Effects Of Fire On Quantitative Characters Of Puccinellia Tenuiflora Grass Tussock Components And Its Relationships In Songnen Grassland

Grassland fire is one of the largest disturbance factors for grassland. The experiment was conducted in spring before the re-growth of grassland, to study the fire effects on quantitative characters of Puccinellia tenuiflora (L.) Beauv grass components and its relationships in Songnen grassland. The aim of this study was to provide some theoretical basis for grassland management and forage production. The results as follows:the height of vegetative shoot and reproductive shootFire treatment decreased the reproductive shoot number per cluster and increased the vegetative shoot number. Compared with control, it decreased 23.36 % and increased 11.34 %. Similar as reproductive shoot number, the height of reproductive shoot was slightly decreased, but it had no effects on the vegetative shoot. The CV of fire treatment was higher than that of control.the biomass of per clusterFire treatment decreased the total biomass per cluster was 29.15 %, the reproductive shoot biomass decreased 41.97 %, and the vegetative shoot biomass decreased 13.68 %. In the reproductive shoot, the spike biomass was decreased by 41.72 %, seed biomass was decreased by 55.56 %. In the vegetative shoot, the stem biomass was decreased by 20.00 %, whereas, the leaf biomass was increased by 8.22 %. Overall, the effect of fire treatment on reproductive shoot biomass was bigger, the CV of fire treatment was more than that of control; and there was no difference on the CV between vegetative shoot biomass and controls.Fire treatment changed the percentage of each component in cluster. That is, each reproductive shoot components percentage decreased, but the ratio of the vegetative shoot components (i.e., stem) increased.The relationships of reproductive and vegetative shoot biomass, number, and total biomassThe reproductive shoot, seed, spike biomass and number was positively correlated with the total biomass. Each correlation coefficient in fire treatment was less than that in control, especially to the spike. This result showed that the fire treatment weakened the relationship of each reproductive shoot components and total biomass. The vegetative shoot, stem, leaf biomass and number also positively correlated with the total biomass, whereas, these relationships was strengthened in fire treatment.Overall, the fire treatment had a negative effect on reproductive process in Puccinellia tenuiflora . It may be correlated with litter, C, and N lost, soil temperature and water evaporation incensement, which resulted from the fire treatment. Thus, the fire treatment in spring wasn't suitable for saline-alkaline regimes of Songnen grassland.