Allelopathy mulching

The presence of crop residues has been reported to both increase (5, 6) and decrease crop yields ( 7) and not tilling to increase certain difficult to control weeds (8). However, other reports indicate that the presence of certain mulches can reduce the biomass of certain weeds (9-15) and allow for higher crop yields ( 5, 6). Thus, under certain conditions, mulches can suppress certain weed species, but determining the reason(s) presents many logistical problems, especially under field conditions. To determine the cause(s), the physical and chemical (i.e., allelopathy) effects of the mulch and the role of soil disturbance (or the lack of, as would be the case in a no-till system) must be separated. 

The purposes of the studies reported here were to (1) characterize the effects of rye and wheat mulch and soil disturbance on certain weed species, (2) determine if allelopathy was involved,... 

Keywords Allelopathy Cover crops Crop residues Intercropping Mulching Organic farming Weeds... 

Except direct use of allelopathic crops as cover crops, smother crops, and intercrops, applications of allelopathy for weed control include the use of allelopathic residues as an herbicide agent, e.g., pellets flours, water extracts, etc. The most common example of crop residue utilization is application of straw on the soil surface (mulching), e.g., rice straw inhibited germination of field bindweed (Convolvulus arvensis L.), winter wild oat (Avena ludoviciana Durieu), and little-seed canarygrass (Phalaris minor Retz.) (Lee et al. 1991 Tamak et al. 1994 Young et al. 1989). 

Shilling DG, Liebl RA, Worsham AD (1985) Rye (Secale cereale L.) and wheat (Triticum aestivum L.) mulch the suppression of certain broadleaved weeds and the isolation and identification of phytotoxins. In Thompson AC (ed) The chemistry of allelopathy biochemical interactions among plants. ACS symposium series, vol 268. American Chemical Society, Washington, DC, pp 243-271... 

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