A feasibility study to assess changes to Tasmanian pastures: implications for NRM

Summary

In 1992 pasture agronomists surveyed 354 pastures on 97 properties in the eastern Tasmania (Figure 1). They collected information on pasture composition (to species level), ground cover estimates, soil nutrients (including soil carbon) and land management practices for the paddock at that time. This valuable dataset formed the basis of a project to assess change in natural resources over time by repeating the survey. In order to explore the stability of the natural resource base underpinning livestock production, we need to account for as many variables as possible that would impact on change to the natural resource base over time. It was proposed that targeting properties that are under the same family ownership for the past 20 years should reduce the number of impacting variables, particularly land management practices. The aim of this feasibility study was to collate baseline information on: changes in land use to the 354 sites; the current ownership of the 97 properties; and farm and paddock level information from a subset of 20 producers via telephone interviews.

A desk-top analysis using SPOT (2010) imagery was undertaken on the 354 sites to determine the extent of land use change over the 20 year period. The majority of sown and native pastures surveyed in 1992, were retained as sown or native pastures in 2010 (Tables 4, 5). Both SPOT imagery and producer interviews indicated that irrigation and cropping had increased over time with producers indicating that 20% of pastures had been converted to cropping. Some cropping activities were for fodder only (Table 6) while others include at least short-term pasture as part of the crop rotation. Some farmers used high value crops to pay for irrigation infrastructure but then used irrigation to develop lamb finishing enterprises. Increases in cropping do not necessarily mean a decrease in livestock production. The extent to which cropping and livestock enterprises are integrated cannot be determined by satellite imagery alone. In depth consultation with producers in addition to pasture surveys are required to assess change to enterprise mix and natural resource condition.

A total of 62 properties were still under the same family ownership in 2011, accounting for 227 of the 354 pasture survey sites. The 227 sites represent all land use classes (1-6) surveyed in 1992 and are across the geographical range of study area. Landholders from 20 properties across the geographical range of the survey were contacted to determine what information was available on the pastures. Four of the 20 did not want to participate in the pilot project. The remainder provided information on land use for the target paddocks, general changes to land use over time in addition to enterprise mix and general financial information. Most of the 16 knew the on their Return on Assets Managed (ROAM) and/or Gross Margins (GM) for their businesses (Table 6).This information allows us to rank producers according to production or profitability values, allowing us to ask the question do the top 20% of producers provide the best natural resource outcomes Drawing information out from producers via telephone interviews is a difficult process unless the interviewer has a good rapport with the interviewee. However, it is doubtful that farmers have detailed paddock records for the past 20 years. They were able to recall when paddocks were sown and talked about general approaches to grazing management and fertiliser use at the farm scale but not necessarily at the paddock scale.

All interviewees said that they had not changed their grazing system (e.g. set stocking or rotational grazing) over time. The change of enterprise mix from mainly livestock to mixed farming indicates that large changes have occurred even within farms under the same ownership. Therefore there appears to be very little advantage in focusing on only those properties under the same ownership. Targeting as many of the 97 owners (354 sites) as possible would provide greater statistical rigour. Records relating to crop area and yield are more likely to be kept than records of pasture management. This information will provide an indication of the length of time and proportion of income that cropping has provided to the farm enterprise, and diversification associated with this. What impact has intensification had on natural resource values Has intensification led to increased meat production by the ability to irrigate pastures within a cropping rotation.

Opportunities exist to explore future meat production at a range of scales: at the farm scale using farming systems approaches to explore the best use of resources to promote meat production within the context of irrigation development; and the paddock, farm and landscape level to assess changes in land use/enterprise mix on natural resources, particularly the perenniality and stability of the pasture resource, soil erosion potential and soil carbon storage and farm and landscape level biodiversity values. Triangulation from a range of sources has been demonstrated to validate a range of different data sets.

Positive outcomes linking grazing management (persistence of perennial pasture base) to carbon storage will help to offset negative images of the livestock industry in a carbon-focused world. Based on the information in this feasibility study, we recommend that as many of the sites as possible be resurveyed in spring 2012 to determine change in land use, enterprise mix and the condition of the natural resource base for red meat producers. The main research questions are: What impact has agricultural intensification had on natural resource values at the paddock, farm and landscape scales? How can we improve the environmental performance of the top 20% of red meat producers?