不同土壤有机碳含量对玉米光合生理及生长发育的影响

Effects of different soil organic carbon contents on photosynthetic physiology and growth of maize

采用农田生态系统大田取样的方法,通过棋盘式布点法定点确定样点位置,按不同土壤有机碳含量选取5种有代表性的土壤有机碳T1(2.44 g·kg^(-1)),T2(3.70 g·kg^(-1)),T3(4.95 g·kg^(-1)),T4(6.14 g·kg^(-1)),T5(7.51 g·kg^(-1)),探究不同土壤有机碳(SOC)含量对玉米光合生理特性、水分利用效率、干物质积累和生长发育的影响。结果表明:玉米净光合速率与土壤有机碳呈显著正相关关系,在抽丝期从T1到T5,净光合速率由31.22μmol·m^(-2)·s^(-1)增加到54.22μmol·m^(-2)·s^(-1);蒸腾速率在各个生育期表现为先减后增的趋势;气孔导度与土壤有机碳呈正相关关系,在开花期从T1到T5,气孔导度由0.06 mol·m^(-2)·s^(-1)增加到0.28 mol·m^(-2)·s^(-1);胞间CO_(2)浓度与土壤有机碳呈负相关关系,在拔节期从T1到T5,胞间CO_(2)浓度由491.57μmol·mol^(-1)波动减少到112.79μmol·mol^(-1);在拔节期从T1到T5,叶片水分利用效率由1.62μmol·mmol^(-1)波动增加到10.22μmol·mmol^(-1);在大喇叭口期叶绿素随着土壤有机碳含量的增加波动升高,而在开花期、抽丝期和成熟期两者无显著相关关系;在开花期从T1到T5,株高增加20.37%,茎粗增加23.70%,单株叶面积增加13.83%,叶面积指数增加13.70%;从T1到T4,玉米单穗穗重从156.13 g·kg^(-1)增加到236.18 g·kg^(-1),地上部分干重从235.7 g增加到380.22 g。土壤有机碳对玉米的光合特性和生长发育状况的影响是积极的,但不是土壤有机碳含量越高越好,土壤有机碳含量6.14 g·kg^(-1)效果较好。

Using the field sampling method of farmland ecosystem,the sample location was determined by the checkerboard distribution method.Five representative soil organic carbon T1(2.44 g·kg^(-1)),T2(3.70 g·kg^(-1)),T3(4.95 g·kg^(-1)),T4(6.14 g·kg^(-1)),T5(7.51 g·kg^(-1))were selected according to different soil organic carbon contents to explore the effects of different soil organic carbon(SOC)contents on the photosynthetic physiological characteristics of maize water use efficiency,dry matter accumulation and growth.The results showed that net photosynthetic rate of maize was positively correlated with SOC,which increased from T1 to T5 in the tapping stage.The net photosynthetic rate increased from 31.22μmol·m^(-2)·S^(-1)to 54.22μmol·m^(-2)·s^(-1).Transpiration rate decreased first and then increased in each growth period.Stomatal conductance increased from 0.06 mol·m^(-2)·s^(-1)to 0.28 mol·m^(-2)·s^(-1)from T1 to T5 at flowering.There was a negative correlation between intercellular CO_(2) concentration and SOC,which increased from T1 to T5 at jointing and decreased from 491.57μmol·mol^(-1)to 112.79μmol·mol^(-1).At jointing,the leaf water use efficiency increased from 1.62μmol·mmol^(-1)to 10.22μmol·mmol^(-1)from T1 to T5.In the opening,chlorophyll increased with the increase of SOC,but there was no significant relationship between them in the flowering,silking and maturing.In flowering,the plant height increased by 20.37%,stem diameter increased by 23.70%,leaf area per plant increased by 13.83%,leaf area index increased by 13.70%.From T1 to T4,single ear weight increased from 156.13 g·kg^(-1)to 236.18 g·kg^(-1),and aboveground dry weight increased from 235.7 g to 380.22 g.The effect of SOC on photosynthetic characteristics and growth and development of maize was positive,but it was not necessarily that the more,the better.T4(6.14 g·kg^(-1))was the most ideal,which could be used as an important reference value for the study of carbon storage,carbon neutralization and carbon peaking in farmland ecosystem.