Effects of Biochar on Soil Nutrient Retention and Microbial Communities in Vegetable Cropping Systems

View the project final report

Commodities

• Vegetables: carrots, peppers

Practices

• Education and Training: demonstration, on-farm/ranch research
• Natural Resources/Environment: carbon sequestration
• Soil Management: soil microbiology, soil quality/health

Biochar is an organic product produced during pyrolysis, which is the burning of biomass in limited oxygen environments. Recently, use of biochar to improve plant and soil health and to increase soil nutrient retention has been attracting interest from growers and researchers alike. Biochar is also gaining interest for its ability to sequester carbon and drawing down atmospheric carbon. In the United States much of the research investigating biochar has been performed in row crops such as corn and soybean. Our intention with this research is to investigate the possible use of biochar and its effect on soil properties and plant health in vegetable cropping systems, especially carrot and pepper cropping production. Fruit and vegetable growers in the North Central region have expressed interest in integrating sustainable soil building practices in their production systems to cut down on nutrient application rates and build soil organic matter. Most growers know or have heard about biochar and its potential soil benefits but are skeptical of its use due to its long lasting effect in the soil.. Fruit and vegetable growers and grower organizations have called for more research into biochar and its potential use in vegetable cropping systems. The objectives of this study are to: 1) study the impact of biochar on soil fertility and nutrient status in- and below the root zone in two soil types (sandy vs. loamy soils, 2) document the effect of biochar on soil biological properties, crop growth and yield. Data will be collected on nutrient leaching, soil microbial population dynamics, and crop growth characteristics, and yield. We will monitor soil temperature and collect soil samples from the root zone and place lysimeters to collect soil leachate for nitrate analysis below the root zone. We believe through this research we will gain a broader understanding of the effects biochar on soil chemical and biological properties in a vegetable production system. Results from this research will be disseminated through grower and national meeting, field days, and research and extension publications. The project will also constitute a grower advisory panel to provide feedback, suggestions, and pass information generated form this project to fellow growers and the grower community.

Soil health and nutrient retention are important aspects of production growers need to consider for long term sustainability of their production systems. Many vegetable producers add organic amendments like compost to their soils to both fertilize and improve soil organic matter. As a short-term outcome, our research will investigate, document, and relay to growers the potential benefit of biochar to improve soil health and nutrient retention. Better grower understanding of biochar and its use in vegetable crop production is a significant short term outcome of this project. An intermediate-term outcome of this research will be to demonstrate an economic and/or environmental justification for adding biochar to soils in vegetable production systems. These economic benefits could be increased crop yield, reduced leaching and better nutrient retention in soil, and a positive long-term impact on soil biology and soil physical characteristics. Other intermediate-term outcomes will include increased adoption of biochar and other sustainable practices by growers based on improved knowledge and comprehensive understanding of how biochar can impact soils in vegetable cropping systems, as well as insight and ideas for future research. A possible long-term outcome would be the development of sustainable uses of biochar for vegetable growers and building up of soils that are productive, resilient, and have the capacity to sustain profitable crop production. Our target audiences consist mainly of small vegetable producers in the north central region of the United States, but the findings could have implications for producers in other temperate regions of the country.