Educating Farmers on Accurate Fertility Testing and Management in Urban and Small Scale High Organic Matter Systems

Commodities

• Vegetables: cabbages, greens (lettuces)

Practices

• Crop Production: application rate management, nutrient cycling, nutrient management
• Education and Training: demonstration
• Soil Management: soil analysis
• Sustainable Communities: urban agriculture

Project focus

Routine soil fertility (RSF) tests are designed for mineral soils with up to 20% organic matter (OM). RSF assesses long-term fertility conditions. Above 20% OM, RSF may incorrectly estimate fertility. Increasingly, Northeast land-grant university (LGU) soil labs are receiving growing materials submitted for RSF that exceed this threshold. High OM samples include soilless media and organic matter/soil blends used to fill raised beds as well as field samples of soils heavily amended with compost and mulch.Raised beds are important for land-limited urban farmers that experience lead and arsenic contaminated soils. Compost and mulch-heavy field soils are common on organic and no-till farms. 

When OM exceeds 20%, a saturated media extract (SME) test is recommended. SME assesses short-term fertility by measuring only water-soluble nutrients. SME and associated recommendations were originally developed for floriculture in controlled growing environments. SME is appropriate for high OM materials and some growers have adopted its use, but recommendations for outdoor operations have not been developed, leaving many farmers behind. Additionally, excessive rainfall can flush water-soluble nutrients from high OM systems, creating challenges with accurate sampling and interpretation of results.

Excess soil OM accumulation (>10%) also creates management challenges in addition to fertility sampling and recommendations. Growers are reaching levels of soil OM associated with yield decline, nutrient leaching, and management challenges with irrigation, drainage, and water retention. Labs are challenged to provide farmers with one-on-one education and custom recommendations as the number of these samples and affected farmers increase. Educators are also challenged because educational resources and recommendations are inconsistent and sparse.

Solution and approach

To address these challenges, this project brings together regional LGU labs, Extension educators, and research faculty. Farmers are educated about sampling, nutrient testing, and fertility management in high OM and raised bed systems through workshops, seven on-farm demonstrations in urban areas, fact sheets, and lab recommendations. Farmers participate in hands-on, applied learning. Farmers increase their knowledge of soil fertility, health, and functioning, developing and applying the skills to make nutrient management plans and strategically manage OM in their operations. SME sampling and fertility management recommendations based on lab test results are refined and adopted by participating labs.

Research investigates raised bed fill materials, including rock dust amendments, and nutrient cycling dynamics in high OM systems. Research is conducted in controlled greenhouse environments and in-field on University research farms. Research results from year 1 trials are incorporated into demonstrations deployed on seven farms in year 2. The demonstrations pair established knowledge and best practices with novel results, engaging stakeholders in the scientific process and enabling farmers to give input on emerging work.

100 farmers will adopt at least one best management practice (optimized fertility testing, fertility applications, material use, etc.) across 500 raised beds and 50 acres of high organic matter fields. 75 farmers will save $500 each by requesting appropriate soil analyses and 20 farmers will report they are better able to navigate threats to operations and/or strengthen local networks.