Stockpiled Pasture: 5. Effect of Stockpile Grazing in Fall on Forage Production the Following Season
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Stockpiling is the practice of saving certain hay or pasture fields for grazing in the fall and winter after forage growth has stopped due to cold weather. Stockpiled pasture is also referred to as fall-saved pasture or deferred grazing. The primary reason for using stockpiled forages is to reduce feed costs. One concern that many livestock producers express is that grazing in the fall will damage the pasture, resulting in reduced forage production in future years. In this update, we examine forage productivity after one or more years of fall clipping or grazing.
Spring yields following fall clipping or grazing were measured on three separate trials. The management of each trial is described below:
After three years of clipping on either September 1, October 1, or November 1, hay yields the following spring ranged from 6500 kg/ha to over 8000 kg/ha, as shown in Figure 1.
Figure 1. Hay yield following clipping the previous 3 years at three different dates in the fall.
There was no difference in spring hay yield between plots harvested the previous fall on September 1 or October 1, but each of these treatments yielded less than plots previously harvested on November 1. This suggests that plots harvested in September and October may not have been completely dormant (a reasonable assumption) and some regrowth occurred, which weakened the reserves available for growth the following spring. Despite this, the absolute yields the following spring were quite acceptable considering the stand was pure grass and 4 years old. There was no difference in spring yield between the Hay or Pasture stockpile management systems (data not shown). The yield of various grass species was not affected by the previous fall harvest date (data not shown).
Spring yield data following sheep grazing is shown in Figure 2.
Figure 2. Spring silage yield (1997) or pasture yield (1998) following sheep grazing at four different dates the previous fall.
Spring yields were collected from areas grazed by sheep in early October, mid-October, early November, and mid-November. In 1997, spring silage yield (cut mid-June) was not affected by the date of grazing the previous fall. In 1998, spring pasture yields (cut mid-May) were not affected by the date of grazing the previous fall. Forage yields the spring after fall grazing were not affected by the stockpile management system used the previous fall (not shown).
Spring forage yield following fall grazing by beef cows is shown in Figure 3.
Figure 3. Spring pasture yield following grazing by beef cows at different dates the previous fall.
There is a trend toward increasing spring pasture yields as the date of fall grazing moved from mid-October to mid-December, although this trend was not statistically significant. Areas that were not grazed the previous fall had absolute yields higher than the grazed areas, but the difference again, was not significant.
Fall grazing has been carried out under clipping, sheep grazing, and beef cow grazing. No serious damage to the pastures has been noted under any system to date. Under clipping, hay yields the following spring were highest when the fall clipping was done in November. Under sheep grazing, fall grazing dates from early October to mid-November did not affect first cut silage or pasture yields the following year. Under cattle grazing, a trend towards higher spring yields with late (mid-December) or no fall grazing was noted, although spring yield differences were not significant.
Our experience with sheep grazing in fall (October and November) suggests that when the period of stay on an individual paddock is relatively short (7 days or less), spring vigour and yield are not adversely affected. The value of the manure and urine from the grazing sheep should be a positive factor in maintaining pasture production. Wet soil conditions do not appear to be a great concern when grazing sheep in fall since the pressure exerted by their hooves is relatively low. By grazing at high stock density for short time periods, pasture recovery seems to be good. Given the ability of sheep to graze quite close to the ground, it is important to provide a back fence to prevent the sheep from completely defoliating the residual forage.
Concerns with grazing on wet soil are likely much more important with cattle. Damage to the pasture was not noted in the cow-grazing trial. By not using a back fence the cattle are allowed to spread out and this may help to prevent excessive trampling damage. In any case, there will be occasions on heavy soils when grazing cannot be carried out because of wet conditions. It may be possible to feed cattle in a sacrifice area until the ground has frozen and then allow them to continue grazing.
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