CASE STUDY : Plantations to Pasture.
East side of Glenarty Road Farm, Karridale
STATE NRM CAPABILITIES,supported by Royalties for Regions
Farming - grazes sheep
Peter & Gina McDonald
Plantations to Pasture project was developed after it was identified there was interest in the process of converting areas of Bluegum plantations to pasture crops in the region.
Important in a successful transition to healthy pastures is the understanding of current soil health. With removal of plantation timber involving stump and tree root removal, the landholders were considering what the process does to soil nutrient levels and structure. With deeper soils being bought to the surface during the process, and several decades of nutrients being used by the timber crops and exported off farm, there were a number of questions that needed to be considered.
The McDonald property on the east side of Glenarty Road on the Blackwood flats was converted to pasture to plantation in 1991, to reduce the overall physical workload for the McDonald family who had run several thousands of sheep on their properties, further at the time, lamb prices were low, it seemed to make economic sense. One fifth of the land in question had virgin bush, this was cleared for the plantation bluegums. When the land was cleared and the area planted in blue gums, the trees grew poorly in this area. Peter & Gina decided to convert this particular section of their plantation land to pasture as they had family return to the area that were keen to run more sheep on the family farm.
After two blue gum harvests, and with the return of family to the area, the McDonalds’ started the conversion back to pasture in a section of their land. Although a massive challenge physically and financially, over the years Peter had invested in machinery that meant that he could do much of the work himself.
The McDonalds’ took up the opportunity to take part in the Plantations to Pasture project and Bob Jeffery, Soil Management Consultant undertook soil testing and research. Soil samples were taken at a depth of 30cm.
Overall, Peter was pleased with the state of the soil, it was nowhere near as bad as he thought it would be. One thing that was very obvious to Peter was the pasture’s soil after the summer months had non wetting characteristics, the oil of the bluegums had leached into the soil making it more difficult for water absorption. The first thing they did was distribute lime sand on the land and then the appropriate amount of fertiliser as recommended by the Soil Management Consultant. In 2018, the sheep are doing extremely well and assisting in the pasture and soil’s regeneration.
Read the full Plantations to Pasture Report
Recommendations by Bob Jeffery - Soil Management Consultant:
With a diverse area of soil types across the farm, it was recommended that the McDonalds use soil testing practices to ensure efficient use of farm resources and accurate fertiliser management for productive farming and healthy waterways.
Soil mapping and analysis are essential aid to planning for pasture crop production after bluegums. The results will integrate the variable effects of soil type, pre bluegum fertiliser/lime history, inputs from burning residues and soil disturbance to dilute top soil fertility.
A comprehensive soil assessment and recommendation program should involve:
Delineation of soil type boundaries by walkover or fly over mapping or based on farmer experience.
Description of soil profiles to determine depth to clay or coffee rock or to a maximum depth of 100cm.
Collection of representative samples for analysis from topsoil and subsoil. Sample intervals should be 0-10, 10-20, 20-30cm for pastures and cereal crops, but deeper samples and samples of clay subsoil should be taken if tree crops or vines are planned as alternative activities.
Analysis should include gravel content, Organic Carbon, pH, EC1:5, Phosphorus Buffer Index, Colwell P&K, and DTPA trace elements for topsoil samples and pH, EC, and Aluminium for subsoil samples. If tree crops or vines are planned interchangable cation analysis is advised if salinity or sodicity issues are suspected.
Depending on soil type and method of disposal of trash, issues such as water repellency (non wetting, MED test) may need to be addressed.
Interpretation of results should be carried out by a Fertcare Accredited Advisor.