Hawke's Bay Regional Council Land Management manager, Garth Eyles, publishes a regular column in Hawke’s Bay Today’s Heartland rural supplement.
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The windy season has well and truly arrived. Driving in to the rugby on Sunday from Taradale along Prebensen Drive a cloud of soil was blowing across the motorway and even affecting houses in Parklands. The soil was from a paddock being cultivated in the strong winds Not a good public relations exercise and definitely not good for the paddock.
We need to realise that soil lost is income lost – both short term and long term. It takes $1,000 of fertiliser to replace the fertility lost from just 1 cm of topsoil. Not to mention the effects on soil moisture and seedling damage. Last year an onion crop on the Ruataniwha Plains had a wind blow and a later analysis of yield indicated that the wind blow caused a loss in excess of $7,000 per hectare. I have seen areas where the soil has been removed down to the plow line, destroying thousands of years of soil development and restricting the area to low quality pasture for many years.
The risk of wind blow can be reduced by effective planning. Some soils should not be cultivated either due to their structure or because they are in an extremely wind-prone environment. The solution is either shelter or minimum tillage.
Shelter is a long term solution as protection occurs out from the shelter 16 times the height of that shelter. The added advantage of shelter is the positive animal health effects of protecting stock from cold, energy sapping winds, especially in winter.
If there is no shelter, minimum tillage is a must in many locations. This can range from zero tillage to strip tillage, with the decision depending on the crop and the soil type. Current trials are showing that leaving small catch strips of pasture at right angles to the wind when cultivating will reduce the risk of a major blow. Alternatively sowing strips of barley as the catch strip will provide protection. These catch strips need to be about 1 metre wide, with up to 40 metre wide cultivated strips between.
If you are new to an area, talk to your long time cropping neighbour. Sometimes experience has identified two passes will not blow but three will. Pugging a soil all winter will mean it has to be over-cultivated in the spring, and over-cultivation increases the risk of windblow as the structure is broken down.
Owners, just remember, a person leasing land is more generally not concerned with maintaining the quality of your soil which is your capital. Contractors often cultivate when they want to rather than when they should and tight planting schedules can ruin your production in future years. Your capital needs to be protected and nurtured - look after the soil and it will look after you.
Every winter in Hawke’s Bay, hill country farmers lose sections of their tracks, culverts and dams due to scouring caused by stormwater overflowing from blocked drainage. Winter flooding on the plains is frequently caused by blocked culverts. In the first rains of winter, when a summer’s accumulation of rubbish is swept into the entrance of a culvert and it gets blocked, the water becomes a major hazard. In soft rock hill country, pumice lands or areas where recent works have been carried out and regrassing has not matured, the effect can be major gullying. Usually when the culvert blows out, it’s in the middle of a storm when access is essential and stress is at its maximum.
Act now while it’s dry, while vehicle access is easy and while you may have some spare time. The following areas need to be checked:
- Track drains and culverts. Along tracks that have drains beside them, remove any debris that is likely to wash down and cause blockages.
- Drains on the plains. Make sure that the prunings from the shelter trees along the edge of drains have been removed. These can very quickly block the drain, causing flooding over your and adjacent landowners properties – which doesn’t go do down very well with neighbours, if it was your prunings at fault.
- Clear cut willows. During the drought you may have been feeding stock from cut willows. Frequently these have been planted to protect valley bottoms from gully erosion. In the photo you can see that the cattle have done an excellent job, but the debris remains. In the first major storm this will be washed down the slope. If there is an embankment across the valley with a culvert in it, the culvert is likely to blow. If there is a farm dam at the bottom of the slope (as is the case in this photo), the material will wash into it and cause problems at that point or block any culverts into the dam.
- Farm dams. Check the overflows to see that there is no debris or chance of blockages. Check that the down slope side of the overflow is capable of taking flows and has not been eroded back so that any new large flow will be likely to cut out the bank. Any overflow pipes through the dam wall need to be carefully checked to make ensure there is no seepage around the pipes and that the end of the pipe, when full, does not form tip the pipe, creating a weak point in the dam wall when this is wet.
