Taumarunui ag consultant Geoff Burton and his wife Ros are creating impressive financial returns from their intensive small scale farm while successfully using summer fallow management. Russell Priest investigates.
For the past 20 years Geoff and the local sustainable land management group have been fine tuning the technique of summer fallowing (SF) or deferred grazing. Ryegrass-based pastures are shut up late spring and summer to allow them to reseed. They build up root reserves and are grazed in the autumn.
The group’s belief that the technique has many significant benefits has until recently been based on anecdotes. But research by AgResearch’s Katherine Tozer strongly suggests the group may be correct (see p71).
“SF is about regenerating the pastures and soils and providing a cheap and valuable source of summer feed,” Geoff said.
As well as working full-time in their farm business consultancy, Geoff and Ros also run their 40-hectare (29ha effective)property in an idyllic setting on the banks of the Whanganui River, 12km south-west of Taumarunui. The 11ha of ineffective land is covered in regenerating native bush sloping down to the river from a farmed pumice terrace. Across the river opposite their block is the 420ha Te Maire native reserve, part of the Whanganui National Park.
The Burtons shifted to their block 35 years ago and set about knocking it into shape in their spare time with limited outside help. Together they have not only created their own piece of paradise but also a working farm generating a healthy income. When the writer visited it in the middle of February’s severe drought it stood out like a green beacon with its deciduous shade trees and with pastures in an ideal state to respond to rain.
The most striking of their pastures had recently gone through the SF programme and were significantly greener and denser, with plants noticeably more vigorous than those in surrounding paddocks.
“They display similar vigour after SF to that shown by young grass paddocks after they’re sown,” Geoff said.
Geoff had shut up two SF paddocks (1.6ha) in November and was break-feeding them in late February to 47 about 400kg R2 heifers. He estimated the paddocks were carrying 4000-5000kg drymatter (DM)/ha and would last them for 30 days.
“I wouldn’t normally graze them this hard but because the store cattle market is so flat at the moment and feed is short I’ve made the decision just to maintain them or even let them lose a bit of weight until it picks up.”
By rubbing seed heads of the species in the two paddocks in his palms Geoff displayed the large quantity of seed that had been set. To achieve good reseeding, the pastures must not be grazed before the seed has fallen on the ground. Trampling by the stock flattens any remaining vegetation and helps push the seed into the seedbed.
“Two years ago I didn’t need my SF pasture because it was such a growthy summer so I flattened it towing a large poplar log behind my truck, because I don’t own any harrows, creating a surprisingly good sward after the seed germinated.”
Geoff’s cattle strategy involves shutting up 0.15ha to 0.2ha per cattle beast of nitrogen-boosted pasture in March/April, buying 50 R1 heifers in late winter and break feeding them from July until the grass starts lifting in October. Then they join the 450 ewe hoggets in a 14 to 20-day spring/summer rotation. Normally he aims to finish them for local trade between February and April at 220kg-250kg carcaseweight.
Formerly, Geoff operated a more complex cattle finishing system involving making hay and grazing stock off. However, he soon realised carrying autumn-saved nitrogen-boosted grass into the winter and buying cattle when they are traditionally cheap was a far easier and more profitable management strategy.
“We must get our heads around good quality grass getting a bit rank because it gives you so much flexibility.”
The Burtons’ June 30 balance date stocking rate is about 19su/ha comprising 450 ewe hoggets and 50 recently bought R1 heifers. Geoff questions how meaningful this stocking rate figure is because to achieve it he has sold his older cattle by autumn, allowing him to carry autumn-saved pasture into the winter for his winter-acquired R1 cattle.
Hoggets high priority
He generally prefers good R1 heifers as finishing stock because R2 cattle are too big for the yards and heifers are cheaper, more feed efficient, and hold their condition better than steers during pinch periods.
“They don’t finish as well when they are running with the hoggets as they would if they were by themselves, however, the hoggets are my higher priority stock.”
