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土壤速效态微量元素测定值与植物吸收的相关性研究

Study on Correlation of Measured Values of Soil Available Trace Elements and Plant Uptake

【作者】 仝淑慧

【导师】 王莉;

【作者基本信息】 山西师范大学 , 生态学, 2012, 硕士

【摘要】 锌、铜、铁、锰是植物必须的微量元素,在植物体中主要是生命活动的活化剂以及组成酶、辅酶的成分,它们的作用较多且专一性很强,如果缺乏就可能成为限制因子影响农作物的产量和品质。植物所利用的微量元素主要来自土壤,因此能够及时根据土壤养分状况合理施肥就显得尤为重要,而进行土壤有效养分的测定正是合理施肥的基础。我国传统的土壤有效锌、铜、铁、锰的测定采用常规方法,酸性土用0.1mol·L-1的盐酸溶液,中性和石灰性土壤通常采用DTPA浸提剂。DTPA浸提土壤是非平衡体系,土样细度、重量、土液比例、振荡强度、振荡时间、浸提温度、浸提剂pH值等都应标准化,且浸提时间长,对大批量样品来说效率较低,分析结果难于及时指导农业生产实践。我国科学工作者相继引进了国外的土壤养分状况系统研究法(ASI法)和Mehlich3法(M3法)等联合浸提剂并作了相关研究。本研究选用ASI法和M3法对我国北方四种主要农田耕地土壤褐土、潮土、棕壤和黑土进行有效锌、铜、铁、锰的浸提,与DTPA法的测定值进行相关性分析和差异性比较,并且结合Tessier多级连续提取法对ASI法和M3法的浸提特征进行了初步探讨,同时进行了盆栽试验以检验ASI法有效锌、铜、铁、锰测定值与植物吸收的相关性,来探讨ASI法在我国北方四种主要农田土壤上测定有效锌、铜、铁、锰的适用性。本论文的主要研究结果与结论如下:(1)ASI法和M3法测定我国北方主要农田土壤有效态Zn、Cu、Fe、Mn和DTPA法相关性极显著(p<0.01),可以替代DTPA法应用于推荐施肥。ASI法和M3法测定土壤有效养分效率大大高于DTPA法,并且三种方法所得到的结论是不一致的。(2)经Tessier法进行ASI法、M3法和DTPA法浸出特征分析,有效态Zn主要浸出交换态和碳酸盐结合态,浸出了少部分铁锰结合态、有机结合态和残渣态,有效态Cu主要浸出交换态和有机结合态,浸出了少部分碳酸盐结合态、铁锰结合态和残渣态。ASI法和M3法对铁锰氧化物结合态和残渣态的浸出高于DTPA法,而有机结合态的浸出低于DTPA法。ASI法、M3法和DTPA法浸出的有效态是土壤溶液中金属离子的活度和这些离子由土壤固相解析补充到溶液中的量的总和。在测土配方施肥时应考虑三种方法的浸出特征,建立相应的微量元素丰缺临界指标。(3)ASI有效Zn、Cu、Fe、Mn测定值与小麦生物量均没有达到显著水平(n=40P>0.05),ASI有效Cu、Fe测定值与小麦吸收Cu、Fe的量均没有达到显著水平(n=40P>0.05),ASI有效Zn、Mn测定值与小麦吸收Zn、Mn的量相关性达到显著水平(n=40P<0.05)。以ASI法临界值的2.5倍为土壤微量元素补充量,小麦吸收Zn是合理有效的,但是小麦吸收Cu、Fe和Mn是不合理且无效的。在我国北方主要农田土壤上确立ASI法土壤养分丰缺指标尚待进一步的研究,使ASI法可以更合理的应用到我国现代农业生产,为合理施肥提供更为科学合理的参考。

