| The agricultural and fruit intercropping compound system can achieve high efficiency in terms of pattern combination,space-time allocation,interspecific competition and complementarity,and can make full use of water,light,land and other resources.In order to explore the photosynthetic physiological mechanism of cotton yield formation in the jujube-cotton intercropping system,optimize the field configuration of jujube-cotton intercropping,and screen out the optimal planting mode of jujube-cotton intercropping suitable for southern Xinjiang,the jujube-cotton intercropping mode is the research object.,three intercropping treatments with distances of 1.4 m(M1),1.0 m(M2),and 0.5 m(M3)from the trees were set,and single-cropping cotton(CK)and single-cropping jujube tree(Sole J)were used as the control,in 2020-2021 Different characteristics of leaf area index(LAI),photosynthetically active radiation interception(PARi)distribution,chlorophyll(SPAD),net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance in the canopy under different planting patterns In order to give full play to the interspecific advantages through reasonable field configuration,improve the utilization efficiency of light resources in the intercropping compound system,and to screen reasonable The planting model provides a theoretical basis.The main findings are as follows:(1)The LAI and PARi of the jujube-cotton intercropping pattern,single-cropping cotton and single-cropping jujube trees at different growth and development stages and time periods were very different.The 2-year trial showed that as the planting density of cotton increased,the population LAI within the intercropping compound system increased significantly,the LAI of M3 treatment was the largest,the M1 treatment was the smallest,and the CK of monoculture was significantly higher than that of jujube.In cotton seedling stage and jujube leaf-expanding stage,the PARi of each intercropping treatment and monocropping system tended to be stable between12:00 and 16:00,and the change of PARi was quite different at 20:00.The population PARi of each treatment in the intercropping compound system was not only related to the spacing of jujube trees,but also closely related to the planting density of cotton.The light utilization intensity of M2 treatment was generally higher than that of M1 treatment,and the PARi of the population under the cotton canopy was higher than that of M3 treatment.(2)The chlorophyll of cotton leaves showed a trend of rising first and then decreasing.With the continuous advancement of cotton growth process,the change difference of SPAD value of leaves in 2020 was higher than that of 2021,and the difference in SPAD value in 2020 was 65,77,97 The SPAD value of single cropping CK was significantly higher than that of the intercropping treatments.In 2021,the SPAD value of single cropping CK was not significantly different from the intercropping treatments on 44 and 73 days.There was a significant difference between the fruit expansion period and the maturity period,and the single-plant M1-J treatment was significantly higher than that of the single-plant Sole J in the fruit expansion period in 2021.(3)In the initial stage of cotton growth and the main stages of reproductive organ growth and development,the Pn,Gs,and Ci of jujube-cotton intercropping in each time period were generally higher than those of single-cropping cotton,and the Tr of each intercropping treatment in 2021 was significantly lower than that of single-cropping Sole C;different planting patterns The Pn,Gs and Ci of leaves under the pre-growth mode of jujube trees were significantly higher than those of single-cropping treatment Sole J,and the overall performance in the later stage was that single-cropping Sole J was significantly higher than that of intercropping jujube trees.The Tr of the leaves treated as a single crop was generally higher than that of the single crop treatment.(4)There were obvious OJIP phases in jujube trees and cotton under different planting modes.In the jujube-cotton intercropping compound system,except for cotton bud stage,there was no significant difference in chlorophyll fluorescence parameters among treatments.The overall performance of PIABS was M2>M1>M3;The difference in kinetic parameters of chlorophyll fluorescence induction in leaves of jujube treatments was higher than that of cotton,and the PIABS of single crop Sole J was generally higher than that of intercropping treatments.(5)In the jujube-cotton intercropping system,the plant height of cotton in each treatment was M3>M2>M1.Except for the early stage of growth and development,there was no significant difference in the stem diameter of each intercropping treatment.The plant height and stem diameter of jujube trees were all realized as M1-J >M2-J>M3-J,indicating that the planting density of jujube-cotton intercropping cotton and the shading produced by jujube trees will have a certain impact on the growth and development of each other;There was no significant effect on boll weight and lint content.The total yield of each intercropping treatment was significantly higher than that of single crop cotton and single crop jujube,and the total yield of M2 treatment was the highest;the LER of each intercropping treatment was greater than 1,and the M2 treatment was significantly higher In M1 and M3 treatments;the jujube-cotton intercropping mode had no effect on the quality of the same cotton variety.Among the different planting modes of jujube-cotton intercropping,the total yield of M2 treatment is the highest in the intercropping compound system,which maximizes the utilization rate of space resources.The competitiveness of cotton and jujube trees is relatively lower than that of M1 and M3 treatments,which improves the intercropping efficiency interspecific advantage. |
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