IMPROVING soil health has been the key to boosting yields on Tom Robinson’s farm at Hoyleton in South Australia’s Mid-North and zero till has been the primary tool in working towards this outcome.
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Speaking at the Victorian No Till Farmers Association annual conference earlier in the month, Mr Robinson said the benefits of 25 years of minimum tillage and 14 years of zero tillage were easily noticeable.
“Zero till really has been the game changer here, it has allowed us to improve our soils, grow our organic matter and by extension improve water use efficiency,” he said.
He said minimum tillage operations in his environment were at a clear advantage yield wise.
“The conventionally cropped district average is around two tonnes to the hectare, whereas for the no till guys it is probably closer to 4t/ha.”
Mr Robinson, who is president of the South Australian No Till Farmers Association, crops around 1620ha to the west of the Clare Valley with annual rainfall ranging between 325 and 425mm annually.
The soils are generally red loams and the rotation focuses on wheat and canola, with barley, lentils, faba beans and field peas also grown.
The enterprise has had no livestock for 25 years, with Mr Robinson saying one of the keys to soil health is staying off the paddock post-harvest.
“We do not have any issues with residue management and that is due to staying off the paddocks until seeding.”
In spite of any perceived difficulties, he said the standing stubble was a vital component in the crop program.
“We’ve tested a 68 per cent wind reduction and 30pc less evaporation at soil level with the standing stubble, it is creating its own little microclimate.”
“It is two to four degrees warmer in the straw canopy during winter and during the summer it is up to 30 degrees cooler than bare paddocks, which is just critical in conserving moisture and the only way to keep the soil cooler is through retaining stubble.”
The next phase in improving the cropping system will be to look at better spreading crop residue at harvest.
“We use a Shelbourne stripper front, which has worked well, you can manage the material going through the front well.”
The stripper fronts have long been a favourite in the rice industry due to their ability to handle slightly green crops by better trash management.
Mr Robinson said the next step would be to work on getting a better flow of trash out the back of the header so it is spread more evenly.
“It’s something I am chatting to the machinery dealers about.”
A novel concept the Robinsons have been experimenting with is that of cover crops, to provide that summer ground cover and to break up compaction layers in the soil.
“We’ve grown tillage radish and sunflowers which can get established in our summers, but with the right moisture we might also grow a legume.”
Mr Robinson said the crops did use moisture, but said it was less than expected.
“We calculated we used 30mm for the sunflowers and they got established without a worry and there are definite benefits to the concept.”
