植物營養(yǎng)元素的土壤化學(xué)土壤中的微量元素

1、會計學(xué)1植物營養(yǎng)元素的土壤化學(xué)土壤中的微量植物營養(yǎng)元素的土壤化學(xué)土壤中的微量元素元素uIntensive plant production practices have increased crop yields, resulting in greater removal of micronutrients from soils.uThe trend toward high-analysis fertilizers has reduced the use of impure salts and organic manures, which formerly supplied significa

2、nt 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.uIncreasing evidence indicates that food grown on soils with low levels of trace

3、elements may provide insufficient human dietary levels of certain elements, even though the crop plants show no signs of deficiency themselves.為何微量元素營養(yǎng)問題越來越重要？為何微量元素營養(yǎng)問題越來越重要？The extent of micronutrient-deficient soils are comparable to that of nitrogen-, phosphorus-, and potassium-deficient soils.

4、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 individuals and about 1 billion people that are or are at risk o

5、f 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 deficiencies) may be as wide spread as iron, iodine and vitam

6、in 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 on global human health. Plant and Soil 247: 8390, 2002.對人體健康的

7、影響？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-production of metals and their common usage in the past centu

8、ry, 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 soils are those connected with anthropogenic activities, such as m

9、etal mining and smelting, production and usage of pesticides and wood preservatives, waste processing and disposal, etc.Characteristics of micronutrient nutrition 需要量少，但不可替代需要量少，但不可替代 缺乏多呈一定的區(qū)域性缺乏多呈一定的區(qū)域性 適宜濃度范圍較窄適宜濃度范圍較窄1.微量元素的生物地球化學(xué)循環(huán)2.土壤中不同微量元素的含量、形態(tài)、轉(zhuǎn)化及有效性3.土壤微量元素與地方病4.微量元素污染及治理1. 1.微量元素的生物地球化學(xué)循

10、環(huán)微量元素的生物地球化學(xué)循環(huán)生物地球化學(xué)循環(huán)(Biogeochemical cycle)生態(tài)系統(tǒng)從大氣、水體及土壤等環(huán)境中獲得營養(yǎng)物質(zhì)，通過綠色植物吸收，生態(tài)系統(tǒng)從大氣、水體及土壤等環(huán)境中獲得營養(yǎng)物質(zhì)，通過綠色植物吸收，進(jìn)入生態(tài)系統(tǒng)，被其它生物重復(fù)利用，最后再歸還于環(huán)境的過程。進(jìn)入生態(tài)系統(tǒng)，被其它生物重復(fù)利用，最后再歸還于環(huán)境的過程。生物地球化學(xué)循環(huán)的過程研究主要是在生態(tài)系統(tǒng)水平和生物圈水平上進(jìn)行的。生產(chǎn)者生產(chǎn)者消費者消費者分解者分解者非生物環(huán)境（無機環(huán)境）非生物環(huán)境（無機環(huán)境）生物地球化學(xué)循環(huán)的類型生物地球化學(xué)循環(huán)的類型植物植物消費者消費者落葉層落葉層土壤土壤土壤溶液土壤溶液沉積型循環(huán)沉積型

11、循環(huán)消費者消費者落葉層落葉層微型分解者微型分解者土壤溶液土壤溶液植物植物微生物微生物大氣大氣氣體型循環(huán)氣體型循環(huán)氣體型循環(huán)氣體型循環(huán)沉積型循環(huán)沉積型循環(huán)氣體型循環(huán)氣體型循環(huán)沉積型循環(huán)沉積型循環(huán)微量元素的生物地球化學(xué)循環(huán)微量元素的生物地球化學(xué)循環(huán)氯，溴，氟等循環(huán)。鐵，錳，銅，鋅等循環(huán)Humans have long influenced Zn inputs to soils. Twothousand years ago, approx. 10 000 tones Zn yr1 were emitted as a result of mining and smelting activities .

