Soil mapping
Soil mapping can save cane growers dollars
By Cindy Benjamin
Serg is working with Tony Crowley from IAR (Independent Agricultural Resources) to measure electrical conductivity (EC) of the soils across his farm. Tony uses a Veris 3100 machine to take electrical conductivity readings as it passes through the soil and combines this with GPS location to generate a map of the block's soils.
The maps are then ground truthed using normal soil testing procedures. The soil tests are more accurate than usual because Serg is able to take samples in each of the different coloured zones across a block and the soil tests show the level of each nutrient present in each of the areas. If done under the usual method of taking samples across the block, mixing them and then taking a subsample, the differences are lost across the block so that some areas will be oversupplied with a particular nutrient while other areas may remain deficient after the fertiliser application.
"In 2004, using the the EC map technique, I saved $3000 in lime alone on a 25 hectare area by only applying lime to the areas that needed it," says Serg. "However, this year the soil tests showed that lime was needed across the block, though at varying rates, so the savings were negligible."
The computer onboard the lime spreading truck calculates the rate needed for each area and automatically adjusts the applicator. The truck takes ground speed into account so is still accurate when the truck slows to turn or cross a drainage line. Conventional lime spreaders are gravity fed and so can not apply the lime at an even rate across a field.
"We are also involved in a project with CSR Distillery at Plane Creek combining soil mapping and targetted soil testing with variable rate application of the single one shot products," says Serg.
"When we harvest the plant cane that was planted with variable rate fertiliser we will monitor any changes in yield across the block and compare that to the EC map," says Serg. "I will also do soil tests in a few of the original sample sites to see how the nutrients applied have been taken up by the crop."
Serg believes that the plant cane has performed as well as could be expected for the season and the varying soil types across the block and so is convinced that the targetted application of fertiliser will not have a detrimental effect on the yield. Leaf tests taken showed that the plant had taken up sufficient nutrients to grow the crop.
Serg sees variable rate technology as part of the controlled traffic farming system. "More widespread use of GPS is allowing growers to be more precise in their farming," says Serg, "applying what is needed, where it is needed."
Controlled traffic
Serg has 117 hectares of cane land and is beginning to convert the farm to the controlled traffic system. Over the last four years Serg has employed a contract billet planter to plant his cane but this contractor left the industry recently and the contractor he now employs only does dual row planting.
"This was a major motivator for me to start the conversion process on the farm," says Serg. "I am still not 100 percent convinced of the benefits to yields but I do see that it is the way to go and that it offers significant opportunities for cost saving."
"There are four or five farms in this area that are 100 percent controlled traffic and while the large yield increases first suggested have not happened in the field, there are obvious benefits in cost efficiency and soil structure," says Serg.
When Serg prepared his first 22 hectare block for controlled traffic he worked it conventionally and marked it out using GPS guidance. He is also going to turn many of his blocks around by 90 degrees to allow more efficient harvesting. Using GPS to plant the blocks makes it much easier to realign the blocks as they come around for planting.
"I am not sure how hard it will be to maintain the permanent beds in good order," says Serg. "I want to avoid conventional tillage if possible and hope to further reduce my costs."
Returning to legumes
When Serg burnt cane he also grew legumes in rotation with the cane. He went out of legumes when he started green cane harvesting in 1995 because he found he needed to contend with nut grass in the fallow period.
"I fallow 15 to 20 percent of the farm and hope to start growing legumes again now there are more options for grass control," says Serg. "Chemical control of grass in soybeans is effective and there is the option of hooded sprayers to control grass in the interspace."
Managing disease threats
Pachymetra is an ongoing concern for Serg and he is careful to select varieties that are resistant to the Pachymetra levels in the soil. As each block comes out, Serg has the soil tested for Pachymetra by the Plane Creek Productivity Service.
"Pachymetra levels built up on my farm when I had a high percentage of Q136," says Serg. "Over the last four years we have been able to better match variety resistance to the pathogen levels in the soil. In time, these pathogens will have less impact on our yields."
Erosion control
Eighty percent of Serg's farm is contour planted. "It has taken ten years to implement the erosion control plan drawn up by the Soil Conservation Service," says Serg. "Between green cane and contour planting we have all but eliminated soil erosion on this farm."
The contour planting has given Serg longer rows across most of the farm allowing for efficient harvesting. The wide grassed waterways allow the haulout vehicles to leave the paddocks without damaging the rows.
Realigning the blocks on the low lying areas is the last phase in the farm redesign.
Working in the industry
Serg Berardi grew up in cane farming but has also worked off farm, both in and out of the cane industry. In the mid 1960s Serg's father and uncles started working the land in partnership. In the mid 70s Serg started working off farm in both the mining and sugar industries. Then in the late 1970s Serg and his father formed a new partnership and Serg supplemented the partnership income with off-farm work in the cane industry.
When he returned to work full time on the farm in 1990, Serg brought with him a desire to make use of the available technology. Earlier this year he and his father negotiated an intergeneration transfer of farm ownership, allowing Serg's father to retire from farming.
"I believe that the more information farmers have about their land the better decisions they can make," says Serg. "Today's technology is giving us lots of opportunities to improve our farming."
