Challenges of dairy farming and building on peat land.
In 1992 Landcorp decided to take Pouarua Block, in the Hauraki Plains, from beef heifer finishing and cow-calf farming to dairying. The old Pouarua station of 2500ha was only half developed under drystock farming, first sheep and then cattle-only. It is now eight adjoining dairy farms with 5000 cows.
The Hauraki Plains contain tracts of peat land, on what was the ancient bed of the Waikato River when it exited to the Firth of Thames. Now the plains are crossed by the Piako and Waihou Rivers and an extensive network of drainage canals.
However as the peat land is developed it consolidates and drops, leaving the surface at or below sea level (in the Firth of Thames), which makes maintaining the water table in dry months and getting rid of excess rainfall in the wet months very difficult. All buildings have very deep foundations and inevitably rise above the level of the surrounding farmland. A feature of the region are the farm buildings and houses which may be two metres above paddock level, on manmade hills or stilts, with ramps.
The peat land was originally covered with manuka scrub, pongas and native trees, which have been logged, and various attempts had been made to farm, judging by the fencelines and pieces of machinery found as Landcorp began clearing. Pouarua adjoins by several DOC wetlands. The standard approach to land development for farming was to clear and burn the scrub cover, cut drains, erect fences and sow pastures. However there are major challenges in developing this unique environment.
Eight dairy farms, 1920ha effective farmed area, 5500 dairy cows, no replacements, 2.7/2.8 cows/ha, eight farm dairies six HB and two rotary. Feed pads or loafing pads. Production last season was 930kg MS/ha.
Starting from cleared land, crops are sown first to help lift the fertility level and develop soil structure. Landcorp was leasing land to squash growers but that market has disappeared and it now grows maize under contract before pasture is established for the first time.
The first fertiliser for the crop might be 1.2-1.5t/ha. Peat land needs massive amounts of lime to get the acidity down from 3.5pH to an acceptable 5.5pH for pasture. Four to six tonnes of lime/ha would be spread before discing and the same again afterwards, then a heavy roller drill used to sow ryegrass, white clover, cocksfoot and lotus.
The last two establish first and then the pasture moves towards more ryegrass and clover in the first phase, which might last five years. It would then have to be re-sown with AR1 ryegrass.
The drains have to be cleared regularly and the scrapings spread on surrounding pastures. Drains only last three to five years before closing up and each paddock reworking must start with new drainage work mole ploughing followed by V drains, which can be 1-2m deep. As reworking brings more acidic soil to the surface, more lime is needed.
The standard annual fertiliser input is compound fertiliser with 45-55kg P/ha, spread one-third at a time at different times in the year. Peat soils are in the process of changing from organic solids with 30-40% carbon at the start to 10-15% as they mineralise.
Holding nutrients in the soil profile is a real challenge, said Simon Moloney, agronomist for Landcorp. This is because of leaching as the water table rises and falls and because of organic binding. So little and often is the fertiliser approach.
Nitrogen is also used to boost pasture growth during the year. You have to be prepared to supply the microbial requirements of nitrogen as the organic matter breaks down as well as the pasture need, Simon said.
Landcorp is seeking soil quality indicators for peat soils with the help of a researcher, because the conventional indicators are not appropriate. This should lead to nutrient use recommendations in future.
Stump clearing is necessary, when stumps rise to the surface. This is done with 20t or 30t diggers, using rakes and thumbs to pull the stumps and pile them up for drying. When the numbers are light, they can be sawn up in the ground with a single circular saw blade on a digger and the pieces forced back underground.
About 50ha/year is treated for stump removal. Piles of stumps are left to dry and for the right conditions to burn, to make sure the peat doesnt catch on fire and the smoke drift across the roads.
Fences require maintenance, with posts to be driven back down into the ground where they have popped because the peat soil has dried out and shrunk.
Drains require regular maintenance, with cleaning and relaying. About 15-20% of all drains are done each year. When pastures are being cultivated and re-grassed, that is the opportunity to do the drainage work also.
Modern constructions on the peat land for Landcorp has favoured the pole foundation and concrete cap method. Treated pine poles 10-12 metres long are driven down into the peat and clay base. Frame and foundations are then built on top of the poles, enabling the concrete base of the house, dairy or feedpad to float above surrounding pastures.
As the soil consolidates, changing from organic to mineral, it shrinks and leaves the buildings high and dry. Various styles of ramps have to be employed. Farm races may also be laid on matting, with many layers of clay and rock, and come to stand a metre or so above the surrounding paddocks.
Landcorp has decided to supply the milk from eight dairy farms on the Hauraki Plains to Open Country Cheese, the new independent milk processor, based at Waharoa. The supply from 5500 cows will be redirected away from Fonterra, despite the fact that several Fonterra factories are located on the plains.
Landcorp CEO Chris Kelly said this should not be seen as criticism of Fonterra, but a strategic risk-mitigation move by Landcorp. Because the farms are close together, economies of scale and cost savings can be achieved to the benefit of both Landcorp and Open Country Cheese.
