Abstract:

Winter wheat is an important ration crop in the Loess Plateau and the yield is greatly affected by rainfall and other factors，in order to study the effect of precipitation on water consumption and yield of winter wheat，the long-term observation data of winter wheat Zhenyuan experimental site of the Gansu academy of agricultural sciences in recent 40 years were collected. The variation trend of winter wheat yield and water consumption with precipitation was illustrated. The results showed that the yield of winter wheat on the loess plateau increased at a rate of 51.2 kg·hm^-2 every year in the past 40 years， but the persistence coefficient was only 0.43. The yield greatly increased with the rise of precipitation from mid-October to mid-November， the first ten days of mid-March， the first ten days of May， and the last ten days of May. The satisfaction rate of precipitation in the whole growth period was 64.4%， but was only 52.7% in the dry year， while at jointing-filling stage was the lowest among different growth stages. The average water consumption during the growth period of winter wheat was 361.3 mm， which showed a downward trend in the past 40 years. The water consumption from sowing to rejuvenation accounted for 34.3% of the total in the whole growth period. In dry years and median water years， the precipitation satisfaction rates were 36.9% at the seedling emergence-jointing stage and 42.2% at jointing-filling stage，respectively. At these 2 stages， precipitation had a significant impact on the yield of winter wheat. According to the yield correlation of winter wheat， the order from high to low was water consumption > panicles > grains per ear > soil moisture before sowing > precipitation during growth period >annual precipitation. Winter wheat yield in the loess plateau area had been poorly stable in recent 40 years due to a large proportion of water consumption from sowing to the regreening stage and insufficient precipitation at this time， affected the tillering and spike formation and water use efficiency of winter wheat. Above results indicated that ensuring the precipitation satisfaction rate of winter wheat in the key growth period and the efficient accumulation of precipitation in the fallow period was an important guarantee for stable and high yield of winter wheat，which were of great significance to the sustainable development of winter wheat industry.

Key words: loess plateau, winter wheat, yield, water consumption, precipitation

摘要：

冬小麦是黄土旱塬区重要口粮作物，产量受降水等因素影响较大，为研究降水对冬小麦耗水规律和产量的影响，收集、统计甘肃省农业科学院镇原试验站近40年冬小麦长期观测数据，分析冬小麦产量、耗水量等指标随降水变化的趋势。结果表明，黄土旱塬区近40年冬小麦产量以每年51.2 kg·hm^-2速度增加，但持续系数仅为0.43；10月中旬至11月中旬、3月中上旬、5月上旬和下旬降水量增加，产量随之显著增加；全生育期降水满足率为64.4%，干旱年型仅为52.7%，不同生育时期中拔节-灌浆期满足率最低。冬小麦生育期耗水量近40年呈降低趋势，平均为361.3 mm，播种-返青期耗水占全生育期的34.3%，为全生育期耗水最大的时期；干旱年和平水年分别在出苗-拔节期和拔节-灌浆期降水满足率最低，分别为36.9%和42.2%，此阶段降水对冬小麦产量影响显著。冬小麦产量相关的因素由高到低依次为耗水量>穗数>穗粒数>播前底墒>生育期降水量>全年降水量。近40年来黄土旱塬区冬小麦稳产性差，原因为播种-返青期耗水占全生育期比重较大，降水满足率低，影响了冬小麦分蘖成穗和水分高效利用。以上结果表明，保证该区冬小麦关键生育期降水满足率和休闲期降水高效蓄集，是冬小麦稳产高产的重要保障，研究结果对冬小麦产业可持续发展具有重要意义。

关键词: 黄土旱塬, 冬小麦, 产量, 耗水规律, 降水