Abstract: With field experiment and based on corresponding meteorological data,this paper studied the quality performance and climatic indexes of warm and cool season grass species in Beijing.The results showed that warm season species had a one-peak curve quality performance,only with good quality in summer,while cool season species had two-peak curve,with good quality from May to June and from September to October.The returning green of cool season species not only had a close correlation with effective accumulated temperature,but also related to critical temperature.The effective accumulated temperature of ≥10 ℃ was regarded as the beginning date index of the first good quality performance for all species,while the effective accumulated stress temperature of ≤10 ℃ was regarded as the index of green color fading and the end date of the second good quality performance for cool season species.The effective accumulated stress temperature of ≤23 ℃ was regarded as the index of green color fading and the end date of good quality performance for warm season species.The accumulation of temperature-humidity index was regarded as the standards of evaluating disease occurring,disease symptom recovery,and the end date of the first good quality performance and the beginning date of the second good quality performance for cool season species.The values of these indexes were determined for each species.

Key words: Water retaining agent, Rice straw mulch, Soil water, Wheat yield