Studies On Water Requirement Of Three Cool-season Turfgrass In Beijing Region

By carrying out the field test and data analysis, the main contents of the study were as follows: 1)the water effect on turf-grasses growth (Tall fescue, Kentucky bluegrass, Perennial reygrass); 2)photosynthesis, transpiration and WUE of three turf-grasses; 3)ET of three grasses under three water condition in SPAC system; 4) the KC of three turf-grasses; 5)daily and monthly dynamic change of soil water during growing season.The followings were the results obtained from the study.1) In the growing period, more water could improve the growth and the regeneration of these grasses. The growth dynamics under different water conditions accorded with Logistic model. The highest growth rate of cool-season grasses was in early September. Under sufficient irrigation, the regeneration of tall fescue was the best and that of the ryegrass was lower. The water content of leaves increased gradually with water increasing and decreased with the temperature rising. The drought resistance of Tall fescue was superior to that of the others. 2) The highest root biomass was in spring and winter was the recovering period. Soil water affected the root growing directly. Light salt force in water conduced to the root growth. But enough water was harmful for the root of tall fescue. The root biomass of tall fescue was more than other turf-grasses'. The distribution of underground root showed exponent relation.3) The ET of turf-grass had direct relation with soil water. The ET increased with soil water increasing. The order of the turf-grasses' ET: Tall fescue>Kentucky bluegrass>Perennial ryegrass. The theorical irrigation supplement of cool-season was less than 500mm, that is, 0.5m3 water for 1 m2 turf.4) The daily soil water changed regularly with time passing. The relationship between soil water and time showed line. The R2 of the relationship was 0.8486~0.9865. The reducing scope of soil water in 5cm is smaller than that of 10cm under lightly force of water.5) Having carried out the correlation analysis and then established optimization pattern among ET and temperature, rainfall, evaporate, relative humidity, irrigation.6) The KC of three turf-grasses was among 0.615~1.167 in Beijing area and the averages were as followed: Tall fescue KC: 0.899, Kentucky bluegrass KC: 0.864, Perennial ryegrass KC: 0.875. The KC of the turf-grasses was close to other crops'. If irrigated properly, the water consumption of turf-grasses was no more than that of the crops.7) The study concluded that irrigation scheme for cool-season turf-grasses in Beijing area was 375mm, 25mm per time and 15 times in a growing period. Contrasting to several crops, trees and forage, the water consumption of turf was less than alfalfa and trees. So water consumption of turf-grasses was not highly.