Sunday, July 27, 2008

Cow Manure for Energy

The concept is not new, with several systems already operating in California.

But it seems some serious R and D effort has gone into actually quantifying the concept. But wait..........lets not get too carried away. The manure has to be collected and transported, so if you are raising livestock on pasture, forget it! However, with dairy cows, some pig production and in feedlots, this is a serious business.

Alas, in Australia with most stock on pasture, it will be a difficult issue, except for those more intensive systems.

But it is worth a read...............

Converting livestock manure into a domestic renewable fuel source could generate enough electricity to meet up to 3pc of North America's entire consumption needs and lead to a significant reduction in greenhouse gas emissions (GHGs), according to research published July 24 in the Institute of Physics' Environmental Research Letters.

The journal paper, Cow Power: The Energy & Emissions Benefits of Converting Manure to Biogas, has implications for all countries with livestock as it is the first attempt to outline a procedure for quantifying the national amount of renewable energy that herds of cattle and other livestock can generate and the concomitant GHG emission reductions. Livestock manure, left to decompose naturally, emits two particularly potent GHGs - nitrous oxide and methane.

According to the Intergovernmental Panel on Climate Change, nitrous oxide warms the atmosphere 310 times more than carbon dioxide; methane does so 21 times more.

Through anaerobic digestion, similar to the process by which compost is created, manure can be turned into energy-rich biogas, which standard microturbines can use to produce electricity.
The hundreds of millions of livestock inhabiting the US could produce approximately 100 billion kilowatt hours of electricity, enough to power millions of homes and offices, according to the paper. Since manure left to decompose naturally can have a damaging effect on the environment, this new waste management system has a net potential GHG emissions reduction of 99 million metric tons, wiping out approximately 4pc of the USA GHG emissions from electricity production.

Authors of the paper, Dr Michael E Webber and Amanda D Cuellar from the University of Texas, noted that the "logistics of widespread biogas production, including feedstock and digestates transportation, must be determined at the local level to produce the most environmentally advantageous, economical, and energy efficient system".

from Feedstuffs, USA

Friday, July 25, 2008

Carbon Trading in Australian Agriculture - the NEW Landcare?

There is going to be an Emissions Trading Scheme in Australia, from 2010, and agriculture is to be excluded, at least for the first 3 years. This is a now a fact in Australia. The Federal Government has released a Green Paper on its policy options for the Scheme, and is doing the rounds of major cities now – with Darwin on the roadshow agenda for Monday July 28. Maybe all will be clearer after that.

This link takes you to the Green Paper documents:

This is a weighty tome, but at least read the Executive Summary.

However, opinions on carbon issues in agriculture are definitely getting a bit steamed up.

It seems to be that soil sequestration is sensible and eminently doable, with benefits to agriculture and the environment. Soil biology is improved, as is soil moisture storage along with improved structure. All these contribute to positives for plant growth and performance……..and nett soil carbon is enhanced.

Measuring soil carbon is not that difficult, although interpreting what is in the soil carbon pool and how labile that is, can get a bit trickier. But if nett soil carbon is increasing surely then, carbon is being sequestered??

The following article appeared on 25 July in one of the major rural newspapers, and evoked a few quite sharp replies. It is worth a read.

Trading in carbon could be a real winner for farmers, if common sense prevails.

The politics of carbon trading are unfortunately well ahead of the science right now, particularly agricultural science.

With most of the nation paranoid about what fuel, electricity and food will do under a carbon trading scheme, few have even thought of where the carbon offsets will come from to "save us all".

Trading in carbon could be a real winner for farmers, if common sense prevails.

Any secondary school student will tell you, the role of agriculture in the carbon cycle is to take carbon from the atmosphere and place it in living things - plants, animals and soil microbes. Wow, that sounds like a great way to reduce atmospheric carbon!

Yes, cows and sheep belch and fart but common sense will tell you that agriculture’s net effect has to be positive if farmers are doing their job properly and profitably.

