气候变化对高寒草甸垂穗披碱草生育期和产量的影响

Effects of Climate Change on Growth Stages and Yield of Elymus nutansin Alpine Meadow in Qinghai-Tibetan Plateau

基于1976～2007年青海省果洛州甘德县基准气候站气象资料和1994～2006年高寒草甸中优势牧草垂穗披碱草生育期和产量的观测资料,运用Pearson相关分析法对垂穗披碱草生育期间产量与气温、降水量的相关性进行分析,结果表明:1976～2007年甘德地区年平均气温呈上升趋势,气候倾向率为0.295℃/10a;降水量表现为微弱下降趋势,线性拟合倾向率为-5.71mm/10a。随着气候的变化,垂穗披碱草的整个生育期延长。垂穗披碱草的返青期、成熟期和枯黄期都呈现延迟趋势,其中枯黄期延迟趋势显著;抽穗期和开花期均呈提前的趋势。返青期与9月的平均气温呈显著正相关,相关系数为0.656(P<0.05),与3月平均气温呈显著负相关,相关系数为-0.577(P<0.05),其他气象因子与返青期相关性均不显著;垂穗披碱草开花期与6月降水量正显著相关,相关系数为0.624(P<0.05),与4月降水量呈负显著相关,相关系数为-0.655(P<0.05);垂穗披碱草抽穗期、成熟期和枯黄期与气候因子的相关系数较低,都未达到显著水平。限制垂穗披碱草产量积累的主要因素是生长季(4～9月)降水量和年降水量,其无偏相关系数分别为0.823(P<0.01)、0.794(P<0.01);气温变化对牧草产量的影响不显著,但是有的年份如2005年和1994年,当气温和降水量都较高时垂穗披碱草产量出现峰值。回归分析与相关性分析结果一致,降水对垂穗披碱草产量的影响大于气温,但生长季(4～9月)降水和气温合理的匹配也是影响垂穗披碱草产量的重要条件。

Based on meteorological data from Gande reference climatologically station, Qinghai prov- ince in 1976 to 2007 and observational data of growth stages of Elyrnus nutans during 1994-2006, the cor- relation between the yield, growth stages of Elymus nutans and air temperature and precipitation was de- termined with Pearson co-relational analysis method, and the major factors controlling the yield and growth stages of Elymus nutans were found out. The results indicated that. the annual average tempera- ture of Gande county in 1976-2007 showed an increasing tendency with a climatic trend rate of 0. 295℃ per 10 years. On the contrary, the precipitation of this area showed a downward trend with --5.71mm /10a from 1976 to 2007. As a result, the length of growing season of Elymus nutans was lengthened with returning green date, mature date and wilting date be delayed more or less whilst the heading date and flowering date became early to different extent. There was a significant positive correla- tion between returning green date and the average temperature in September, with an correlation coeffi- cient of 0. 656（P〈0.05）. The significant positive correlation was also found between flowering date and precipitation in June （correlation coefficient was 0. 624, P〈0.05）. However, there were still significant negative correlation existed between returning green date and the average temperature in March （correla- tion coefficient was -0. 577,P〈0.05）, and between flowering date and precipitation in April （correlation coefficient was -0. 655,P〈0.05）. Moreover, the study of the correlation between the heading date, ma- ture date and wilting date and the meteorological factors showed that their correlation coefficient were all not significant at 0.05 level. The major factors that limit Elymus nutans production accumulation were precipitation and annual precipitation in the growth season （April to September）,the partial correlation co- efficients were 0. 823（ P 〈 0.01） ,0. 794（ P 〈0.01） ; According to the study, the temperature variation had no significant influence on the production of Elyrnus nutans, but in some years such as 1994 and 2005 when the temperature and precipitation both were high, the production of Elymus nutans performed a peak value. Moreover, consistent result from both regression analysis and correlation analysis showed that effect of temperature on production was also less important than precipitation. However the reasonable matching of temperature and precipitation in growing season （April to September） also impacted the pro- duction of Elyrnus nutans significantly.