A windy, warm and dry summer has been the pattern so far for much of New Zealand – not much good for beach and barbecues, and not much good for your pasture either.
The wind and sun keep coming, but the rain does not, and almost overnight the lush green pastures of spring have turned into a brown landscape.
Dry and droughty conditions have become commonplace for much of the north and east of the country in recent years, and without irrigation, the only plants that do well under these conditions are precisely those you don’t want to flourish in your paddocks: dock, ragwort and thistles.
Drought conditions begin to bite when soil moisture deficits begin to affect the performance of grass species. Growth slows, then stops, and the plants brown off, all the while the nutritional value declining.
Horses, however, are well-suited to eating low-quality grass, and in fact many will do better on this ‘standing hay’ than they do on lush dairy pasture.
The problem is that the grass doesn’t grow back. The roots will be stressed, and you’ll be left with bare paddocks, and hungry horses – so you’ll have to provide them with hay, baleage or silage to meet the shortfall in forage.
Erosion
Land degradation begins with a combination of hoof and grazing pressure; allowing horses to graze paddocks down to ground level, coupled with their habits of standing around in certain areas (such as around the gateways and troughs). Over time, the degradation leads to erosion, especially if the land is sloping as water will run over the bare land more qiuckly, causing erosion channels.
These conditions usually occur in high traffic areas such as raceways, near gates and shady areas. The weight of the horses compact the soil, and without the cushioning effect of grass, the problem is exacerbated. Compacted soil lacks oxygen as the air is forced out, and at this stage, even if the horses were removed, grass can’t grow there (apart from hardy weeds) due to the hard soil and lack of air spaces.
When it rains, the water can’t penetrate, and runs off, taking the topsoil with it. As the weather dries out the areas become dust bowls, and the wind takes even more topsoil. This is the start of erosion, and it’s easy to see how it can soon become a downward spiral.
A healthy vegetative cover is essential for good soil. Even weeds are better than nothing, and no matter how unsightly, don’t remove them until the dry conditions have eased and you are ready and able to replace them with a preferred species. Out-competing the weeds with the preferred species is better than complete removal in many cases, as then the land is never completely bare.
Tips to help prevent degradation
- Fence off areas that are prone to erosion, including steep hillsides and creeks
- reduce the amount of ‘standing around’ time your horses have in the paddock, especially during drought conditions. Turning them out for a couple of grazing periods per 24 hours, if you can manage it, ensures that when they are in the paddock, they get on with eating. The rest of the time, the horses are in yards or a sacrifice paddock, and the rest of the pasture can rest and recuperate.
- only have horses shod if it’s necessary
- plan shelter belts to protect the soil from the wind; trees and other vegetation help bind the soil
- control and prevent water from running across areas of bare soil. You need to understand how your land drains, where the water runs, and how it pools. Areas with a lot of run-off need vegetative cover to protect it
- don’t overstock your land, and don’t allow overgrazing, by moving horses on when the grass is down to 5-8cm average.
- cover bare patches in the paddock with old hay, or well-composted manure
Weed control
What is a weed? A plant that is in the wrong place at the wrong time is one definition. What is a weed to one person may be a beneficial herb to another.
Some weeds are noxious to stock and the environment (such as ragwort). Others, such as gorse, rather than being dangerous, are simply plants with little or no feed value to horses. They take up space, compete with pasture grasses for moisture and nutrients, and cost time and money to control.
Weeds arrive on your land in various ways; they can blow in from neighbouring properties, be carried in by birds, and can stick to other objects such as car tyres. They can also come in hay, soil and even loads of gravel.
Poor paddock management allows weeds to take over, until there are more weeds than grass.
There are several strategies you can use, and often more than one option works best.
- Mechanical control via mowing, hand-pulling or using a weed-whacker. This can be effective, but must be done at the right time to avoid spreading seeds. Must be done regularly to be effective
- Organic control, which tends to take longer, but is better for the environment. Cross-grazing with sheep, cattle or goats can be useful, as can mulching with wood chips or old carpet to smother weeds in some areas. Changing the chemical balance of the soil can control certain weeds. Research has shown weed seeds don’t tend to survive passing through the digestive systems of ducks, chickens, sheep and cattle. Keeping chickens and letting them free range to ‘sort’ through manure for seeds helps reduce the numbers that get into the ground.
- Chemical control. Effective but can be harmful for the environment. Plants must only be sprayed when the are growing, green and before setting seed, and spray on still days when at least 12 hours of dry weather is expected. Don’t spray within 100m of dams, wetlands and creeks. And be aware that some chemicals will kill desirable plants such as clovers, along with the weeds.
Slashing and mowing
If you are not able to use cows or sheep to eat down the grasses that the horses leave, then your paddocks should be slashed or mowed immediately after the horses have been moved on. Mowing is preferable, as then the plants are mulched into small pieces, which add condition to the soil as they break down.
Slashing and mowing helps remove old, tough, rank grass and encourages the growth of young green grass, which results in more uniform regrowth. Mowing grasses before they set seed will encourage them to produce leafier and more nutritious vegetation.
Mowing the pasture during a period of rapid growth can also be an advantage. Ideally, the pasture should be mowed to a height of 8-10cm, which encourages the horses to graze the whole area.
Mowing weeds before they set seed is an important weed control strategy for most upright weeds, such as thistles. Mowing them at the wrong time (when they have seed heads) can actually spread them around your paddock.
Harrowing
Harrowing is a manure management strategy which has the added benefit of improving pasture. By spreading manure around the paddock rather than allowing it to stay in areas called roughs, the paddock will be more evenly grazed in the future and will benefit from the nutrients in the mature.
Harrows can be homemade from old gates, tyres etc, but commercial pasture harrows are more effective as they are flexible (being chain link) and have spikes that can aerate the soil.
However, harrowing is only effective if you are able to rest the paddocks for a suitable period before re-grazing, to allow the dung to break down and the worm larvae to die as they are exposed to the air (this will happen more quickly in hot, dry or frosty weather). If the weather is humid and warm, the paddock will need a lengthy rest before horses can be put back on it.
Picking up and removing the manure, either by hand or by using a specially-designed machine, is recommended on smaller properties, or if you don’t have the ability to rest paddocks for long periods.
Improving pasture
Signs that your paddocks need renovation include bare patches, weeds, and the appearance of obvious ‘roughs’ and ‘lawns’. You need to make a plan before tackling the renovation, to ensure success.
The time of year is critical, as there must be enough water in the soil, and you need to be able to rest the newly-renovated pasture for some time, putting more pressure on other paddocks.
Renovation checklist
- Have soil tests done to help determine which area to renovate first – pick an area that has the most chance of success
- control weeds, and graze pasture hard or spray
- fertilise if necessary
- select your grass species and source quality, certified seed
- prepare the ground for sowing by scraping the surface with harrows
- broadcast the seeds (spreading them across the surface) by hand or seed spreader.
This article was first published in the February 2017 issue of NZ Horse & Pony
