Tuesday, September 24, 2013

A vital tool for managing Americas largest crop

If you ask anyone what the largest crop in America is, you would get quite a varied assortment of answers; corn, alfalfa, wheat, soybeans - but in fact - the largest crop in America is turfgrass.  In fact the amount of land under cultivation with turf grass is more than three times the next most common crop. There are approximately 128,000 square kilometers of cultivated turfgrass in the United States, while the next largest crop is 43,000 square kilometers of corn.  Massachusetts has approximately 4,183 square kilometers of turfgrass under various levels of management.  

My initial reaction was one of shock with quickly morphed to concern. That is quite a lot of land to be managed or potentially mismanaged.   That amount of turfgrass makes quite a large environmental impact. It naturally requires quite a large amount of water and could account for quite a lot of chemical input to the ecosystem.  However, once again, conventional wisdom proves to be neither.  But more on that later.

Data can save the day.

With such a turfgrass being such a major component of our nations landscape, such a significant agricultural industry, and such a vital cover crop - there can be little doubt that the government plays a vital role. This is role is most exemplified by the county extension services, agricultural schools with turfgrass science programs, and government backed academic research efforts.  If you have a project, such as a school or park, which may involve large areas of turfgrass - all of the above listed resources can be extremely helpful. 

 One however, can go along way to determining the success or failure of a project.  That is the NTEP program.  NTEP stands for the National Turf Grass Evaluation Program.  The NTEP program is a University based turfgrass evaluation program. It evaluates seventeen turfgrass species in as many as forty U.S. states and six Canadian provinces.   

Turfgrass is evaluated and cultivars are cross compared for such traits as disease resistance, drought tolerance, traffic durability, plant density, color, heat and cold tolerance, and quality.  This data can be used to make environmentally sound decisions by choosing the cultivar that most meets a projects particular needs.   You can use this data, for instance, to choose a type of turf that might thrive without irrigation,  or perhaps might fare better in a drought prone area, or, may fare better without pesticides.  You may have a project that will likely see severe compaction or traffic. The selection of the proper cultivar  could prevent the stand of turf grass from deteriorating and thus allowing weeds to propagate or surface erosion to occur.  One caution is due.  Too often people will look at NTEP data and just assume that the one that scores the highest is the "best".  This is not always the case. What you need to do is to carefully asses your needs, prioritize them, and then choose the cultivar or blend of cultivars that will meet as many of your concerns as possible. 

It is remarkable to me how many architects, designers, and even landscape architects are unaware of this resource. Too often a bid will spec "turfgrass" , "sod", or,  "kentucky blue grass blend" or some other generic terminology.  It makes no sense to design a water efficient landscape and not spec an appropriate turfgrass cultivar.  It makes no sense to design a beautiful landscape, and have it wash into a nearby stream. It makes no sense to build a state of the art recycled water system and have the grass die due to salt intolerance. A poor choice at the design phase leads to, at best, intensive maintenance issues, and at worst, a failed design element.  In any event, both outcomes mean a higher environmental cost.

Why not just eliminate it?

At this point you may be thinking, "why not minimize the turf grass and reap the benefits".  This is where we get back to conventional wisdom being not quite so wise.  When the International Green Building Code was being developed, just such a debate occurred.  The idea, based on the conventional wisdom, was put forth that to be "green" turf area should be limited.  It seemed to make sense, less turf means less water use, less fertilizer and nutrient issues, less pesticides. The end result was that the conventional wisdom did not quite pan out and the turf limitation was removed with the consent of all parties including the EPA.  It turns out that the research demonstrated that health turf grass actually reduced pollutant loads  in surface waters. Healthy turf grass, even one that was regularly treated with fertilizers, pesticides, and herbicides was actually significantly better for surface water quality than even untreated, poorly maintained,  grass.  The ecosystem services such as nitrogen capture, carbon sequestration, air and water filtration, oxygen generation, heat island mitigation, habitat, mico flora and fauna, and storm water interception and groundwater recharge were all net positives. An area of turfgrass 50 feet square generates enough oxygen to meet the needs of a family of four and  an acre can absorb hundreds of pounds of atmospheric Sulfur Dioxide, a primary driver of acid rain. The human centric benefits such as aesthetics, texture, functionality, fire control, erosion control, and ease of maintenance were also positive. The negatives could be addressed and mitigated by Best Management Practices, modern techniques, and proper plant selection.

Kevin Dufour is an Environmental Scientist with Viridis Advisors. He collaborates with Tom Irwin on creating greener greenscapes. The opinions expressed by member bloggers are their own and not necessarily those of the USGBC Massachusetts Chapter.

1 comment:

  1. Kevin Thanks for mentioning the NTEP, in your article. The results of NTEP, is a great tool that can be used to determine the cultivars for different regions. If that is real, these results (NTEP) can also be used by the commercial producers of turfs grass to market the various types of cultivars to their environmentally friendly regions.


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