Bill Darrington (Persia, IA) Readingfor this week
Read the attached article and submit answers using WO before the start of classthis Friday (8/2).1) Describe several factors contributing to deep root growth on Bill Darringtonsfarm.2) The article refers to Ray Rawson as the guru of "vertical farming"... what is"vertical farming“ and what did Bill Darrington learn from Ray Rawson about soilaeration?3) Why does Bill Darrington dig so many soil pits and what does he look for?4) What is Bill Darringtons perspective on anhydrous ammonia? Do you agreewith this perspective?5) If you had a chance to meet Mr. Darrington, what would you want to ask him?6) Have you ever looked at roots in a soil pit? If so, describe something youobserved. If not, when do you think you will have an opportunity to look at someroots? What do you think you will see?
Getting dirty with 2 champions of Vertical Farming Francis ChildsRay Rawson VF = Management system for optimum root extension and function
Tillage systems affect root extension and function Adapted from Hunt et al. (1986)
Shallow high-speed vertical tillage tools can be part of a vertical farming system shallow high-speed vertical tillage tools = VF http://www.farm-equipment.com/pages/Vertical-Tillage-Product-Showcase.php
main purpose = sizing residuehttp://media.yetterco.com/726JDVTA.jpg
High-speed vertical tillage tools preserve root channels!1 pass with high-speed vertical tillage tools leaves most of theprevious year’s corn roots intact, anchored and still in place.Regardless of soil type, 22,000 – 25,000 corn root systemsper acre were observed in place. http://www.soils.wisc.edu/extension/wcmc/2011/ppt/Klingberg.pdf
Disk ripping in late fall at the Allison Farm 14”
“Horizontal tillage, works soil uniformly in a horizontalplane. Years ago, horizontal tillage meant moldboardplowing. Today, it typically involves running a fieldcultivator, disk or soil finisher 3" or 4" deep in the springbefore planting. Following soybeans, it often meansdoing no tillage in the fall and making one pass with asoil finisher before planting corn in the spring. Its areliable way to get fast emergence and uniform stands”."The downside of horizontal tillage is that it createsan abrupt change in soil density between the workedsoil and the layer at the bottom of the implementsworking depth."Comments by Ken Ferrie in Farm Journal - September 1, 2006
“Whether a density change becomes a problem depends onthe year. Heavy rains early in the season may pond on thesudden density change leading to nitrogen loss and planthealth problems - If its hot and dry in July and August andthe first three sets of crown roots turn on the sudden densitylayer, you wont have the root depth to get through adrought.“"One of our primary goals is to get the first three sets ofcrown roots deep into the soil… In vertical-tillage, no-tillor strip-till conditions, the first set of crown roots will godown. But, when we do horizontal tillage before planting-except in a few conditions like sand-no matter what we didin the fall, the first two sets of crown roots almost alwaysturn on the dense layer. Hopefully, with fall vertical tillage,the third set will penetrate.“Comments by Ken Ferrie in Farm Journal - September 1, 2006
Long term no-till (w/ healthy soil biology) Intensive tillage Network Plow pan of cracks and bioporesOntario Ministry of Ag and Food
When do roots pull out ofKen Ferrie inspecting corn roots on the Noland Farm in Blue Mound, IL the ground like this?
Proof that you are using the right system John McGillicuddy IA crop scout
extensive white color growth into Healthy shoot growth the sub-soilproliferate and high minimal in all yields evidence ofdirections deformities Efficient use of soil resources
Understanding corn root developmentThe seed roots stopgrowing shortly after the coleoptile emerges from the soil surface. The nodal root system becomes visible at ~ V1. The nodal root system becomes the dominant system by V6.
4 weeks Corn root development documented in the 1920s 8 weeks 16 weeksIf this was possible 90 years ago, just think what is possible today? 7 feet deep !!
All you need to do to grow healthy roots is use rootworm resistant genetics… right??When rootworm pressure is high, rootworm resistant genetics normally result in much healthier roots
Rootworm resistant genetics are not a silver bullet ! Severe damage by corn rootworm larvae to roots of a biotech corn rootworm hybrid http://www.ipm.iastate.edu/ipm/icm/2006/11-13/btcorn.html
We have witnessed historically low densities of Europeancorn borers across Illinois and some nearby states that arenow believed to be linked to the widespread adoption of Bt corn hybrids. Will we see a similar phenomenon unfold with western corn rootworms? I suspect we might beheaded down this road. Will western corn rootworms adapt as they have repeatedly done so in the past? If we dont integrate management tactics, we could have the answer sooner than we would like.
