Project Overview
Commodities
- Fruits: grapes
Practices
- Education and Training: demonstration, on-farm/ranch research
- Farm Business Management: feasibility study
- Soil Management: soil quality/health
Summary:
The use of biochar in agriculture has been considered to be a “win-win” proposition as it can improve agriculture sustainability by enhancing soil health while mitigating climate change via carbon sequestration in the soil (Filiberto and Gaunt, 2013). Even though biochar has been used in crop production for several decades, it has not been widely adopted due to inconsistent crop yield responses (Jeffery et al, 2011) and to several economic obstacles, including high costs and lack of a consistent return on investment (Bach et al, 2016; Filiberto and Gaunt, 2013). Recent trials on biochar application in vineyards have also shown inconsistent yield responses as well, with several reports of positive yield responses up to 50% during the first four years after application (Genesio et al 2015, Monterey 2021), while others report (Garcia-Jaramillo et al 2021) no positive yield response at all to biochar applications at two vineyard sites the year after application. Before biochar can be more widely adopted in vineyards in general, and in the North Coast of California in particular, there needs to be a better understanding whether biochar application may result in improved yields.
The lack of consistent yield response may be due to several factors including source of biochar feedstock material and processing, initial soil conditions, and crop (Guo, 2020). A recent meta-data analysis (Jefferey et al 2011) of previous biochar trials indicated that positive crop yield responses were more likely to occur on soils with an acidic or neutral pH or on soils with a coarse or medium texture, which suggests that the mechanisms for yield improvements that are the often observed include a liming effect on the soil or an improved water holding capacity with biochar applications. Indeed, biochar amendments will likely improve overall soil health (Guo, 2020) by improving soil physical (reduce bulk density, increase soil porosity and hydraulic conductivity, increase soil aggregate stability and available water holding capacity), chemical (reduce soil acidity, raise soil cation exchange capacity or CEC) and biological (increase available organic carbon and favorable habitat for microbial activity) characteristics of the soil.
Although Biochar amendments to soil alone may not lead to a positive yield increase for some crops, they can improve yield responses from inorganic (NPK) and organic fertilizer (Schulz and Glaser, 2012) due to improved nutrient retention as measured with higher CEC. Combining biochar and compost can lead to a synergistic response in plant growth and productivity (Fischer and Glaser 2012, Schulz and Glaser 2012). Therefore, even if a biochar application alone does not improve crop yield it may provide positive yield response if accompanied by compost addition.
The vineyards in the North Coast may require biochar or compost amendments. A recent trial (Wilson et al 2021) investigating the response of vineyards to compost applications in North Coast showed a positive yield response when rates were greater than 10 tons per acre. The soils in that trial were acidic and characterized as being degraded with very low concentrations of total carbon. The application of compost improved the carbon level significantly, raised CEC and soil pH, which was to be be anticipated with a biochar application. Therefore, there is a potential positive response in soil health and vineyard productivity to applications of biochar alone or in combination with a compost application in North Coast vineyards.
A field trial has been undertaken comparing the application of biochar (at 10 tons per acre) to an application of compost (20 tons per acre) and a combined application of biochar and compost. These applications were made in the fall of 2021. The impacts of these amendments on soil health, vine nutrient status, vine water status, vine yield and fruit composition will be determined during the next two vintages. A cost analysis and a break-even analysis has been completed and the economic threshold for adoption of biochar applications in North Coast vineyards is lower than the threshold for field crops.
Project objectives:
The first objective of this trial was to determine the impact of biochar and compost alone or in combination on soil health parameters in North Coast Soils utilizing the Cornell Comprehensive Assessment of Soil Health (CASH) (Moebius-Clune et al., 2016). The second objective was to determine if there is a potential yield increase due to an application of biochar, compost or a combination of biochar and compost that would justify adoption of these practices in North Coast vineyards.
Objectives of the Trial. The specific objectives of the trial can be summarized as follows.
- To assess the potential for biochar and compost separately or in combination to improve soil health parameters of North Coast Vineyard soils.
- To assess the impact of biochar and compost application on vine nutrition.
- To assess the impact of biochar and compost application on vine growth and yield.
- To assess the potential impact of biochar and compost applications on the grape composition.
- To assess the potential economic return from applications of biochar and compost separately or in combination for vineyards in North Coast.