Effects Of Different Strip-widths On Grain Yield And Rhizosphere Ecology In Maize And Sweet Potato Relay Strip Intercropping System

In order to explore the reasonable symbiosis between sweet potato and maize,the experiment is based on the sweet potato variety?Yuhongxin98?and the corn variety?sanxiayu6?.The relay strip intercropping system were studied within 3 different strip-width plant patterns?80cm,100cm and 120cm?.Studied the effects of different strip-widths configurations on crop yield,crop growth environmental factors,photosynthetic characteristics,root vigor,plant nutrients,soil nutrients,soil enzymes,soil microbes,and set up root-separation tests to explore under the intercropping mode,whether there is a competitive relationship between the two crops,exploring the relative contribution of the above-ground and underground factors to the intercropping advantages,clearly defining the rhizosphere influence law between different strip-widths,enriching the theoretical advantages of the intercropping group,and screening the optimal strip-widths allocation method is to provide a theoretical basis for the optimization of the maize and sweet potato strip and the yield advantage.Research indicates:1.Effects of different strip-widths on photosynthetic characteristics of sweet potatoDifferent strip-widths significantly affected the monoculture photosynthetic rate?Pn?,stomatal conductance?Gs?,intercellular CO₂ concentration?Ci?,and transpiration rate?Tr?of sweet potato functional leaves,all of which showed an increase with increasing strip-width,and the rate of monoculter photosynthetic is significantly higher than the intercropping.There was no significant effect on the photosynthetic characteristics of sweet potato between the roots separation.The average values of Pn,Tr,Gs and Ci for sweet potato Compared with the strip-width?120cm?treatment,it decreased by 39.4%,22.49%,34.5%,and 4.47%,respectively.2.Chlorophyll content and leaf area indexDuring the symbiotic period of intercropping,the changes of chlorophyll content were different under different strip-widths treatments.The chlorophyll content of different strip-width treatments varied,and there was a significant difference between the strip-width treatments.With the increase of strip-width,the contents of chlorophyll a and chlorophyll b increased first and then decreased.There was no significant difference in chlorophyll between the roots separation.There is no difference between the different strip-widths under the monoculture processing.With the increase of the strip-width,the leaf area index did not reach significant level.3.Effects of different strip-widths and roots separation on nitrogen,phosphorus and potassium in plantsCompared with the monoculture system,the total nitrogen,total phosphorus and total potassium of the sweet potato and maize strip system were reduced.The nitrogen accumulation of maize plants increased first and then decreased with the increase of strip-width in the intercropping system.Contrary to sweet potato,there was no significant effect of strip-width on the accumulation of nitrogen,phosphorus and potassium in crops.and the accumulation of nitrogen,phosphorus and potassium in root treatment was not significant.The amount of Nutrition?N P K?was higher than that when the roots were not separated.The competition ratio of Nutrition?N P K?of corn in the intercropping system was higher than that of the sweet potato.This indicates that maize is a competitive advantage crop within the system.The analysis of competition intensity of sweet potato and maize found that above-ground competition is the main competition mode.4.The impact of different strip-width and roots separation on root vigorDifferent strip-widths and roots separation had no significant effect on the root vigor of maize and sweet potato.The growth rate of the root not separation was higher than the root separation treatment.Under the treatment of intercropping,the root activity of sweet potato increased first and then decreased with the increase of strip-width.Under the strip-width of 100cm reached the maximum value.The root activity of maize gradually decreased with the growth period.5.Effects of different strip-widths and roots separation on soil enzyme activityThere was no significant effect on the urease catalase in the rhizosphere soil of maize and sweet potato of root separation.During the symbiotic period of crop,the trend of soil urease increased firstly with the advancement of the symbiotic period,and then decreased,showing a parabola with a downward opening.The urea urease activity of the roots not separation treated was higher than that the roots separation,and the sweet potato and maize showed the same performance.With the increase of the strip-width,the soil urease in the roots of maize increased first and then decreased.The monoculture change trend is consistent,and the enzyme activity is higher than the monoculture.Catalase is consistent with the trend of soil urease.6.Effects of different strip-widths and roots separation on soil microbesUnder the intercropping system,the soil microbial biomass carbon and nitrogen were higher than the monoculture treatment.Under the intercropping system treatment,the microbial biomass carbon reached the maximum?100cm?.In sweet potato,the soil microbial carbon and nitrogen were higher than the root not separate treatment,and there was no significant difference between the barrier and the non-separation.Under the root not separate treatment,the number of microorganisms decreased first and then increased with the increase of strip-width.7.Effects of different strip-widths and roots separation on soil nutrientsRoot separation treatment did not had a significant difference in soil nutrient changes.Under the root separate treatment,the alkali nitrogen,available phosphorus and available potassium in the rhizosphere soil of maize were lower than those without root separation,and the treatment in the intercropping system was lower than the monoculture treatment.Under the treatment of roots not separation,the content of alkaline nitrogen and available phosphorus in maize rhizosphere soil decreased first and then increased with the increase of strip-widths.The nutrient content of each treatment in sweet potato intercropping system was higher than monoculture operation.During the whole symbiotic period of the intercropping system,the alkali-dissolving nitrogen,available phosphorus and available potassium were higher than the root separation treatment,and under the strip-width of 100cm was the most effective phosphorus and available potassium.8.Influence of different strip-widths and roots separation on yield traitsThe strip-width allocation can significantly affect the yield of sweet potato,which has no significant effect on maize yield.Intercropping treatment had no significant effect on maize yield,sweet potato yield and LER in the relay intercropping system.The monoculture sweet potato yield was higher than the relay intercropping.The monoculture sweet potato yield increased first and then decreased with the increase of the strip-width.Under the strip-width of 100cm,the sweet potato yield was consistent with the monoculture crop change.There was no significant difference in the yield of maize between monoculture and intercropping.9.Correlation analysis between indicatorsThere was a significant positive correlation between the number of microbial bacteria and the number of fungi in the rhizosphere soil of sweet potato,and there was a significant positive correlation between available phosphorus and available potassium.There was a very significant positive correlation between catalase and urease and soil available phosphorus.