Abstract: In order to understand the function of trace elements in agricultural system,the changes of Fe and Mn contents in soil-crop system in different rotation patterns were studied,which would offer theoretical help and production instruction for nutrient management.Four cropping patterns,which were wheatmaize(W-M),wheat-soybean (W-B),wheat-peanut (W-P) and wheat-sweet potato (W-S),were conducted in the rhizoboxes.And inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the contents of Fe and Mn in soil and crop plant samples.The accumulation amount of Fe and Mn in the above-ground part of different crops and the enrichment coefficients of different crops in maturity stage were calculated.The results showed that,the Fe and Mn contents in the above-ground part of wheat and summer crop in W-M and W-B modes were increased gradually over each growth stage.However,in W-P mode,the Fe content was gradually decreased in the above-ground part of wheat.And the Fe and Mn accumulation amounts in the above-ground part of summer crop in W-P mode showed a trend of climbingup first and then dropping-down with different growth satge.In W-S mode,the accumulation amount of Fe and Mn in the above-ground part of wheat gradually increased,but the accumulation amount of Fe and Mn in the above-ground part of the summer crop increased first and then decreased with different growth satge.The contents of Fe and Mn in soils gradually decreased in different rotation patterns.In 0—20 cm and 20—50 cm soil layers,the W-M model had the highest Fe and Mn content in October 2018,but in the depth of 50—80 cm soil layer,the W-B and W-S modes had higher Fe and Mn content in October 2018.And the Fe enrichment coefficients of different crops were less than Mn.The enrichment coefficient of Fe and Mn in W-S mode were the highest in wheat.The Fe enrichment coefficient of W-M mode was highest in summer crop,and the Mn enrichment coefficient of W-B mode was highest in summer crop at the same time.

Key words: Rotation mode, Soil-crop system, Trace element, Fe, Mn, Accumulation amount, Enrichment coefficient

摘要： 为探讨微量元素在农业生产中的作用，研究不同轮作模式下土壤-作物系统内Fe、Mn含量变化，为基于轮作模式的土壤-作物系统中Fe、Mn养分管理提供理论依据和生产指导。采用根箱试验方法，设置了小麦-玉米（W-M）、小麦-大豆（W-B）、小麦-花生（W-P）和小麦-甘薯（W-S）4种轮作模式，使用电感耦合等离子体质谱法（ICP-MS）测定不同处理土壤与作物体内Fe、Mn含量，计算作物地上部Fe、Mn累积量和成熟期Fe、Mn富集系数。结果表明，W-M、W-B模式下小麦和夏季作物地上部Fe、Mn含量均随生育时期的推进而逐渐增加，而W-P模式小麦地上部分Fe含量则逐渐递减；W-P模式夏季作物地上部分Fe、Mn累积量随生育时期的推进呈先增加后减少的趋势，W-S模式小麦地上部分Fe、Mn累积量均随生育时期的推进而逐渐增加，但是夏季作物地上部分Fe、Mn累积量均随生育时期的推进先增加后减少。在不同轮作模式下，土壤中Fe、Mn含量均逐渐减少；在0~20、20~50 cm土层深度，W-M模式在2018年10月Fe、Mn含量均最高，在50~80 cm土层深度，W-B、W-S模式在2018年10月Fe、Mn含量较高；不同作物在表层土壤中的Fe富集系数均小于Mn；小麦Fe、Mn富集系数均为W-S模式最高；夏季作物W-M模式Fe富集系数最高，W-B模式Mn富集系数最高。

关键词: 轮作模式, 土壤-作物系统, 微量元素, 铁, 锰, 累积量, 富集系数