Prioritising stock classes based on their financial return is one of Geoff’s pet subjects that he encourages his clients to use, particularly when feed supply becomes scarce.
This year’s drought presented Geoff with the ideal opportunity to put this into practice. With limited feed available he decided to keep feeding the sheep well and reduce the feed to the cattle based on the significantly better estimated return per kg DM from the sheep.
When it became obvious he couldn’t finish the heifers he had to make the difficult decision as to how he should apportion the SF pasture to them.
Should he give them a maintenance ration and hope for rain and a lift in store price? Or give them a more generous break and hope for rain soon enough to generate enough grass to finish some or all of them? Or should he apply this to the better conditioned ones and keep the rest on a maintenance ration? He chose the first scenario because he had 1.6ha of SF and this, he calculated, would maintain the heifers for a month at best.
In making his decision he was mindful of the 450 ewe lambs coming in mid-April.
“I’m cut-throat when it comes to making decisions about when cattle must leave the farm so there’s no way I would let the decision jeopardise my sheep wintering programme.”
Fast forward a month and the rain came to Geoff’s rescue. The SF paddocks were cleaned up and are now springing into life as is the rest of the farm in readiness for the arrival of 450 ewe lambs. And the store cattle market lifted enough ($2.20/kg LW) to justify his decision to retain them until it did, although they did lose some weight as expected.
The SF area proved its worth by taking grazing pressure off other areas. Without it his financial return on the cattle would have taken a significantly bigger hit.
In spite of this setback his budget is likely to remain on track because the price he paid for ewe lambs is less than budgeted as is the likely price (budget $700) he will have to pay in winter for finishing heifers.
In hindsight Geoff confesses he should have sold some of the heifers about Christmas.
“I’m pretty keen on feed budgeting, particularly with the type of system we’re running, and it tells me our crunch period is during the summer, which was spot on this year.”
The cattle are Geoff’s safety valve and this year they demonstrated their role superbly.
“This summer we had to be flexible and change our cattle policy in response to the drought and as a result we’ve got good amounts of quality grass in an ideal state to respond when the rains come.”
Geoff has been practising SF for the last 20 years and maintains it works particularly well on fragile soils like pumice. About half his farm is covered in pumice and he has also worked extensively with landowners farming pumice soils.
“The pumice soils around Taupo are even more fragile than here. They are very low in both nitrogen and potash, which leach readily, and they have very shallow topsoil because of the short time they have been supporting vegetation.”
The Burton block has three terraces: one adjacent to the river, composed almost entirely of river silt; above this, a 60m-80m deep pumice terrace that comprises about half of the farmed area; and an upper terrace of much older ash soil derived from a lahar originating from Mt Tongariro.
Bubbling up out of this lahar is an extremely reliable source of high-quality artesian water that is gravity fed to the whole farm and hasn’t missed a beat since the Burtons arrived there.
The ash and pumice soils have completely different characteristics.
“The ash soil has superior water-holding capacity to the pumice, with a significantly deeper topsoil and is relatively old.”
Soil fertility levels are generally excellent with different readings for the two soil types:
Pumice soils – PH 5.9, Olsen P 42, potash 4, organic sulphurs 11.
Ash soils – PH 5.7, Olsen P 31, potash 7 and organic sulphur 16.
Low potash levels are almost impossible to lift on pumice soils.
Annual maintenance fertiliser varies according to soil tests but is normally about 300kg/ha of 15% or 20% potassic super fortified with copper, cobalt and selenium with 1-2t/ha of lime applied about every five years. Occasionally only lime mixed with sulphur and potash is applied as the phosphate levels are more than adequate. Fertiliser is applied to 75% of the farm (the flats) in the spring and to the hills in February.
Nitrogen at 30 units/ha is applied annually to about half the farm in the autumn and occasionally in the spring.
