Research On The Effects Of Imperata Cylindrica On Three Kinds Of Cold Season Turfgrass’ Growth And Competition

Imperata cylindrical is one of the most universal weeds in mixed cold season turfgrass of the subtropical area, and it always leads to the actual production issues such as the structure of lawn communities’ destruction, the loss of function. Imperata cylindrical invades into three kinds of important cold season turf which includes Poa pratensis L., Festuca arundinacea S. and Lolium perenne L., causing serious harm to the quality of turfgrass. According to this fact, the allelopathy effects and inter-specific competition were studied by setting the different concentrations of aquatic extracts from Imperata cylindrica and the different ratios of Imperata cylindrica’s intrusion to intimate the way that Imperata cylindrica’s invasion. The relevant indicators on the allelopathy effects and inter-specific competition can show the differences of turfgrass in germination, growth, shape as well as physiological or biochemical aspects, reveal the invasion pathways of Imperata cylindrical and indicate the response mechanism response mechanism of turfgrass. Thus, the effective methods to seed lawn and inhibit Imperata cylindrical in lawn can be supported in theoretical basis. The main research results are as follows:This research studied on the allelopathy effects of three types of turfgrass by dealing them with the Imperata cylindrical’s aquatic extracts of different concentrations,which in order to detect the inhibition rate of germination rate, the germination rate,the germination index, the shoot height, the root length as well as the fresh or dry weight indicators of seedling and root. It turns out that high concentration of aquatic extract has an obvious allelopathy effect on three seeds’ germination(P < 0.05), the low concentration just affects Poa pratensis clearly(P < 0.05); the shoot heights are promoted in low concentration and inhibited in high concentration while the root lengths are obviously inhibited in high concentration(P<0.05); besides, the higher the concentration, the stronger the inhibiting effect on the biomass of three turfgrass; what’s more, the aquatic extracts with high concentration obviously inhibits the seedling growth(P<0.05). The allelopathy effects of three kinds of turfgrass dealt by the aquatic extracts of Imperata cylindrical with different concentrations become weaker and weaker from Poa pratensis to Festuca arundinacea then to Lolium perenne.By replacing the experimental design, this research stimulates the process that Imperata cylindrical invades turfgrass then forms the mixed community and it also studies Imperata cylindrical’s effect on the inter-specific competition of three types of turfgrass, in terms of the attack, the competitiveness,the shape, the biomass and the physiological index. The result shows that the shoot height, the tiller and the biomassare obviously inhibited(P < 0.05); although Imperata cylindrica’s intrusion have different ratios, all of them have evidently effect on the attack, the competitiveness, the relative yield and the relative yield total(P<0.05); the chlorophylls, the activity of SOD,POD and CAT, the contents of soluble protein as well as MDA decrease with the intrusion of Imperata cylindrical; while the contents of the soluble sugar and the free protein increase with the low intrusion of Imperata cylindrical, but this contents decrease with the intrusive ratio becoming higher. An antagonism exists between two species, which means the two species compete for the same resources.In total, the Imperata cylindrica make a damage to three types of cold season turfgrass from the following two ways: the allelopathy effects and the inter-specific competition. Different types of turfgrass have different response to Imperata cylindrica’s intrusion.Thus, take treasures in these two aspects can be effective and necessary to the lawn’s establishment and the Imperata cylindrical’s inhibition.