The beneficial use of vesicular–arbuscular mycorrhizae (VAM) in mineral soils is well-documented, but little is known about the effect of soilless mixes on mycorrhizal colonization of roots. Previous research indicates that mycorrhizal colonization is affected by pH, soluble salts, phosphorus levels, cation exchange capacity, percent organic matter, and some peats. No other research has been published, to our knowledge, on the role of commonly used horticultural composts and mycorrhizal establishment. This study examined four different composts for their effect on VAM establishment using onion roots as an indicator. The composts used in the study were vermicompost, spent mushroom compost, yard waste compost, and processed manure fiber. Plant growth parameters, phosphorus (P) levels and rate of desorption, and microbial populations were analyzed in relation to the percent of VAM colonization of the roots. Significant differences were found in percent VAM colonization between composts. The primary factors influencing VAM colonization were the initial levels of P in the blends and the rate and amount of P released. The experiment raised questions about the balance between mineralized P and organic P in composts and their effect on VAM fungal spore germination.
Hard cider is an important and growing part of the U.S. beverage market. Previous research suggests there is an opportunity for growers interested in selling locally grown cider-specific apple (Malus domestica) varieties. However, cider apple growers face production, distribution, and marketing challenges. This article fills a gap in the literature using survey data from four states. We find that growers are interested in expanding cider apple production to supply local craft cider makers, but may be constrained by gaps in current production information, such as how to grow cider varieties. Uncertainty about the regional suitability of different varieties, disease management, and the willingness of cider makers to pay a premium for cider apple production constitute significant concerns. Survey respondents most commonly requested information on horticultural qualities of varieties and disease management. Top marketing needs include the ability to garner premium prices. A regional “terroir” approach to cider marketing holds promise.