So what is soil health - living soil

So what is soil health?

So what is soil health?

or Understanding and Managing Soil Biology

Soil health is a made up of its physical, chemical and living components, but can only be assessed by its living components, if the soil has no living components then it’s dirt. If the physical and chemical components are correctly balanced, but other factors stop the growth of life, then it is unlikely that soil could maintain a healthy status. New research has shown the critical importance of Soil health and organic carbon balance to soil health. Soil organic carbon is the main component of soil organic matter, or the broken-down remains of plant and animal life. So what is the connection between soil carbon, soil health and soil biology?

Here is the important bit

“Organic matter can not break down by itself!”

What's Composting?

Decomposition is done by a vast army of shredders, fungal feeders, predators and herbivores that devour plant and animal matter whole, dissolve it with acids and enzymes, grind it to a paste, and suck its juices! This work is carried out beneath the surface of the soil by creatures that can number billions of organisms per gram of healthy soil, imagine one teaspoon of soil can containing up to 1 billion bacteria. That equals a mass of over two tonnes of livestock per hectare! No wonder some people talk of ‘micro herds’.

The challenge for modern farming
is to understand the needs of the ‘micro herds’
and how to best use the hard work of these creatures to
improve the health and sustainability of our farms.

Imagine a farm where most of the required soil nutrients are provided free, where workers manage pests and diseases at no cost, and where weeds no longer require the unrelenting program of expensive spraying. Right now that might sound impractical, but solid scientific research is showing that with proper management of the biological component of our soils, these objectives don’t sound so crazy.

Science has long known and understood the nature of suppressive soils.  Suppressive soils resist diseases; with research is showing that we can grow massive biomass crops using only 10-20% of current nitrogen inputs; farmers are discovering a reduction in weed pressures when the underlying causes of the weeds are understood. These findings have a common explanation in soil biology.

It’s not the soil that’s weed suppressive,
Its whats living in the soil.

Soil Survey

These benefits are coming from bacteria, fungi and other micro-organisms that are controlling pathogens, fixing free nitrogen from the air, and maintaining nutritionally balanced soils. Proper management of soil biology is central to sustainable agriculture. These skills have to be learned and applied across the full range of agricultural landscapes. This book represents one step on a journey into a new way of thinking about agricultural sustainability. It provides growers with practical help to start thinking about soils as ecosystems. What is a good bug and what is bad? How many is enough, too much or too little? What do these bugs tell me? And how can I adapt my management practices so that I am not working against the billions of organisms in my soil that can work for me?

There is an old saying that the best fertiliser is the farmer’s footprints – i.e. there is nothing as valuable as having a good close look at what is happening at ground level in the paddock. Central to discovering soil biology is development of the ancient art of observation. Although most farmers feel there is not enough time in the day, it is hoped that a focus on soil biology will encourage growers to climb down from the tractor, take out a 10x lens and take a really good look at what is going on down where it matters, in the soil. What changes are happening seasonally? How has a particular activity impacted on bug numbers? What can I do to boost their numbers? What benefits can I observe from looking after the micro herds?

The pressure from declining terms of trade has promoted a quantity mindset with quality in second place. That pressure threatens to push farms beyond their productive capacity with resulting declines in productivity, rises in pest and disease pressure, and a range of off-site environmental impacts such as sediment or nutrient export to waterways. Managing for quality as well as quantity depends on improved understanding of the soil as an ecosystem. Such knowledge will support landholders’ aspirations to farm sustainably and leave the land in as good or better condition than when they took over.

Compost builds a healthy soil with healthy biological function will produce healthy food and healthy livestock. It may not produce greater quantities of food or livestock, but it can produce comparable quantity with greater quality.

Soils Alive!

Understanding and Managing Soil Biology
Authors: Declan McDonald, Section Leader
Denis Rodgers, Soil Ecosystems Project Officer
Sustainable Land Use, Land Conservation Branch,
Resource Management and Conservation Division
Department of Primary Industries, Parks, Water and Environment
What's Composting ?

What’s Composting?

Composting is the breakdown of organic material into a dark, soil-like material where none of the original organic materials can be identified.  Most organic waste materials can be used to make compost such as husks, manure, effluent, vegetable and plant waste, stubble and so on can be used.

There are three types of composting

  • Vermicomposting – using composting worms
  • Passive composting – the natural and slow decomposition of plant waste
  • Active or Thermophilic composting – the rapid breakdown of organic material using machinery, heat and water to sterilise seeds and pathogens.

The Benefits of Composting

There are many benefits of using composting. The main benefits are the addition of organic matter, and micro flora and fauna. The organic matter provides food for soil life and increases stability of the soil so it becomes more resistant to erosion and compaction and holds more moisture. The micro flora and fauna are important in the recycling of nutrients within in the soil ecosystem.

What’s a soil ecosystem?

