Building-in Soil and Market Diversity for Greater Farm and Community Wellbeing

Commodities

• Agronomic: clovers, corn
• Vegetables: beans, carrots, greens (leafy)

Practices

• Crop Production: nutrient management
• Farm Business Management: farmers' markets/farm stands
• Natural Resources/Environment: carbon sequestration

Many soils in the Southeastern USA are depleted of soil carbon. Growers over the last decades have been trying to rebuild soil fertility by adding carbon from composts and manures. These carbon-rich amendments (CRA) are often slow to mineralize N, and as such, growers are advised to apply very large amounts to provide the plant with required N. A means to shorten the time N becomes plant available and increase the amount of plant available N provided is needed to reduce costs to growers and increase grower profitability. While CRAs have increased soil carbon, they have also resulted in an imbalance of soil nutrients such as P. This can be a problem when growers are making every effort to be sustainable because an excess of P can lead to environmental problems. In recent years, a locally derived bioinoculant (LEM) has been shown to  increase N mineralization (Ney et al., 2020) and to decrease ammonia volatilization in the first weeks after application. But we do not know what the effect of LEM is on N₂O emissions. The LEM has also been shown to increase plant available P and to increase crop nutrient density (Mahmud et al., 2021).  While growers have interest in LEM, they also have  several questions about the bioinoculant and about how being more sustainable will help them be more profitable. Some of those farmer questions are: will LEM made locally improve plant nutrient availability in their soil? Will consumers with knowledge that these crops are more nutrient dense or more sustainable prefer these products or value them more?  For what crops or value-added products would consumers go to a particular market to purchase?   As scientists, we have additional questions related to agronomic efficiencies of  building soil carbon and to food safety issues associated with management practices that utilize CRAs.  Which CRA crop management system is most efficient in utilizing and retaining nutrients within the crop or soil?  The management systems to study are no CRA in an effort to draw down existing high soil P, and top dressing or incorporating CRA with or without LEM on three annual cropping sequences that grow cash crops or cover crop all year long. Many farmers’ markets are not open all year and many growers and farmers’ markets have are still struggling to find their niche.  As part of this proposal, we will  work with farmers and markets to connect farmers markets together and develop a network of communicating and collaborating farmers’ markets.  Through this effort, we hope to help them find farmers that will do well in their markets and to help farmers and markets find their best niche. Utilizing the LEM bioinoculant can increase nutrient use efficiency of CRA.  In this proposal, we expect to determine if this is the case for farms in both GA and AR and if improved productivity and communication between farmers, farmer markets and consumers will improve quality of life for the grower and the community at large by improving local food security and economics.

1. As all farmers have decided to top dress compost and determine most effective application rate of Locally effective microorganisms (LEM) only one farm (UGA Hort farm will not apply compost.  Growers preferred to apply compost for  segments corn/green bean.  No farms will be applying compost in winter segment (kale, carrot or clover).  In essence this turns the UGA Horticulture Farm into a phosphorus draw down experiment.  Can growers that have an imbalance of N to P soil ratios (applying CRA at plant N requirement and have over applied P) drawdown P with plant uptake while not impacting productivity, nutrient density, and sweetness of corn, greenbean and either kale, carrot, and crimson (Objective 1c). Farms where each objective will be carried out are indicated by the following abbreviations (AK, Arkansas farm; HH, Hearts of Harvest Farm; BC, Buffalo Creek Farm; and UH, UGA Horticulture Organic Farm.

   1. Determine the most effective (productivity, nutrient density, and sweetness) agronomic management system (compost application method with and without LEM) for each individual crop within the annual sequence and total yearly productivity.
      1. Determine which rate of LEM (zero LEM, 1.8 Lm^-2 or 3.6 Lm^-2 ) will improve productivity, nutrient density, and sweetness of corn, greenbean and either kale, Carrot or crimson clover for each segment when compost is top dressed.(AK, HH, BC)
      2. Determine which rate of LEM (zero LEM, 1.8 Lm^-2 or 3.6 Lm^-2 ) will improve productivity, nutrient density, and sweetness of corn, greenbean and either Kale, Carrot or crimson clover for each segment when no compost has been applied (UH).
      3. Determine which cropping sequence corn/greenbean/kale, corn/greenbean/carrot, corn/greenbean/clover draws down the greatest amount of P in the soil. (AK, HH, BC, and UH)
      4. Determine soil health factors plant available N, potential N mineralization, total N, Total P, organic P, plant available P loss on ignition C, permanganate oxidizable carbon, base saturation, and pH. (AK, HH, BC, and UH)
      5. Determine N mineralization rates for each of the farms (AK, HH, BC, and UH) at baseline and after two years of treatments in an incubation study when LEM has been applied at zero LEM, 1.8 Lm^-2 or 3.6 Lm^-2

    

   2. Determine which agronomic management system is most nutrient use efficient and reduces ammonia volatilization and nitrous oxide emissions per mass of crops grown on an annual basis.
      1. Determine nutrient use efficiency (N, P, K, and Ca, Mg, and Zn) on an annual basis and for individual partitions of each of the crops within the annual cropping sequence. (AK, HH, BC, and UH)
      2. Determine if LOI carbon and/or Permanganate carbon influence nutrient use efficiency. (AK, HH, BC, and UH)
      3. Compare rates of ammonia volatilization and nitrous oxide emissions for each cropping sequence corn/greenbean/kale, corn/greenbean/carrot, and corn/greenbean/clover when amended with zero LEM, 1.8 Lm^-2 LEM or 3.6 L/m^-2 LEM from each of the farms when compost is applied and not applied after two years of LEM and crop sequence treatments. (AK, HH, BC, and UH)
      4. Compare N mineralization rates for soil collected from soil collect from each of the farms (AK, HH, BC, and UH) at baseline and after two years of treatments in an incubation study when LEM has been applied at zero LEM, 1.8 Lm^-2 LEM or 3.6 Lm^-2 LEM
   3. Determine effect of agronomic management system on soil biological diversity and presence or absence of human pathogens related to food safety.
   4. Develop and build connectivity of farmers, farmers markets and consumers to identify potential value-added products, consumer preferences, and markets interested.
   5. Develop a series of workshops on making LEM, fertigation, building and connecting with farmer’s markets, to improve local year-round food access.