12、 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. The ratio of Zn emissions arising from anthropogenic and natural inputs is estimated to be 20:1. 人類活動對微量元素循環(huán)的影響人類活動對微量元素循環(huán)的影響Other anthropogenic inputs

13、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), lsewage sludge (91 49 000 g Zn g1), lother agrochemicalslparticles from galvanized (Zn-plated) surfaces and rubber mulches.土壤中微量元素的循環(huán)土壤中微量元素的循

14、環(huán)Plant uptakeM+n MChe(Soil solution)Removal in harvestBiomassResiduesInsoluble formOrganic chelatesM+nCO2Decay2. Contents, forms and availability of micronutrients in soilsThe initial trace element content of soils reflectsthe materials from which they form, but pedogenicprocesses and landscape age

15、introduce much variation.Iron, Zn, Mn, and Cu are somewhat more abundant in basalt; B and Mo are more concentrated in granite.花崗巖花崗巖玄武巖玄武巖頁巖頁巖石灰石石灰石砂巖砂巖輝長巖輝長巖斜長石斜長石輝石輝石橄欖石橄欖石Advances including the global positioning system (GPS), geographic information systems (GIS), inductively coupled plasma (ICP)

16、 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 (1999) 11-26Example

17、Fig. 5. Map of kriged estimates of total soil zinc for the conterminous USA classed by deciles using data from USGS and USEPA soil studies (White et al., 1997). Crosses indicate sites of three high-zinc outliers excluded from the USGS data set.ExampleFig. 3. Geographic distribution of low-, variable

18、-, and adequate-selenium areas in the USA (after Kubota and Allaway, 1972).uWeathering of underlying parent materials, uNatural processes (e.g., gases from volcanic eruption, rain/snow, marine aerosols, continental dust, forest firesuAnthropogenic processes (industrial and automobile discharges, add

19、ition of fertilizers, lime, pesticides, manures, sewage sludges).Available micronutrients in soil are derived from:Contents of different micronutrients in soils of China（mg/kg）MicronutrientBZnMnFeCuMoRange0-5003-79042-300010000-1000003-3000.1-6Mean64100710221.7Forms of micronutrients dominant in the

20、 soil solutionBZnMnFeCuMoCICoNiH3BO3, H2BO3-Zn2+，Zn(OH)+Mn2+Fe2+, Fe(OH)2+, Fe(OH)2+, Fe3+Cu2+, Cu(OH)+MoO42-, HMoO4-CI-Co2+Ni2+,Ni3+It is bio-available metal species present in soil solution rather than high amounts of metals in solid phase that cause adverse biological effects on soil biota, contr

21、ol the uptake of metals by higher plants, and their input into the food chain.Speciation of trace metalsSpeciation (in the context of soils) refers to both the process and the quantification of the different defined species, forms and phases of a trace element. The speciation of trace metals in soil

22、s is related to their biogeochemical reactivity and to several physicochemical conditions of the soil.qWater-solubleAs free cationAs complexes with organic and inorganic ligandsqOn exchange sites of clay minerals (can be extracted with a weak exchanger, such as NH4+)qSpecifically adsorbed (Some trac

23、e elements (e.g., Cu2+) are retained by clay minerals and/or Fe and Mn oxides in the presence of a large excess of Ca2+ or some other electrostatically bounded cation)qAdsorbed or complexed by organic mattersqAs insoluble precipitates, including occlusion by Fe and Mn oxidesqAs the primary mineralsF

24、orms of micronutrients in soilFractionation of micronutrients in soilThe sequential fractionation scheme: Based on the ability of certain solvents to remove specific bound forms of the metal. Forms of Copper1. Soil solution2. Exchangeable3. Specifically adsorbed-4. Oxide occluded5. Biologically occl