Geoff’s strategy when renewing pasture on the pumice soil is to disturb the topsoil as little as possible. While he’s not opposed to renewing pasture using cropping rotations, doing this via the SF method suits his management system and gives him excellent cost-effective results.
Geoff’s also drawn on his 40 years of working with Lake Taupo landowners who have traditionally grown large areas of winter crops.
“After these areas are sown back into young grass they flourish for three or four years with all the nitrogen being pumped back into them. However, after that they quickly revert to browntop if not managed very carefully.”
If Geoff wants to introduce new species to his pastures he SFs the area. In February, before the autumn rains, he oversows the required species with a bit of nitrogen. Then the animals graze it off and trample the seed into the seedbed left by the rotting vegetation.
Neither of the paddocks this year require oversowing because this was done eight years ago when they last went through a SF. A mixture of species including ryegrass, plantain, chicory and a number of different clovers was introduced. Of these, only the grasses and clovers have persisted but the others delivered valuable short-term feed.
The naturally occurring herb yarrow is held in high regard by Geoff as a source of quality feed and fortunately it persists under SF.
“It’s an extremely valuable species, especially in my summer/autumn pastures, and the lambs thrive on it.”
Geoff says it’s important on lower fertility soils like pumice to oversow species, especially grasses that persist for a long period without needing unduly high fertiliser inputs.
Geoff’s summer fallow system is cost effective both as a source of valuable summer feed and as a means of renewing pasture. It costs him nothing unless he is sowing new pastures species. He then broadcasts with some nitrogen.
The pasture species in his sward include ryegrasses that are not dependent on high levels of N input. There are an assortment of clovers including white, red and subterranean,plus yarrow, paspalum, chicory, plantain and cocksfoot.
Tough wintering regime
The priority stock on the Burton farm are 450 Coopworth Romney ewe lambs bought in mid-April from Rangiwahia’s Philip McKinnon. They arrive onto pasture covers of about 1900kg DM/ha, quarantine drenched at 35kg and enter a 40-day rotation for April/May followed by 30 days for June/July and 20 days for August/September. This tough wintering regime involving a maintenance-only level of feeding from June to September results in their gaining only about 7kg.
Joined by the cattle at the end of September, they then enter a rotation varying from 14 to 20 days during which they get four or five paddocks every two or three days.
“They are a good, even line of all-round sheep, are easy to shift and we only lose about 2%. They have reasonable eczema tolerance because we have only ever had one showing clinical signs in four years.”
Geoff says low or non-existent eczema spore counts and internal parasite egg counts are a feature of SF pastures identified by Tozer’s research.
Pastures start to respond to warmer temperatures in September when the hoggets are given a B12 injection along with their five-weekly drench. By October pastures are starting to get ahead of them so the cattle are introduced to achieve control while the rotation continues. From this time through to sale in mid-January the hoggets average 220g live weight gain a day.
Geoff’s target liveweight is 60kg by January, and by sale day this year they were 63kg. At the annual Te Kuiti two-tooth ewe fair they topped the sale for the second consecutive year, at $295.
Geoff’s been buying the McKinnon sheep for four years and stresses when buying trading stock you must first establish what your market is.
“Buying ewe lambs for growing out and selling as breeding stock is a completely different proposition to buying finishing stock. You’ve got to consider what they look like ‘cos no one’s going to buy them if they don’t look the part.”
The Burtons are strong advocates of the concept of sustainable farming, which is the central focus of the TSLMG group.
The four most important sustainability issues for the Burtons are:
- Making a good profit
- Looking after their soils and pastures
- Looking after their own mental and physical welfare
- Respecting other people both locally and internationally whose lives are affected by their farming activities.
- Strong advocates of summer fallowing
- Intensively farmed 40ha (29ha effective) farm.
- GFI $2841/ha and NFI $1369/ha.
- Buy 450 Coopworth Romney ewe lambs and sell as two tooths.
- Finish 50 R1 heifers for local trade.