Long-term research guides future agricultural development by identifying the effects of crop rotation, variety development, fertilizer use, aerial and surface contamination, and organic amendments on soil productivity and other beneficial soil properties. Comprehension and evaluation of any changes attributed to agronomic practices often requires 10-20 years to identify and quantify. Soil microflora and soil-borne plant pathogens require from 2-8 years in a new cropping sequence or tillage system to reach a stable equilibrium. To this end, long-term experimentation is required to understand interactions among soil, water, and plant factors. This information is essential for both agronomic and agricultural policy decisions.
The Columbia Basin Agricultural Research Center (CBARC) has several ongoing long-term experiments (LTEs). The oldest LTEs in the Pacific Northwest(PNW) and western U.S. are at Pendleton, in the intermediate rainfall zone. The earliest was started in 1931 and the latest in 1997. The Residue Management and Tillage-Fertility experiments are among the oldest replicated research experiments in the western U.S. All have a documented history of crop variety, tillage, date of seeding, and grain yield. The studies are representative of most of the cropping systems in the Pacific Northwest intermountain cereal region that receives less than 18-inches of precipitation.
Agronomic and Policy Implications
Development of sustainable cropping systems relies heavily on understanding of numerous and complex interactions among plant, soil, water, and pest factors. Cropping systems effects on these interactions are often slow and only well-established long-term experiments and their related sets of measurements provide the framework for detecting and understanding the processes involved.
Long-term data is not only important in the formulation of sound crop management decisions but also in agricultural policy formulations. Politicians debate changes in our environment and agriculture and allocate funds for farm programs and related research based on long-term information. It is for this reason that long-term experimentation in the PNW should be supported and funded at reasonable levels to generate relevant information. The PNW has unique weather, soils, and topography. Long-term effects of these characteristics on agricultural sustainability should be documented and presented to law makers for consideration during agricultural policy and farm program formulations.