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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
OZturners visit Ian Townsend's Stanthorpe compost facility

OZturners visit Ian Townson’s Stanthorpe compost production facility

Today we travel with JPH and OZturners managing director jarn Hanson to visit Ian Townsend on his retail compost production facility south of Stanthorpe on the Queensland New South Wales border.

Ian has been particularly focused on reducing the production time and maximising his composting returns after starting with an end loader, he then purchased a JPH CT360 compost turner from Oz turners, that radically improved the quality and speed of composting.

As you can see, Iain technique is to use the maximum wind row size and a slower turning speed produce a larger amount of compost for the same investment of effort. The JPH CT360 compost Turner’s efficiency means that normally only a single pass is needed as water can be added at the same time as turning, producing a richer and more finished product in as little as only 6 weeks.

If you’d like to know more about any of the JPH equipment products or any of the other products sold by Oz Turner’s visit OZturners.com.au or call 0411 695 335

 

 

Bagger3_HD

NEW Sandbagger with 1 tonne bag option

New to OZ turners from JPH equipment, is the upgraded Bagger 3 HD with built in one tonne sandbag filling option and dual weighing scales, 

The Bagger 3 HD is a flexible, multi-use machine for filling both 1 tonne sandbags and 10/20/25 KG bags, it’s flexible heavy duty design, can hold 3 m³ of sand in the hopper and can reduce sandbagging to a one-man operation, also available is a companion loading conveyor as a companion product that lets you fill the hopper with smaller equipment like a dingo, kanga or bobcat just as easy filling using a skid steer loader.

 Bagger3 HD Dual Weighing Controls   Bagger3_HD 1 Tonne Weigh Plate

Sandbags, Builders Bags, 1 tonne bag, Bulka Bag, Jumbo Bag call them whatever you like, the Bagger 3 HD from OZ Turners is should be on your list of bulk/sandbag filling systems The Bagger 3 HD reduces the risk of injury staff and minimise wasted time by making each bag filling operation fast and easy while maximising production efficiency.  It perfect for Landscape Suppliers & Building Suppliers, suppling bulk sandbag and other products for building sites. It is also ideal for Quarries selling special products.

 1 Tonne Sand Bags,   The Bagger 3 HD is a Australian-Made and designed to fill Mulch, compost, stone, potting mix, garden mix, grain, manure, sand, soil, gravel, stone, woodchip, scoria, stock feed, rock, pebble, sawdust, metal dust, salt, stock feed, dirt, bark and more.   The Bagger 3 hopper is made from 4mm plate and heavy duty square tubing for the supports. The machine is fitted with a height adjustable galvanised roller conveyor table for filling small size bags. A 2.2kw motor turns the heavy duty feed belt and it is also fitted with it’s own compressor for the pneumatic foot pedals which operate the bag holding and the 600mm wide sealing unit.  An easy to use digital fill timer is attached, which allows timing to 1/100 seconds, ensuring and even bag fill.  Forklift inserts are also attached to allow safety in moving the unit around to your desired position. The 3 cubic metre hopper can easily be filled by a front end loader or skid steer (bobcat).

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.

SES Bagger 2 -Sand Bagging Day

Caloundra SES Sandbagging Day

SES Bagger 2 - operational useThe Queensland SES

The Caloundra unit of the Queensland SES recently had all hands on deck for a sandbagging day, in preparation for the impending summer wet season.  All over Queensland the SES stock piles sand bags to to provide instant capability to assist residents to be more self-reliant and resilient during flooding events, as do more than 300 other SES Groups throughout the state. The stockpile site (like many others) spread strategically across the state provide a first line of disaster response to protect Queensland business and residences from water inundation.
SES Bagger 2 - operations

The  Bagger 2

The Bagger 2 sand bagging machine, fitted standard to a road registrable trailer that’s easily tow-able by most standard vehicles to allow it to move to wherever it might be needed, it can fill a 15kg sandbag in 5-6 seconds, producing up to 350+ bags in an hour. It’s a fully self-contained unit, with on-board generator, 1.5kW belt drive motor, digital fill timing control, air compressor, bag sealing unit and bag handling roller table.

