have ever grafted one! This is the time of year when we do both budding and grafting of pecan trees.  In fact, you may have a local field day in the orchard where a demonstration of both will be given.

Why now?  This is the time of year when we say that the “bark is slipping.”  What we mean is that it is the time of year when water is moving up as the tree is rapidly growing.  This water movement and consequent growth of the tree, leaves and bark, means that the bark can be easily pulled away or slipped.  Because of this slipping we can slide in a pecan bud or “inlay” in a piece of pecan graftwood into a branch or trunk. So, give it a try and see if you grow a new pecan!

Top Ten Strategies for Survival with Forage

Kleingrass Pasture

Dr. Larry Redmon was the featured speaker at a Livestock Forage Seminar a few years back when we were having another one of our periodic droughts!  Dr. Redmon is an Extension Forage Specialist and has been for many years.  Basically, he has lots of experience meaning he has about seen it all!!   Certainly Dr. Redmon has been through a number of droughts and even though this one now is severe, basically there is always one thing you can count on in a drought – forage is scarce.  Knowing this Dr. Redmon shared his Top Ten List with the group, and it works now…

Number one – Have a plan.  I visit with lots of livestock producers and still I am amazed at how few have any idea what to do.  Even if raising livestock is not a full-time occupation still it is important to know where you are going. 

Number two – soil test to know what you have.  With the very high cost of fertilizers (organic or conventional), it is important to know what you have in the soil and what you might need to buy.  A soil test costs $15 and will probably save you hundreds.

Number three – practice good weed and insect control.  I am a real believer in weed control since every pound of weeds controlled means at least one pound of extra grass and many times 3 or 4 pounds. Organic growers must use their cattle to mob graze weeds early and do it often.  The insects to control are grasshoppers and armyworms.  Both are not hard to control if caught early which means you should be walking your pastures often.  We have several organic sprays that work well.

Number four – consider alternative fertilizers.  It may not be feasible for all producers, but some may have access to poultry litter, cattle manure, even biosolids.  These can be less expensive but only if shipping and application doesn’t cost too much. (Organic growers understand this but also consider supplementing your manure with beneficial microbes to stimulate natural nitrogen cycling.)

Number five – consider forage legumes in grazing pastures.  This is a long shot since legumes do well here some years and others they don’t even come up.  Legumes can do well when we get fall rains but  in years like this, we never see them grow. 

Number six – evaluate your stocking rate!!  This is the most important part of drought management.  A livestock producers best friend is the stock trailer in a drought but unfortunately no one wants to sell a single animal believing instead that they can make it.  Ideally no range or pasture should be stocked above 70% of its capacity always leaving forage for years like this.  Instead, livestock producers think the good years are the ones that determine stocking rate when in fact we live in Texas where droughts are more common than rain.  What causes overstocking?  Larger cattle, weeds and brush taking over pastures, not fertilizing, not selling!

Number seven – purchase hay rather than produce it.  Unless you have lots of hay pastures you cannot justify owning hay equipment.

Number eight – analyze your hay for nutritive content.  Sometimes producers overestimate their hay quality and animal performance suffers but definitely you can save on supplements if your hay is higher in quality.

Number nine – consider stockpiling forage for winter feeding.  This is not a new concept, but I do believe one that has been forgotten.  Basically, you take a pasture that has been grazed short and close the gate by September 1st.   Fertilize it like you are growing hay and don’t turn the cattle in till you are ready to start feeding hay.  This standing forage is high in nutrition and certainly cheaper than baled hay.

Number ten – consider your forage base.  This last one has to do with considering native grasses versus bermudagrasses that need to be fertilized.  Dr. Redmon took the group through a few scenarios based on commonly accepted stocking rates for bermudagrass and native pastures.  It does take more acres per animal unit for native pastures, but you save on the cost of fertilizer.  For example, if you have 300 acres and it takes 12 acres per animal unit for native and 5 for bermudagrass then you have 25 cows on the native and 60 cows on the bermudagrass.  If both have an average weaning percentage of 90% then you have 23 calves produced on the native and 54 on the bermudagrass.  At $1,000 per calf that is $23,000 income on the native and $54,000 on the bermudagrass – quite a difference!    Now subtract $400 per cow per year for maintenance costs or $10,000 on the native and $24,000 on the bermudagrass leaving $13,000 for the native and $30,000 for the bermudagrass.  Now let’s subtract the $100 per acre for the fertilizer cost (organic or conventional are about the same this year).  $0 for the native and $30,000 for the bermudagrass pasture leaving $13,000 income for the native and, you guessed it, $0 for the bermudagrass!  If you don’t like these numbers just change them but it will be hard to beat the native grass.  Why? Natives are adapted to produce more on less and at a higher nutritional level.

Number eleven? Maybe this is just an addendum instead of an actual number 11! It applies to those who are trying to figure out what grasses to use and I thought it was appropriate to add it.  Dr. Redmon has said this at many of his forage programs and it is even more important with high input prices.  “A point could also be made regarding the use of other introduced forages that require little to no fertilizer under grazing. Examples are Bahiagrass east of IH 35/45; Kleingrass, WW-BDahl Old World bluestem, one of the lovegrasses (weeping, Wilman), others? Just a thought…” 

In Central Texas we have consistently seeded Kleingrass, Wilman, and WW-BDahl mixes with outstanding results. It takes a few years to establish but the cattle seem to love it and the fertilizer costs make it well worth it!