长期定位施肥对棕壤重金属全量及其有效性影响

以沈阳农业大学长期定位试验为基础,选取（0～20cm）不同年限土壤样品,分析了无肥对照（CK）、单施化肥（N4P2）、中量有机肥（M2）、高量有机肥（M4）和高量有机肥＋化肥（M4＋N2P1）5个处理下土壤重金属元素Cu、Zn、Pb和Cd全量及其有效态含量的变化。结果表明,20多年的定位施肥增加了土壤中重金属元素Cu、Zn、Pb和Cd全量,虽然有所波动但总的趋势明显,其中以M4＋N2P1处理对Cu和Zn增加最为明显,而Pb和Cd在M4处理增长量最大,单施N4P2处理对4种重金属元素全量影响不明显。施有机肥能显著提高Cu、Zn和Cd有效态含量,与对照相比分别平均提高61.28%、169.3%和123.7%,不同施肥处理土壤中Cd含量已超标,属污染水平。有效态Pb在N4P2处理要显著高于其他各处理,而各年份M4处理有效态Pb的含量要低于CK处理。20年来有效态Pb含量相对于CK平均降低了4%。土壤中4种重金属全量与其有效态含量相关性表明：Cu、Zn和Cd全量与其有效态含量呈极显著正相关关系,全量Pb与有效态Pb呈显著负相关而与有效态Cu和Zn不显著相关。

Effects of Long-term Located Fertilization on Heavy Metals and Their Availability in Brown Earth

Based on the long-term located experiment in Shenyang Agricultural University,the contents of heavy metals（Cu,Zn,Pb and Cd） in soil were determined in five treatments,such as no fertilizer contro（lCK）,a single application of chemical fertilizer（N4P2）,the moderate level of organic manure（M2）,high level of organic fertilizer（M4）,and high level of organic manure mixed with chemical fertilizer（M4＋N2P1）.The results showed that after 20 years of applying fertilization,the contents of Cu,Zn,Pb and Cd in soil increased generally.Treatments with high organic manure mixed with chemical fertilizers made significant impacts for Cu and Zn.While the Pb and Cd contents were increased significantly in M4.Chemical fertilizer treatmen（tN4P2）had not affected the contents of Cu,Zn,Pb and Cd.The available contents of Cu,Zn,Cd and Pb in soil were enhanced in the treatments of manure applied,with the average increase of 61.28%,169.3% and 123.7% compared with CK.The contents of available Pb in N4P2 was significantly high compared with other treatments,and the contents of available Pb in M4 was lower than CK in different years.During the past 20 years,the content of available Pb reduced 4% compared with CK.The correlation and their availability showed that the contents of Cu,Zn and Cd highly were significant positive correlation.The content of Pb and its availability were significantly negative related and not significantly related with available Cu and available Zn in soils.