Measuring Interference from Midseason Tall Morningglory (Ipomoea purpurea) to Develop a Model for Teaching Weed Seedbank Effects on Chile Pepper

Abstract

Tactics that target seedbanks are important components of weed management systems; however, such tactics can be difficult to adopt because consequences of seedbank reduction are often unclear. This study developed model-based software to provide insights on the economic outcomes, in the context of chile pepper production, of additions to tall morningglory seedbanks. Data for the model were derived from this and previous studies. In this study, field experiments were conducted to determine chile pepper yield and harvest efficiency responses to mid-season tall morningglory infestations. The experimental treatments were factorial combinations of herbicide (pendimethalin-treated, nontreated) and tall morningglory density (0, 4, 8, 12, 16, 20 plants 10-m row–1). Treatments were installed 9.5 weeks after crop seeding. Data collected included fresh weight of marketable chile peppers and time required for one individual to harvest 10-m of crop row, which was used to calculate the amount of chile pepper harvested in 1 min (harvest efficiency). Results indicated that crop yield was not influenced by tall morningglory density, pendimethalin treatment and interactions between tall morningglory density and pendimethalin. Harvest efficiency was influenced by tall morningglory density but was not influenced by herbicide treatment or interactions between herbicide treatment and tall morningglory density. Each additional tall morningglory plant decreased the amount of chile pepper harvested in 1 min by 9.7 g. The results of this and previous studies were used to develop model-based software that presents tall morningglory seedbank density effects on: (1) tall morningglory seedling densities after pendimethalin, (2) time requirements for hand-hoeing after pendimethalin, and (3) time requirements for hand-harvesting to acquire yield goals. The model-based software is intended to be used in the instruction of weed seedbank management strategies. By presenting seedbank density effects on weed control outcomes and crop production expenses, the model-based software might promote adoption of seedbank reduction strategies.