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On-farm compost making

SO you need compost. Fine. But how do you make tonnes of it, on your own property, quickly and efficiently? Here are plenty of ideas collected from articles in past issues of the TROPO magazine GOING ORGANIC.

The high level of interest in large-scale compost making was evident by the excellent turnout at a TROPO field day at which Federal orchardist Mike O'Shea told how he makes 60 tonnes or more at a time.

Mike O'Shea's method

  • He showed visitors two recent heaps, each about 18m long by 3m wide and about 2m high (the height drops about 40cm as the heap matures).

  • He says his five years of compost making proves that mechanisation is essential - he uses a muck spreader and a front end loader to make each heap.

  • Ingredients vary according to what he has available but his usual heaps each consisted of two loader buckets of macadamia husks, one of chicken litter, one of topsoil, half of blue metal crusher dust and one of green vegetation. Ideally, all are dampened before mixing. He uses BD preparations to activate his compost.

  • Mike's aim is to eventually use only on-farm inputs. He feels soil is an important ingredient as it helps transfer helpful bacteria to the pile but also stresses that manure is absolutely essential. However, unlike some other mass compost makers, he doesn't think it is important to cover the heap with soil.

  • Mike uses his spreader to thoroughly mix and distribute the ingredients as he feels its action helps aerate the heaps. He makes no attempt to layer the ingredients. He uses his front end loader to feed the spreader and later to turn the piles.

  • Mike has tried piping water through 50mm poly pipe directly to the top of the heaps to keep them moist but feels a series of small sprinklers would spread the moisture better. A direct flow often just sinks straight down.

  • "It's important not to over-wet the heap after it has been built," he said . His heaps are built on slight slopes to minimise ponding caused by heavy rain.

  • he turns his heaps quickly, skimming off 30cm or so at a time and pushing it forwards, so that the whole heap ends up moving forward about three or four metres. He also adds a light sprinkling of lime.

  • Asked when to turn, Mike said: "Use your eyes, nose and fingers to check out the heap. It depends a lot on the weather at the time. If you can smell too much ammonia the heap has gone wrong."

  • "It helps to think of the heap as a living organism - a centre of an enormous amount of life. Care for it and it will be OK."

  • For North Coast growers August is the ideal month in which to make compost as the skies are usually overcast, temperatures are mild and humidity is reasonable.

David Roby's method

  • Uralba avocado grower David Roby also makes bulk compost but using an entirely different method. His heaps are usually made of chicken litter Plus either hardwood sawdust, kikuyu or barner grass.

  • He collects the greenery with forage harvester. He finds the harvester does any excellent job, specially with barner grass, as it crushes as well as cuts.

  • At first David turned the heap by hand but found the work far too laborious and time-consuming. Now he has his heaps turned every two weeks by a contractor using a Bobcat.

  • He says the Bobcat is more manoeuverable and quicker to turn than front end loaders. Also, because of the way it operates, the Bobcat does not have to drive over the heap when turning the mix, thus avoiding compaction.

  • Like Mike O'Shea, he also believes in trying to wet the ingredients before mixing. Kikuyu is particularly hard to dampen once in a heap - by the time you do, the manure in the mix has started to wash away!

  • Whereas Mike says no more than IO%.of any compost should be shredded barner grass, Dave feels it can be up to 90%.

  • Dave also makes a mix using chicken litter and hardwood sawdust. This compost often has ingredients like rock phosphate, wood ash, and Boron added. This pile is made with the bobcat but turned using a mini excavator which is much faster and turns the pile without moving backwards and forwards repeatedly. Much less compaction.

Leigh Davison's method

  • Out at The Channon, organic grower Leigh Davison is developing a system designed to produce enough compost for a two-acre small cropping enterprise.

  • Inputs are nearly all derived from an associated cattle raising operation. Slashed pasture and cow dung are the major ingredients along with small amounts of soil and cheese whey.

  • Dolomite and a little blood and bone (to boost the nitrogen content if necessary) are currently the only imported inputs apart from biodynamic composting preparations.

  • A typical heaps consists of:

    1. 8-10m3 of paddock slashings (including some manure)

    2. 3m' cow dung

    3. 3m~ soil

    4. 50kg dolomite

    5. 50kg blood and bone if the grass is not green

    6. 100 gallons cheese whey

  • Paddocks are slashed with a sickle bar mower after grazing and raked with a stick rake. This tends to pick up some of the manure with the grass while leaving the remainder spread fairly evenly over the paddock.

  • The heaps, 2m wide and 1.5m high, are put together by hand in a random rather than layered manner while a fine spray of water plays over the ingredients.

  • Leigh covers the heap with soil to inhibit the escape of nitrogen. The result has been a much more uniform temperature distribution during the early heat-up phase. " The heap gets extremely hot to within inches of the surface since I started encasing it in soil."

  • After Lejgh applies the biodynamic preparations he covers the heap with a thatch of baled straw. The "books" of straw are laid on like shingles to shed water.

  • If the heap needs to be turned the straw thatch is removed first as it is not considered part of the heap. Turning is done mechanically using the stick rake - attached to the tractor with two metre (6ft) extension arms to roll the heap forward.

  • Additional whey might be added at this time before the heap is rethatched.

  • After three or four months the compost is spread while still slightly incomplete. It is either spread over the soil and hoed in or banded into furrows to be covered by soil when beds are formed. In no-dig or minimum disturbance patches the compost is just added to the surface and mulched over.

Compost in the field - the Indian way

  • A quick acting field method of composting is becoming very popular in India, according to Mr T.G.K. Menon, director of the Kasturbagram Research Station, who spoke at a recent TROPO meeting.

  • Rows about 1m high and no more than 2m wide are made in the fields using about 60% organic materials, 20% cow dung and urine and 20% soil from the same field. (Mr Menon emphasises the importance of using the soil that's immediately at hand).

  • The materials are placed in layers as in conventional heaps. The rows can be as long as you like.

  • In India the composting ingredients are kept in place by building a wall of bricks on either side of the row, although Mr Menon said other materials like timber offcuts or sticks have been used. The top is covered with mud, cow dung and grass to shed heavy rain.

  • "After 110 days we get very good compost", Mr Menon reported. This Nadep composting method - named after its developer - provides more nitrogen and humus for the fields than some other methods and needs no turning.


    Readers' Comments

    I've made my compost walls out of straw bales. In santa fe they last about three years, and are then ready to join in the action, to be replaced by the new bales on the block. now living 20 miles from the wettest city north of 87 S things are slightly different. Cover everything with macadamia nut compost and step back!!

    horticulturlty yours, dick cohen

    Contributed by dick cohen zendj2004@verizon.net on 8 July 2004.


    If you have some relevant experience, please send us your comments to be added to this page.


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