| Soil dissolved organic matter(DOM) mainly contains dissolved organiccarbon(DOC), dissolved organic nitrogen(DON) and dissolved organic phosphorus(DOP). They are the most active parts in soil carbon, nitrogen and phosphorus, whichplay an important role in plant growth and development, the global cycles of carbon,nitrogen and phosphorus as well as all kinds of environmental issues. The contentcharacters of DOC, DON and DOP under four mainly different land use types–thepeach garden, the corn soil, the grapery garden and the vegetable soil, in Longquanyi ofChengdu were studied with field investigation, sampling and laboratorial analysis. Theexperiment results were as follows:(1) The study of the content of DOCIn July, the average content of DOC in the four different land use types was thecorn soil＞the peach garden＞the grapery garden＞the vegetable soil, and the averagecontent of DOC in the corn soil was1.166times higher than that in peach garden,2.081times higher than the that in grapery garden and2.467times higher than that invegetables soil. In August, the average content of DOC in the four different land usetypes was the vegetable soil＞the grapery garden＞the corn soil＞the peach garden, andthe average content of DOC in the vegetable soil was1.114times higher than that ingrapery garden,1.194times higher than that in corn soil and1.227times higher thanthat in peach garden. In September, the average content of DOC in the four differentland use types was corn soil＞peach garden＞grapery garden＞vegetable soil, and theaverage content of DOC in corn soil was1.113times higher than that in peach garden,1.216times higher than that in grapery garden and2.133times higher than that in vegetable soil.In peach garden, the change tendency of the average content of DOC in differentmonths was July＞September＞August, and the average content of DOC in July was1.531times higher than that in September and2.009times higher than that in August. Incorn soil the order was July＞September＞August, and the average content of DOC inJuly was1.604times higher than that in September and2.280times higher than that inAugust. In grapery garden the order was September＞July＞August, the averagecontent of DOC in September was1.067times higher than that in July and1.091timeshigher than that in August. In vegetable soil the order was August＞July＞September,and the average content of DOC in August was1.293times higher than that in July and1.792times higher than that in September. With the change of time, the average contentof DOC in peach garden, corn soil and grapery garden was all decreased first and thenincreased, while the vegetable soil was opposite.In July, with the increasing depth of profiles, DOC content changes of the soilprofiles in peach garden were firstly increased then decreased to a minimum value andthen fell down. In corn soil they increased first and then decreased. Both In graperygarden and vegetable soil, the DOC content changes of the soil profiles were decreasedwith the increasing depth of profiles. In August and September, the DOC contentchanges of the soil in four different land use types were all decreased in general with theincreasing depth of profiles although with some different fluctuation in different layers.(2) The study of the content of DONIn July, the average content of DON in the four different land use types was thegrapery garden＞the peach garden＞the vegetable soil＞the corn soil, the averagecontent of DON in the grapery garden was4.390times higher than that in the peachgarden,4.972times higher than that in vegetables soil and21.021times higher than thatin the corn soil. In August, the average content of DON in the four different land usetypes were the grapery garden＞the peach garden＞the vegetable soil＞the corn soil,the average content of DON in the grapery garden was3.966times higher than that inthe peach garden,6.093times higher than that in vegetable soil and6.640times higherthan that in corn soil. In September, the average content of DON in the four differentland use types was grapery garden＞vegetable soil＞corn soil＞peach garden, theaverage content of DON in grapery garden was2.437times higher than that invegetable soil,3.348times higher than that in corn soil and7.921times higher than thatin peach garden. In peach garden, the change tendency of the average content of DON in differentmonths was July＞September＞August, the average content of DON in July was5.518times higher than that in September and6.074times higher than that in August. In cornsoil was September＞July＞August, the average content of DON in September was2.053times higher than that in July and4.360times higher than that in August. Ingrapery garden was July＞September＞August, the average content of DON in Julywas3.059times higher than that in September and6.723times higher than that inAugust. In vegetable soil was July＞September＞August, the average content of DONin July was1.499times higher than that in September and8.237times higher than thatin August. With months changing, the average content of DON in four different land usetypes was all decreased first and then increased.In July, with the increasing depth of profiles, DON content changes of the soilprofiles in peach garden were firstly increased then decreased to minimum and then felldown. DON content changes of the soil profiles in corn soil were decreased with theincreasing depth of profiles. In grapery garden and vegetable soil, the DON contentchanges of the soil profiles were decreased with the increasing depth of profiles. InAugust and September, the DON content changes of the soil in the four different landuse types were all decreased in general with the increasing depth of profiles, while indifferent layers had different fluctuation.(3) The study of the content of DOPIn July, the average content of DOP in the four different land use types was thecorn soil＞the grapery garden＞the peach garden＞the vegetable soil, and the averagecontent of DOP in the corn soil was1.129times higher than that in the grapery garden,1.481times higher than that in the peach garden and1.562times higher than that invegetables soil. In August, the average content of DOP in the four different land usetypes was the vegetable soil＞the corn soil＞the peach garden＞the grapery garden, andthe average content of DOP in the vegetable soil was1.863times higher than that in thecorn soil,2.558times higher than that in peach garden and2.696times higher than thatin grapery garden. In September, the average content of DOP in the four different landuse types was vegetable soil＞peach garden＞grapery garden＞corn soil, the averagecontent of DOP in vegetable soil was1.304times higher than that in peach garden,1.361times higher than that in grapery garden and1.472times higher than that in cornsoil.In peach garden, the change tendency of the average content of DOP in different months was September＞August＞July, the average content of DOP in September was1.885times higher than that in August and4.039times higher than that in July. In cornsoil the changes regulation was September＞August＞July, and the average content ofDOP in September was1.216times higher than that in August and2.417times higherthan that in July. In grapery garden the change regulation was September＞August＞July, the average content of DOP in September was1.904times higher than that inAugust and2.950times higher than that in July. In vegetable soil the change regulationwas August＞September＞July, the average content of DOP in August was1.041timeshigher than that in September and5.781times higher than that in July. With monthschanging, the average content of DON in the peach garden, the corn soil, the graperygarden was all increased, but in the vegetable soil it was increased first then decreased.In July, with the increasing depth of profiles, DOP content changes of the soilprofiles in peach garden were firstly increased and then decreased to minimum andfinally fell down. DOP content changes of the soil profiles in corn soil were decreasedwith the increasing depth of profiles. Both in grapery garden and vegetable soil, theDOP content changes of the soil profiles were increased first then decreased with theincreasing depth of profiles. In August and September, the DOP content changes of thesoil in four different land use types were all decreased in general with the increasingdepth of profiles, while in different layers had different fluctuation.(4) The correlation among soil DOC, DON, DOP content and other soil nutrientCorrelation analysis showed that:1)any two of the three elements content values ofthe four different land use types showed a remarkable positive correlation trend exceptthe content of DOC、DON in the corn field as well as the peach garden and the contentof DOC、DOP in the corn field;2)the soil DOC,DON,DOP content of the four differentland use types and other soil nutrient had correlation with different levels, and themajority of the indicators could arrived the standard of marked positive correlation. |
PDF Full Text Request