Allelopathic Effect of some Crops Residues on Germination and Growth of Four Weed Species

Abstract

This study was conducted in the glasshouse in Biology Depertment College of Sciences Mosul University to study the effect of the crops (wheat, Barley, corn) residues that added to the soil at ratio (10,15%) W:W in seed germination and growth of four weeds includes (Silybum marianum L., Lolium rigidum. L., Sonchus oleraceus L., Panicum Spp.). The results showed inhibition in seed germination and growth of the weeds growing in the soil containing the crops residues compared with the plant (weeds) growing in control soil (with out residues). Also the result showed variation in the crops allelopathic effect on germination and growth of the weeds treated with the crops residues. Moreover, the results show a difference in allelopathic effect of the crops residues, in addition the weed species differ in their response to the effect There is significant difference between the type of residues rather than weed species, it was found that the highest inhibition in seed germination was in (Panicum) seeds affected by corn residues added at ratio 15% which reached up to (44.4), while in the growth of the weeds, the highest reduction in shoot length recorded (78.4) noticed in Lolium at the ratio 15% of Wheat residues but in the root length highest reduction recorded (58.4%) noticed in Panicum at the ratio 15% of Barley residues ,in dry weight the highest inhibition noticed in Lolium affected by Wheat residues added at ratio 15% whicht reached up to (95.18). The initial detection of the active compounds in the crops residues indicate the exsistance of the compounds include (Alkaloids, Glycosides, Flavonoids, Tannins and Saponins) which had inhibition effect and can be converted to simpler or more complicated forms after being released to the soil.