Arthur Temple College of Forestry and Agriculture

HillFor more than three years, Stephen F. Austin State University’s Arthur Temple College of Forestry and Agriculture doctoral student Jodi Hill, under the direction of Arnold Distinguished Professor Dr. Kenneth Farrish, has conducted research on a particular method of agriculture production that could help restore Texas’ shrinking land base, as well as assist with other environmental factors facing farmers.

Silvopasture is a form of agroforestry that combines the production of trees with an understory component of forage and livestock, Hill said.

“We have changes in climate that are making it difficult for producers to be sustainable and to count on an annual income,” Hill said.

By diversifying their agricultural system, farmers can potentially increase their output on marginally productive soils within the same parcel of land, she said.

To provide the quantitative data needed to fully assess silvopasture’s potential in East Texas, SFA collaborated with the U.S. Department of Agriculture Natural Resources Conservation Service’s East Texas Plant Materials Center to evaluate the quality and yield of seven native and introduced warm-season forages grown under a shade structure to mimic the coverage of a loblolly pine canopy.

As Hill enters the final year of data collection, she said the preliminary results are encouraging.

“We’re showing improved forage quality underneath the partial shade, and in response to that, we’re seeing an improvement of the beef cattle or grazing animal component,” Hill said.

These results are due in large part to the temperature regulation created by the partial shade of the canopy, she said. The shade not only regulates soil temperature, but also provides protection for livestock during seasonal weather extremes.

Consider the common East Texas summer image of cattle huddled underneath the shade of a single tree. Hill said this concentration of livestock in one area degrades soil and forage quality. On the other hand, she said, if the livestock have shade throughout their grazing area, they are more likely to disperse and continue grazing, defusing the stress incurred on the forage’s root systems. This leads to better forage production, as well as beef cattle gains.  

Hill said she also is impressed by the nutritional composition of the forage currently under assessment. The slight reduction seen in forage yield due to the decrease in solar radiation is compensated with a higher concentration of crude protein levels and improved digestibility.

“So for every bite the cow takes, she’s getting more protein per bite,” Hill said. “They’re also experiencing less heat and are moving around and eating more, so you actually have increased gains with your cow because of the increase in forage quality.”

The multiple root systems of the forage and tree species also increase soil structure and health and improve nutrient cycling.

Furthermore, silvopasture mitigates water quality and erosion issues incurred through large-scale agriculture. The forage and trees provide a ground-level, as well as a multi-strata root barrier against nutrients like phosphorus, which can negatively affect water bodies through run-off.

Hill said that although further research investigating the economic return of the method’s use in the region is needed, economic studies conducted elsewhere have been positive.  

“This is really an underutilized method,” Hill said. “Our soils could be so much more productive, and with the increase in human population and the decrease in available land, we’re going to have to increase our food production per land unit area if we want to feed everyone. This (silvopasture) is one way we can do that sustainably and help protect the environment.”


Gamma Grass

Eastern Gamagrass, shown in the photo, is one of seven native and introduced forages investigated by Hill. She said though there has been a slight reduction in yield due to the decrease in solar radiation, concentrations of crude protein levels have increased, and forage digestibility has improved.