秸秆不同还田量对宁南旱区土壤水分、玉米生长及光合特性的影响

Effects of different straw returning treatments on soil water,maize growth and photosynthetic characteristics in the semi-arid area of Southern Ningxia

在宁南半干旱区通过大田定位试验研究了不同秸秆还田量对农田土壤水分、春玉米生长性状、关键生育期光合特性及产量的影响。试验设计为3个秸秆还田量水平,小麦秸秆按3000 kg/hm2(L)、6000 kg/hm2(M)、,9000 kg/hm2(H)粉碎还田;玉米秸秆按4500 kg/hm2(L)、9000 kg/hm2(M)、13500 kg/hm2(H)粉碎还田,对照为秸秆不还田。每个处理设3次重复,随机区组排列,秸秆被粉碎机打碎成5cm左右的小段,人工均匀翻埋至25cm左右深度的土层。结果表明,不同秸秆还田量(高、中、低)下,播前各处理0—200cm土层土壤贮水量均较CK(对照)有显著提高,秸秆还田量由高到低,0—200cm土层土壤贮水量增加量是30.17—32.83 mm,不同还田量之间没有显著差异。玉米株高、茎粗和单株叶面积显著增加,和对照比较差异达显著水平(P<0.05)。还田处理玉米叶片的光合速率和蒸腾速率在12:00—15:00持续出现高值,高、中、低3个秸秆还田量处理的叶片光合速率分别显著高出对照6.52、3.74、3.20μmol.m-.2s-1(P<0.05),蒸腾速率分别高于对照2.08、1.63、0.72μmol.m-.2s-1。随秸秆还田量由高到低,高、中、低3个不同秸秆还田量处理的玉米籽粒产量较对照分别提高了58.3%、36.7%和5.4%,玉米水分利用效率(WUE)较CK分别提高38.5%、31%和0.9%。秸秆还田可提高土壤的水分利用率和蓄水能力,促进作物的光合作用,进而使作物增产。不同土壤含水量条件下,光合速率、蒸腾速率的日变化规律不同,土壤水分亏缺对干旱地区作物光合作用来说将是最大的限制因子。

In order to study the effect of different straw returning treatments on the yield of corn、soil water、the growth characteristics of spring corn and the photosynthetic characteristics on key growth period,a field experiment was conducted in the area of southern Ningxia.The experiment of straw returning consists 3 levels which is 3000 kg/hm2（L）,6000 kg/hm2（M）,9000 kg/hm2（H）for wheat straw and 4500 kg/hm2（L）,9000 kg/hm2（M）,13500 kg/hm2（H）for corn straw.The control treatment has no straw returning.There is three times of every treatment.With the completely randomized block arrangement,straw is chopped at the length about 5cm and is uniform buried in the soil about 25cm layer.The results show that,the soil water storage of 0-200cm soil layer significantly increased,which enhanced 30.17mm,31.13 mm,32.83 mm respectively follow the amount of straw returning from high to low compared to CK.Compared with CK,the maize height,the stem diameter and leaf area have significantly increased（P0.05）.The photosynthetic rate and transpiration rate of corn leaf on different straw returning treatments that follow the amount of straw returning from high to low is in sustainable high level during 12：00—15：00 a day,compared with CK,the photosynthetic rate enhanced 6.52,3.74,3.20μmol · m-2 · s-1 respectively,the transpiration rate increased 2.08,1.63,0.72μmol · m-2 · s-1 respectively（P0.05）.Follow the amount of straw returning from high to low,compared with CK,grain yield of corn increased 58.3%,36.7% and 5.4% respectively;WUE of corn increased 38.5%,31% and 0.9%respectively.The results of experiment from 2007-2009 showed that straw returning treatments in the area of southern Ningxia can increase WUE and the ability of soil water storage,promote the photosynthesis of corn,and then increases the yield of corn.The daily variation regularity of the photosynthetic rate and the transpiration rate is different on different soil moisture.The main limiting factor is water deficit of soil for the photosynthesis of crop in the arid area of Ningxia Province.