SES Bagger 2 - Bobcat Dingo KangaIn Use

The Bagger 2 sand bagging machine works with wet sand and the 2mt hopper can be filled with sand by by a bobcat or front-end loader, or it can be supplied with an optional lifting conveyor to allow filling by smaller Dingo and Kanga mini loaders.  The use of the popular/handyman style mini machines allows more of the SES crew to fill the machine with reduced training

A major OH&S feature of all our baggers is that the operator can stand straight whilst operating the machine, reducing stress, fatigue and RSI. 20 years’ design and manufacturing experience allows us to create equipment with operator safety, comfort, structural strength and durability in mind.

Custom options include stitcher or heat sealed bag sealer, product table and timed or weighed fill for accurate metering. Manufactured in Australia for Australian conditions.

 

 

 

 

Compost sales

Opportunities and barriers to on-farm composting

A recent European study assesses the challenges to marketing on-farm composting startups

Four recent studies, based on surveys of European farmers, assess the challenges to marketing of compost and the barriers to farmer uptake of composts and organic farmers expectations.
These studies indicate that relatively few publications to date address composting (and other recycled nutrient) with a marketing customer focused approach, rather than the producer of the products. Studies of surveys of compost marketing information online and on 21 in-depth interviews (June~December 2014) with companies marketing compost were selected across  Germany, Switzerland, Austria, Netherlands and France. These interviews included composters, biogas plant operators, agricultural contractors, soil and organic fertiliser manufacturers, brokers and technology suppliers.

Key issues for marketing

  • Compost & Digestate marketing is often driven by difficulties of disposing of local / regional nutrient surpluses or because the operator itself does not control farmland
  • New business niches: e.g. agricultural contractors or organic fertiliser manufacturers can act as value-chain intermediates finding customers and suitable applications for product.
  • Certain products a best used in specific markets: organic farming, speciality horticulture and home gardening
  • Product quality is the key to marketing, including hygienisation (pathogen limits), nutrient content, contaminants and foreign materials (glass, stones). Quality control systems, for both feedstock and output are vital.
  • The product quantity will help define possible markets and appropriate product packaging and distribution channels
Sale prices depend on whether it is sold in bulk or in small-scale/retail, as well as on the degree of additional processing. While farmers often understand the ability of compost & digestate to bring organic carbon to the soil and also calculate the economy against traditional fertiliser.
Composting wet hay

Composting Spoiled Hay

In recent years many areas of Australia have been impacted by heavy rains and flooding spoiling hay and crops, Composting has been found to have the greatest potential to return some benefit to the farm and this is the focus of this fact sheet by Declan McDonald, Kevin Wilkinson and Sally Stead from the Victorian Department of Environment and Primary Industries.

What is compost?

Aerobic composting is the rapid decomposition of organic materials into a humus-rich product ideally suited to soil improvement. High temperatures are naturally generated during the composting process resulting in the destruction of any weed seeds and pathogens that may be present in the raw organic materials.

Why do it?

If your farm produces sizeable quantities of ‘waste’ materials each year (e.g. spoiled hay, silage, manures etc.), then composting is a good way of improving your soil and extracting extra value from what was previously often regarded as waste.

Compost contains valuable nutrients and is rich in humus. Humus is long-lasting in the soil and can be beneficial in providing for improved physical, chemical and biological conditions.

How to compost anything!

This photograph shows the compost window

Figure 1. A compost windrow

While there are numerous composting methods available, the most simple and cost effective for farmers is the ‘Turned Windrow’ method. This involves piling organic materials in correct proportions, and with adequate moisture, in rows on a suitable surface and then mixing well. The dimensions of the windrow depend on the types of materials being composted, the space available and equipment being used. For a manure-based operation, the height of the windrow will be typically around 1.5m, with the base at two to three metres wide. The length of the row can be as long as space permits (Figure 1).

Many farm wastes (e.g. manure, hay, silage, sawdust) can be composted with minimal pre-treatment. Other wastes that become available from time to time (e.g. woody wastes) may need to be chopped up because they are too coarse. Once the wastes are correctly mixed in the right proportions, and at the right moisture content, the composting process will begin.

Composting is a biological process, carried out by microorganisms that are naturally present in the environment – so no special inoculants are required. All you need to do is provide organic materials in the right proportions, with moisture, and the microbes will do the rest!