25、uded6. Mineral latticeOn ClayOn O.M.On OxidesCaCl2Acetic acidK. pyrophosphateOxalate + UVHFStevenson FJ, 1986. pp-342土壤中一些金屬離子可與土壤中存在的有機物，如腐殖質(zhì)、蛋白質(zhì)、有機酸等土壤中一些金屬離子可與土壤中存在的有機物，如腐殖質(zhì)、蛋白質(zhì)、有機酸等絡(luò)合。絡(luò)合。有機物中具有絡(luò)合作用的基團(tuán)有機物中具有絡(luò)合作用的基團(tuán)?羥基羥基 OH羧基羧基 COOH羰基羰基 =CO氨基氨基 NH2亞氨基亞氨基=NH金屬離子 + 絡(luò)合物金屬離子-絡(luò)合物Metal ion + chelateMeta

26、l ion-chelate穩(wěn)定常數(shù)（K, stability constant）K =Metal ionchelateMetal ionchelate穩(wěn)定常數(shù)越大，金屬離子與絡(luò)合劑結(jié)合的能力越強，形成的絡(luò)合物越穩(wěn)定。 Nutrients in chelate formsNutrients in chelate forms甘氨酸酒石酸EDTAEDTA:乙二胺四乙酸HEDTA:羥乙基乙二胺三乙酸EDDHA:乙二胺二鄰位苯酚乙酸Table Stability constants (Log K) for selected chelating agents and nutrient cationsChe

27、lating agentFe3+Fe2+Zn2+Cu2+Mn2+Ca2+Relative costEDTA25.014.2714.8718.7013.8111.04.4EDDHA33.914.316.823.94-7.243HEEDTA19.612.214.517.410.78.05.5Citrate8-Gluconate37.21.01.736.6-1.211.0Brady NC, Well RR. 1996Availability of micronutrients in soilUptake of micronutrients by plant i

28、s largely dependent on the availability of these elements in soils.The availability of micronutrients is not only related to the total contents of these elements in soil, but also to soil properties, such as soil pH, Eh, and texture, etc.qHighly leached, acid, sandy soilsqOrganic soilsqSoils of very

29、 high pHqSoils that have been very intensively cropped and heavily fertilized with macronutrient only Micronutrients are most apt to limit crop growth in 黃土高原地區(qū)黃土高原地區(qū)土壤多數(shù)微量元素含量分布具有明顯土壤多數(shù)微量元素含量分布具有明顯的從西北向東南逐漸增加的趨勢。的從西北向東南逐漸增加的趨勢。(其中其中B、Mo由西由西北向東南含量增加的趨勢不明顯北向東南含量增加的趨勢不明顯)黃土高原地區(qū)不同微量元素的含量水平：黃土高原地區(qū)不同微量元素

30、的含量水平：u鋅、錳含量中等偏低鋅、錳含量中等偏低u銅、硼中等銅、硼中等u鉬的含量很低鉬的含量很低原因？原因？1) CK (對照,N 60 kg/ hm2 + P 26. 4 kg/ hm2) ; 2) Zn ( NP, 施Zn , ZnSO4 15 kg/ hm2) ; 3) Mn (NP, 施Mn ,MnSO4 22.5 kg/ hm2) 4) Cu (NP, 施Cu , CuSO4 15 kg/ hm2)處理處理有效有效Cu有效有效Zn有效有效MnCK0.7760.561151.2Zn-2.568-Mn-191.3Cu5.240-長期施用微量元素肥料對土壤微量元素有效性的影響長期施用微量

31、元素肥料對土壤微量元素有效性的影響（mg/kg）1984-2003陜西陜西 長武長武(郝明德等郝明德等, 2006)基性火成巖發(fā)育的土壤含鋅量高于酸性巖q 礦質(zhì)態(tài)鋅q 交換態(tài)鋅q 水溶性鋅含鋅的礦物有：閃鋅礦、紅鋅礦、菱鋅礦等。 90% 2.1 Zinc(Zn)(1)Content(2)FormsExchangeable Zn typically ranges from 0.1 to 2 g Zn g1Concentrations of water-soluble Zn in the bulk soil solution are low, typically between 41010 and

