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利用黄土高原半干旱区胡麻生长发育定位观测资料和同期气象观测资料,分析气候变化对胡麻生长发育的影响,以及胡麻水分利用效率与气象条件的关系.结果表明:研究区年降水量呈下降趋势,其气候倾向率为-15.80mm·(10a)-1,年降水量存在3a、6a的周期变化;年均气温呈上升趋势,其气候倾向率为0.36℃·(10a)-1;作物生长季干燥指数呈显著上升趋势,其气候倾向率为0.12·(10a)-1,20世纪90年代初至2009年明显趋于干旱化.研究区胡麻全生育期天数为120～150d,≥0℃积温为1700～2100℃·d,降水量为200～250mm,日照时数为1000～1300h.影响黄土高原半干旱雨养农业区胡麻生长发育的主导气象因子是气温和降水量.气温增高导致胡麻生育前期的营养生长阶段缩短;而气温增高、降水量减少,则导致生殖生长阶段延长,从而使全生育期延长.除出苗期和成熟期外,气温对其余时期的胡麻产量形成均表现为负效应,现蕾期对气温变化十分敏感;除开花期外,其余时段降水量对胡麻产量形成均为正效应,胡麻出苗期对降水量变化十分敏感.胡麻水分利用率与胡麻出苗期气温、日照时数和现蕾-成熟期干燥度呈显著正相关,与胡麻现蕾-成熟期降水量呈显著负相关.研究区5—7月干燥度是影响胡麻水分利用率的关键因子.
The effects of climate change on flax growth and development and the relationship between water use efficiency and weather conditions of flax were analyzed by using the observation data of flax growth and development in the semi-arid region of the Loess Plateau and meteorological observation data of the same period.The results showed that the annual precipitation decreased , With a climatic propensity of -15.80mm · (10a) -1. There was a periodical change of 3a and 6a in annual precipitation. The average annual temperature showed an upward trend with a climatic propensity of 0.36 ℃ · (10a) -1. The seasonal dryness index showed a significant upward trend with a climatic propensity score of 0.12 · (10a) -1. The trend toward aridification was evident from the early 1990s to 2009. The days of flax growing in the study area ranged from 120 to 150 days and ≥0 ℃ The accumulative temperature is 1700 ~ 2100 ℃ · d, the precipitation is 200 ~ 250mm and the sunshine duration is 1000 ~ 1300h.The main meteorological factors influencing the growth and development of flax in the semi-arid rain-fed agricultural area of the Loess Plateau are air temperature and precipitation.The increase of temperature causes flax The stage of vegetative growth was shortened in early stage of growth, while the increase of temperature and decrease of precipitation led to the prolongation of reproductive stage, which prolonged the whole stage of growth.In addition to the emergence and maturation stages, Is a negative effect, the budding period is very sensitive to temperature changes; except flowering, the rest of the precipitation during the formation of flax yield are positive effects, flax seedling is very sensitive to changes in precipitation. Flax moisture utilization and flax germination There was a significant positive correlation between temperature, sunshine hours and bud-maturity dryness, but negatively correlated with bud-maturity precipitation.The dryness of May-July in the study area was the key factor affecting the water use efficiency of flax.