微集雨模式与降雨变律对燕麦大田水生态过程的影响

The effects of micro-rainwater harvesting pattern and rainfall variability onwater ecological stoichiometry in oat (Avena sativa L.) field

以春燕麦坝莜3号品种为试材,分别于2009年和2010年在甘肃省定西市农业气象站进行大田试验。两个生育期的降雨总量基本一致,其中2009年生长季的降雨变律特征与多年观察值相似,而2010年则表现为"前半期降雨多、后半期降雨少"的变律特征。微集雨技术共含8个不同处理,包括①平地不种植(裸地)、②平地种植和③6个垄沟和覆膜处理组(3种垄沟宽度比(2∶1、1∶1和2∶3)×2种覆膜方式(垄上覆膜和不覆膜)),测定了各处理组土壤剖面贮水量、耗水量、水分利用效率和产量相关指标。结果表明,垄上覆膜处理组的叶面积指数、水分利用效率和产量显著高于其它处理组,同时提高了雨水转化为土壤水和作物水的转化效率,并促进了生育后期土壤贮水量的迅速回升。就不同垄沟比来说,各参数值在垄沟比为1∶1的处理组中最高。此外,就两种降雨变律年型而言,"降雨量前倾"的2010年燕麦的水分利用效率、产量和叶面积指数显著高于2009年(P<0.05),且显著提高了0—130 cm剖面土壤贮水量。

Over last two decades,micro-rainwater harvesting technology has been widely used in dryland agricultural practice,but the effects of the design of this technique and the variability of regional rainfall on the storage,migration and utilization of rainwater in soil is very rare.Field experiments were conducted using the spring oat（Avena sativa L.） variety,Dingyou 3 as test material,at Dingxi Agricultural Meterological Experimental Station of Gansu Province in 2009 and 2010.Despite the total rainfall amount for the growing period of oat being basically consistent in 2009 and 2010,there was a significant difference in the temporal distribution of rainfall in the two growing seasons.In 2009,the rainfall distribution was similar to the long-term trend in rainfall（consisting of 33.1% of total rainfall in the first half and 66.9% in the second half of whole growth period）.Conversely,the year 2010 turned to be characterized by ＂more in the first half and less in the second half＂（accounting for 46.4% and 53.6% of total rainfall of whole growth period,respectively）.The coefficients of variation of rainfall distribution were 1.0 and 0.8 in 2009 to 2010,respectively.In this study,eight treatments of micro-rainwater harvesting were designed,including：（1） the flat bare plot without cultivation（CK group 1）,（2） flat plot with cultivation（CK group 2）,and（3） six treatments with ridge-furrow and plastic mulch（3 width ratios of ridge to furrow（2∶1,1∶1 and 2∶3）,and two mulching patterns（plastic mulch and no mulch）.Water storage and consumption in the soil profile,water use efficiency and yield-related indicators were collected from all the treatment groups in both years.The data from the two years showed that the leaf area index,water use efficiency and yield were significantly higher in the three treatments with film mulching on the ridge than those of other treatments.The patterns of film mulching on the ridge were found to improve water conversion efficiency from rainwater into soil and crop,and induced a rapid recovery of the water stored in soil in the later growth period.With respect at the width ratios of ridge to furrow,the parameters mentioned above were the highest in the treatment groups with 1∶1 width ratios of ridge to furrow in all treatments.Furthermore,the stored water in the treatments of 1∶1 or 2∶1 width ratios from ridge to furrow was significantly greater than that of the 2∶3 ratio treatment groups.Importantly,analysis of the performance in the two years with different temporal variability in rainfall showed that water use efficiency,grain yield and leaf area index of oat were all significantly higher in 2010 than those in 2009（P0.05）,and the total volume of water stored in 0—130 cm soil profile were also higher in 2010 than 2009.Our results suggest that the ＂forward transfer＂ of rainfall distribution was conducive to optimizing the soil ecological processes in the case of similar total rainfall amount.Our study provides a foundation for future understanding on the effects of micro-rainwater harvesting pattern and rainfall change on ecological processes of dryland agriculture,and also provides a new strategy for phenological management in rain-fed farming regions.