Study On Rhizosphere Surface Chemistry Of Red Soil And Yellow Cinnamon Soil Under Planting Different Crops

Rhizosphere soil is the centeral interface that is matter commutation and energy to deliver in the soil and plant system. The difference exist between rhizosphere and non-rhizosphere soils in chemisty character and ion adsorption due to the variety between the permanent charge soil and the variable charge soil. In the present study, corn, wheat and rapeseed were planted through a grouping potted plant on yellow cinnamon soil (the permanent charge soil) and red soil (the variable charge soil). The pH, available nutrients, organic matter, CEC, point zero of charge, charge capacities and Cu²⁺ adsorption on rhizosphere soil of red soil and yellow cinnamon soil and non-rhizosphere soil separated through 32μm nylon membrane were determined by conventional agro-chemical analysis. The main results were as following:1) On base of corn, wheat and rapeseed growth, except wheat rhizosphere soil of red soil, all alkali discomposed N content of rhizosphere soil was maximal, non- rhizosphere least, meant rhizosphere could activate or enrich this form N; the available phosphorus content of non-rhizosphere red soil was 28%-44% more than that of rhizosphere; for yellow cinnamon soil, available phosphorus content of non-rhizosphere was 29%-57% higher than that of rhizosphere soil, showed available phosphorus in rhizosphere wane; the organic matter content of rhizosphere soil and non-rhizosphere soil had a little variation, but the difference was not obvious.2) After the crops grew, all CEC of rhizosphere soil was maximal, non-rhizosphere least. Except wheat rhizosphere of red soil and corn rhizosphere of yellow cinnamon, all the difference of rhizosphere soil's CEC was obvious; for red soil, CEC of rhizosphere was 0.20-0.60 cmol/kg higher than that of non-rhizosphere soil; for yellow cinnamon soil, that of rhizosphere was 0.56-1.19 cmol/kg higher than non-rhizosphere soil.3) When the three crops were planted, all point of zero charge (PZC) of red soil was increased. The PZC of rhizosphere soil was 3.30-3.77, and non-rhizosphere 3.29-3.61. This meant that the PZC in rhizosphere soil would be higher than that in non-rhizosphere.4) On base of corn, wheat and rapeseed growth, the total negative charge quantity (CEC_8.2), permanent charge quantity (CEC_p) and variable charge quantity (CEC_v) of soil changed. For red soil, CEC_8.2, CEC_p and CEC_v of rhizosphere were less than those of non-rhizosphere. The CEC_p of rhizosphere was 5.98-7.40 cmol/kg, and CEC_v was 6.41-8.57 cmol/kg, but the difference was not obvious. For yellow cinnamon, CEC_p didn't change at all. The CEC_8.2, CEC_p and CEC_v of rhizosphere were higher than those of non-rhizosphere. The CEC_8.2 of rhizosphere was 1.82-2.51 cmol/kg higher than that of...