Pineapple Farmers’ DayANOTHER STEP TOWARDS

BIOLOGICAL PINEAPPLE

CULTIVATION FOR SA PRODUCERS.

3rd MARCH 2011

BATHURST.

IMPORTANCE OF SOIL BIODIVERSITY FOR

SUSTAINABLE BIOLOGICAL FARMING.

byWillie Pretorius Technical Manager

for Tola Organics.

What are we going to cover?

• An understanding of Soil biodiversity• Soil in harmony.• Illustration of some practical

microbiological – plant interactions.• The important carbon factor.• Where did things go wrong.• Understanding biological farming.

“WE ARE NOT STANDING ON

DIRT WE ARE STANDING ON

THE ROOF OF ANOTHER

WORLD”

--Kevin Davidson.

THIS WORLD IS REPRESENTED BY

• THE MOST INTRICATE AND MOST VALUABLE ECOSYSTEM KNOWN TO MANKIND.

• IT IS THEREFORE EXTREMELY IMPORTANT TO NURTURE AND PROTECT THIS SYSTEM, JUST AS WE PROTECT OUR WILD LIFE.

WHAT IS SOIL BIODIVERSITY.

SOIL BIODIVERSITY REFLECTS THE MIX OF LIVING ORGANISMS IN THE SOIL.

THESE ORGANISMS INTERACT WITH ONE ANOTHER AND WITH PLANTS AND PLANT ROOTS AS WELL AS WITH SMALL ANIMALS FORMING A WEB OF BIOLOGICAL ACTIVITY.

SOIL BIODIVERSITY.

• Soil one of the most diverse habitats on earth.• 1 gram of soil can contain millions of individual and

thousands of different species of bacteria, yeasts and moulds.

• The soil biota also harbour Micro organisms (Bacteria and Fungi), Micro fauna (Protozoa & Nematodes), Meso fauna (ascari, springtails etc) Macro fauna (Insects, Earth worms etc)

• Interacting with each other as well as with plant roots.• The above interactions generate several thousand

chemical and biochemical substances that have an influence on the “system”

THE SOIL FOOD WEB.

• A wide variety of organisms provide checks and balances to the soil food web through population control, mobility and survival from season to season.

• The end result of a stable soil food web is that no one specie will dominate over any other.

The Soil Food Web:

                                                                                                                                                                   

ECOSYSTEM SERVICES.• Decomposing organic matter.

• Cycling and immobilizing inorganic nutrients.

• Filtering and bioremediating soil contaminants.

• Suppressing and causing plant diseases.

• Producing and releasing greenhouse gasses.

• Improving soil porosity, aggregation and water infiltration.

The Soil in Harmony.

• The Knysna forests is an example of a complete ecosystem in harmony.

• The Savannah grasslands is another example.– Receives no fertilizers.– No agricultural chemicals of any nature.

• Yet the forest and grasslands grow without any serious problems.

INTERACTION BETWEEN COMPONENTS in the

RHIZOSPHERE.• The rhizosphere (the root zone) is an area

of intense signaling between plant roots and microbes.

• These signaling processes can result in positive or negative outcomes for the signal providing plant.

• The “signals” are chemical excretions known as root exudates.

POSITIVE OUTCOMES FROM PLANT ROOT SIGNALS.

• Two very well known processes are initiated and maintained by these root exudates.

• Both of these processes are known as a mutualistic symbiotic process where both agents benefit from the process.

– Nitrogen binding by Rhizobium bacteria on Leguminous plants.

– Mycorrhizal association between roots of most plants and this fungal complex.

NEGATIVE OUTCOMES FROM PLANT ROOT SIGNALING.

• Signaling signs of distress to Pathogens.

• Plants under stress excrete particular root exudates that attract the specific pathogenic micro organism that thrives under the created stress condition of the plant under stress.

THE RHIZOBIUM NITROGEN FIXING PROCESS.

• There are 19 different Rhizobium species known (there could be more) which are very plant specific.

• The host plant will exude a specific flavanoid that is recognized by the Rhizobium for it to enter through a nodule that is formed as a result of the flavanoid exudate.

MYCORRHIZAL ASSOCIATION.

• Once again the host plant excretes a particular flavanoid that attracts the spore of a specific combination of Mycorrhizae fungi.

• These spores then germinate and colonize the host roots. The result is an intense web of fungal hyphae (strands) that extend the plant roots for several kilometers.

