【作者】 刘景；

【导师】 吕家珑； 徐明岗；

【作者基本信息】 西北农林科技大学 ， 农业环境保护与食品安全， 2009， 硕士

【摘要】 对起始于1990年左右的三种典型土壤旱地红壤、中层黑土和灰漠土长期肥料试验进行了分析研究,以阐明土壤重金属全量及有效态时间和空间上的演变特征及其原因和长期施肥对红壤作物重金属含量的影响及安全风险,研究结果表明:在红壤和黑土的有机肥处理(M)和有机肥加化肥处理(NPKM),高量有机肥加化肥(1.5NPKM)处理中存在土壤Cu风险;Zn元素在红壤和黑土的NPKM\1.5NPKM\M处理略微上升,灰漠土Zn含量呈下降的趋势。红壤和黑土在NPKM\1.5NPKM\M处理中随着施肥年限的增加Cd含量上升显著,红壤NPKM和M处理中Cd含量2006年分别为1.48mg/kg和1.31mg/kg,年平均上升0.09mg/kg和0.08mg/kg,达到极显著水平(rNPKM2= 0.8871** rM2=0.9459**, n=6)。Cr元素在红壤和黑土没有风险。Pb元素在三种土壤均没有风险。红壤施有机肥(猪粪)处理存在Cu、Cd污染,黑土施有机肥(牛粪)处理存在Cu、Zn、Cd污染,灰漠土中没有重金属风险。红壤NPKM处理中Cu含量超过国家二级标准,在NPKM和M处理中土壤Cd含量均超过的国家环境质量三级标准。黑土NPKM处理土壤Cd含量超过国家二级标准,1.5NPKM处理中土壤Cd含量超过国家三级标准。红壤的土壤环境质量超标严重,应予以重视。红壤和黑土的有效Cu、有效Pb含量在NPKM\1.5NPKM\M处理都成上升趋势,快慢为红壤大于黑土,灰漠土的有效Cu含量16年基本持平。有效Zn在三种土壤的变化基本一致,对照(CK)和化肥处理(N\NP\NK\KP\NPK)的处理含量变化不明显,NPKM\1.5NPKM\M肥处理的有效Zn随年份呈上升趋势,上升的快慢为红壤大于黑土大于灰漠土。有效Cd三种土壤均有所上升,其中红壤上升的最快,NPKM和M处理的土壤有效Cd含量从试验起始的0.03 mg/kg分别上升到2006年的0.53 mg/kg和0.58 mg/kg,呈极显著的线性上升趋势(rNPKM2=0.883** rM2=0.952**,n=5)。黑土和灰漠土都表现为后期有机肥处理的有效态Cd略有上升,且灰漠土后期N处理的有效态Cd也略有增加。红壤有效态Cd和黑土有效态Cu、Cd在对照(CK)和化肥处理(N\NP\NK\PK\NPK)含量高低取决与pH和全量含量的变化,pH越低,有效态含量越高,全量越高,有效态含量也越高。NPKM\1.5NPKM\M处理中红壤有效态Cd含量与pH和全量含量的呈极显著正相关,黑土有效态Cu、Cd含量与有机质和全量都的呈极显著正相关。红壤对照(CK)和化肥处理(N\NP\NK\KP\NPK)的Cu活化率变化不显著,Cd的活化率高于Cu,且随时间呈显著上升趋势。红壤Cd的活化率与土壤pH呈显著的负相关,在酸化严重的氮处理(N)上活化率达95.7%。NPKM\1.5NPKM\M处理有机肥的红壤Cu、Cd的活化率随施肥年限呈显著的上升趋势,且Cd活化率与土壤有机质含量呈显著正相关。黑土Cu活化率变化不显著,Cd活化率在化肥和有机肥处理都上升。黑土Cu、Cd活化率在对照(CK)和化肥处理(N\NP\NK\KP\NPK)处理中与pH值呈负相关关系,在NPKM\1.5NPKM\M处理中,与有机质含量呈正相关。2006年红壤玉米和籽粒在1.5NPKM处理和M处理存在Cu累积,玉米秸秆存在着Zn累积,玉米和小麦的籽粒秸秆Pb含量在NPKM处理、1.5NPKM处理和M处理玉米秸秆Pb含量较低,化肥处理偏高。小麦和玉米籽粒和秸秆Cd含量都在NPKM和1.5NPKM处理较高,土壤有效态Cd含量与小麦籽粒和玉米籽粒的Cd含量均达到了显著的正相关关系(r小麦2=0.8623,n=6)(r玉米2=0.7694,n=5),土壤有效Cd含量越高,籽粒中的Cd含量也越高,存在着严重的Cd污染的安全风险。Cu元素的富集系数在玉米籽粒NPK处理中最高,为133.88%。Zn元素的富集系数小麦籽粒高于玉米籽粒,且小麦籽粒在施N处理上高达712.34%。Pb元素玉米籽粒的富集系数高于小麦。Cr元素小麦籽粒的富集系数高于玉米,且在施化肥处理中小麦籽粒的富集系数可高达2954.81%。Cd元素小麦和玉米籽粒的富集系数从对照处理到化肥处理再到有机肥处理富依次降低,且玉米的富集系数大于小麦。小麦、玉米籽粒Pb、Cd和Cr元素含量都有超标现象,小麦各处理籽粒中Pb元素全部超标,玉米籽粒Pb在N、NPK处理超标严重,为国家标准的6-7倍。Cr元素由于红壤中的背景值较高,作物中的Cr元素超标。小麦籽粒在NPKM和1.5NPKM处理中Cd严重超标,存在较高的粮食安全风险。更多还原

