Carbon & my business – a dilemma needing facts?

The importance of soil organic carbon to soil health and sustainable agriculture has been recognised by farmers and scientists for many years. The role of soil organic carbon in the emerging carbon economy is less well understood. There is a critical need for scientifically based data on the relationship between soil carbon and profitable farming system design. Without this datafarmers cannot make sense of the many, often confusing, claims about opportunities in the emerging carbon future.

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CWFS research aims to provide practical opportunities and research results for members. This will allow for informed decisions about farm business design into the future.

For further information please contact James Mwendwa on (02) 68 951 050 or mobile 0427 951 050.

This project is supported by funding from the Australian Government Department of Agriculture, Fisheries & Forestry as part of its Carbon Farming Futures – Action on the Ground program.

Project title: The impact of farming systems on soil carbon and health in a dry land cropping zone

Project term: 15 June 2012 – 30 June 2015

Project Background information

A great window of opportunity exists for a detailed study of a long term farming systems trial established in 1998 in the dry cropping zone of central New South Wales. The farming systems comparison trial on the Condobolin Agricultural Research and Advisory Station (ARAS) investigated the management, profitability and sustainability of four farming systems on 160 ha. The extensive trial was widely replicated to meet the needs of both research and farmers. Local farmers had input into the trial treatments ensuring the treatments imitated a true representation of localised farm management practices for extension purposes.

The four systems described below were replicated four times with every rotational phase within each system present in each year. Each of the five plots across all cropping systems in each replicate was approx. 2 ha. The systems were:

  • Traditional (mixed farming) system – The five-year rotation consisted of long fallow wheat (LFW), followed by short fallow wheat undersown (SFWu/s) with a lucerne/clover/medic-based pasture, then three years of grazed pasture.
  • Reduced tillage including livestock (mixed farming) system – This system grew all wheat crops on long fallow. The rotation was long fallow wheat (LFW), skip a year (stubble maintained, weeds controlled by grazing and a chemical application in August), long fallow wheat undersown (LFWu/s) with a lucerne/clover/medic-based pasture, then two years grazed pasture.
  • No tillage, no livestock (continuous cropping) system – This system was reliant on chemicals only for weed control. The five-year cropping rotation was canola, wheat (SFWaC), pulse, wheat (SFWaP) and a green manure crop. This system represented a significant intensification of cropping in this district and no perennial species were included in the system.
  • Perennial pasture system – Each replicate in the perennial pasture system was approximately 10 ha and was divided into 12 equal-sized segments radiating from a central watering point. Sheep were rotationally grazed with half-weekly intervals on each segment.

This farming systems comparison trial is still running with data being collected for different projects based on trial objectives. Therefore, it provides an ideal opportunity to collect data measurements to assess soil carbon sequestration and soil structural information; including infiltration, nutrition and soil water storage capacity. Based on the long-term history of the trial site there could be valuable soil data for regional and national benchmarking backed by detailed paddock and economic records to interpret the soil health results.

Project Description

The project will trial and demonstrate four innovative on-farm  farming systems to increase the sequestration of carbon in soil by using traditional cropping-grazing, reduced tillage cropping -grazing mixed, continuous cropping-rotation and perennial pasture-grazing with sheep) to improve soil structure, water permeability, reduce wind and water erosion and increase organic matter in the soils. Analysis of the historical and current data from the established long term farming systems comparison trial will be done. In addition trials and demonstration plots will be set at three participating commercial farms in the dry cropping zone of central NSW and at the Condobolin ARAS.

Objectives

  • To demonstrate farm systems management practices that can be used to increase and maintain the amount of carbon stored in the soil and improve soil health.
  • To provide better understanding of some of the crop types and pasture rotations that can profitably build up or maintain soil carbon
  • To determine suitable and adaptable farming system practices for a variable climate to maintain the resilience of farm systems to climate change.
  • To asses, the economic and natural resource management benefits of practice change to farming systems.
  • To provide a forum for growers in the Central west NSW to discuss ways to increase and maintain soil carbon and soil health during field days and workshops.
  • To extent and educate landholders of the outcomes within this project
  • To provide data for the federal government carbon farming initiatives and soil carbon research/modelling programs for future projects

Project Activities

The following activities will be undertaken:

  • Preparation and submission of a project plan detailing:
    • governance and management arrangements risk, financial management and peer review
    • project methodology, including selection and management of control and trial sites, management practices and treatments to be trialled
    • key project activities, including monitoring, evaluation and reporting and
    • the project timeline covering when these activities will occur over the life of the project
  • Establishment of agreements with project partners and participants for delivery of trials, on-ground monitoring and data collection, analysis, and communication activities; including establishment of the project steering committee;
  • Identification and establishment of trial sites on 3 participating farms, including baseline land use histories, and collection of soil carbon data;
  • Commencement and management of trials utilising four farming systems (traditional cropping-grazing, reduced tillage cropping -grazing mixed, continuous cropping-rotation and perennial pasture-grazing with sheep)
  • Ongoing monitoring, evaluation and reporting for trial sites including:
  • collection of data on farming systems trails, including production, soil health and soil carbon data and climatic conditions
  • Collection and analysis of soil samples for soil carbon using procedures consistent with the Soil Carbon Research Program (SCaRP). See also http://www.csiro.au/science/Soil-Carbon-Research-Program and http://www.clw.csiro.au/publications/science/2011/SAF-SCaRP-methods.pdf
  • Evaluation of project data and reporting of outcomes in terms of increased sequestered carbon in soil, property productivity and production costs for practices and treatments trialled and
  • Raise the awareness of stakeholders and demonstrate the outcomes of the project through:
    • field days and farmer group information sessions, including the Condobolin ARAS field days
    • newsletters, websites, commercial media and through CANFA and LCMA
    • Peer reviewed project report and information sheets.

Current and proposed trials

1. Comparison of accumulated soil carbon, organic matter, nutrition and soil physical characteristics between farming systems treatments over the past 14 years

  1. Historical Soil carbon measurements data (0, 5 and 10 years).These are soil samples taken in 1999, 2004 and 2008)
  • Surface (Top) soil – 0-10cm
  • Deep core (0-10, 10-30, 30-50, 50-70, 70-100cm)
  1. Current soil carbon and health measurements to benchmark -14yrs and Final- Next 3yrs)
  • Soil organic matter
  • Soil carbon (0-5, 5-10, 10-20, 20-30cm)
  • Nutrition- deep core (0-10, 10-30, 30-50, 50-70, 70-100cm)

2. Replicated trials to demonstrate management practices likely to influence the levels of soil carbon and economic benefits on the four farming systems.

3. On-farm demonstration plots will be set up at 3 other farms within the region where similar farm system practices have been practised for a long period such as no till and conventional farming.

4. Develop an extension and education package for growers based on the main findings of this trial and any other related trail outcomes in other regions that may be applicable to this region.

Expected Outcomes

  1. The project will trial and demonstrate four farming systems (traditional cropping-grazing, reduced tillage cropping -grazing mixed, continuous cropping-rotation and perennial pasture-grazing with sheep) to demonstrate their potential to increase the sequestration of carbon in soil in the dry cropping zone of central NSW.
  2. The project will monitor soil health parameters over time to determine changes in water use efficiency and soil organic carbon of different farm management systems.
  3. The potential for public benefits by addressing the following natural resource condition issues;
  • Soil structure decline
  • Surface soil sealing
  • Soil erosion from wind & water
  • Declining soil organic matter & soil carbon
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