【Abstract】 The trace elements of Zn, Cu, Fe, and Mn are necessarynutrients for plants. They play a number of functions and havestronger specificity, and are mainly the activators of the lifeactivities as well as the composition of enzyme and coenzyme in theplantkindom. The shortage of these elements will result into adecrease in crop yield and quality, and become the limiting factorsfor plant growth.The trace elements utilized by plant mainly come from the soils.Therefore, timely and reasonable fertilization based on soil nutrientstatus is particularly important. Moreover, the exactly testing forsoil available nutrient is a base for the reasonable fertilization. InChina, the conventional methods has been used for traditionaltesting for available Zn, Cu, Fe, and Mn in soils. For example, thedetermination of trace elements in the acid soil was extracted by0.1mol·L-1HCl solution, and the DTPA extracts reagent were used tousually extract the neutral and the calcareous soils. Because theDTPA extracting soil is a non-equilibrium system, the soil sample fineness, weight, soil liquid ratio, vibration intensity, vibration time,leaching temperature, and extracting reagent pH value should bestandardized. On the other hand, as much time is spent on thisextracting, and so extracting efficient is relatively lower for a largeamount of samples. Therefore, the analysis results are difficult tobe used for timely guiding the production practice of agriculture.Chinese scientists have introduced some foreign systematicresearch methods for soil nutrient status such as ASI method andMehlich3method (M3method), etc. and joint-extracts were used forrelative studies.In this study, ASI and M3methods were used to extract fourmain farmland soils in northern area of China including thecinnamon soil, moisture soil, brown soil and black soil for thedtermination of available Zn, Cu, Fe, and Mn, and performedcorrelation and difference analysis with measured values of theconventional methods, and the extracting characteristics of ASImethod and M3method was also assessed by combining with r fivestep sequential extraction from Tessier method. Meanwhile, a potexperiment was carried out to measure the relevance between theavailable Zn, Cu, Fe extracted by ASI method, and is expected toexplore the application possibility of ASI method in the four majorarable soils in northern China. The major conclusions are stated asfollows:(1) The determination of soil available Zn, Cu, Fe, Mn by boththe ASI and M3methods are significantly correlated with DTPAmethod for in the major agricultural soils in northern China(p<0.01),and ASI and M3methods can replace the DTPA method for application in soil testing and fertilizer recommendation. Thedetermination efficiency of soil available nutrient by the ASI and M3methods are significantly higher than that by DTPA method, and thatthe conclusions from the three methods are inconsistent.(2) Analysis on the extracting characteristic from ASI method,M3method, DTPA method and the Tessier method suggested thatavailable Zn extracted are mainly composed of exchangeable andcarbonate bound fractions with a little of iron manganese-bound,organic matter-bound and residuals. Available Cu extracted mainlyincludes exchangeable and organic matter bound fractions with apart of carbonate-bound, iron manganese bound, and residuals.Data showed that compared with DTPA method, ASI method and M3method could extract more available Zn, Cu fractions of ironmanganese-bound as well as the residual states, although theamounts of organic matter-bound forms extracted are lower. Theeffective states extracted by ASI method, M3method and DTPAmethod represents metal ion activity in soil solution and totalcapacity of these ions desorbed from the soil solid phase. Therefore,it is necessary that extracting characteristics from three methodsduring formula soil testing and fertilization should be consideredaccordingly to establish critical index of abundance and deficiencyof trace elements.(3) Both the determination values of available Zn, Cu, Fe, Mn byASI and wheat biomass are not reached significant correlation (n=40P>0.05), and determination value ofCu, Fe by the ASI and uptakeof Cu, Fe by wheat are not reached significant correlation (n=40P>0.05), while determination values of available Zn, Mn by the ASI and uptake of Zn, Mn by plant, are significantly correlated (n=40, P<0.05). We conclude that supplementation of the trace elementcould be2.5times of critical value by ASI method for the soil. Theuptake of Zn by wheat is reasonable and effective, but uptake of Cu,Fe and Mn is unreasonable and invalid, suggesting that theestablishment of ASI method for soil nutrient index remains to bestudied for providing more scientific and reasonable reference forreasonable fertilization in the northern farmland area of ourcountry.

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