- Cleaning dams. While the farm dams are empty or almost empty, take the opportunity to clean them up. Make sure the material is deposited at a sufficient distance from the dam that the sediment will not wash back into it - which sounds simple enough, but frequently this happens. It might be easier to cart the material away on a truck or trailer but, at the very least, make sure it is downstream of the dam wall. Once this is done, it’s worthwhile to look upstream to find where the sediment comes from and take action to minimise this.
A small amount of time now spent clearing debris can save you a lot of expense at a very stressful time later in the winter.
“Biodiversity” is the in word at the moment. What it really means is looking after and increasing the native plants on your property.
Contrary to what you may believe, this is not a difficult task. It can be a task for the whole family, involving the kids as well as the adults, and it can be fun - especially if you ‘eco source’ the plant material (that’s another bit of jargon which means collecting the seed or plants from the local area). I am doing this with kahikatea (white pine) at Tutira Country Park. We are collecting seeds and getting these grown to be planted in a kahikatea forest we plan to start next year.
On your farm, all you need to do is fence out an area of native bush so it is completely stock proof - you will be surprised how rapidly the native plants thicken up. Control the possums and the native birds will come back. The fun part is collecting and raising seeds, planting the native plants and then watching them grow over time.
With kahikatea, find one that is fruiting. Only female trees fruit - a small red fruit with a black seed. Either pick the seeds off the tree or scoop up the duff (duff is the soil litter under a tree) and sort the seeds. If using the duff, remember there are lots of bugs there which eat the seeds so it could be worth sorting before storage. Plant the seeds in a potting mix and keep moist. Kahikatea seeds take about three years from sowing until you are planting out a 400-500mm high plant. In the interim look after them in the family garden, keeping the pots moist and fertilized.
There are a number of books that tell you how to raise from seed but Regional Council can also help with some Environment Topics that give excellent summaries. Both the topics “Raising Native Plants From Seed’ and ‘Raising Native Plants From Cuttings’ can be accessed from the web site or copies can be sent to you.
Above: Duff from under a kahikatea tree showing the fresh red seeds and older dark seeds. These can be planted in moist soil and will grow.
Lifestyle blocks are an important part of our community. Yeah right! you might say.
Okay, let’s look at some facts. These properties comprise more than 45% of all the properties over 1 ha in the Hawke’s Bay region. There are over 4,000 properties between one and 9ha - that’s about as many as there are over 50 ha.
The first thing urbanites see when driving into the country are lifestyle blocks - to them lifestyle blocks are ‘the country’. The last thing farmers see when driving into town are lifestyle blocks - to them these are an extension of town.
So management on these blocks has a major impact on all sectors of our community - but lifestyle blocks are notoriously difficult to manage.
Having a few small paddocks makes pasture management difficult. Without irrigation, pastures die off early requiring the small flock to either be fed from expensive supplementary feed or sold at rock bottom prices. Irrigation for small areas is expensive so many owners revert to using their garden sprinklers, which, commonly, do not do a good job.
Owners get no advantage from economies of scale either. Farm items are expensive as materials are only needed in small amounts or used seasonally. Buying animals is expensive – you only need a few and it’s difficult to get the best lines. Once on the property animals may have to put up with poor quality pasture, water problems and being hassled by the neighbours’ dogs.
All this while both partners are often working off the farm to pay the mortgage! While the average townie is enjoying their weekend, the average lifestyler is doing all of the “farming tasks” as well as organising the kids’ sport.
On the positive side, a lifestyle block means owners can enjoy more space, not have the neighbours listening to conversations and have fabulous views. They also have the opportunity to live sustainably, design and create a landscaped environment of their own making or develop a highly intensive production unit – whatever suits the conditions.
