Maintaining fields in autumn

The behaviour of the horse on grass

Horses are particular about the way in which they choose their feeding sites. They maintain short grazed areas where the vegetation is of good quality (deciduous stage) and leave areas of tall grass (gone to seed, harder and less digestible) for defecation.

At the beginning of the grazing period, the horse selects areas with the highest plant cover (~15 cm), where the proportion of leaves enables the horse to ingest dry matter at a maximum rate.

Feeding time is gradually delayed on grass in short areas, not as a strategy to control parasites (by moving away from latrines where there are more parasite larvae from manure) but to maximise the intake of digestible nutrients that are richer in protein.

By choosing different feeding sites and through their high activity, horses can quickly deplete plant cover. Some areas become short or even bare while others are completely rejected and abandoned leading to the development of woody plants (bushes) to the detriment of vegetation suitable for grazing (grasses).

In addition, undesirable plants that are not consumed, known as "weeds", are able to take root and multiply. This is particularly the case for rumex, nettles, thistles and Ranunculus (also known as buttercup), if their development is not hindered by treatment. Maintenance consists in encouraging productive and homogeneous growth of the plant cover, which is favourable to grazing.

In contrast, grasses that go to seed no longer produce leaves. Any existing leaves fall into senescence (death). Grazing, mowing or topping allows the start of a new leaf production cycle.

Insufficient load

Permanent grazing and overgrazing

Overgrazing (areas less than 3 cm high) exhausts the grasses and intensive trampling compacts the soil. These two phenomena eventually lead to the disappearance of grasses which make way for plants that are more resistant to trampling such as clover and rosette plants (dandelions, broadleaf plantain, etc.).

Excessive trampling can even lead to the disappearance of the herbaceous cover. Thus, in the following season, the free space (bare soil) will be occupied by plants with strong colonising power (annual plantain, bent grass, camomile, rumex, thistles, etc.) which are not desirable (not consumed) in a pasture.

Seed infestation

Feeding in a field with hay contaminated with weed seeds (dandelion, thistle, dock) and repeated trampling causes weeds to proliferate around the hayracks and feed areas.

Similarly, spreading manure with seeds in it increases the development of undesirable plants. These seeds will have more opportunities to germinate the longer the pasture is kept in moist (winter) conditions.

Appropriate load

If there are too few animals to ensure the consumption of grass produced according to the season, it is normal to see areas which the animals refuse. The load (number of animals/ha) must be adapted either by reserving part of the plot for mowing or by practicing rotational grazing.

Mixed grazing with cattle or sheep is also a good solution as they will consume areas that horses leave behind. This may be:

• Alternating: putting cattle in the field in the autumn to consume what the horses have refused in the summer
• Or simultaneous: mixing horses and cattle at the same time.

Fencing will then be required for both types of animals. Beware of sheep fences where there is a risk of horses getting a limb stuck.

Topping

Be careful not to carry out topping when the grass is too high (more than 20 cm), thinking this will maintain a sufficient density to continue grazing or to make it look “tidy”. It will have the effect of accumulating dead matter at the base of the plant, hindering access to light and thus photosynthesis. It will also have the effect of leaving plant matter (old leaves) in place, not encouraging the production of new leaves (the process of ‘tillerage’, when new shoots appear at the base of the herbaceous plant).

Topping woody plants (brush, wasteland) can be useful for encouraging the regrowth of the grasses underneath. This should ideally be done at the end of autumn, when the plants are in the declining phase of their development. If strimming is done in the spring, the woody plants will have time to grow tall and hard, shading the grasses, which then develop less and less. Early spring grazing will be required to encourage the leafy stage of woody plants and limit their development.

Selective weeding

If there are too many unwanted plants, weeding will be the quickest solution to limit their spread. It is essential to avoid treating the whole plot with a herbicide, especially if it is a natural meadow with a wide variety of species. Herbicidal treatments that are conventionally used to control rumex or thistles are often “broadleaf weed killers”. These substances destroy all plants other than monocot grasses. They will destroy other plants, including leguminous plants such as clover and lotus, which are valuable for their protein content in the horse's diet. These herbicidal treatments lead to the formation of exposed areas of land where undesirable plants (bent grass, rumex...) will regrow.

