Effects of management practices on crop growth and yields may or may not be mediated through crop‐weed interactions. Our objective was to detect and confirm a relationship between the influence of crop management factors on spring barley (Hordeum vulgare L.) and the potential occurrence of crop‐weed interference. A field study was established on a Normandin clay (fine, mixed, frigid Humic Cryaquept) at Normandin in Québec to investigate the effects of crop rotation, tillage (chisel plow, CP; moldboard plow, MP), and nutrient source on midseason aboveground dry weight and seed yield of barley and residual weed populations. Barley‐weed interference was detected using ANOVA, principal components analysis, and analysis of covariance. A reduction in midseason dry weight (36%) and seed yield (59%) of barley in the CP relative to the MP treatment in 1994 was associated with interference from broadleaf plantain (Plantago major L.) and dandelion (Taraxacum officinale Weber in Wiggers). A 20% reduction in midseason dry weight and seed yield with CP tillage in 1995 was associated with interference from volunteer timothy (Phleum pratense L.) and Kentucky bluegrass (Poa pratensis L.). Barley dry weight and seed yield were 29 and 26% greater in the barley‐forage rotation compared with the monoculture in all years except 1995, despite greater weed pressure in the barley‐forage rotation, confirming the benefits of forages to subsequent crops in a rotation. Compared with mineral fertilizer, application of manure resulted in lower dry weight and seed yield for barley; however, this reduction was not associated with weed interference. In contrast to tillage, crop rotation and nutrient source effects on crop variables appeared mediated through factors other than weed interference.
No takes yet. Share an insight, caveat, or question.
Stevenson et al. (1998) studied this question.