Study on the relationship between grass growth and meteorological conditions in subalpine meadow

By using the observed data related to grass growth and meteorological conditions in the subalpine meadow, the relationship between grass growth and meteorological conditions were analyzed. The results showed that the growth period from regreening to ripeness was 140 to 150 days, the requirement of accumulated temperature above 0 ℃ was about 1 000 to 1 200 ℃, the requirement of precipitation was about 400 to 450 mm, the requirement of sunshine duration was about 1 000 to 1 100 hours. The growth rate of grassed reached the highest on 88th day after regreening and slowed down after 112 days. The effect of temperature on grass yield was positive from regreening to heading and withering stages and it was sensitive in the jointing, heading and ripening stages. The effect of precipitation on grass yield was positive except in ripening stage and it was sensitive in tillering and jointing stages. The effect of sunshine duration on grass yield was positive in tillering, ripening and withering stages and it was sensitive in heading stage.