LTRAS Objectives in Focus

The overall objectives of the Long Term Research on Agricultural Systems project (LTRAS) are concisely stated on a sign marking the entrance to the site -"a facility to study sustainability of agricultural systems and their impact on the environment [emphases added]." Most of the current effort at LTRAS is on the first long-term experiment -a 100 year study of annual field crop systems. However, this 72-acre experiment still leaves much of the 300acre site available for additional experiments on the sustainability and environmental impact of agriculture. Thus LTRAS is a facility, not just a single experiment. Each experiment at the site is also expected to serve as a multipurpose facility so long as that does not conflict with its specific goals. For example, atmospheric dust from field operations was not considered in the design of the first experiment, but a proposal to monitor dust (respirable silica) production at the site, in response to cropping system and implement speed, is now being reviewed by the EPA. Similarly, LTRAS is expected to contribute to teaching and extension as well as research. The word sustainability applied to agriculture is subject to at least two distinct types of controversy. People may disagree on the criteria that define sustainability as well as on which agricultural practices best meet their preferred criteria. LTRAS may not contribute much to settling the first type of controversy, but should help with the second. A cropping system is sustainable in an agronomic sense if long-term yield trends increase or remain constant, unless maintaining yields requires ever increasing levels of inputs. However, economic and social sustainability also depend on market conditions (consumer preferences, trade barriers, etc.) and responses of the political system to actual or perceived problems of environmental quality or social and economic equity. Because certain types of environmental impacts may be of considerable public concern without directly affecting the agronomic sustainability of a particular agricultural system, environmental impact was explicitly included in the research mission of LTRAS. For example, low levels of nitrate in groundwater or surface waters may have little direct adverse effect on agriculture, but nitrate contamination of drinking water could indirectly affect agricultural sustainability by leading to new restrictions on the use of synthetic nitrogen fertilizers or animal manure.