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1、第六章 土壤微量元素Chapter 6 Micronutrients in Soil高等植物必需的营养元素（16+1 或+2）C,H,O,N,P,K,Ca,Mg,S,Cu,Zn,Mn,Fe,B,Mo,CI,Ni，Co大量元素微量元素Other elements, such as silicon (Si), vanadium (V), and sodium (Na), appears to improve the growth of at least certain plant species. Animals, including humans, also requires most iodi
2、ne (I), and fluorine (F), have been shown to be essential for animal growth but are apparently not required by plants. uIntensive plant production practices have increased crop yields, resulting in greater removal of micronutrients from soils.uThe trend toward high-analysis fertilizers has reduced t
3、he use of impure salts and organic manures, which formerly supplied significant amounts of micronutrients.uIncreased knowledge of plant nutrition and improved methods of analysis in the laboratory are helping in the diagnosis of micronutrient deficiencies that might formerly have gone unnoticed.uInc
4、reasing evidence indicates that food grown on soils with low levels of trace elements may provide insufficient human dietary levels of certain elements, even though the crop plants show no signs of deficiency themselves.为何微量元素营养问题越来越重要？The extent of micronutrient-deficient soils are comparable to th
5、at of nitrogen-, phosphorus-, and potassium-deficient soils. Summary data (Table 1) from an extensive effort that examined 190 soil samples from 15 countries revealed that 49% of these soils were low in zinc and 31% low in boron (Sillanpaa, 1990). Today, there are over 3.7 billion iron-deficient ind
6、ividuals and about 1 billion people that are or are at risk of developing iodine deficiency disorders. Additionally, there are over 200 million people that are vitamin A deficient (World Health Organization, 1999). Other micronutrient deficiencies (e.g., Zn, Se, vitamin C, vitamin D, and folic acid
7、deficiencies) may be as wide spread as iron, iodine and vitamin A deficiencies, but there are no reliable data to confirm this although circumstantial evidence suggests that this may be so (Combs et al., 1996; World Health Organization, 1999).Welch R M. The impact of mineral nutrients in food crops
8、on global human health. Plant and Soil 247: 8390, 2002.对人体健康的影响？Figure 1. Global distribution of Fe, vitamin A and I deficiencies (map modified from Sanghvi, 1996).Toxicity of some micronutrient in soils. Expanding interests in the field of heavy metal research were associated with increasing world-
9、 production of metals and their common usage in the past century, and consequently, with their increasing emissions into the environment. This resulted in growing hazard to humans health posed by elevated metal concentrations in air, water, and food.The most important sources of heavy metals in soil
10、s are those connected with anthropogenic activities, such as metal mining and smelting, production and usage of pesticides and wood preservatives, waste processing and disposal, etc.Characteristics of micronutrient nutrition需要量少，但不可替代缺乏多呈一定的区域性适宜浓度范围较窄1.微量元素的生物地球化学循环2.土壤中不同微量元素的含量、形态、 转化及有效性3.土壤微量元素
11、与地方病4.微量元素污染及治理1.微量元素的生物地球化学循环生物地球化学循环(Biogeochemical cycle)生态系统从大气、水体及土壤等环境中获得营养物质，通 过绿色植物吸收，进入生态系统，被其它生物重复利用， 最后再归还于环境的过程。生物地球化学循环的过程研究主要是在生态系统水 平和生物圈水平上进行的。生产者 消费者 分解者 非生物环境（无机环境）生物地球化学循环的类型植物消费者落叶层土壤土壤溶液沉积型循环消费者落叶层微型分解者土壤溶液植物微生物大气气体型循环 气体型循环 沉积型循环 气体型循环 沉积型循环微量元素的生物地球化学循环氯，溴，氟等循环。铁，锰，铜，锌等循环Human
12、s have long influenced Zn inputs to soils. Two thousand years ago, approx. 10 000 tones Zn yr1 were emitted as a result of mining and smelting activities .Since 1850, emissions have increased 10-fold, peaking at 3.4 Mt Zn yr1 in the early 1980s, and then declining to 2.7 Mt Zn yr1 by the early 1990s
13、. The ratio of Zn emissions arising from anthropogenic and natural inputs is estimated to be 20:1. 人类活动对微量元素循环的影响Other anthropogenic inputs of Zn to soils：lfossil fuel combustion, lmine waste, lphosphatic fertilizers (typically 501450 g Zn g1), llimestone (10450 g Zn g1), lmanure (15250 g Zn g1), ls
14、ewage sludge (91 49 000 g Zn g1), lother agrochemicals lparticles from galvanized (Zn-plated) surfaces and rubber mulches.土壤中微量元素的循环Plant uptakeM+n MChe (Soil solution)Removal in harvestBiomassResiduesInsoluble formOrganic chelatesM+nCO2Decay2. Contents, forms and availability of micronutrients in s
15、oilsThe initial trace element content of soils reflects the materials from which they form, but pedogenic processes and landscape age introduce much variation.Iron, Zn, Mn, and Cu are somewhat more abundant in basalt; B and Mo are more concentrated in granite.花岗岩 玄武岩 页岩 石灰石 砂岩 辉长岩 斜长石 辉石 橄榄石Advances
16、 including the global positioning system (GPS), geographic information systems (GIS), inductively coupled plasma (ICP) spectrometry, geostatistics, and precision agriculture facilitate soil micronutrient mapping and provide quantitative support for decision and policy making to improve agricultural approaches to balanced micronutrient nutrition.Mapping soil micronutrientsField Crops Research, 60