The more efficiently carbon is fixed into living things, the better it should be for the environment.
Inefficient use of fertiliser, fuel, feed or even fire, constitute losses of carbon. Farmers are in the business of growing a natural resource, not losing it and this fits in perfectly with carbon trading.

The advent of the Landcare movement in Victoria over 20 years ago, led to the recognition of farmers as good land managers, before the movement was sadly hijacked by bureaucracy and died.

The carbon debate should again prove that good farmers build things from carbon - it's how they have made a living since the first seed was planted by man.

Could carbon trading be the next Landcare?

The financial opportunities stemming from carbon trading could be enormous and systems in the United States are already rewarding farmers for their soil carbon management. You don’t have to plant trees and leave them there forever to help save the planet. Stubble retention, minimum tillage and building up fertility in soil may well be a great way to make money as well as practise good agriculture. All we need to wait for is some good science, good policies and hopefully some good seasons.

Stock & Land, Vic,au

Responses were pretty sharp and immediate.......

When lamb or beef is exported, the recipient is the user of the carbon absorbed and should be recognised as the user of that carbon, I agree with the above article, New Zealand has got it wrong with regard to the suggested carbon emmisions from farming.

Posted by teanau8 on 25/07/2008

Soil carbon will likely prove to be the eventual winner in the race for supremacy within the carbon sequestration race. Forest sinks are susceptible to environmental events such as drought (any forest becomes an emitter if it does not receive its required allotment of moisture), fire, insect attack, fungal and bacterial disease, all of which reduce or reverse the carbon fixing or sequestering cycle.
Where as sequestered carbon into soils will stay and build at a predictable rate. Yes all of the required science is not in yet to determine the best way to assess consistency of accumulation, but there has been an old and proven method of determining soil carbon as part of business as usual on any soil test done over at least the last at least ten years. The labile or active carbon is where the relative unknown factor is, but soil carbon loss will only occur if a farmer changes practice from sustainable no or minimal till and minimisation or elimination of synthetic fertilisers that has allowed for sequestration cycle of the soil carbon to accumulate.

Drought will have some effect but on the whole soil sequestration is far more secure a method to travel down than forest sinks, and on top of that, the amount of abatement that can be calculated through less fuel use and not losing the fixed carbon that is included as part of the soil integrity as shown by simple Albrecht soil testing procedures is of a phenomenal rate and to determine the exact amount of carbon that has not been released to atmosphere is determinable by pure mathematical calculation (old science) and so as the Commonwealth Government has not seen fit to include soil carbon sequestration as part of the climate change action plan possibly until 2015 science research pending, shows that there is still a lot of unexplained action taking place.

In the mean time reduction or abatement actions that can be verified will be the most easily accessible plan for farmers to become involved in the sustainable agriculture industry drive.
Anthony Foo Managing Director Skyfarms Australia P/L

Posted by Anthony Foo on 25/07/2008 9:16:17 AM

The carbon trade will attract all the shonks, wide boys, white shoe brigade, fedora fat men & junk bond floggers. Markets are about fear & greed there is nothing noble in a market. The people trading carbon will never see it or understand it, they will just flog it. We already have laws about pollution & waste. Make them tougher & expand them. Make it a licence & permit scheme. A trade run by bankers & commodity traders will be just as damaging as one run by the bob browns.
Posted by THE FARMER on 25/07/2008 [ I love this one - soooooooo true!]

The debate between soil carbon and trees as the best sequesterer of carbon needs to be stopped. Both have a critical role to play in mitigating climate change and dealing with current, historical and future emissions. The issues with soil carbon are well documented and I do not know anyone who does not think soil carbon should play a role but not until the risks and legislation is in place to deal with many of the issues, in particular measuring, monitoring and landholder rights. Let us remember that trees grow in soil as well and they do increase the soil carbon content over time.