32、 4106 M (Barber, 1995),Soil Zn fractions in the solid phase can be quantified using sequential extractions or isotopic dilution techniques (Young et al., 2006).FormsExtractantWater solubleH2OExchangeableKNO3Organically boundNa4P2O7Carbonate/noncrystalline iron occludedEDTAManganese oxide occludedNH2

33、OHCrystalline iron oxide occludedNa2S2O4SulphidesHNO3ResidualHNO3 + H2O2% of total soil ZnSoil from Indiana,USA0.210.07.53.332.3%(Miller & McFee, 1983). soil pH organic matter others (P in soil)一般認(rèn)為，土壤有機質(zhì)水平與有效鋅含量間呈正相關(guān)。但有機質(zhì)含量過高的土壤如泥炭土，鋅的有效性會降低。(3) Factors affecting Zn availability in so

34、ilpH值大于6-6.5時，鋅主要以Zn(OH)2形態(tài)存在，溶解度小。因此，土壤pH6.5, 土壤可能缺鋅。石灰性土壤上，鋅可與碳酸鹽反應(yīng)，形成沉淀。隨土壤pH值的變化,土壤中鋅的存在形態(tài) Zn2+Zn(OH)+Zn(OH)2Zn(OH)3-pH值3-46-88表 不同碳酸鈣含量塿土對鋅的吸附強度余存祖等，余存祖等，1984土土 壤壤施鋅量施鋅量mg/kgDTPA提取的鋅含量提取的鋅含量(mg/kg)吸附強吸附強度度(%)第一次第一次第二次第二次第三次第三次合計合計中鈣土壤中鈣土壤(CaCO3 73g/kg,OM 11.5 g/kg)01.340.700.532.62102.701.921.2

35、05.8268.010021.408.005.1034.5068.2高鈣土壤高鈣土壤(CaCO3 160g/kg,OM 4.1 g/kg)082.87101.561.360.903.8790.51007.402.962.1612.5290.4鋅的吸附可用Langmuir方程描述式中：式中：x表示吸附平衡時的吸附量表示吸附平衡時的吸附量 xm表示最大吸附量表示最大吸附量 Kl為為Langmuir吸附常數(shù)吸附常數(shù) C平衡時溶液中吸附物的濃度平衡時溶液中吸附物的濃度1lmlK CxxK CLangmuir吸附常數(shù)吸附常數(shù)xm、Kl被用于評價土壤對鋅的吸附特性被用于評價土壤對鋅的

36、吸附特性整理Langmuir方程得：1lmlK CxxK C1mlmCCxxK xCC/x1/xm1/Klxm表 不同質(zhì)地土壤對鋅吸附的Langmuir方程參數(shù)土土 壤壤顆粒組成顆粒組成%最大吸最大吸附量附量（Xm）吸附常吸附常數(shù)數(shù)K土壤吸持土壤吸持性性Xm.K0.01 mm0.001mm壩富黏層壩富黏層64.7331.205.7510.2161.243坡紅黏土坡紅黏土60.6833.855.0670.1460.740壩輕壤層壩輕壤層28.6413.443.8400.0980.377壩輕壤層壩輕壤層26.4613.413.7830.0990.375畢銀麗等，畢銀麗等，1997u石灰性土壤多采用

37、DTPA浸提，臨界指標(biāo)為 0.5mg/kg,u酸性土壤用 0.1 M 鹽酸浸提，臨界指標(biāo)為 1.5mg/kg 5.0很低低中高很高酸性土壤石灰性及中性土壤 4.0(4)How to evaluate Zn availability in soil? 我國缺鋅鋅土壤的分布主要分布在我國北方，與石灰性土壤的分布模式基本一致。包括黃潮土、棕壤、褐土、栗鈣土、灰鈣土、黃綿土和漠境土等。南方長江沖積物和南方石灰?guī)r母質(zhì)發(fā)育的土壤亦易發(fā)生缺鋅。表 鋅肥在土壤(塿土)中的殘留(mg/kg)施鋅量施鋅量1981.8.10不同時期土壤有效鋅含量不同時期土壤有效鋅含量鋅在土壤鋅在土壤中殘留率中殘留率（%）1981.