Understanding the conditions required by the composting microbes is paramount to successful composting. Microorganisms have three basic needs and when these are provided the composting process will proceed and the mix will heat up. These needs are:

  1. oxygen
  2. adequate moisture
  3. suitable food supply.

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Large scale composting

Improving soil with compost and cover

Improving soil with compost and ground covers is easy, you can make your own compost. In fact, you may be throwing away the materials you need to make this valuable resource. As an alternative, you can purchase compost and soil conditioners in bags or by the truck load from dealers. This can get a little expensive, especially considering compost should be added each year to Improve the soil but it’s worth it.

Composting is simply the act of helping natural materials such as leaves, grass clippings, and vegetable scraps to break down. Composting methods can be grouped into two categories: passive or active. Passive composting methods allow nature to do most of the work, but take a lot longer to get a finished product. In passive composting, raw materials such as leaves, straw, grass clippings, and vegetable scraps are stacked into a free standing pile or placed inside a composting bin and allowed to break down on their own over the course of two to three years. This method produces good compost, just not very quickly.

Active composting can produce ready to use compost in as little as two months, but takes more work on your part. In active composting, raw materials are made into a pile similar to passive composting, but then the pile is turned every week to encourage rapid break down.

To build a compost heap, pile green and brown materials in 3”- 4” thick alternating layers in a free standing pile or inside a compost bin. Examples of brown materials include leaves, straw, newspapers, and wood chips. Green materials include vegetable scraps, grass clippings, plant debris, coffee grinds, and animal manure, but avoid pest waste, which can contain harmful bacteria. A few other things that should not be added to compost piles include meat and bone scraps, dairy products, grease or oil, perennial weed roots like Florida betony or dollarweed, and diseased plants, since the pile may not reach high enough temperatures to kill plant disease organisms.

Make sure to water each layer as you stack it so the finished pile has the moisture content of a damp sponge. Turn the pile every 5 to 7 days until you can no longer recognise any of the original materials because they have all broken down to a crumbly brown soil like consistency that has an earthy smell. This should take two to three months. To mix compost into the improving soil, spread a layer over the surface and then till in 150mm to 200mm deep.

COVER CROPS

Green manures are cover crops that are seeded directly into empty garden areas, allowed to grow for several weeks until they reach bloom stage, and are then tilled into the soil. Tilling crops into the soil adds nutrients and increases organic matter, and is much like growing compost directly.

 

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Written By

N.C. Cooperative Extension

NC State University and N.C. A&T State University work in tandem, along with
US federal, state and local governments, to form a strategic partnership
called the N.C. Cooperative Extension

 

 

nitrate chemicals from farm fertilisers are polluting the rocks beneath our feet

Nitrate fertilisers a pollution timebomb

Researchers at the British Geological Survey say Nitrate fertilisers are a pollution timebomb that could have severe global-scale consequences for rivers, water supplies, human health and the economy.

They say huge quantities of nitrate chemicals from farm fertilisers are polluting the rocks beneath our feet, a study says over time the nitrate will be released from the rocks into rivers via springs. That will cause toxic algal blooms and fish deaths, and will cost industry and consumers billions of pounds a year in extra water treatment.

In a paper in Nature Communications, the scientists from BGS and Lancaster University estimate that up to 180 million tonnes of nitrate are stored in rocks worldwide – perhaps twice the amount stored in soils.  They say this is the first global estimate of the amount of nitrate trapped between the soil layer and the water-bearing aquifers below. They warn that over time the nitrate will inevitably slowly seep into the aquifers.

 

The EU is trying to clamp down on careless application of nitrates but farmers say the fertilisers are vital for agricultural productivity.

The UK government has said all EU environmental laws will be brought into British law after Brexit. But a legal taskforce set up by the UK Environmental Law Association (UKELA) to examine the risks of Brexit identified nitrate pollution as an example of the protections that will be at risk when European laws are rolled over into domestic legislation in 2019.

 

Soil organisms are essential for keeping plants well supplied with nutrients because they break down organic matter.