The big issues are the long term maintenance of soil and tree carbon and that must be addressed. Carbon in farming is going to change so much in the farming context that farmers really need to be aware of all the complexities. I have been involved in carbon and agriculture for over five years and it iwas very difficult to engage farmers and farmer bodies until it became apparent that there may be some cost or benefit involved. Farmers need to see carbon as part of the farming cycle and farming business, beware of the long term commitments and of the administrative burden, be careful what you wish for. Make no mistake those promoting soil carbon are aiming to make money out of it and if landholders are not aware of the long term implications they could enter into a 100 year management nightmare. I would advise any landholder to move cautiously and get expert advice.
Posted by the lorax on 25/07/2008

Monday, July 07, 2008

Oxygation Improves Sub-surface Drip Irrigation Efficiency

Glasshouse results have been repeated in field trials with oxygation.

We are very pro the concept of subsurface drip irrigation, as there are potential increases in watering efficiency, avoidance of wind which can influence irrigation distribution, opportunities to use recycled effluent - away from contact with people, and opportunities to arrange irrigation scheduling at your most convenient time - baesd on water availabiity and site usage. It has a lot going for it! It can also significantly reduce vandalism on sprinkler systems, often a scourge for operators.

We favour the system developed in Australia [see], which offers improved and more even distribution, especially for open space and or turf areas. We even have a few posts about the system [see posts list]. And there are other supplier systems too, but not as efficient as KISSS.

While we were aware of the potential for using air injection with subsurface irrigation, and there have been some detailed research papers published, the media release [amended slightly] below has confirmed the very real potential for the air injection option in real world situations. was on heavy soils, something that is not that common for horticulture and definitely not an ideal soil for well used turf eg ovals, sporting fields. However, extension of the thinking may even allow further reductions in water use on predominantly urban turf areas, if similar results are obtained for lighter soils.

Air injection is not overly expensive, and can be easily installed on existing irrigation systems.

[media release partially sourced from Qld Rural News]

Irrigators may not be familiar with the term "oxygation", but for cotton water use efficiency researcher, Lance Pendergast, it is a sub-surface drip irrigation system that has delivered 12–23pc yield increases.

Mr Pendergast is a Queensland Department of Primary Industries and Fisheries rural water use efficiency development extension officer based at Emerald, and is finalising his PhD research examining the potential for SDI oxygation technology.

The 5.2 hectare sub-surface drip irrigation trial site on Tony Ronnfeldt's Emerald Irrigation Area farm, Nyang, was established seven years ago by the Department of Natural Resources and Water. This project was to evaluate water use efficiency and levels of herbicide, pesticide and fertiliser chemicals in irrigation runoff of SDI compared with conventional furrow irrigation. The site has 12 individually irrigated experimental blocks with SDI lines buried 300mm under the soil surface which are scheduled to deliver the precise volume of water to maintain optimum soil moisture in the crop root zone.

With a question mark over the below-expectation yield performance of cotton crops irrigated by SDI, Mr Pendergast's PhD project was to see if promising glasshouse experimental results using oxygation translated to the field. The trials were overseen by Central Queensland University's Professor David Midmore and have examined the potential benefits of oxygation – a technique that involves entraining air into irrigation water delivered via sub-surface drip lines. "Because of the high moisture holding capacity of the heavy soil, it was determined that the cotton plants were being subjected to episodic water logging events after each irrigation," Mr Pedergast said. "Although each event was short term, the cumulated effect incurred a final yield penalty preventing SDI irrigated cotton from achieving its full potential."

Mr Pendergast began field trialling oxygation technology three years ago using Mazzi injectors that were adjusted to deliver a 12pc air by volume mix into the water lines to alleviate the root zone water-logging. When comparing the crop performance of sub-surface drip between oxygated and non-oxygated blocks, there was a significant yield increase achieved through oxygation for the 2004-05 and 2005-06 trial crops (27pc and 16pc respectively). "The oxygation trials show that we can achieve significant increases in both yield and water use efficiency using this technique," Mr Pendergast said. "When we add up the water saving advantages and improved yield of oxygated sub-surface drip, growers who are prepared to adopt and manage the technology are in a better position to justify the high SDI capital cost of around $3500 to $4500/ha."