A local treatment carried out using a hand-held sprayer or behind a quad or tractor seems best suited to treat contaminated areas (dock, thistle, nettle).

Harrowing

Chain harrows are used to pull out:

• Creeping plants such as creeping bentgrass. These result in heaps of dead plants and have an anti-germinating effect on other plants;
• Ranunculus (buttercup) which forms runners (aerial stems forming roots on the ground).

It is important to collect the waste. They can either be composted with manure or burnt, to avoid contributing towards colonisation of other areas of the plot!

Healthy soil enrichment (compost, liming)

Organic soil enrichment (manure, compost) encourages the intake of organic matter...nitrogen, phosphorus and potassium. These elements are conducive to soil structure and plant development. This contribution is all the more valuable in pastured areas where a lot of nutrients are exported (through animal consumption) and little natural fertilizers (dung, urine) are added (the concentration of excreta is more likely to take place in areas they refuse to graze on).

Manure compost, which has reached a temperature that guarantees the destruction of weed seeds, acts as a hygienic organic fertiliser, unlike raw manure which is loaded with seeds (from cereals from concentrates and weeds contained in hay).

Warning: it will be necessary to first carry out a soil analysis to check that the soil pH is below 6.5. Over-liming can cause phosphorus and trace elements to become trapped in the soil. The productivity of the field will be greatly affected.

Cover bare areas

Any bare area will be at risk of being colonised by undesirable plants (seeds present in the soil), which are quicker to develop than the desired grasses. Overseeding consists of sowing plant species that are favourable to grazing (grass species which are resistant to trampling) in fields that are already established but which have deteriorated, with bare areas (plot entrances, around racks and watering troughs). This involves sowing the seeds "on the fly" on bare ground areas, then rolling with a machine or having horses trample on the ground while the seeds are taking root.

Overseeding takes place in early autumn, during fairly wet periods, to promote germination and then seed development. Animals should then be avoided in these sensitive areas during the winter.

Winter rest

Resting the plot during the winter period is essential to ensure plant regeneration. It is part of good grassland maintenance practice. A minimum period of three months without animals allows the plot to rest and it will not be trampled or grazed down to the roots, as horses can do in winter. The ground will also be able to rest. Earthworms will thus be able to dig galleries and aerate the soil. Free harrowing!

If horses are to be kept outside during the winter:

• The plot used to overwinter the horses will have to be left to rest in the spring. It can then later be used as a mowing area at the end of the following spring.
• Or two lots of plots should be planned: some that will be grazed on from October to December and others that will be grazed on from January to March.

In winter, a small number of horses can also be kept on a large area of grassland (very low load with more than one hectare/horse). As a result, trampling and excessive plant deterioration is limited.

Ideally, however, there should be a stabilised area adjacent to a shelter, where horses can move freely without damaging the fields.

Fields are living things with production cycles that vary greatly from season to season. A weekly "tour" of the plot should be carried out to assess the vegetative stage of the ground cover. The extent to which it has deteriorated will also be observed by the appearance of bare areas or areas contaminated by undesirable plants. The conduct of the animals and surfaces can then be adapted.

Feeding your horse year-round with grass and harvested fodder is possible if regular maintenance and resting of the meadows is practiced.

CERTIPHYTO : individual certificate to ensure the safe use of phytosanitary products
(herbicides, insecticides, fungicides)

All professionals (farm manager and employees) who work with phytosanitary products are covered by French and European regulations. The European Directive (2009/928/EC) provides for compulsory initial and continuing training to acquire and update skills in the use of phytosanitary products. The Certiphyto certificate has been mandatory for all users since 1 October 2014. Contact the DRAFF (Direction Régionale de l'Alimentation, de l'Agriculture et de la Forêt) in your region for more information.