• The Mycorrhizae provide nutrients and water to the host plant while the host plant provides carbohydrates to the fungus. (a perfect mutualistic symbioses)

MORE PROTECTION BY THE TRICHODERMA FUNGUS.

• ONCE THE MYCORRHIZAE HAS COLONIZED THE HOST PLANT ROOTS THE TRICHODERMA FUNGUS WILL GROW AROUND THE OUTER PERIMETER OF THE ROOT / MYCORRHIZAE MASS AND COVER IT LIKE A GLOVE PROVIDING COMPLETE PROTECTION AGAINST ANY OUTSIDE PATHOGENIC AGENT.

THIS SCHEMATIC PRESENTATION INDICATES HOW STABLE CARBON

PROVIDES AN IMPROVED EFFICIENCY OF THE MYCORRHIZAL COLONIZATION

PROCESS.

Active Fungi in roots.

A Fungus within the root tissue as seen under a fluorescent microscopy. Probably the first signs of VAM colonization. Where this association is inplace the roots are protected from pathogens as well as pathogenic nematodes.

Mycorrhizal hyphae moving from root to root.

Trichoderma forming a “blanket or glove” around the root and Mycorrhizae – HOWZAT FOR PROTECTION AGAINST PATHOGEN INTRODERS

Trichoderma sporulates after 3 to 4 months still leaving the Mycorrhizae

on the host plant.

Soil Protozoa (Cilliate) feeding on bacteria.

Soil Protozoa feed on bacteria keeping bacterial communities growing and

thus releasing Nitrogen and other nutrients in plant available forms to roots.

BACTERIA-FEEDING NEMATODE

An example of nematode feeding on bacteria and not plant roots.

Bacteria have a high protein content and as the bacteria are digested, nitrogen

in plant available forms are excreted by the beneficial nematodes.

Fungal-feeding nematode.

Example of a beneficial nematode feeding on soil fungi. Once again fungi are high

in protein and the digested product excreted by the nematode is root available nitrogen.

Where this natural nitrogen cycling occurs less nitrogen needs to be applied.

Predatory nematode that eats other nematodes.

Example of a beneficial nematode that hunts and eats other nematodes in the soil.

Predatory nematodes helps to keep the different nematode populations in balance

and also cycle nutrients.

MIMICING NATURE IN THE LABORATORY.

The following slides indicate how Microbial Carbon under controlled laboratory conditions keeps 6 of the most feared soil borne pathogens in check

The first slide shows how Fusarium inoculated on a growing medium (4 inoculation points) completely colonizes the four quadrants of the Petri dish.

In the following slides the inhibition by the added MC inoculation on the pathogens are clearly visible.

Fusarium isolates on PDA without MC inoculation as a control.

Fusarium isolates on PDA with MC extract

Fusarium inoculation

MC Extract inoculation

Pythium isolates on PDA with MC Extract.

Pythium inoculation

Microbial carbon inoculation

Phytophthora isolates on PDA with MC Extract.

Phytophthora inoculation

MC inoculation

Rhizoctonia inoculation on PDA with MC extract

Rhizoctonia inoculation

Microbial carbon inoculation

.Sclerotinia inoculationSclerotinia isolates on PDA with MC Extract

Sclerotinia inoculation

MC inoculation

.Pseudomonas isolates on PDA with MC Extract

Pseudomonas inoculation.

MC extract inoculation

Note antagonistic borders between pathogen and MC inoculant

UNDERSTANDING THE CARBON FACTOR.

• Soil Organic Matter in soil is presented as a continuum from very easily microbial “digestible” Carbon to a completely stable form.

• The easy digestible form is soft herbaceous tissue in the early stages of degradation with the release of CO2 into the atmosphere. This carbon is known as active carbon.

• The stable form of Carbon is that form that has been degraded through the lignin phase to Humic and “black carbon” substances.

The Soil Carbon Balance

THE ACTIVE CARBON FACTOR.

• Raw organic matter is the feed stock for micro organisms as it is degraded to more stable forms of carbon and mineralized plant nutrients.

• The rate at which this humification process occurs will limit or promote the co-existence of the ecosystem.

• The decomposition process causes complex organic substances to be broken down into simple sugars, amino acids, aliphatic and phenolic organic acids. These substances are then transformed into microbial biomass.

THE STABLE CARBON FACTOR.

• These are the sites that facilitate all the reactions within the rhizospheer.

