Effect Of Rhamnolipid On Soil Amelioration And Growth Of Malus Hupehensis

Soil compactness,manganese toxicity and saline-alkali are the most common obstructing factors in orchard,which seriously restrict the healthy development of apple industry.The experiment was conducted in nanxiao experimental Station of Shandong Agricultural University from May to October in 2021,and the effects of rhamnolipid at different concentrations on the improvement of three kinds of disturbed soil were studied using Malus hupehensis seedlings as test materials.The main results are as follows:1.Improvement effect of rhamnoid on soil compaction stress: different concentrations of rhamnoid（CK1:0g/L,JS1:1g/L,JS2:1.5g/L,JS3:2g/L,JS4:2.5g/L,JS5:3g/L）had significant effects on soil physical properties and growth of Malus hupehensis.Compared with no rhamnolipid application,rhamnolipid application at 2.5g/L significantly reduced soil bulk density and soil compactness.Application of 3g/L rhamnol significantly increased biomass,root indexes,photosynthetic indexes,SOD,POD and CAT activities,and decreased malondialdehyde（MDA）content of Malus hupehensis.2.Improvement effect of rhamnoid on soil manganese stress: Different concentrations of rhamnoid（CK2:0g /L,M1:1g/L,M2:1.5g/L,M3:2g/L,M4:2.5g/L,M5:3g/L）had significant effects on soil manganese content and the growth of Malus hupehensis.Compared with no rhamnolipid application,application of 3g/L rhamnolipid could significantly reduce soil manganese concentration.Application of rhamnol 2g/L significantly increased biomass index of Malus hupehensis,but had no significant effect on chlorophyll,significantly increased photosynthetic index and related photosynthetic index,SOD,POD and CAT enzyme activities,and decreased malondialdehyde（MDA）,manganese concentration in abovementground part and underground part of Malus hupehensis.3.Improvement effect of rhamnoid on saline-alkali soil stress: Different concentrations of rhamnoid（CK3:0g /L,Y1:1g /L,Y2:1.5g /L,Y3:2g /L,Y4:2.5g /L,Y5:3g /L）had significant effects on soil physical and chemical properties and growth of Malus hupehensis.Compared with no rhamnolipid application,2.5g/L rhamnolipid application significantly reduced soil bulk density,compactness and soil EC value,while 3g/L rhamnolipid application significantly reduced soil p H.Applying 3g/L rhamnol significantly increased biomass index,root index,photosynthetic index and related photosynthetic index,increased SOD,POD and CAT enzyme activities,decreased malondialdehyde（MDA）content,and decreased relative electrical conductivity and salt injury index.