The supply will be 1.8 million kgs milk solids, or about 20 million litres of milk annually.
The Hauraki Plains contain tracts of peat land, on what was the ancient bed of the Waikato River when it exited to the Firth of Thames. Now the plains are crossed by the Piako and Waihou Rivers and an extensive network of drainage canals.
However as the peat land is developed it consolidates and drops, leaving the surface at or below sea level (in the Firth of Thames), which makes maintaining the water table in dry months and getting rid of excess rainfall in the wet months very difficult. All buildings have very deep foundations and inevitably rise above the level of the surrounding farmland. A feature of the region are the farm buildings and houses which may be two metres above paddock level, on manmade hills or stilts, with ramps.
The peat land was originally covered with manuka scrub, pongas and native trees, which have been logged, and various attempts had been made to farm, judging by the fencelines and pieces of machinery found as Landcorp began clearing. Pouarua adjoins by several DOC wetlands. The standard approach to land development for farming was to clear and burn the scrub cover, cut drains, erect fences and sow pastures. However there are major challenges in developing this unique environment.
Eight dairy farms, 1920ha effective farmed area, 5500 dairy cows, no replacements, 2.7/2.8 cows/ha, eight farm dairies six HB and two rotary. Feed pads or loafing pads. Production last season was 930kg MS/ha.
Starting from cleared land, crops are sown first to help lift the fertility level and develop soil structure. Landcorp was leasing land to squash growers but that market has disappeared and it now grows maize under contract before pasture is established for the first time.
The first fertiliser for the crop might be 1.2-1.5t/ha. Peat land needs massive amounts of lime to get the acidity down from 3.5pH to an acceptable 5.5pH for pasture. Four to six tonnes of lime/ha would be spread before discing and the same again afterwards, then a heavy roller drill used to sow ryegrass, white clover, cocksfoot and lotus.
The last two establish first and then the pasture moves towards more ryegrass and clover in the first phase, which might last five years. It would then have to be re-sown with AR1 ryegrass.
The drains have to be cleared regularly and the scrapings spread on surrounding pastures. Drains only last three to five years before closing up and each paddock reworking must start with new drainage work mole ploughing followed by V drains, which can be 1-2m deep. As reworking brings more acidic soil to the surface, more lime is needed.
The standard annual fertiliser input is compound fertiliser with 45-55kg P/ha, spread one-third at a time at different times in the year. Peat soils are in the process of changing from organic solids with 30-40% carbon at the start to 10-15% as they mineralise.
Holding nutrients in the soil profile is a real challenge, said Simon Moloney, agronomist for Landcorp. This is because of leaching as the water table rises and falls and because of organic binding. So little and often is the fertiliser approach.
Nitrogen is also used to boost pasture growth during the year. You have to be prepared to supply the microbial requirements of nitrogen as the organic matter breaks down as well as the pasture need, Simon said.
Landcorp is seeking soil quality indicators for peat soils with the help of a researcher, because the conventional indicators are not appropriate. This should lead to nutrient use recommendations in future.
Stump clearing is necessary, when stumps rise to the surface. This is done with 20t or 30t diggers, using rakes and thumbs to pull the stumps and pile them up for drying. When the numbers are light, they can be sawn up in the ground with a single circular saw blade on a digger and the pieces forced back underground.
About 50ha/year is treated for stump removal. Piles of stumps are left to dry and for the right conditions to burn, to make sure the peat doesnt catch on fire and the smoke drift across the roads.
Fences require maintenance, with posts to be driven back down into the ground where they have popped because the peat soil has dried out and shrunk.
Drains require regular maintenance, with cleaning and relaying. About 15-20% of all drains are done each year. When pastures are being cultivated and re-grassed, that is the opportunity to do the drainage work also.
Modern constructions on the peat land for Landcorp has favoured the pole foundation and concrete cap method. Treated pine poles 10-12 metres long are driven down into the peat and clay base. Frame and foundations are then built on top of the poles, enabling the concrete base of the house, dairy or feedpad to float above surrounding pastures.
As the soil consolidates, changing from organic to mineral, it shrinks and leaves the buildings high and dry. Various styles of ramps have to be employed. Farm races may also be laid on matting, with many layers of clay and rock, and come to stand a metre or so above the surrounding paddocks.
Landcorp has decided to supply the milk from eight dairy farms on the Hauraki Plains to Open Country Cheese, the new independent milk processor, based at Waharoa. The supply from 5500 cows will be redirected away from Fonterra, despite the fact that several Fonterra factories are located on the plains.
Landcorp CEO Chris Kelly said this should not be seen as criticism of Fonterra, but a strategic risk-mitigation move by Landcorp. Because the farms are close together, economies of scale and cost savings can be achieved to the benefit of both Landcorp and Open Country Cheese.
The supply will be 1.8 million kgs milk solids, or about 20 million litres of milk annually.