Sustaining winter wheat production using biochar amendments in northeast Oregon

View the project final report

Commodities

• Agronomic: wheat

Practices

• Crop Production: cropping systems
• Education and Training: participatory research
• Natural Resources/Environment: carbon sequestration

Sustaining Winter Wheat Production using Biochar Amendments in Northeast Oregon

Sustainability of winter wheat – summer fallow (WW-SF), the predominant cropping system in inland Pacific Northwest (iPNW) is under threat from soil health deterioration attributable to soil organic carbon (SOC) depletion (>60% of original SOC) and soil acidification (pH<5.5). Growing one crop in two years produces insufficient residues for SOC accretion in both conventional and no-till WW-SF systems. Lowering of soil pH is largely due to continuous use of ammonia-based fertilizer that produce acidity (H⁺) when converting to nitrate, the nutrient that plants readily absorb. However, WW-SF system remains popular and more reliable than annual cropping in low precipitation zones (<12 inches).

We propose to improve soil health and enhance sustainability of WW-SF systems using biochar, charcoal produced from pyrolysis (biomass combustion at low oxygen levels). Biochar is high in organic carbon that is resistant to decomposition and can increase SOC instantly while lowering soil acidity if it is alkaline.

Our objectives are to 1) evaluate the impact of biochar derived from wheat and Douglas Fir on soil physical, chemical, and biological properties including SOC and pH, 2) evaluate how these changes impact wheat productivity, 3) determine if biochar impacts last beyond one year, and 4) share results with growers, extension agents, and crop consultants to facilitate adoption of biochar practices.

Biochar will be applied only once on 5 farms within a 100 mile radius in 2019-20 crop-year and evaluated for at least two crop-years to fulfil above objectives. Results will be disseminated through grower-led field tours, extension publications, newspapers, radio, webinar, and journal articles. Based on our preliminary results, biochar increased grain yield by 12%, translating into gross profits of about $94 million. Biochar carryover effects can improve soil health and sustainability of WW-SF system.

Our preliminary studies [20], showing positive impacts of biochar on SOC and soil pH were obtained from very small experimental plots (5 x 20 ft) that farmers can hardly relate to. For growers to adopt biochar amendment practices, we plan to scale up and evaluate biochar amendments in commercial-sized and commercially managed plots. Five growers, namely Gary Betts, Eric Nelson, Kevin Melville, Virginia Blakelock, and Bob Johns have volunteered to use their land for biochar evaluation (see attached letters of support and cooperation). These growers are interested in improving soil health and sustainable crop production. The main objectives are:

1) To evaluate the impacts of biochar amendments on SOC, pH, active C, mineralizable C and N, bulk density, water holding capacity (WHC), electrical conductivity (EC), cation exchange capacity (CEC), base saturation, N, P, K, Ca, Mg, S, Na, Al, Fe, Mn, and Zn. Available literature indicates that biochar has potential to improve soil physical, chemical, or biological properties and thereby provide promising agronomic effects [14-18].

2) To investigate if soil improvements (Objective 1) due to biochar amendments increase wheat emergence, biomass accumulation, wheat N use efficiency, water use efficiency, and grain yield.

3) To determine if biochar impacts persist beyond the first year. Biochar carbon is resistant to decomposition and is known to last for hundreds of years. We are interested in knowing whether this is also true for associated changes in soil properties and grain yield.

4) To communicate the research and disseminate findings through an effective education and outreach plan.