You have your own reasons for buying a lifestyle block but think through all the implications as well as the opportunities. Carefully plan what you want to achieve from your block before committing yourself. It’s great fun trying things out but to get it right first time, talk to the experts. There’s now an experienced group of consultants that are able to advise you - even do the grunt work for you. So don’t avoid paying for good advice as it will save you heaps in the long run.
The skill is in having a good understanding of what life will be like before you make the move to live in the country and knowing where to get good advice and the best deals.
A great place to start is at the Lifestyle Block Field Day being run by the Hawke’s Bay Regional Council at the Hawke’s Bay Showgrounds on Saturday 31 March. It’s an opportunity for you to meet the experts, get some advice, learn about topical issues in workshops and talk to others with the same issues - and options. Come along and enjoy the day, you will find it very rewarding.
The summer dry is now starting to bite. In most areas feed is starting to get short (or has been for some time) while the ewes need to be set up for tupping. What are the alternatives? On most hill country farms there are very few alternatives. Winter hay once gone is not available later and the wet paddock? – drained!
But most farms have one supplementary food source and that’s the poplars and willows planted for erosion control purposes. I spent a couple of hours a few weeks ago watching Alec Olsen providing supplementary feed for his cattle. He was doing it three ways:
- In a large gully he had a group of Matsudana willows he topped every two to three years. He had topped the trees the first year then topped some each 2-3 years. By topping regularly he rapidly formed a “nest” which provided a safe place to cut the smallish branches (photo1). It’s critical to cut the branches regularly as large branches are dangerous to cut so he has designed a three year cycle for his willow grove.
- He side-prunes the young poplars each year. He prunes as far up as is safe and could treat them as timber trees, pruning up 6 or more metres.
- Where he has planted poplars on relatively gently slopes, but is not interested in timber, he has begun pollarding them, ie he cuts them off at shoulder height and the trees sprout and re-grow rapidly. If he can cut above cattle browse height there are no restrictions on grazing; otherwise he needs to restrict cattle until the shoots are cattle resistant.
At Tutira Country Park I have cut 30 year old willows at shoulder height and a significant number have shot, providing strong growth. Restricting cattle from the paddocks has meant they have a good chance to re-grow but it’s amazing how high some sheep can stretch!
Many hill country farms have numbers of old willows on hill slopes. Many have large and dense canopies and are past their use-by date. A summer drought is the time to drop them as they have a lot of food. There is an argument they only create a pile of rubbish. Alec Olsen’s experience is that the cattle eat everything up to about 2 cm diameter, the rest makes great chips and firewood! Properly sequenced you have an annual supply of fodder and firewood, while the pruned trees rapidly re-grow but don’t create major shaded areas, resulting in more grass.
If you are interested in finding out more about the use of poplars and willows for fodder, you are invited to a Sustainable Farming Fund field day at Alec Olsen’s property, Glengarry Rd, on 20 March. For details check Hawke’s Bay Today for advertisements or contact your local Land Management officer at the Regional Council.
Above: Mature willows are being topped for cattle fodder. The “nest” of branches at the top of the trunk makes a safe position from which to cut the 2 to 3 year old branches. Care is needed to ensure cattle aren’t hurt by falling branches.
One of the most disappointing sights I see on farms are seemingly healthy, 4-7 year old poplar or willow trees broken off when in full leaf. What a waste of time and effort getting the tree to where it’s just starting to work – stopping soil erosion, creating shelter and looking really nice, not to mention the cost – only to have it destroyed.
Poplar and willow trees planted as poles are protected from animal browse by plastic sleeves – either solid plastic for protection against cattle or a loose knit against sheep. By the time poplars and willows outgrow the sleeves they should have developed a hard, stock resistant bark, but modern poles generally grow so quickly they don’t have this protective bark by the time they outgrow the protection.
So there is a dangerous period immediately following the removal of the sleeve when the bark may be soft. It can take a number of weeks to harden up, and for a few years, the tree will still be susceptible to bark damage.