Most of a farm’s life exists underground and out of sight. Billions of organisms inhabit the soil, breaking down dead organic matter and releasing the nutrients necessary for plant growth. MICRO-organisms like bacteria, actinomycetes, algae and fungi, MACRO-organisms include earthworms and arthropods such as insects, mites and millipedes. Each group plays a role in the soil and assist the farmer in producing a healthy crop.

Adding Compost also:

  • adds natural organic carbon (C)
  • protects soil from erosion
  • increases soil structural stability
  • improves moisture holding capacity
  • increases water infiltration and reduces water run off
  • adds nutrients (as slow release)
  • encourages a wide range of soil organisms.

What You Need to Make a Good Compost ?

What's Composting?

The rules of composting are widely known and the same whether you are making a small pile for your own garden or a large commercial windrow for commercial production. The key elements needed when making good active or thermophilic compost are.

Aeration

The micro flora and fauna require air and by turning the pile regularly and include a range of different sized and shaped materials. BUT, remember that large pieces of woody material will take much longer to break down than smaller ‘chips’.

Moisture

Ideally, water content when composting should be 50 to 60% (it feels like a damp sponge but no water comes out when you squeeze it with your fingers). To make sure the compost pile stays wet enough during the composting process you will need to apply water to keep moisture up to the pile.

Organic ingredients

Good compost must have a balance of carbon-rich brown material (Straw, hay, woody material) and nitrogen rich green material (green leafy matter or manure) materials, to make the correct mix of carbon.

The Carbon to Nitrogen Ratio

The Carbon to Nitrogen ratio can be determined easily when you know the C and N values and weight of the product you are using. To calculate the C:N ratio, divide the total carbon % of your selected materials—or ingredients— by the total nitrogen % of your materials. You can have as many materials as you like.

An area suitable for composting

You will need to dedicate an area for at least 8–12 weeks. The area you identify should be relatively flat and free of stones, tree stumps, drainage lines and weeds (especially bulbous weeds). You can make a good base for the compost pile using crushed road base, granite or blue metal dust.   There should be enough room for machinery needed to turn the compost. The pile should be located so it will not contaminate adjacent land or waterways via wind drift and water runoff.

Machinery

If making a large amount of compost, you will need a Compost Turner or other machinery to turn the pile. A front-end loader or excavator will let you get started. Alternatively, you may consider using a contractor.

Cover

You may need to cover your pile if there is excessive rainfall.

How Do You Create Good Compost?

What's CompostingConstructing a pile

Mix all materials and construct a pile that is between 1.5 and 2 metres high and 2.5 to 3.6 metres wide. It can be as long as you need. Every 1 metre in length will make about 4 cubic metres (m3) of compost at these dimensions. Add water so that the pile is wet through but not soaked. Check a sample of material from the pile; if it glistens with water but doesn’t drip excess water then it is wet enough.

Turning the compost pile

After about one week, check the temperature in the pile. It should be between 50 and 650C (this is now considered a thermophilic compost). Use a shovel to dig a hole in the middle of the pile. You will probably notice steam rising and the compost should feel uncomfortably hot. You can check the temperature accurately with a thermometer or a data logger, which transfers temperature information to your computer.  If the temperature is right, turn your pile about seven days after measurement, or when the temperature starts to decline. If the temperature is above 70oC turn the pile immediately and reduce pile height to a maximum of 1.5m.

When turning the pile, ensure the materials from the outside of the pile are placed on the inside. This can be achieved by rolling the pile over using a front-end loader or lifting the pile and dropping in its original place using an excavator.

Monitoring the temperature

Adding water to make compostKeep monitoring the temperature on a weekly basis and turn the pile after the correct temperature has been reached each time. The pile will probably need to be turned at least three times before the compost is ready for use but may need up to six turns, depending on the materials used. Once the pile has stopped producing heat let it ‘cure’ for at least two weeks before use.

NOTE: It is very important for the windrow or compost heap to reach about 60oC to kill any pathogens, seeds and to break down all the material properly. However, It should not get hotter than 70oC as this will reduce the nutrient and carbon value of your compost and kill beneficial decomposer organisms.

When Is It Ready?

Good quality compost will take about 6-8 weeks if done properly heaver products like macadamia husk can take up to 12 weeks. It’s important not to use compost before it is ready as the oganic matter will still be nitrogen will have been temporarily taken by the decay organisms and be unavailable to plants.

Good quality compost that’s read to be used has the following characteristics.

  • Temperature; the windrow or pile has stopped getting hot.
  • Smell; a nice earthy smell, with no bad, sour or rotting odour.
  • Feel; The feel will be moist and earthy, not wet and sloppy or dry and powdery
  • Look; A rich dark soil sized where none of the original organic materials is distinguishable.

 

If you would like to know more the ACT Environment, Planning and Sustainable Development Directorate produces a 4 page publication by to provide existing or prospective operators of composting facilities with the background information when establishing a commercial composting operation. This guide is also a reference guide to the large volume of resources readily available and accessible.