Study On Allelopathy Of Hite Clover (Trifolium Repense L.) Plant Decomposition

White clover(Trifolium repens L.), a perennial creeping type herb, is a common lawn plant. In recent years, it was found that white cover can encroch the turf grass in practice of planting it with turf grass to improve the ornamental effect but the encroching mechanism is not clear. Allelopathy of white clover may be one of the factors which encroch the grassy carpet. Research has been done on the aqueous extract of white clover, but whether the decomposition of whole plant has allelopathy and the mechanism of white clover affecting turf grass are not clear. So allelopathy of white clover plant decomposition was researched systemically in this experiment to reveal effective mechanism, and provides the theoretical basis to work out ornamental lawn configuration more reasonable. The main results were as follows:1. The extracting decomposition method was used to obtain white clover decomposed liquids. Allelopathy of white clover decomposed liquids were researched by five receptors seed germination test experiment, compared the effects of seed germination, seedling growth. The results showed that the decomposed liquids had double effects on all test turfgrasses seed germination and seedling growth, which means that it has some improve effect at low concentration (0.011g·mL-1) but has significant inhibitive effect at high concentration (0.090 g·mL-1) (P<0.05). After treatment, the decomposed liquids decreased the turf grasses seed germination and inhibited the growth of seedling. Generally, all the receptors were inhibited in different degree, the sensitive order was kentucky blue turf (Poa pratensis L.)>red fescue (Festuce rubra L.)>creeping bentgrass (Agrostis stolonifera L.)>tall fescue (Festuce arundinacea S.)>ryegrass (Lolium perenne L.). A preliminary analysis of allelochemicals showed that there were plenty of phenolics in the decomposed liquids.2. The decomposition fermentation method was used to obtain white clover decomposition. The effects of decomposition temperature, decomposition content and decomposition time on the allelopathy of white clover were studied by measuring the inhibitive effects on ryegrass seedling growth. The results showed that all the three factors have effect on the allelopathy of white clover decomposition to different degree. The intensity sequence of decomposition temperature was 30℃>10℃>20℃.4.5% was the critical concentration of white clover decomposition. It had an obvious inhibitory effect on ryegrass growth at the higher concentration of 4.5%. The decomposition of white clover has a significant inhibitory effect on ryegrass growth in the initial decomposition stage, but showed a promotion effect gradually with the time.3. The effects of dry and fresh white clover decomposition on ryegrass, red fescue, tall fescue, creeping bentgrass and kentucky blue turf seedlings growth at different stage were studied and compared the allelopathy of the two decomposition methods of white clover. The results showed that decomposition of the two methods had different effect on all five turf grasses. Generally, the intensity sequence of dry decomposition on the five receptors was red fescue>creeping bentgrass>ryegrass>tall fescue>Kentucky blue turf, while the sequence of fresh decomposition was red fescue> ryegrass>kentucky blue turf>tall fescue> creeping bentgrass. Decomposition of fresh white clover improved the seedling growth of five turf grasses from the whole aspect comparing with dry white clover.