A team of ISU entomologists led by Dr. Aaron Gassman hasfound evidence of root worm resistance to the Cry3Bb1strain of protein toxin from Bacillus thuringiensis found inMonsanto Bt corn varieties."We report that fields identified by farmers as having severerootworm feeding injury to Bt maize contained populations ofwestern corn rootworm that displayed significantly highersurvival on Cry3Bb1 maize in laboratory bioassays than didwestern corn rootworm from fields not associated with suchfeeding injury," the researchers said in an article publishedon July 29 in the scientific journal PLoS ONE.
A significant correlation was found between the number of years Cry3Bb1 corn had been grown in a field and survival of western corn rootworm on Cry3Bb1 corn.Interviews with farmers indicated Cry3Bb1 corn had been grown for at least three consecutive years in all of the fields containing resistant corn borers. The researchers concluded insufficient planting ofrefuges and non-recessive inheritance of resistance may have contributed to resistance.They noted a 2009 study done by the Center for Science in the Public Interest indicated only 50% of Bt maize planted in Midwest complied with EPA requirements for refuge size and proximity to Bt fields. http://cornandsoybeandigest.com/blog/bt-resistant-corn-borers-spur-concerns
“Most important, though, for effective corn rootwormmanagement is to consider a long-term, integratedapproach that includes multiple tactics, such as adultsuppression programs, use of soil insecticides atplanting, rotation of Bt hybrids that express different Cryproteins, and rotation to nonhost crops. Many producershave relied on a single tactic for too many years, andunfortunate consequences are beginning to emerge.As harvest gets under way this fall, I suspect that moreproducers in northwestern Illinois will encounter lodgedcorn that has been severely damaged by western cornrootworms. As I learn more about this evolving situation,I will keep you informed”.Mike Gray – U of I Extension Entomologist
What do you know about corn rootworm biology ?? Western corn rootworm beetle Northern corn rootworm beetle Diabrotica virgifera Diabrotica barberi
In North and South America, corn rootworms are attacked by many pathogens, predators and parasitoids, some of which are specialized natural enemies of corn rootworms. European entomologists are studying natural predators of corn rootworms (collected from soils in N. and S. America) for use incontrolling corn rootworms in Europe (where rootworms are not native)
Studies have shown thatmany of the natural enemiesof CRW are more common inreduced-tillage systems, andin fields with higher levels of organic matter.
Journal of Economic EntomologyArticle: pp. 330-339 | Abstract | PDF (1.44M)Disruption of Host Location of Western Corn Rootworm Larvae withCarbon DioxideE. J. Bernklau, E. A. Fromm, and L. B. BjostadDepartment of Bioagricultural Sciences and Pest Management, ColoradoState University, Fort Collins, CO 80523Elevated concentrations of carbon dioxide (CO2) prevented western cornrootworms from locating the roots of growing corn in behavioral bioassaysconducted in soil tubs. When CO2 was pumped into one end of a soil tub,significantly more larvae were recovered from soil at the treated end thanfrom soil around a growing corn plant at the opposite end of the tub. Incontrols with ambient air pumped into one end of a soil tub, significantlymore larvae were recovered from the soil around the corn plant than fromsoil on the treated side. Larvae were unable to locate the roots of cornseedlings when CO2-generating materials were mixed into the soil.
When damaged by corn rootworms, the roots ofsome corn plants release a chemical called (E)-β-caryophyllene that recruits an entomopathogenic nematode (Heterorhabditis megidis) to feed on corn rootworms.Corn breeding has resulted in loss of the (E)-β-caryophyllene signal in some varieties, drastically reducing their ability to recruit H. megidis. Under field conditions, the infection rate of corn rootworms with H. megidis were found to be 5x higher on a corn variety producing thebelow-ground signal than on a variety that does not. Moreover, spiking the root system of a non-producing variety with synthetic (E)-β- caryophyllene decreased the emergence of corn rootworm adults by > 50%.
competition parasitism Soil biology can both promote and inhibit crop root growth and functionantibiosis induced resistance
The growth promoting effects of soil biology are underappreciated
Dramatic effect of steamsterilization and compost on growth of pepper plants
This unfortunately is the norm in agriculture Acute root VS.disease Chronic root malfunction
Chemical toxicitiescan inhibit root growth Aluminum toxicity Aluminum toxicityAl toxicity is very common in the SE US and in tropical countries like Brazil
Understanding aluminum toxicity Fe and Mn toxicities also occur at lower pHs Toxic forms of Al are bioavailable at pHs < 5.5 Aluminum toxicity is minimal above a water pH of 5.5 http://www2.ctahr.hawaii.edu/tpss/research_extension/rxsoil/alroot.gif
What damaged these corn roots? B was included in starter fertilizer
In-row fertilizer can damage crop rootshttp://www.sdstate.edu/ps/soil-lab/loader.cfm?csModule=security/getfile&PageID=788496
Why do crops on tiled-drained land tend to be more drought resistant ? Do crop roots grow toward water? Roots elongate in aerobic soil!Ontario Ministry of Ag and Food
Sub-soil waterand nutrients Brady and Weil (2002)
Waiting for drier soil Sidewall compactionis the most important strategy
You really won’t know what is happening underground unless you take a look…
All you need is a shop-vac and a hose!Its just like going to the dentist!
