Western PA Nitrogen Trial- What We Learned from Second Harvest

In terms of yield, to say the second cutting was inconsistent would be an understatement. Depending on the treatment, the plots produce between 400 and 1,400 lbs. of hay per acre. Control plots were on the lower end, while ESN and urea-treated plots were on the higher side. What can be interpreted from this?  A better fertility program on cool-season grasses will provide better opportunities for production during periods of high heat and drought. Let's dig into this a little more.

Weather

Between the first and second harvests (May 20 and July 15), this area of Washington County received 2.25" of rain. This area also had about 1,207 GGD, about 20% warmer than usual. Considering these temperatures and the amount of precipitation, it is typical for cool-season grasses like fescue and orchardgrass to slow down and become dormant; this is often called the summer slump. However, the yield was considerably different when we compared the control and split-applied urea plots. Table 1 shows that the control average was 0.3 tons per acre of 15% moisture hay, while the split-applied urea average was 0.7 tons per acre of 15% moisture hay. This indicates that adding nitrogen, even in drought and stress, is not always wasted and can improve forage quantity.

Quality

The control plots' average crude protein and RFV values were 9.9% and 106, respectively. The average value of crude protein and RFV for the ESN and urea were 12.8% and 110, respectively. What does this tell us? First, speciation difference in the plots. Images show the dramatic difference between clover and orchardgrass in the ESN and urea-treated plot, compared to the plantain and weed-dominated control plot. Second, protein is nitrogen. This may be an oversimplification, but plant protein will be reduced if soil and available N are lacking. This is apparent in these samples. In the control, where no N was applied, protein is 9.9%. However, as the ESN is still slowly released, it provides the N needed to increase the protein content in the grass.

Economics

Most research or fact sheets related to cutting grass hay in a drought situation recommend cutting only if it is cost-effective. But how do we know what is cost-effective? Quite a few factors influence this decision, and ultimately, it is something that all producers will have to decide on their own. In this case, we chose to rotary mow the plot rather than harvest for hay. The plots were rotary mowed at a height of 5" to clip the tops of weeds and release new tillers. With the combination of rotary mowing and little top growth, there is very little remaining residue that will cause issues in the next harvest.

I will explain how we came to this decision. Pricing can be considered two ways: price per bale or per acre. Either way, the more bales produced, the higher the cost, but the less the price per ton of hay produced. For this project, we used price-per-acre rates. Based on custom rates, in the mid-Atlantic, it costs an average of $55 an acre to mow, ted, rake, and round bale (approximately 600 lbs. or 3 bales per ton). The control produced 0.2 tons per acre of hay or less than a bale acre. Productions for this are $275 a ton to just harvest and bale. For the split application of urea, production was 0.7 tons per acre of hay, or two bales per acre, with a production cost of $98 a ton, which includes the additional fertilizer cost. We also considered the amount of nutrients removed in the harvest that may be returned to the soil during decomposition. Lastly, we assessed the field's total production, not just the plot area. It would have been economic if the entire 3-acre field yielded two bales an acre. However, there was only about ¼ an acre yielding this high, while the remaining 2.75 acres yielded less than a bale an acre.

The argument could be made that any hay is better than no hay, and our favorite saying, "It eats better than snowballs," but is that true? Based on the hay auction in New Holland, PA, good quality prairie/ meadow grass was sold for $190-250 a ton. Good quality has a crude protein of 9-13% for reference. As shown in Table 1, this is equal to or better than the quality of the control, with the potential of $100 less a ton. Understand that shipping and other fees are involved, but this is something to consider.

What's next?

As difficult as this summer has been, it has provided a good opportunity to see how different fertilized forages will respond to conditions compared to unfertilized ones. We will continue to monitor and assess the forages going into September. We will take third-cutting samples later in the year before running the final analysis of economics and statistics.

If you want more context on this article, please read Western Pennsylvania Nitrogen Trial on Grass Hay and Western PA Nitrogen Trial- First Harvest.  Two educational events will also be held at Flat Stone Lick Farm to discuss this work and its implications. One will be an all-day Beef Cattle and Grazing Management Workshop (click to register), and the other will be an evening meeting reviewing forage fertility, alfalfa, and summer annual management. The Washington County Conservation District sponsors the evening event, which will be from 6-8 on Tuesday, September 25. Please Call the Conservation District at 724-705-7098.

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Special thanks to the Washington County Conservation District Staff and their Board. Also, thank you to the Midla's and Flat Stone Lick Farm for hosting the trial.