| Intercropping,as a kind of ecology-friendly agriculture,has been practiced in semi-arid area due to its advantage of preventing environment agaist wind erosion,mitigating the risk of climate change at agriculture,high resource use efficiency and farmland productivity.The field experiment was conducted in FuXin in semi-arid area in 2015,2016 and 2017.three replacement intercropping systems consisted of a maize/peanut intercropping(4 rows of maize intercropped with 4 rows of peanut),a sole maize and a sole peanut,was characterized by three maize intra-row spacing of 33cm,22cm and 17cm.the main results and conclusions were as follow:The sample was taken from top,middle and bottom of intercropped and sole crops in all tested systems in order to quantify the difference of leaf area index(LAI),special leaf area,SPAD and photosynthesis traits of maize and peanut between in intercropping and in sole systems,and further idenfity their effect on light interception,LUE and yield in intercropping with the help of FSP model.The LAI,SPAD,Pnmax and canopy photosynthesis efficiency(ALUE)of leaf at middle and bottom of intercropped maize,was significantly higher than sole maize;the light distribution in spacial and temperial level was more uniform in intercropping than sole,which was supported by the results that the PAR at middle intensity was more in intercropping than sole;the light interception,LUE,dry matter and yield of intercropped maize were significantly higher than of sole maize;the intercropped peanut had a strikingly lower LAI,SPAD and Pnmax,but a signicantly higher SLA,PnLUE and ALUE comparing with sole peanut;the dry matter and yield of intercropped peanut was significantly lower than sole peanut.The LER,DMLER and LUER over 1,indicated that intercropping has advantage of using light more efficiency and outyielding than sole system.The DMLER over LUER shows that the intercropping also enables capture light more efficiency than sole.Therefore,the maize/peanut was outyielding than sole,due to capturing and using light more efficiency.The advantage of light interception in maize/peanut intercropping was due to(1)increased light interception of maize due to increased LAI;(2)a compensation of light intercepted by intercropped peanut due to a increased SLA.The advantage of light use efficiency inintercropping was due to improved canopy photosynthesis efficiency for intercropped maize due to uniformed light distribution,and for peanut due to increased the proportion of diffuse radiation with lower intensity.The response of light interception,LUE and yield in intercropping to plant density of maize was studied by a comparative analysis of all tested indices of intercropped maize with sole maize and indentifying the response of all indices of intercropped peanut to maize plant density.In maize/peanut intercropping,comparing with sole maize,increased maize plant density amplified the yield advantage of intercropped maize in first border row due to an increased ear and kernel numbers,but suppressed yield of those in second border row via reducing kernel numbers,finally leading to the maximum border advantage and LER in 122 replacement intercropping system.The HI of intercropped maize significantly decreased with plant density,but there was a slightly decrease in yield and HI of intercropped peanut with maize plant density.The LAI,DM,light interception and LUE significantly increased for intercropped maize and sole maize,but the intercropped maize had more increase than sole maize.The LAI,DM and LI slightly decreased with maize plant density,but there was no significant difference in its LUE.The DMLER,but not LUER,increased with maize plant density,which indicated that the increased yield in intercropping is profitable in increased light interception as the plant density of maize increasing.So,optimized plant density of maize(9 plants m-2)was a promising option for maize/peanut intercropping system to improve border advantage and light interception,and thus enhance system productivity in semi-arid area. |
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