【Abstract】 this paper studies on the change of the heavy metals and with time and space in the situation of long-term fertilization in three typical soil of our country. Meantime, studies on effect of long-term fertilization on heavy metal content and quality risk in crop. Results showed as follows:There were copper risks in the M and MPKM fertilizer treatments in red soil and blank soil. Zn in the M fertilizer treatment in blank soil increased slightly, decreased in gray desert soil. Cd in the M fertilizer treatment in red soil and blank soil increased by fertilized year significantly. The contents of Cd were 1.31~1.48 mg/kg in 2006,and annual increased 0.09 mg/kg and0.08 mg?kg-1 .in NPKM and M fertilizer treatments. Cd had no risks in red soil and blank soil. Pd had no risks in the three kind of soil.There was pollution with Cd and Zn that application of organic manure(pig manure) in red soil ,and application of organic manure(cow dung)in black soil had Cu, Zn, Cd risk.There was no risk of heavy metal pollution in gray desert soil. The content of Cu in NPMK fertilizer treatment in red soil more than secondary national standards. In NPKM and M fertilizer treatments, the content of Cd in red soil more than tertiary national environmental quality standards. In NPKM fertilizer treatment,the content of Cd in black soil more than national standards,In 1.5NPKM fertilizer treatment,the content of Cd more than tertiary national environmental quality standards. Red soil environmental quality standard seriously, should take it seriously.Extractable Cu and extractable Pb in the NPKM and1.5NPKM fertilizer treatments had an upward trend, their speed followed by red soil > blank soil, extractable Cu in gray desert soil had a Stable level for 16 years. The changes of extractable Zn in three kinds of soil had a same trend, and did not change significantly in the CK, N, NP, NK, PK and NPK fertilizer treatments, extractable Zn in the NPKM and 1.5NPKM fertilizer treatments increased by years, speed follow by red soil > blank soil > gray desert soil. Extractable Cd in three kinds of soil both raised, in which extractable Cd changed fastly, extractable Cd in the NPKM and M fertilizer treatments raised from 0.03 mg kg-1 in beginning of experiment to 0.53 mg kg-1 and 0.58 mg kg-1in 2006 and it were increased significantly with time. Extractable Cd in the M treatment in the blank soil and gray desert soil, extractable Cd in N fertilizer treatment in gray desert soil increased slightly in end of experiment. The content of red soil extractable Cd and black soil extractable Cu, Cd depends on PH and changes of total contents in CK and fertilizer treatment (N\NP\NK\PK\NPK), The lower PH, the higher extractable. The higher total contents, the higher extractable. red soil extractable Cd had a highly significant positive correlations with PH and total contents, black soil extractable Cu, Cd had a highly significant positive correlations with organic matter and total content in organic fertilizer treatment.The activity index of Cu in CK and N\NP\NK\PK\NPK fertilizer treatment didn’t significantly change, and The activity index of Cd was higher than Cu in the red soil, and there were rising significantly trend with time. The activity index of Cd of red soil and soil pH was significantly negatively correlated, its activity index was 95.7% in the N fertilizer of serious acidification treatment. The activity index of Cu and Cd were rising significantly trend with the fixed number of fertilization years in red soil which was combined application by NPKM or M fertilizer treatment, and The activity index of Cd had a significant positive correlation with the soil organic matter content. The activity index of Cu and Cd in black soil had a significantly negative correlation with pH value in CK and N\NP\NK\PK\NPK fertilizer treatment, on the contrary, they had a positive correlation in the NPKM\1.5NPKM\M treatment.In red soil, there was the content of Cu accumulation in 1.5NPKM and M fertilizer treatments of maize grains 2006, the content of Zn accumulation in corn straw. The content of Pb in corn straw was low in NPKM, 1.5NPKM and M fertilizer treatments, the content in chemical fertilizer treatment is high in straw and grain of maize and wheat. The content of Cd in straw and grain of maize and wheat were more high in M fertilizer treatment. Extractable Cd content in soil positive correlation with maize grains and wheat grains(r 2=0.8623,n=6)( r 2=0.7694,n=5). The extractable Cd content in soil increased with the content of Cd in grains. There was a serious security risk of Cd pollution.The enrichment coefficient of Cu in maize grains was the highest in NPK fertilizer treatment(133.88%). Not only enrichment coefficient of Zn in wheat grains higher than in maize grains,but also in N fertilizer treatment ,up to 712.34%. The enrichment coefficient of Pb in maize grains were higher than in wheat grains.The enrichment coefficient Cr in wheat grains were higher than maize grains, the enrichment coefficient of Cr in wheat are up to 2954.81% in chemical fertilizer treatments. The enrichment coefficient of Cd in treatments sort high to lowis: CK,chemical fertilizer,organic fertilizer,and enrichment coefficient in wheat is hiher than in wheat.It was Over the phenomenon that the content of Pb,Cd,Cr in wheat and in maize of red soil. Pb contents was over the phenomenon in all fertilizer treatments in wheat. The content of Pb in maize grains was over the phenomenon serious sixfold to septuple than national standard. As a result of higher background value, the content of Cr will be over standard. The content of Cd in maize grains exceeded seriously,in NPKM and 1.5NPKM fertilizer treatments. There are serious food security risk.更多还原