Influence of herbicide applications on the decomposition, microbial biomass, and microbial activity of pasture shoot and root litter

摘要

Abstract Pure swards of each of four pasture species (Lolium perenne L., Trifolium repens L., Senecio jacobaea L., and Carduus nutans L.) were established in glasshouse conditions and subjected to one of three treatments: spraying with 2,4‐D/picloram mix; spraying with glyphosate; or unsprayed. After the sprayed swards died, all above‐ground and below‐ground tissue was harvested, air‐dried, and placed in nylon mesh litter‐bags which were positioned in the field. Decomposition, microbial basal respiration, and substrate‐induced respiration (proportionally related to the glucose‐responsive microbial biomass) of this litter was then monitored over 338 days. Both herbicide treatments inhibited decomposition of T. repens and L. perenne shoot tissue and C. nutans root tissue, but stimulated that of C. nutans shoot tissue, indicating that herbicides may influence decomposition of different species in different ways; the possible reasons for this are discussed. However, the rapid decomposition of most of the tiss...