Effects Of Different Organic Materials And Different Concentrations Of Exogenous Copper On Soil And Pak-choi

A pot experiment was conducted to study the effects of different organic materials and different concentrations of exogenous copper on the nutrients contents, copper concentrations, copper forms of soil, and the growth and nutrients contents of pak-choi, and the content and distribution of copper in pak-choi. The results were shown as follows:1. Organic materials generally had promoted the growth of pak-choi. plant height, The root length, fresh weight per plant, plant plant dry weight, root fresh weight per plant, root fresh weight per plant of pak-choi applied with organic materials were all higher than that in CK. Pig manure had the biggest promoting effectiveness on pak-choi growth. The plant height, fresh weight per plant, root fresh weight per plant of pak-choi all rose firstly then dropped, but the roots length, root dry weight per plant, plant dry weight per plant of pak-choi all declined as the concentration of exogenous copper increased. Maize straw and turf grass both had better effect on pak-choi growth than other experimental organic materials at the higher concentration of exogenous copper.2. The nitrogen contents of pak-choi applied with different organic materials were significantly lower than that in CK. The contents of nitrogen, phosphorus, and potassium of pak-choi increased all firstly and then dropped as the concentration of exogenous copper increased. The phosphorus content of pak-choi in lawn grass treatment was significantly lower than that in CK, but the phosphorus contents of pak-choi in treatments of maize straw, chicken manure, cattle manure, pig manure, peat, and weathered coal were all higher than that in CK. Except the potassium contents of pak-choi in the chicken manure and weathered coal treatments were higher than that in CK, the potassium contents of pak-choi in the treatments of other experimental organic materials were significantly lower than that in CK.3. The Cu contents of pak-choi shoot in pig manure and peat treatments were significantly higher than that in CK, but the Cu contents of pak-choi shoot in treatments of lawn grass, corn stalk, chicken manure, cattle manure, and weathered coal were significantly lower than that in CK. The copper contents of pak-choi root in chicken manure and peat treatments were significantly higher than that in CK, but the copper contents of pak-choi root in treatments of lawn grass, corn stalk, pig manure, cattle manure, and weathering coal were significantly lower than that in CK. The copper contents in aboveground and underground parts of pak-choi increased as the concentration of exogenous copper increased in all treatments of different experimental organic materials. Application of organic materials generally reduced the total copper contents in both aboveground and underground parts of pak-choi, and the effect of pig manure was relatively biggest. The copper absorbed by pak-choi mainly accumulated in the roots.4. The total nitrogen contents of soil in lawn grass and pig manure treatments were significantly higher than that in CK, but the total nitrogen contents of soil in weathered coal and cattle manure treatments were significantly lower than that in CK. The effects of exogenous copper on the total nitrogen contents of soil were different in different organic material treatments, but lower exogenous copper concentration had certain promoting effect. The available phosphorus contents of soil in treatments of chicken manure, pig manure, cattle manure, and peat were significantly higher than that in CK, but in corn straw and weathered coal treatments were significantly lower than that in CK. Excepting corn straw, chicken manure, weathered coal, the available phosphorus contents of soil increased firstly and then dropped as the concentration of exogenous Cu increased in the other expeimental organic material treatments. The available potassium contents of soil applied with organic materials were generally higher than that in CK. The organic matter contents of soil in the treatments of pig manure, peat, and weathered coal were significantly higher than that in CK, but in corn straw and cattle manure treatments were significantly lower than that in CK.5. The total copper contents of soil were increased as the concentration of exogenous copper increased in different organic material treatments. The total copper contents of soil in pig manure, peat, and weathered coal treatments were significantly higher than that in CK, but in lawn grass treatment was significantly lower than that in CK. The exchangeable copper, carbonate combined copper, iron-manganese oxidation state copper, organic combination state copper, and residual state copper all increased as the concentration of exogenous copper increased in different organic material treatments. The exchangeable state and iron-manganese oxidation state copper contents of soil were significantly higher than that in CK in pig manure and peat treatments. The copper state from high to low was as:carbonate combined copper> iron-manganese oxidation state> residual state> organic combination state> exchangeable state in the treatments of CK, lawn grass, chicken manure, pig manure, cattle manure, and peat, but the residues state was greater than the iron manganese oxidation state in corn straw treatment.