Improve Soil Carbon for Higher Yields

Benefits of building soil organic matter go beyond sequestering carbon.

Increasing plant-available water capacity, maintaining better soil structure and improving yields were important benefits from building soil organic matter according to a key speaker at the Grains Research and Development Corporation (GRDC) Update at Manangatang on August 19.

Dr Peter Fisher of the Victorian Department of Primary Industries told more than 100 growers attending that while soil organic carbon levels could be boosted by increasing soil organic matter, the benefits went beyond measures to reduce climate impacts. Dr Fisher said trials at irrigated sites in northern Victoria and southern New South Wales found that increasing soil organic matter throughput – the rate at which it is added to the soil to be broken down and recycled – over several years would boost soil carbon levels. “At the paired sites studied, every tonne per hectare per year of extra above- and below-ground organic matter – maintained for 10 years – resulted in approximately 0.2 per cent higher soil carbon,” he said. “This increase is greater than most carbon modelling suggests.” Dr Fisher said the experiment had demonstrated a clear relationship between higher levels of organic soil matter and higher yields.

“Yield benefits from higher soil carbon values are very hard to measure and there is little reported data,” he said. “This is because soil carbon changes occur slowly, and thus the impacts are difficult to separate from other factors. “These trials compared long-term yields from paired paddocks with low and high soil organic matter levels.

At sites where wheat and canola have been grown for the past 10 years, the average yields for each paddock with high organic matter levels were equal to or higher than yields from paddocks with low organic matter. “The results are quite startling, and although it’s not scientific proof, the data does constitute convincing evidence for growers.”

While this data covers only the typical temperate grain farming areas, it is indicative of the facts.......improving the soil carbon can lead to higher yields. Other work also investigated issues surrounding fertiliser usage, availability and soil retention of nutrients. More benefits.

Can you afford NOT to consider using management practices that build soil carbon?

[partially sourced from GRDC media reports]

Glomalin - Not Heard of it Then Take Note - THE Soil Carbon Fixer

A soil constituent known as glomalin provides a secure vault for the world's soil carbon. That’s according to Kristine Nichols, a microbiologist at the Agricultural Research Service (ARS) Northern Great Plains Research Laboratory in North Dakota, USA.

Glomalin is a sticky substance secreted by threadlike fungal structures called hyphae that funnel nutrients and water to plant roots. Glomalin acts like little globs of chewing gum on strings or strands of plant roots and the fungal hyphae. Into this sticky “string bag” fall the sand, silt and clay particles that make up soil, along with plant debris and other carbon-containing organic matter. The sand, silt and clay stick to the glomalin, starting aggregate formation, a major step in soil creation.

On the surface of soil aggregates, glomalin forms a lattice-like waxy coating to keep water from flowing rapidly into the aggregate and washing away everything, including the carbon. As the builder of the formation “bag” for soil, glomalin is vital globally to soil building, productivity and sustainability, as well as to carbon storage.
Nichols uses glomalin measurements to gauge which farming or rangeland practices work best for storing carbon. Since glomalin levels can reflect how much carbon each practice is storing, they could be used in conjunction with carbon credit trading programs.

In studies on cropland, Nichols has found that both tilling and leaving land idle--as is common in arid regions--lower glomalin levels by destroying living hyphal fungal networks. The networks need live roots and do better in undisturbed soil.

When glomalin binds with iron or other heavy metals, it can keep carbon from decomposing for up to 100 years.
Even without heavy metals, glomalin stores carbon in the inner recesses of soil particles where only slow-acting microbes live.

This carbon in organic matter is also saved, like a slow-release fertilizer, for later use by plants and hyphae.

Glomalin is one of the factors that help build soil carbon stores. Othes include biochar or agrichar, another form of macro carbon materials, said to be the underlying factor aiding high productivity of terra preta soils in Brazil.

Voluntary Carbon Trading in Australia

It does not look too positive for the early adopters who have been trying to do the right thing with carbon reduction.

It seems according to recent publicity that carbon credit and voluntary carbon trading schemes - NSW excepted - may not get a gig inside the new Carbon Reduction Scheme of the Federal government. It is still open to further discussion, and no doubt there will be some serious argy-bargy, but rumour hath it that they will be excluded.

That may be detrimental for agriculture and soil carbon storage, at least in the short term, outside the "to be developed" Australian Government scheme, as it would be very definitely excluded. It seems that voluntary schemes will not co-exist with the new government scheme.

Whether that will mean you cannot trade via other mechanisms eg overseas on instruments such as the Chicago Climate Exchange is unclear now. It also means that existing offset programs may not have the carbon reduction counted either. That last one would be a serious issue in the Northern Territory if the West Arnhem Savannah Burning Reduction Program that is funded to aim to offset the carbon emissions of a local LNG producer. Further similar schemes are planned, and with 40% of the NT carbon diooxide emissions coming from uncontrolled savannah fires, these finded offset programs are a subtle link in reducing CO2 and offering land management jobs for the local indigenous people. See: http://www.hreoc.gov.au/Social_Justice/nt_report/ntreport07/chapter12.html for a more detailed description.

Others, small and large, with accumulating soil carbon credits coming from farm management practices such as conservation tillage are also likely not to be accepted. Essentially what is done before the scheme starts does not count! That is a bit wacky if the object of the exercise is to reduce carbon and put a value on carbon saved. Moreover, with Australian agriculture working mostly with poor soils of low organic carbon levels, there are significant benefits operational as well investor interest in the accumulated soil carbon.

They intimidate that soil carbon is hard to measure accurately - I disagree, especially if you are measuring differences between years or over multiple year spans. You measure get what is there. You can get tied up with forms of carbon, labile and non labile carbon pools, and so on. Organic carbon has been measured in soils for many years. What is so hard? Plenty of others also concur with this approach.

Farm Kangaroos - Reduce the Methane

While it is known that ruminants do produce methane, the corollorary of that is that simple gutted animals do not. Enter the kangaroo. The dearly loved emblem on the coat of arms of Australia that is hunted, shot, eats grain crops, makes great leather shoes, is an excellent meat for dog food and so on. And does not produce methane. And is not farmed.

So the scenario for Australia goes something like this.........we will replace all cows with farmed kangaroos, reduce the methane emissions and all live happily everafter. NOT!!!

Read the following, especially the comments.

http://qcl.farmonline.com.au/article.aspx?id=1238718&page=1

An academic exercise, with little practical application. So sad. But I bet the author is being paid a lot of money for totally impractical applications.

[photo courtesy www.longgrasssystems.com.au]