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A Win-Win: Building Soil Health While Gaining Yield & Profit

A 375-horsepower crawler tractor pulls a 1,000-gallon tank cart and a 32-foot-wide undercutter implement during primary spring tillage plus nitrogen and sulfur fertilizer injection in May. The undercutter’s narrow­-pitched and overlapping wide V-blades slice beneath the soil at a depth of five inches to completely sever capillary channels and halt the upward movement of liquid water to retain seed-zone water in summer fallow for late-summer planting of winter wheat. Most of the winter wheat residue from the previous crop is retained on the surface to control wind erosion.

Soil health and soil quality are two synonymous terms that are defined interchangeably by the Natural Resources Conservation Service (NRCS) as follows: “Soil health, also referred to as soil quality, is the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans”. As a complicated bioecological system, soil is a living system with an abundance of diverse bacteria, fungi, and other microbes that have significant effects on soil physical and biological properties. Healthy soils provide a healthy physical, chemical, and biological environment for optimal crop growth.

Inherent soil properties that contribute to soil health, such as soil texture, are determined by the natural parent material and the environmental conditions during soil formation, in the absence of human impacts. Soil health is dynamic, rather than static, and can be degraded or improved with time as a result of soil use and management by humans. Soil degradation causes soil organic matter, fertility, structure, and biodiversity to decline and soil acidification to increase. As a result, crop productivity can decrease, crop diseases and weed problems can increase, and environmental quality can suffer.

Building soil health is becoming increasingly important worldwide. Soil imbalances in essential crop nutrients can be addressed by applying fertilizer and organic amendments. And soil chemical, physical, and biological properties can be significantly improved by adopting management practices such as no-tillage or reduced tillage.

A recently published article, Best Management Practices for Summer Fallow in the World’s Driest Rainfed Wheat Region, compares the effects of three fallow management practices on soil water dynamics, wheat stand establishment, grain yield, and economic returns. This research was conducted on two farms in the driest rainfed wheat production region in Washington (WA). At the drier site, results from the 5-year study indicated that late-planted winter wheat on no-tillage fallow was as profitable as on tilled fallow. Additionally, the study found that, at the slightly wetter site, undercutter tillage resulted in equal or greater grain yield compared with both traditional tillage and no-tillage.

Another recently published article, Wheat Farmers Adopt the Undercutter Fallow Method to Reduce Wind Erosion and Sustain Profits, surveyed 47 farmers who had been practicing undercutter tillage for several years. Farms were located in the low-rainfall (< 12 inches annually) zone of east-central WA and north-central Oregon (OR). Interviewers asked farmers to compare the agronomic and economic performance between undercutter tillage and conventional tillage. Results of this survey concluded that, on average, undercutter and conventional tillage systems have equal profitability. However, the undercutter system offers a costless air quality gain and a soil health benefit in terms of reducing wind erosion.


For questions or comments, contact Dr. Douglas L. Young (dlyoung@wsu.edu), Professor, in the School of Economic Sciences, or Dr. Bill Schillinger (William.schillinger@wsu.edu), Professor, in the Department of Crop and Soil Sciences at the Washington State University.

 

Washington State University