Sometimes, instead of protectors, an owner chooses to temporarily fence out the newly planted poles. This is usually done by a single wire electric fence. It is surprising how often cattle get through these fences and damage the trees.
For some unknown reason cattle will suddenly start scraping bark off and eating it, leaving strips of exposed wood underneath. Cattle will do this even when they are not hungry. The reason is not known but is probably because the stock can smell particular types of sap movement.
Stripping the bark doesn’t kill the tree. Instead, the bark heals while the surface of the wood generally dies and often a fungal infection can develop. The tree looks to have survived and continues to grow until a major wind blow two to three years later. The trunk will break at the weak point caused by the dead wood, and the tree will fall across this dead wood like a scarf.
The best management is to protect the trees until the bark is roughened up and hard enough to resist any stock damage. If cattle must be grazed, keep a very close eye on them, removing them as soon as they start playing with the trees. It is essential stock do not break the bark. The bigger the strip de-barked, the more susceptible the tree is to wind blow in the next few years or until the bark has re joined over the cut (if it does).
Bark stripped trees can be cut down there and then, instead of waiting for them to fall during a major gale at some future date. It’s your decision - but you can keep the tree. Make a clean cut across the trunk immediately below the lower break in the bark and put a protective fence around it. Protected from further browse, the tree will re-shoot and grow rapidly.
Willows are an essential erosion control measure for earth flows, gullies and for stream banks but they are the natural enemy of New Zealand wetlands.
Why is this? In the northern hemisphere wetlands are the natural environment for willows but in New Zealand, they out-compete our native wetland vegetation forming wetland forests.
An extreme example of this invasion was the Pekapeka Wetland, adjacent to State Highway 2 south of Hastings. In the 1960s, raupo dominated and willows grew only in small clumps; 40 years later willows covered 90% of the wetland. This has required six years of intense spraying and ground clearing to remove the willows and the job is not complete. It will take at least another five years and will require monitoring for many years to come.
The culprits are pussy willow, crack willow and golden willow. These are all old ‘willows’ which were planted out in New Zealand prior to any breeding programme taking place. Now most willows released by the Regional Council and other councils are male clones only. These are selected and bulked up for distribution during breeding programmes, reducing the risk of seed dispersal.
On farms, save yourself the problem of having to clear willows from your wetland at some stage in the future by ensuring any seedlings are removed before they get too big. Seedlings can be pulled out by the roots when they’re small; when they become saplings cut the stem and paint the butt with Glyphosate using a mix of up to 50% with clean water. Ensure the painting is done within 10 minutes of the cut or the cells will have sealed. Remove the cut stem away from the wetland so that it doesn’t sprout and continue to grow. For the big willows, either aerial spray, poison, or cut and remove, making sure that broken branches don’t sprout and regenerate.
Willow seeds are blown long distances (kilometres) so you will need to check every couple of years or they will re-establish. It is much cheaper to remove the occasional willow than to wait until the problem has got to the stage where mechanical removal or aerial spraying is required.
Remember – a healthy wetland contains no willows.
Some experts say there will be an El Nino this summer - though they temper that statement with the qualifier that it will be mild one.
At the moment we cannot say whether this will result in a traditional Hawke’s Bay summer – dry from January to March - or an early drought, or whether it will be too mild to notice. However, there are sensible precautions landowners can take.
El Nino’s mean westerly winds. That means the equinoxial gales are likely to scream out from the ranges and across the plains. We have had examples of this already this season. Farmers cultivating the light Takapau soils into a fine tilth are in for major wind blows. There should be no sympathy for these farmers who cause wind blows, as there are now proven alternative technologies to traditional cultivation that can minimise the wind erosion risk. People who cultivate in these areas not only risk the long term productivity of the blown paddock but damage other people’s land and crops.