In addition to the most obvious functionsphysical support and uptake of water and nutrients ROOTS are: Carbon pumps that feed soil organisms and contribute to soil organic matter Storage organs Chemical factories that change soil pH, poison competitors, filter out toxins, concentrate rare elements, etc. A sensor network that helps regulate plant growth
Micro-anatomy of rootshttp://www.sparknotes.com/biology/plants/plantstructures/section2.rhtml
Physical protection source of lubrication, & sensor of gravityWhat is the function of the root cap?
The cell wall of the endodermis (pink inner strip of cells) is waterproofed by theCasparian strip, which forces water to enter the symplast before it can enter theroot xylem phloem root hair xylemepidermis endodermis cortex
Apoplast vs. symplastThe movement of fluids from the root hairs to the xylemcan occur through one of two conductive pathways– theapoplast and the symplast.The apoplast route consists of inter-cellular spaceswithin the root cortex along which water and solutes candiffuse.The symplast route consists of channels through cellsalong which water and solutes are actively transported.
K+ H+ - The pH of a plant’s NO3 rhizosphere changes as the plant regulates itsH+ internal charge balance.
Which plant received nitrate (NO3-)?Which plant received ammonium (NH4+)? http://departments.agri.huji.ac.il/plantscience/topics_irrigation/uzifert/4thmeet.htm
The ins and outs of plant nutrition H20 Root exudates N, S, P activate soil microbes Transpirational stream H 20 Diffusion Root growth Microorganisms produce most but not all of theenzymes need to digest OM
Plants take up mostly inorganic forms of nutrientswhen inorganic forms of nutrients are readily available In some natural ecosystems (e.g., tundra), organic forms of nutrients are very important
Why does water move up into plants?Water moves upward through plantswhenever there is anegative gradient ofwater potential along the soil-plant- atmosphere continuum
H20A continuous Solar energychain of water drives the molecules is process pulled up through the Plants provide plant the conduit H20 H20 H20
Rhizosphere Roots normallyoccupy < 1% of topsoil volume The rhizosphere is normally << 10 % of Zone of root topsoil volume influence
Navigating the rhizosphere End of the Rhizoplane rhizosphere Endo- Rhizosphere Ecto-RhizosphereMicrobial activity > 90% < 10% of soil volume of soil volume A few millimeters (Lavelle and Spain, 2001)
Inoculation groups for commonly grown legumes Alfalfa Group Alfalfa (Rhizobium meliloti) Black medic Bur clover Button clover White sweetclover Yellow sweetclover Clover Group Alsike clover (Rhizobium trifolii) Arrowleaf clover* Ball clover Berseem clover Crimson clover Hop clover Persian clover Red clover Rose clover* Subterranean clover* White clover Cowpea Group AlycecloverSoybean has its own inoculation group!! (Bradyrhizobium japonicum spp.) Cowpea Kudzu Peanut
How much N do soybeans fix and how much of this N is left behind after harvest? N -N A good soybean crop will fix >150 lbs of N/ac but>200 lbs of N may be removed in the harvested beans.
Historically crop rotationsrevolved around LEGUMES
2 main types of mycorrhizal associations Ectomycorrhizae AM endomycorrhizaeArbutoidmycorrhizae Ericoid endomycorrhizae Orchid endomycorrhizae Lavelle and Spain (2001)
Mycorrhizal Networks: Connecting plants intra- and interspecifically •Many plants are connected underground by mycorrhizal hyphal interconnections. •Mycorrhizal (AM) fungi are not host specific.Illustration by Mark Brundrett
Increase nutrient (P) uptake suppress pathogens Mediate plant competition Improve soil structure Glomalin Superglue of the soil ??
There are many mycorrhizal inoculants on the market and some evidence that they work but it isimportant to keep inmind that they are a much less proven technology than legume inoculants
There are lots of examples of dramaticresponses to mycorrhizal inoculation in reforestation projects
Is this really possible?Tree roots often extend >2 times farther than the canopy