Effects Of Peanut-sorghum Intercropping System On Peanut Growth And Development In Saline And Alkaline Soils

The present study was performed in the experiment and demonstration base(plough layer salt content,0.35%)of modern agriculture of Yellow River Delta,Shandong Academy of Shandong Agricultural Sciences in 2017.A peanut variety of Huayu No.25,and a sorghum variety,Jiliang No.1,were selected as the experimental materials for the present study.Three modes,peanut-sorghum intercropping of 3:4,monocultural sorghum and peanut were set to study the effects of peanut-sorghum intercropping to peanut on growth and development,yield and quality traits in such system under saline and alkaline soil conditions as well as variations of water content,salt content,and organic content in soil layers up to 40 cm deep from surface soil at all peanut growth stages were characterized.Findings are listed below: 1.Effects of peanut-sorghum intercropping system on peanut growth and developmentThe intercropping system promoted height of main stem and length of lateral branch,while reduced number of main stem node,leaf area index and dry matter weight.Such system enhanced peanut vegetation growth,alleviated the inhibition of growth by saline and alkaline conditions.2.Effects of peanut-sorghum intercropping system on photosynthetic properties offunctional leaves of peanutIn all rows of the intercropping system,photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)were significantly decreased,and additionally,photosynthetic performance drop was gradually increased coupled with proceeding growth stages.Photosynthetic performance drop of marginal rows was more than that of middle rows.Actual photochemical efficiency of fluorescence parameters(?PS?)and Electron transfer efficiency(ETR)was gradually declined along with growth stages,whereas in contrast to monocultural peanut,intercropped peanut had significantly augmented functional leaves,suggesting the adaptability of peanut to low light conditions of the intercropping system.At vegetative growth stage,pigments such as chlorophyll a,chlorophyll b,carotenoids and chlorophyll(a+b)of functional leaves showed a tendency of pigment contents of middle rows > marginal rows > monoculture,and chlorophyll(a+b)contents of monoculture > middle rows > marginal rows.3.Effects of peanut-sorghum intercropping system on enzymatic activities of peanut leavesActivities of SOD,POD,and CAT of intercropped peanut leaves were all lower than those of the monocultural counterpart.The activities of the three enzymes first went up and then went down with growth stages proceeding.Fancy stitch stage,pod bearing stage,and full fruiting stage of the marginal rows under intercropping had large differences compared to monocultural peanut,while between marginal rows and middle rows of the intercropping system showed insignificant differences.However,MDA content was increased with growth stages,indicating that the intercropping system resulted in MDA accumulation.At harvesting stage,MDA content of marginal rows was notably greater than those of monoculture and middle rows.4.Effects of peanut-sorghum intercropping system on soil propertiesAt the same growth stages,water content of the intercropping system was higher than that of monoculture.Water content of middle rows was lower than that of marginal rows.However,salt content of monocultural plot was greater than that of the intercropping system,and salt content of middle rows was higher than that of marginal rows at the same growth stages.Differences in salt contents at some growth stages reached significant levels.Organic content of the intercropping system was higher than that of monoculture.5.Effects of peanut-sorghum intercropping system on production and quality traits in peanutPeanut-sorghum intercropping had significant effects on production and quality in peanut.Number of full fruit,number of fruit with more than two kernels,fruit weight per plant were decreased to some degree.Soluble sugar and fat contents dropped by 5.41% and 4.37%,respectively,whereas protein content rose by 3.6%,soluble sugar contents of which had significant differences.Production of intercropped sorghum was reduced by 33.72% in relation to that of monocultural sorghum,and yet,net area production of the former was enlarged by 32.55%.On the other hand,production of intercropped peanut was 60.03% lower than that of monocultural peanut,with a decrease of 20.06% in net area production.Differences of the above mentioned productions were significant.The land equivalent ration of the present study was 1.06,greater than 1,and therefore the peanut-sorghum intercropping system had recognizable advantages on saline and alkaline lands.