When planting poplar and willow poles, make sure they are well planted – deep, with the surface around the pole well compacted. A loose pole will die in dry conditions as the air gets down the hole and dries out the roots. Poles wobbling in the wind have their small roots broken. With a shovel carefully clear a hollow round the pole so that any rain will be concentrated round it and will sink in. This is especially useful where poles are planted on slopes. Release spraying around poles reduces competition for water. However, thistle invasion can then be a problem.
In mudstone soils, where contraction occurs with drying, you will need to check poles every couple of weeks. If any are loose, re-compact with your boot heel or a rammer. But beware – don’t’ damage the bark as disease will get in and rot the pole.
Watering can save trees in a dry season, especially if you have only a few or there are some you particularly want to save. One trick is to use drench (or other chemical) containers with taps. After triple rinsing these, place them next to a pole or tree with the tap turned to allow a slow drip, and fill with water.
In the traditional El Nino season, poles that are well sited, planted and maintained have a good chance of survival. Frequently, we have a dry, windy period through late October, November and December followed by rain. It is these early droughts, combined with the strong westerlies, which burn the newly sprouted leaves that do the most damage. Currently the new leaves are looking great. The different colours of the different clones are standing out and looking brilliant. Let’s hope we get sufficient rains to enable this winter’s plantings to grow all season.
For those of you suffering from slips this winter read on...
If left alone, an individual slip will only slowly recover. Studies have shown that it will take at least 40 years for the production on the slip face to recover to pre-slip levels. The debris tail will most likely be a sea of thistles by next autumn.
Farmers who want to get the slips back into production as rapidly as possible need to get a pasture mix to establish on the slip. To do this, there needs to be places for the grass to establish instead of washing off with the next rain. A couple of options are:
- If the slip is real eyesore, chip the face and then oversow. This is very labour intensive but it does work (I know as I spent a summer holiday as a student doing this). It works best where the face is on soft rock. Using a spade, chip out terraces down the face and then oversow the face with a standard pasture mix. Run a small mob of sheep over the sown face to finish the process.
- Another way is to concentrate a mob of sheep on and over the slip face before it has completely dried out, but not when it is wet and puggy. The sheep will create a mosaic of holes. Oversow the face and then put the mob over again to cover the seed. Make sure the stock are not too heavy and do not stay too long or the slip will be scoured rather than pock marked.
When to oversow is always a tricky question. As the soil has gone, there is little moisture holding capacity left. Any new grasses will, therefore, be very susceptible to drought. The choice is up to you, but don’t leave it too late.
The debris tail, below the slip face, is where all the soil has been deposited. If the tail is shallow it may wash away quickly, depending on whether the following rains beat any regrowth; if it is deep, it will remain. If not re-grassed these areas very rapidly become a great crop of thistles. So it is best to get them into grass as soon as possible.
Re-grassing is best done following a cultivation as it smoothes the surface and provides a good seed bed. The other option is to use the mob of sheep to do the cultivation, then oversowing and using the mob again to bury the seed. A solid topdressing will encourage rapid growth.
Oversowing and topdressing will generally provide a rapid ground cover, but for generations the slip face will be more susceptible to drought than the adjacent unslipped slopes.
It is best to reduce the risk of erosion by space planting poplars and willows on erodible slopes well before the rainfall event occurs. Remember poles take 5 years or more to effectively reduce erosion risk. See your local land management advisor now for advice.
Weather predictions by NIWA are for more north-easterly air flows than normal for the next 3 months, and above normal rainfalls and soil moisture levels. This suggests the recent trend of increased earthflow movement and landslide erosion around the region’s hills will continue.
Because of the recent downturn of the economy some farmers have reduced, or even stopped, their soil conservation plantings. This is risky - unless a planting programme is completed as planned, your farm will remain vulnerable to erosion when high intensity rainfall strikes an already wet landscape.
Hawke's Bay Regional Council land management advisors are able to give advice on plant species for erosion control purposes. They can also advise on whether you will be eligible for a financial grant.