38、8.101982.9.131983.9.231984.9.2801.250.841.101.20-105.527.808.504.7035.010042.630.619.021.019.8余存祖等，余存祖等，1986土壤中含量較高南方土壤高于北方土壤2.2 Manganese(Mn)q 礦質(zhì)態(tài)錳q 易還原態(tài)錳q 交換態(tài)錳q 水溶性錳(1)Content(2)Forms與鐵鎂礦物共生，風(fēng)化釋放與鐵鎂礦物共生，風(fēng)化釋放易還原態(tài)錳為高價錳（通常為三價）；西北易還原態(tài)錳為高價錳（通常為三價）；西北干旱及半干旱區(qū)土壤含量干旱及半干旱區(qū)土壤含量19-254 mg/kg易還原態(tài)錳、交換態(tài)錳和水溶性錳總和稱為

39、活性錳黃土高原區(qū)交換性錳含量黃土高原區(qū)交換性錳含量, 3 mg/kgManganese（Mn） 錳在土壤中的轉(zhuǎn)化示意圖Mn2+Mn3+Mn2O3.nH2OMn4+MnO2.nH2OMnO2ReductionOxidation Soil pH Soil Eh 土壤pH值在4-9范圍內(nèi)，pH值每上升1個單位，土壤可給態(tài)錳會降低100倍。故缺錳多發(fā)生在pH值高的土壤上。(3) Factors affecting Mn availability in soiln多采用DTPA浸提，臨界指標(biāo)為7 mg/kg,或n活性錳（1M 醋酸銨+0.2%的對苯二酚），100mg/kg 300很低低中豐富過量活性錳D

40、TPA浸提錳 15(4)How to evaluate Mn availability in soil? Problem soils of Mn deficiencyManganese deficiencies are most common in sands, organic soils, high-pH calcareous soils, and in soil growing fruits, small grains, and leafy vegetables.Problem soils in China在我國，缺錳土壤主要為北方石灰性土壤，如黃潮土、棕壤、褐土、栗鈣土、灰鈣土、黃綿土和

41、漠境土等。南方酸性土壤大量施用石灰后，交換態(tài)錳減少，有時會導(dǎo)致“誘發(fā)性缺錳”。表 錳在土壤(塿土)中的殘效施錳量施錳量1981.5.23土壤有效錳含量（土壤有效錳含量（mg/kg）198119821985013.010.47.42026.016.210.820032.525.027.3余存祖等，余存祖等，1986(1)Contentq基性火成巖發(fā)育的土壤含銅量高于酸性巖q含硫礦物中銅的含量高n 礦質(zhì)態(tài)銅n 交換態(tài)銅n 水溶性銅(2)Forms含銅的礦物有：孔雀石、黃銅礦、輝銅礦等2.3 Copper (Cu) organic matter soil pH一般認(rèn)為，土壤有機質(zhì)水平與有效銅含量間呈

42、負(fù)相關(guān)。銅可被有機質(zhì)牢牢吸附或絡(luò)合。相對于鋅、錳來說，土壤pH對銅有效性的影響較小。(3) Factors affecting Cu availability in soilThe general order of affinity for metal cations complexed by organic matter follows: Cu2+ Cd2+ Fe2+ Pb2+ Ni2+ Co2+ Mn2+ Zn2+u石灰性土壤多采用DTPA浸提，臨界指標(biāo)為 1.mg/kg,u酸性土壤用 0.1 M 鹽酸浸提，臨界指標(biāo)為 1.9mg/kg(4) How to evaluate Cu avai