Why Building Organic matter in soil Is Important

Beneficial Effects of Soil Organisms

Soil organisms are essential for building soil organic matter and  keeping plants well supplied with nutrients because they break down organic matter. These organisms make nutrients available by freeing them from organic molecules. Some bacteria fix nitrogen gas from the atmosphere, making it available to plants. Other organisms dissolve minerals and make phosphorus more available. If soil organisms aren’t present and active, more fertilizers will be needed to supply plant nutrients. A varied community of organisms is your best protection against major pest outbreaks and soil fertility problems. A soil rich in organic matter and continually supplied with different types of fresh residues is home to a much more diverse group of organisms than soil depleted of organic matter. This greater diversity of organisms helps insure that fewer potentially harmful organisms will be able to develop sufficient populations to reduce crop yields.

Soil Tilth

By building soil organic matter, soil has a favorable physical condition for growing plants, it is said to have good tilth. Such a soil is porous and allows water to enter easily, instead of running off the surface. More water is stored in the soil for plants to use between rains, and less erosion occurs. Good tilth also means that the soil is well aerated. Roots can easily obtain oxygen and get rid of carbon dioxide. A porous soil does not restrict root development and exploration. When a soil has poor tilth, the soil’s structure deteriorates and soil aggregates break down, causing increased compaction and decreased aeration and water storage. A soil layer can become so compacted that roots can’t grow. A soil with excellent physical properties will have numerous channels and pores of many different sizes.
Studies on both undisturbed and agricultural soils show that when building soil organic matter, soils tend to be less compact and have more space for air passage and water storage. Sticky substances are produced during the decomposition of plant residues. Along with plant roots and fungal hyphae, they bind mineral particles together into clumps, or aggregates. In addition, the sticky secretions of mycorrhizal fungi—beneficial fungi that enter roots and help plants get more water and nutrients—are important binding material in soils. The arrangement and collection of minerals as aggregates and the degree of soil compaction have huge effects on plant growth (see chapters 5 and 6). The development of aggregates is desirable in all types of soils because it promotes better drainage, aeration, and water storage. The one exception is for wetland crops, such as rice, when you want a dense, puddled soil to keep it flooded.

Building soil organic matter, as residue on the soil surface or as a binding agent for aggregates near the surface, plays an important role in decreasing soil erosion. Surface residues intercept raindrops and decrease their potential to detach soil particles. These surface residues also slow water as it flows across the field, giving it a better chance to infiltrate into the soil. Aggregates and large channels greatly enhance the ability of soil to conduct water from the surface into the subsoil.

Most farmers can tell that one soil is better than another by looking at them, seeing how they work up when tilled, or even by sensing how they feel when walked on or touched. What they are seeing or sensing is really good tilth. For an example, see the photo on the back cover of this book. It shows that soil differences can be created by different management strategies. Farmers and gardeners would certainly rather grow their crops on the more porous soil depicted in the photo on the right.

Since erosion tends to remove the most fertile part of the soil, it can cause a significant reduction in crop yields. In some soils, the loss of just a few inches of topsoil may result in a yield reduction of 50%. The surface of some soils low in organic matter may seal over, or crust, as rainfall breaks down aggregates and pores near the surface fill with solids. When this happens, water that can’t infiltrate into the soil runs off the field, carrying valuable topsoil Large soil pores, or channels, are very important because of their ability to allow a lot of water to flow rapidly into the soil. Larger pores are formed in a number of ways. Old root channels may remain open for some time after the root decomposes. Larger soil organisms, such as insects and earthworms, create channels as they move through the soil. The mucus that earthworms secrete to keep their skin from drying out also helps to keep their channels open for a long time.

Protection of the Soil against Rapid Changes in Acidity

Acids and bases are released as minerals dissolve and organisms go about their normal functions of decomposing organic materials or fixing nitrogen. Acids or bases are excreted by the roots of plants, and acids form in the soil from the use of nitrogen fertilizers. It is best for plants if the soil acidity status, referred to as pH, does not swing too wildly during the season. The pH scale is a way of expressing the amount of free hydrogen (H+) in the soil water. More acidic conditions, with greater amounts of hydrogen, are indicated by lower numbers. A soil at pH 4 is very acid. Its solution is ten times more acid than a soil at pH 5. A soil at pH 7 is neutral—there is just as much base in the water as there is acid. Most crops do best when the soil is slightly acid and the pH is around 6 to 7. Essential nutrients are more available to plants in this pH range than when soils are either more acidic or more basic. Soil organic matter is able to slow down, or buffer, changes in pH by taking free hydrogen out of solution as acids are produced or by giving off hydrogen as bases are produced.

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