Utility Arborists Association
What does ROW soil have to do with anything?
Right-of-Way Vegetation Management: Developed. Fine-tuned. Firmly Established.
But what about the SOIL?
Should we even ask that question (with all its associated, complex data) when ROW VM is already so thoroughly cultivated? If “firmly established” also means firmly compacted, it may be a good question.
When speaking of soil, compaction equals desolation. In today’s world in which people increasingly understand the value of thriving ecosystems, utility companies also strive to become good corporate citizens and to encourage healthy environments. If the current management practices are leaving vast expanses of “green area” dead, or even with problematic weed explosions or unhealthy conditions, then inquiring about soil health could lead to better management practices that enable greater work efficiency and environmental consideration. Huge potential may lay in further developing cultural and biological IVM BMPs, where the focus is on ROW functionality, as well as healthy land.
Our VM practices evolved from cutting most ROW vegetation by hand, to applying herbicides to unwanted vegetation, to creating the Integrated Vegetation Management (IVM) framework. To handle developing philosophies and the addition of new information and techniques, Best Management Practices were born. Today, a Utility can become certified by the Right of Way Stewardship Council by applying the latest prescribed Best Management Practices (BMP) to their ROWs.
BMPs currently divide ROW vegetation work methods into four main categories: Mechanical, Chemical, Cultural, and Biological. Mechanical and chemical methods concentrate on removing or eradicating undesirable ROW vegetation. A lot of research has gone into these methods, resulting in a vast array of tools and techniques. The less-developed BMP methods are cultural and biological. Both have a tendency to focus on and encourage desirable vegetation. Cultural methods modify habitats to discourage incompatible vegetation and to establish and manage desirable plant communities. Biological control methods focus on (maintaining) desirable vegetation to make it difficult for undesirable vegetation to establish.
What, then, does this talk of BMPs have to do with ROW soil? Our interest is whether most of our ROWs have the proper conditions to let desirable vegetation flourish. Beneath the surface of the question may be our answer: SOIL. Even the USDA and NRCS have acknowledged the importance of this factor by declaring 2015 to be “The Year of Soil”, uncovering its power potential. Desirable vegetation equals efficient work. But could it be that many of our ROWs do not have desirable vegetation because their soils suffer from unfavorable conditions, such as compaction?
Compacted soil limits aeration significantly, meaning a fresh supply of oxygen is not available to certain soil microorganisms which depend on it for their survival. These beneficial aerobic soil organisms, i.e., bacteria, nematodes, flagellates, amoeba, micro-arthropods and other organisms (See USDA, NRCS website on the Soil Food Web), are microscopic and supply nutrients to plants roots; in return, the plant provides sugar water (a product of photosynthesis). However, if there is a lack of oxygen due to soil compaction, the plants' sugar water (called exudates) will ferment and produce alcohol, killing the cellular tissues of plant roots. The practical effect is that only shallow rooting plants are able to grow, and these are usually the fast growing weeds or pioneer species. These are the plants which invest a lot of their energy above ground, in green mass, and in high-volume seed production, and little energy is dedicated to root development. These types have a survival strategy designed to grow tall quickly and to disperse many seeds, and therefore are usually listed as undesirable ROW vegetation (especially on gas pipe line ROWs).
In addition to limited oxygen, compacted soil signifies a breakdown of the nutrient channels that healthy soil needs. The result is that they usually carry high levels of bacteria and very little organic matter. One remedy is to add organic matter to compacted soils because it carries many nutrients that plants like and acts like a sponge to absorb water and oxygen. In addition to organic matter, introducing earthworms and fungi strands provide oxygen pathways in the soil. Healthy soils have the right balance of beneficial bacteria, microorganisms, organic matter, and fungi strands.
To take it a step further, certain soil scientists (i.e, Dr. Eldor Paul, Dr. David Coleman, Dr. Elaine Ingham) made it their life's work to observe natural succession and study the kinds of vegetation that grow in various types of soil. Some of them looked at early and late succession plants and collected data on the bacteria-to-fungi ratio of the soils in which they grew – they found that early successional plants seem to thrive in bacteria dominated soils, while late successional plants do better in fungi dominated soils. They mapped out a number of different plant types and species and placed them on a scale from very bacterial to very fungal dominant soils. The soil research is enticing. It suggests that a general knowledge and understanding of soil on our ROW sites would increase their desirable vegetation. To gain the practical knowledge, tools, and techniques, we could glimpse into unconventional agriculture. Unconventional agricultural practices have contributed significantly to reintroducing healthy top soils, favoring cultivation practices in which organic matter is added to the soil instead of removed. For example, holistic “mob grazing” is promoted by Allan Savory. Savory designed a grazing technique mimicking natural herd grazing behavior that benefits prairie and other deep rooted grass land vegetation – a type of vegetation some ROWs try to achieve. His practice of holistic grazing is becoming increasingly popular with contract grazing companies who are constantly fine tuning their contract structures, education, and knowledge. We could also learn from certain permaculture techniques. Permaculture is a practice which mainly works with perennials.
Mark Sheppard is a known permaculture advocate who runs a profitable permaculture farm. His aim is to demonstrate the success of his STUN technique (Sheer Total Utter Neglect.) to grow specific perennials. During the creation of BMPs, it is common to draw from other industries' knowledge and expertise. In the spirit of advancement, NiSource launched a gas pipe line ROW soil research project in the Spring of 2015, North of Pittsburgh, near Emlenton, Pennsylvania. On several ROW test plots, soil compaction was measured using a soil penetrometer and its microbiology was analyzed under a microscope. So far, bacteria dominated and compacted soils have been the norm. Methods to bring back a wider variety of soil microbiology as well as their “housing structure” organic matter are being applied to these test plots. These methods required NiSource to work with VM contractors willing to receive additional training and to purchase associated equipment. The immediate goal is to create favorable soil conditions to help desirable vegetation establish. It is too early to draw positive or negative conclusions; however, additional challenges have already been identified. ROWs, as opposed to agricultural fields, are cultivated and worked sporadically. Another consideration is the linear nature of ROWs: they embody many different soil types, topographies, (micro) climates, and are subject to various sunlight exposure – all of which must be considered when working with soil.
As with any research project, a good question will open the door to additional questions that prepare us better. How can we minimize soil compaction during ROW construction? What cost effective practices are available to enhance ROW soils? Are current ROW practices damaging to healthy soil life? How can we improve cooperation between ROW construction and vegetation management maintenance departments to reduce vegetation concerns? NiSource is currently creating a corporate-wide conservation framework, incorporating responsible ROW vegetation management practices to establish desirable plant communities paying attention to ROW soil. We believe that encouraging and focusing on desirable ROW vegetation should take the health of soils into consideration.