Research Update: Effect of Soil Fertility on Triticale Yield and Quality

Many producers recognize the value of winter forages, such as triticale, as a high-yielding and high quality forage for feeding livestock. The yield potential for winter forages is largely based on planting date and fall nitrogen availability; these two critical factors determine the number of fall tillers, which sets the yield potential for the following spring. Winter forages like triticale can also serve as a high quality forage source and can be a good source of protein, potentially making them a more economical alternative to other feed ingredients such as soybean meal for meeting ration protein needs.

It has been well established that nitrogen fertility can influence forage protein concentrations, but nutrient management regulations can limit nitrogen application rates due to the potential for nutrient leaching and runoff. Although this concern is valid, research from other states and preliminary research by our team in Maryland using higher nitrogen rates, has shown promise that triticale can take up additional nitrogen without increasing leaching losses.

The objectives of this study are to investigate the effect of increasing nitrogen fertility rates with and without sulfur on triticale forage to determine 1) the effects on forage yield, 2) if using a higher fertilization rate will the increase the value of the forage through increased protein concentrations, and 3) the resulting implications of incorporating that forage into the ration for lactating dairy cattle. The research will include an initial field trial to assess soil nutrient status, forage quality, and forage yield under varying nitrogen and sulfur fertility treatments. This will be followed by a feeding study to assess dairy cow milk production and performance when fed the resulting forage, and then finally, an economic analysis to assess the effectiveness of the system.

“...additional nitrogen fertility can influence forage protein concentrations and triticale can take up additional nitrogen without increasing leaching losses.“

Methods

In the fall of 2020, triticale was established in replicated fields at both the Central (Clarksville) and Western (Keedysville) Maryland Research and Education Centers. Fertility treatments included increasing levels of nitrogen with and without the addition of sulfur (Table 1). Fertility treatments were applied in March 2021, and soil nitrate samples were collected before and after fertilizer application to test for potential losses from nitrate leaching. Triticale plots were harvested when forage reached the boot stage on April 26 and April 27 at Keedysville and Clarksville, respectively. At both locations, plots were harvested mechanically using a forage harvester (Figure 1). Harvested forage was weighed for yield determination and samples were taken for forage quality analysis.

Results

Forage yields for the fertility treatments that included nitrogen were similar but were increased compared to the CON and SUL control treatments (Figure 2). This pattern held true at each location, with yields averaging 2.0 T/A at Clarksville and 2.7 T/A at Keedysville.

At both locations, forage crude protein (CP) concentrations were lowest for the CON and SUL treatments (average 8.7% CP) and increased with increasing fertility, with the NHIGH and NSHIGH treatments containing the greatest amount of protein (average 18% CP; Figure 3). Across all fertility treatments, the addition of sulfur did not further increase forage CP concentrations, likely because fields were not limiting in sulfur prior to this experiment.

Neutral detergent fiber concentrations did not differ between fertility treatments at either location, averaging 51% across all locations and treatments. Similarly, total digestible nutrients did not differ between fertility treatments at either location, averaging 65% across all locations and treatments.

At both locations, nitrate concentrations in soil samples taken both pre-and post-fertilizer application remained minimal, indicating no additional nitrogen losses due to leaching.

Conclusions

Overall, these preliminary results indicate that additional nitrogen fertility can influence forage protein concentrations, and that triticale can take up additional nitrogen without increasing leaching losses.

Future Plans

At the Clarksville location, triticale with similar fertility treatments (low, moderate, and high nitrogen) was also planted on a larger field scale, harvested, and ensiled using Ag bags. This forage is currently being used for a feeding study happening this fall. Dietary treatments include triticale silage grown under low, moderate, and high nitrogen fertility compared to a control ration made up of a corn silage/alfalfa base; for the triticale dietary treatments, triticale silage is being included in the ration at 30% DM. The goal of this feeding study is to test the effects of triticale incorporation on feed intake, milk production, milk components, and health parameters when included in the diet of lactating dairy cows.

Following this feeding study, an economic comparison of the cost of meeting ration protein needs through increased soil fertility (i.e. increased triticale protein concentrations) versus through traditional sources such as soybean meal or alfalfa will also be completed. The entire study will also be repeated with similar methodology in 2022.