Effects of Multicropping Plastic Mulch on Soil Dynamics and Yield in Vegetable Production

The use of plastic mulching for vegetable production systems is a common practice in the southeastern United States. Plastic mulching is known to benefit crop growth and yield. However, plastic mulch application and removal from fields is time-consuming and expensive. To reduce the time and expense of application and removal, growers have double-, triple-, or even quadruple-cropped on a single application of plastic mulch, where a second, third, or fourth crop is grown on the mulch after the preceding crop is harvested. To evaluate the potential detrimental effects of multicropping plastic mulch systems, an on-farm experiment was conducted to quantify the impact of single-, double-, and triple-cropped plastic mulches on soil physical properties and productivity of zucchini and yellow squash. Results indicated that soil penetration resistance increased with the use of double- and triple-cropped plastic mulches compared with single-cropped plastic. No significant soil compaction differences between double- and triple-cropped plastic much at 0 (507.8 kPa) and 20 (577.37 kPa) days after planting (DAP) were measured. Conversely, increasing successive use of plastic mulch increased soil compaction substantially later in the season. The maximum soil penetration resistance in the first 20-cm soil depth with single-, double-, and triple-cropped plastic mulch was 760.29, 1363.49, and 1941.72 kPa, respectively, at 40 DAP. Soil volumetric water content was affected significantly by multicropping plastic. Soil volumetric water content in the top 8 inches of soil decreased by 16% in double-cropped and 9% in triple-cropped plastic mulch at 20 DAP and by 35% in double-cropped and 41% in triple-cropped plastic mulch at 40 DAP compared with single-cropped plastic mulch. The greatest aboveground dry biomass at 40 DAP was observed in single-cropped plastic mulch, averaging 64.5 g and 83.66 g for yellow squash and zucchini, respectively. Single-cropped plastic produced the greatest total yield for yellow squash and zucchini. However, there were no significant differences in total yield between single- and double-cropped plastic for zucchini. This research is a promising start to identifying the point at which the short-term benefits of successive plastic mulch use is offset by reductions in soil quality and crop yield. The findings from this study demonstrate the potential to refine crop rotation and extended plastic mulch lifetime decisions in multicropped vegetable plasticulture systems as a cost-effective and environmentally sound plastic mulching approach.