Summarized with Permission of International Allelopathy Foundation

A number of studies have shown that inhibitory activity of residues in the field decline over time (Glass 1976 Bhowmik and Doll 1983 Einhellig 1987 Blum et al. 1992 Yenish et al. 1995 Bonanomi et al. 2006). We found the following  

3 Plant-Plant Allelopathic Interaction. Phase 11 Field/Laboratory Experiments 

Blum et al. (1997) found that soil pH values of no-till systems were not significantly modified by the presence of glyphosate-desiccated rye, wheat, crimson clover and subterranean clover cover crops. In this field study a substantial portion (estimated to be roughly 50%) of the cover crop residues was located on the soil surface and thus only had an indirect impact on soil pH by way of leachates generated 

3 Plant-Plant AUelopathic Interaction. Phase II Field/Laboratory Experiments 100 

Adding Hoagland s solution in addition to sunflower tissues eliminated the inhibitory effects of sunflower tissues on pigweed seedling biomass. Thus, it would appear that nutrients in plant tissues mixed into soil might modify plant-plant allelo-pathic interactions differently than nutrients/fertilizer directly applied to surface of the soil or mixed into the soil. The functional role of nutrients in small grain and clover cover crop residues is presently not known. 

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Determine the Respective Importance of Shoot and Root Residues in Regulating Early Broadleaf Weed Seedling Emergence (Blum et al. (2002) Summarized with Permission of International Allelopathy Foundation)... 

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