Rory Lewandowski, Extension Educator, Athens County and Buckeye Hills EERA
It’s time for my annual reminder that early to mid-August is a good time to set aside some pasture paddocks to stockpile growth for winter grazing. On many farms the actual implementation of stockpiling can be traced back to management decisions in June and July as pasture paddock rotations were adjusted to set up this practice.
Tall fescue is the forage of choice to stockpile for winter grazing. Compared to other cool season grass species tall fescue produces more fall growth and does the best job of maintaining forage quality throughout the winter period. Tall fescue also accumulates high levels of non-structural carbohydrates and has improved palatability when grown under cool as compared to warm or hot weather conditions. In addition, we have a high percentage of endophyte infected fescue in our area. The toxic alkaloids associated with infected fescue reduce forage palatability and depress animal performance over the summer months. However, research done in Missouri has shown that those alkaloids decrease significantly by about mid-January in stockpiled fescue. This provides another reason why fescue should be stockpiled and used for winter grazing rather than trying to force cattle to graze it during August and September.
After the initial decision is made to stockpile, the next decision is whether or not nitrogen fertilizer should be applied. The application of nitrogen will increase the dry matter (DM) yield of stockpiled fescue as well as the quality of the stockpiled forage. If a paddock has a uniform 30% legume percentage it may not be necessary to add supplemental nitrogen. If legumes are not uniform throughout the field or are less than 30% of the stand then supplemental nitrogen can be beneficial.
Field trials done in southeastern Ohio compared the effect of nitrogen fertilization versus no nitrogen fertilization on stockpiled fescue yield. In that work, 46 lbs of nitrogen/acre applied on August 20 produced an additional 1400 lbs of DM per acre compared to a stockpiled plot with no nitrogen application. In that same study, when nitrogen application was delayed a month to September 20 there was still a yield response, but it was decreased with the fertilized plot accumulating an additional 980 lbs of DM/acre compared to the unfertilized plot. A 3-year study in Kentucky showed a yield increase, on average, of an additional 1100 lbs of DM/acre when stockpiled fescue was fertilized with 46 lbs/acre of nitrogen in mid-August compared to stockpiled fescue without any additional nitrogen fertilizer.
With regard to forage quality, crude protein (CP) content is increased when nitrogen is applied to stockpiled forage. In southeastern Ohio field trials the effect of date of nitrogen fertilization was examined. Stockpiled plots received 46 lbs of nitrogen/acre on either August 20 or September 24. The plots receiving nitrogen in August averaged over 14% CP on November 3 and over 10% CP on February 11. The plots receiving nitrogen in September averaged over 17% CP on November 3 and close to 12% CP on February 11.
On some farms, especially those where the stocking rate is closely matched to the pasture acreage, stockpiling paddocks for winter grazing may be linked to a decision to feed hay during the stockpiling period. This may end up being a wise decision for a couple of reasons. First, it may be the best use of low quality hay. Second, it leverages the use of low quality hay for the production and use of higher quality stockpiled forage. This stockpiled forage is more likely to match up with the nutrient requirements of pregnant cows during the winter than low quality first cutting hay.
The decision to stockpile is not without risk. We have experienced dry falls the last several years. Stockpiling is dependent upon some rainfall for grass growth. Up to this point in late July, we have continued to get timely rains and soil moisture levels are good in many pastures. Grazing and clipping management decisions can enhance the rainfall we have received and conserve soil moisture. Those paddocks that have been managed to insure that there is always at least a 4 inch residue are more likely to allow all rainfall to penetrate into the soil profile and to provide an environment where less soil moisture is lost from evaporation. Clip or graze high on those paddocks that will be stockpiled. There is nothing wrong with clipping off any seedheads and leaving a 5 to 6 inch residue to begin stockpiling. Think of it as a risk management decision.