43、lability in soil? Problem soils of Cu deficiencyNewly cultivated organic soils (reclamation disease)Sandy soilsCalcareous soils with the high pHCompetition of copper with other metals (Al, Zn, Fe)我國缺銅銅土壤的分布從目前資料看，我國多數(shù)土壤有效銅含量較豐富從目前資料看，我國多數(shù)土壤有效銅含量較豐富或適中，但黃土區(qū)土壤有效銅含量較低。據(jù)水保或適中，但黃土區(qū)土壤有效銅含量較低。據(jù)水保所彭琳等研究，該區(qū)約

44、有所彭琳等研究，該區(qū)約有1/31/3土壤有效銅不足。特土壤有效銅不足。特別是質(zhì)地較粗、肥力低的土壤。別是質(zhì)地較粗、肥力低的土壤。另外，沼澤土、泥炭土易發(fā)生缺銅問題。另外，沼澤土、泥炭土易發(fā)生缺銅問題。表 銅在土壤(黑壚土)中的殘效施銅量（施銅量（mg/kg）1984.5土壤有效銅土壤有效銅（1985.7）小麥籽粒含銅小麥籽粒含銅00.863.711.133.852.375.7104.317.03011.597.5余存祖等，余存祖等，1986(1)Content是土壤含量最低的微量元素之一；含量與成土母質(zhì)關(guān)系密切。 2.4 鉬(Molybdenum, Mo)花崗巖母質(zhì)發(fā)育的土壤含鉬量高黃土母質(zhì)發(fā)

45、育的土壤含鉬量低黃土和黃土狀母質(zhì)發(fā)育的土壤全鉬含量為 0.21-1.45 mg/kg,平均為0.62 mg/kg，遠(yuǎn)遠(yuǎn)低于全國平均水平（1.7 mg/kg）(2)FormqAs anionic form（MoO42-, HMoO4-）qIts behavior in soil resembles phosphate or sulfateSoil pHTotal Mo content in soilMo availability in soil increases with soil pH土壤pH 3-6：鉬的吸附量最大；土壤pH 6: 鉬的吸附量減弱；土壤pH 8: 土壤膠體幾乎不再吸附鉬酸鹽

46、。(3) Factors affecting Mo availability in soilpH每增加一個單位，鉬酸根離子的濃度增大100倍！H2MoO4HMoO4- + H2OMoO42- + H2O+H+H+OH-+OH-多采用草酸-草酸銨浸提，臨界指標(biāo)為 0.15 mg/kg,(4) How to evaluate Mo availability in soil? Problem soils of Mo deficiencyMolybdenum deficiencies will be most common in acidic sandy soils, where leaching l

47、osses, strong molybdate adsorption, and few molybdenum minerals exist.我國缺鉬鉬土壤的分布 北方缺鉬，主要是由于成土母質(zhì)含鉬量極低； 南方土壤全鉬含量并不低，但由于鉬的有效性低，故土壤有效鉬含量不足。華北及黃土高原地區(qū)是我著名的低鉬區(qū)，估計約有華北及黃土高原地區(qū)是我著名的低鉬區(qū)，估計約有2/3耕地土壤鉬供應(yīng)不耕地土壤鉬供應(yīng)不足足(余存祖，余存祖，2004)Mo toxicitySoils which are high in Mo and give rise to herbage containing high levels

48、of Mo causing molybdenosis in cattle and sheep. (1)Content是巖石和土壤中含量最高的四個元素（O, Si, AI, Fe）之一。 土壤Fe2O3含量可達(dá)3.8%q 礦質(zhì)態(tài)q 有機結(jié)合態(tài) q 交換態(tài)q 水溶性(2)Forms含鐵的礦物有：磁鐵礦、赤鐵礦、針鐵礦等2.5 Iron (Fe) Soil pH Soil Eh organic matter Soil moisture others(3)Factors affecting Fe availability in soil土壤pH每增加一個單位，溶液中活性鐵減少約1000倍。 Fe2+