Regional Land Care Grants are available to assist you with:
- Fencing off gullies and gorges where the risk of erosion is extreme
- Joint ventures for erosion control forest on land with a severe erosion risk
- Space planting of trees on pasture land where there is a significant erosion risk
- Gully erosion control through structures, retirement or planting
- Shelter belts on soils with a very severe wind erosion risk.
If you want to undertake any of these tasks this winter, please contact the land management officer for your area. They will visit to discuss the issue with you and, if your project meets the criteria, will get you to complete an application form. Following approval you can be reimbursed up to 50% of the costs of the project. The Council’s free call number is 0800 108 838.
With the winter rains coming, it’s also time for the essential task of checking your drains and culverts for debris. On a hill country farm, culverts are generally the most susceptible structures to flood damage as they block up causing overflow and scour. This can often take out the track and spew debris down the hillside or along the track. The major danger period is early in the winter when the debris, branches and other material which has built up all summer, is washed down into the drain.
Pair planted willows, along ephemeral waterways need to be cleared around. Branches cut for fodder or pruned shelterbelt trees are another major cause of drain blocking. Remember, the less likely a waterway is to be blocked, the less damage will occur to your tracks in a storm.
It’s that time of year again …
Hawke's Bay Regional Council land management staff are encouraging farmers to put orders in for willow and poplar poles to control erosion prone land.
Soil erosion is a continuing risk on Hawke’s Bay soft rock hill country.
Significant soil erosion usually happens in storms where more than 200mm of rain falls in two or three days, but where the soil is “wetted up” much lower rainfalls can cause damage. Generally smaller storms tend to clean out the debris left by larger storms.
In central Hawke’s Bay, earthflows which had not moved for 10-15 years re-activated in the winter of 2004. They did not move in the February Porongahau event but did so later in the winter when the subsoil had “wetted up” and the winter rains had further saturated the soil profile.
The northern part of the region, with its more silty soils, is particularly prone to slip erosion. Farmers will remember that in Cyclone Bola 80% of the sediment came from slopes steeper than 25 degrees and these slopes covered nearly a third of the catchment area.
More than 50% of the sediment which moves in big storms enters streams and rivers, leading to silting along the banks on the lower terraces and in the coastal estuaries.
Space planting of willows and poplars helps control this erosion. However the trees need to be well-established for maximum benefit to be achieved. It pays to remember that preventative planting needs to be done 5 or more years before it can be expected to work.
Interest in planting has definitely increased amongst farmers - 29,000 poles were supplied from the Council’s nursery in 2002 compared to 46,000 total in the 2005 planting season. More than 260 farmers ordered stocks last year.
Hawke's Bay Regional Council supplies pole stock from our nursery in Allen Rd, Pakowhai. We prepared 37,000 three metre poles last season, and brought in nearly 10,000 extras because of demand. Additional demand also came from flood control replanting along the rivers to replace trees devastated by willow sawfly and nearly 20,000 poles went to this crucial Council project.
The nursery offers a range of different poplar and willow clones suitable for different farm environment, so you need to discuss what is the best clone for your particular environment with your land management officer.
There are also a range of sizes available – 3m poled for steep grades, 2.5 m for temporarily retired areas, and wands for retired sites where there is significant earthflow of gully erosion.
Dynex and netlon pole protectors are also available.
Landowners who are already on farm plan regimes have received order forms from their land management officers.
The Regional Council also runs a grant scheme providing up to a 50% grant for pole planting or retirement in badly eroded areas.
Planting changes the landscape. Many Hawke’s Bay people think that the bare hillsides are ‘natural’, but in fact considerable amounts of bush and forest were the natural cover. Slips still occurred because of the soil types and steepness, but this increased significantly when the bush was cleared after settlement. What we have now is a hugely modified landscape and many landowners are making concerted - and expensive - efforts to restore the balance.
To talk about managing your erosion prone land contact a local land management officer at Hawke’s Bay Regional Council 0800 108 838 or call Wairoa 06-835 8527 or Waipukurau 06-858 8636.