Labour costs fall as soil improves with use of compost
Four years ago, compost processor Len, asked local vegetable producer Frank to establish vegetable cropping under the centre pivot adjacent to his compost processing site. Len had started applying 20m3/ha of compost to the heavy clay soil beneath half the pivot in an effort to turn unmanageable land into good vegetable producing soil.
Establishment of cropping on the site proved to be difficult initially. Continual bogging of the centre pivot in the heavy soils had Frank wishing he’d never taken on the site. At harvest, potato sized clods of soil were going through to the bins, requiring six people on the back of the harvester to re-sort. The difficult ground made harvest slow, managing just 28 bins in the five hours of picking each morning.
Now, four years down the track, changes are obvious both in the appearance of the soil and in production at the site. Bogging of the pivot is now a rare event. At harvest, the improvement in the soil makes the going easier, and there are now just two people on the back of the harvester sorting. The team now manages 60-80 bins in the five hours of harvest each morning. Frank attributes these changes in the soil to the compost “it’s the only thing that’s done it, the only thing we’ve put in there”.
The saving of four people, costed at $20/hr, five hours a day for six days a week over the four to five week period of harvest on the 30ha of potatoes gave savings of $9,600-$12,000. On a per hectare basis, these savings in labour costs were $320-$400/ha.
Improved infiltration of moisture into the soil has been a major advantage. Not only has this reduced problems with bogging of the pivot, but Len and Frank also see better lateral movement of water through the soil, providing more uniform soil moisture. “Compost softened the ground, improved the drainage and helped prevent watermarking”. Feedback from the packing shed has suggested the site is producing more uniformly sized and better quality potatoes too.
Frank, initially a sceptic, now recognizes the benefits of compost in vegetable producing soils, but concedes that making the change will be challenging for many growers. Changes in routine and budgeting may prevent some growers from trying something new, and “others will need to be assured of the benefits in improved packouts before they take it up”.
Growers will be able to view the changes in soil and hear directly from Len and Frank on their experiences over the past four years at regular grower days to be held at the site during 2007. Contact Domenic Cavallaro at the Northern Adelaide Plains Land Management Group on 0417 839 082 or dpflowers@picknowl.com.au or Industry Development Officers Tony Burfield or Katie Webster.