- Crop Production: conservation tillage, cover crops, no-till
Stony Creek Colors sells clean and safe natural dyes to the textile and fashion industries, allowing its customers to offer environmentally conscious premium products. Through its flagship natural indigo product, the company has developed and proven a complete agricultural supply chain to replace synthetic dyes with plant-based drop-in solutions. Innovations across the complete crop and processing value chain allow Stony Creek to sustainably produce plant-based dyes with full transparency and authenticity, meeting the technical performance and volume requirements of textile mills and fashion brands worldwide without compromising product integrity. In 2015, Stony Creek Colors began partnering with a network of local farmers to plant and farm this alternative crop, and the company has relied on their collective knowledge and expertise to ensure a high-quality product coming from the field into the processing facility on a daily basis. Currently, indigo is grown as a transplant crop using greenhouse, planting, and cultivation assets which exist within this network of largely tobacco farmers and allow for an easy transition between tobacco and indigo farming. As such, the company’s indigo is grown as a transplant crop in a method similar to tobacco production, where seed is germinated in a greenhouse or float bed, and then transplanted in the field via mechanical transplanter. Since there are no listed herbicides for indigo, weed control has initially been managed through pre-planting tillage and mechanical cultivation of the crop during the growing season, especially in early summer prior to crop canopy closure. This manual cultivation process takes time, equipment, and fuel away from the farmer during the busy spring and summer season. To combat this problem, Stony Creek Colors looked to progressive farmers in the area and decided to explore strip-till and no-till transplanting for its indigo crops. In 2016, Stony Creek Colors had expanded its field production to roughly 100 acres, planted primarily in varieties of Japanese indigo (Persicaria tinctoria), and the SARE project was written with this in mind. During the subsequent seasons, one of Stony Creek Colors minor tropical crop varieties (Indigofera suffruticosa) emerged as the higher yielding indigo dye crop for the the northern Middle Tennessee area, and the company ultimately made a near-full crop change to tropical indigo by the 2019 season. For this reason, Stony Creek modified its strip-till / no-till in-field research from Japanese to tropical indigo and ultimately found success in doing so. Over the course of two seasons of in-field research, comparing conventional-till, strip-till, and no-till crops of tropical indigo, Stony Creek Colors was able to observe increased weed control in the strip-till and no-till fields with lower inputs of labor or herbicide with no observable loss in plant height, biomass, or indigo dye yield. Ultimately, as a result of the research undertaken in this SARE project, Stony Creek Colors has been able to recommend strip-till and no-till as agricultural best practices for our indigo farmers, resulting in 140 acres – over a third of the 2019 crop – being planted this season using strip-till and no-till transplanting.
The goal of this project was to identify and validate methods for transplant-based production of indigo crop which are low impact with regard to chemical addition and soil runoff and which are consistent with the sustainable production values of Stony Creek Colors. Particularly, the evaluation of strip-till / no-till methods and cover crop selection for Japanese, and later tropical, indigo production was evaluated to determine efficacy of weed control and impacts on the indigo plants with regard to yield and growth rate. The key objective and deliverable for this project was an evaluation and recommendation to farmers for optimum indigo transplant methods including cover crop selection, field preparation, plant density, and weed suppression methods without significant use of chemical amendments or soil degradation.