Turfgrass Evapotranspiration And Drought Stress Indexes Diagnoses Research

Turfgrass evapotranspiration (ET) is researched in this paper to point out the economy irrigation. And the way of diagnosing drought stress was researched to make sure of the exact time point for irrigation. In the meanwhile, a handy turf-soil moisture measure was designed help to turf manager grasp the time point of irrigation. The aim of all these research is to realize water-saved irrigation to turf that can alleviate the burden of city water supply.4 species of turfgrass are researched to measure their evapotranspiration under different water condition. The result indicate that the ET of 4 turfgrass is mainly influenced by turfgrass species, the second factor is water condition, in the sufficient irrigation condition, the order of the 4 turfgrass is that: tall fescue (799.6mm) >Kentucky bluegrass (762.7mm) Bermudagrass (737.6mm) > lawngrass (591.8mm). the same order was concluded in the unsufficient condition.The result of the analysis to the turfgrass ET in the different seasons shows that 4 turgrass have the similar regulation that is " two peak type", two high water consume peak appear in May and Aug. what the difference is that the highest peak of cool-season turfgrass come in May, but warm-season turfgrass come in Aug. that attribute to the growth characteristic of turfgrass.The estimate to whole year water need is 212.8mm-385.0mm. there is a tremendous gap with the fact that is 600mm-l200mm. this means the current unscientific turf irrigation system has been wasting a grate lot of water. And as long as the mistake is removed away, the water would be saved.Kentucky bluegrass and Festuca are chose to be treated by different irrigation level which are sufficient irrigation and unsufficient irrigation. Three physiological indexes and three morphologic indexes are determined continually to find out how much response to appearance of turfgrass drought stress. The results indicated that the way using physiological indexes changes to diagnose turfgrass drought stress is quite sensitive and accurate. Comparatively, using morphologic indexes changes convenient.According to function model of soil moisture and soil resistivity, a soil moisture measure was designed. The test to the measure show that the error is in ±2%.