Urban farmers across Indiana are facing the effects of rising fertilizer, chemical, and energy prices. In this climate, soil health has emerged as a top priority. In a 2023 statewide survey of Indiana urban farmers, 91.6% expressed interest in learning more about improving soil health (n=81), underscoring a strong desire for practical, sustainable strategies that reduce costs and boost productivity. Cover crops and compost application represent two fundamental approaches to improving soil health and fertility. Implementing cover crops and incorporating compost are essential practices for regenerating and maintaining healthy soil ecosystems. Farmers seeking to enhance soil vitality often rely on two primary methods: planting cover crops and applying compost. Soil health can be significantly improved through the integration of cover cropping systems and regular compost applications. hairy vetch, sunn hemp, rye, and mustard, are gaining traction as an alternative or complement to compost. These crops can trap nitrogen, build organic matter, and improve water retention, which are relevant benefits in compacted, nutrient-depleted, and low-organic-matter soils common in urban spaces. However, barriers like limited space, short-term leases, and concerns about short-term yield reduction can make adoption difficult for small-scale growers. When managed properly, composting transforms organic waste like food scraps, straw, and manure into a slow-release soil amendment that boosts organic matter, microbial life, and nutrient retention. However, not all compost is created equal. Overapplication, especially of manure-based compost, can lead to nutrient imbalances, phosphorus buildup, nitrate leaching, and elevated pH, which may reduce yields. Urban farmers are encouraged to test compost for nutrient content and monitor soil health regularly to guide application timing and rates. The Soil to Market project, an ongoing Purdue-led study launched in 2021, is evaluating cover crop and compost combinations at multiple Indiana locations. At the Meigs Purdue Agriculture Center in Lafayette, IN, cover crops alone, particularly sorghum and sunn hemp, did not significantly increase total available phosphorus (P). In contrast, compost treatments, especially high volume (2 yd³), manure-based applications, resulted in statistically significant increases in soil P, with mean values ranging from 280 to 365 mg/kg. These treatments highlight potential effectiveness in improving P availability in nutrient-depleted, urban soils. However, high phosphorus levels in compost treatments highlight the need for careful, adaptive management in sensitive environments, such as near waterways due to the increased risk of P runoff or leaching. Management of application timing, placement, and rates is crucial to maximize benefits while minimizing environmental impacts on urban farms.