• The Humic fraction facilitates cation chelation, (cec) water retention and aids the soil buffering system amongst other functions.

• The “Black carbon” fraction acts as a safe biota for the beneficial microbial complex.

WHERE DID THINGS GO WRONG?

• More N, P & K• Puts C/N Ratio out of balance. Ideal is between

10 to 30.– If this is too high then nitrogen will be withheld from

crop (negative N period)– If it is too low (over fertilizing with N) microbial action

will come to standstill as a result of too little carbon (organic matter)

• Increased Salinity.• Decrease in soil structure.

INDISCRIMINATE USE OF HARSH AGRO CHEMICALS.

• COMPLETE SOIL STERILANTS.– Kills everything in the soil the pathogens and

the beneficials.

• INSECTICIDES, FUNGICIDES and HERBICIDES.– The continual use must have a negative effect

on the soil rhizosphere.– This together with the over application of

inorganic fertilizers has a knock on effect.

BIOLOGICAL FARMING.

• In this instance Gary Zimmer is a well known proponent on this topic

• His definition of Biological Farming is classic; By farming biologically you strive to maximize production and profits over time by understanding and working with biological processes ; whereas conventional farming strives to maximize profits in the shortest time and don’t give a /?#@* about the biological processes.

GETTING STARTED WITH BIOLOGICAL FARMING.

• The most important is for the Grower to be serious and to make the paradigm shift.

• Establish where you are ito soil health.• Get the organic material and important

carbon levels to acceptable levels.• Inoculate and maintain the good

microbiology.• Use harsh chemicals only when absolutely

necessary.

SOME ISSUES TO DEAL WITH IN BIOLOGICAL FARMING.

• There is a BIG difference between Biological and Organic farming.

• Mono culture cropping does upset the natural balance.

• To achieve a profitable crop there are definite N, P, K and other nutrient requirements that will be difficult to obtain through organic systems only.

TAKING STOCK OF WHERE YOU ARE?

• The testing to establish this is vast and costly.

• In this instance the University of Cornell in NY, USA have taken a leading position.

• To access their site go to http://soilhealth.cals.cornell.edu

• They provide a very comprehensive soil health testing program from which we have taken a queue.

CHROMA of a good compost.

USING CHROMAS AS AN INDICATOR OF SOIL ACTIVITY.

EXAMPLE OF A GOOD AND MICROBIALLY ACTIVE SOIL

Identify 4 zones on chroma from middle to outside.1-organic matter & physical structure. 2-Fungal activity and mineral content. 3-Protein content and amino acids.4-Enzymatic activity and sugars

Example of a poor and “dead” soil.

Proteins is an expression of life and represented by clear spokes

in the chroma. Note the absence here.

COMING TO GRIPS WITH ALL OF THIS.

• What is really important to establish?

• What do you as a farmer want to know?– Is my soil good enough to grow the crop?– How far has it deteriorated?– What do I need to do to turn the deterioration

around?– What is the nutritional, physical and biological

state of my soil.

SUGGESTED TESTING.

• NUTRITIONAL. (CHEMICAL)– Standard N,P,K inclusive of pH and

Resistance.– 1:1 Soil :Water Resistance reading in dS/m.

• Multiply this figure by 640 to give Total salts in ppm. This will give an indication of the salinity. Readings above 4 (2560 ppm) is the top threshold.

– Use the Albrecht system to rectify and balance the nutritional status.

PHYSICAL TESTING.

• Suggest a Surface and Sub surface hardness test with a penetrometer.

• Other available tests.– Aggregate stability.– Water holding capacity.

BIOLOGICAL TESTING.

• SUGGESTED TESTING.– Stable carbon. (presently a hot potato in most

labs)– Active carbon. (Energy source available to

microbial life) – Total organic matter.– Potential Mineralizable Nitrogen. (An

indication of soil biological activity)– Chromas.

BIOLOGICAL FARMING MANAGEMENT CONSIDERATIONS.

• Cultivation.

• Compaction.

• Pest control.

• Fertility.

• Cover crops and crop rotation.

• Crop residue management.

REMEMBER

IT IS NOT NECESSARY TO CHANGE, SURVIVAL IS NOT

MANDATORY.

ITS YOUR OWN CHOICE.

THANKS FOR YOUR ATTENTION.

• MY CONTACT DETAILS ARE AS FOLLOWS:-

• Willie Pretorius.

• 083 458 9854.

• willie@tolaorganics.co.za