49、+ 3OH-1 Fe(OH)3 Fe3+ Fe(OH)2+ Fe(OH)2+Fe(OH)3OH-1OH-1OH-1Simple cation(Soluble)Hydroxy metal cations(Soluble)Hydroxide(Insoluble)Soil pH and Fe availabilitySoil Eh淹水后三價鐵可以還原為二價鐵Fe(OH)3 + e-1 + 3H+ Fe2+ + 3H2OSoil organic matter有機質(zhì)可以增加土壤中鐵的有效性（why？）（有機酸的絡(luò)合、酸化作用以及還原性物質(zhì)）Soil moisture石灰性土壤通氣不良易發(fā)生缺鐵失綠癥（l

50、ime induced chlorosis）(原因？)HCO3- affects the uptake and translocation of Fe CaCO3 + H2O + CO2 Ca2+ + HCO3-How to solve the problem? Improve soil structure Soil water management Application of organic manures石灰性土壤多采用DTPA浸提，臨界指標(biāo)為 2.5mg/kg,缺乏臨界適量石灰性土壤 4.5(4) How to evaluate Fe availability in soil? Soi

51、ls deficient in FeIron deficiencies are most common in calcareous soils, in arid soils cropped to high-iron-demand plants.High levels of bicarbonate and phosphates also lower iron availability of plant.我國缺鐵鐵土壤的分布主要分布在我國北方，與石灰性土壤的分布模式基本一致。南方土壤上常常會發(fā)生鐵中毒現(xiàn)象。(1)Content2.6 Boron(B)花崗巖及其他酸性火成巖、片麻巖、紅砂巖等成土母質(zhì)

52、發(fā)育的土壤，全硼及水溶性硼含量往往偏低。沉積物發(fā)育的土壤火成巖發(fā)育的土壤干旱地區(qū)濕潤地區(qū)我國主要土壤硼含量的一般規(guī)律：有由北向南、由西向東逐漸降低的趨勢。西部內(nèi)陸地區(qū)土壤含硼較高，東南部紅壤含硼低。q Mineral-Bq Organic-Bq Adsorbed-Bq B-in solution(2) Forms of B in soil礦質(zhì)態(tài)硼存在于礦物晶格內(nèi)，經(jīng)過風(fēng)化后才可釋放。土壤中含硼的礦物以電氣石為主，含B 3%左右有機態(tài)硼包括含硼的有機化合物和被有機物吸附的硼Soil colloidOOBOH Soil pH Clay types Organic contents(3) Facto

53、rs affecting B availability in soil土壤pH值在4.7-6.7范圍內(nèi)，水溶性硼隨pH值上升而增加，但當(dāng)pH值7,水溶性硼隨pH值上升而降低(原因？)（專性吸附增強，與鈣、鎂等形成沉淀）Illite Kaolinite (伊利石高嶺石)有機質(zhì)對硼有效性的影響，看法不一(4) How to evaluate B availability in soil? 我國多采用沸水浸提、姜黃素比色法測定土壤有效性硼的含量。一般以我國多采用沸水浸提、姜黃素比色法測定土壤有效性硼的含量。一般以0.5 mg/kg0.5 mg/kg作為臨界指標(biāo)作為臨界指標(biāo) 2.50很低低適量豐富過量

54、中毒Problem soils of B deficiencyuStrongly weathered coarse textured soil with low base exchange developing under humid conditions.uSandy soils (very low in B and prone to leaching)Soils potentially deficient of B in China包括紅壤、磚紅壤、赤紅壤和紫色土等。分布包括紅壤、磚紅壤、赤紅壤和紫色土等。分布于廣東、福建、江西南部、浙江西部和南部和于廣東、福建、江西南部、浙江西部和南部和

55、四川等地。土壤全硼和水溶性硼含量均較低。四川等地。土壤全硼和水溶性硼含量均較低。南方缺硼紅壤區(qū)北方缺硼土壤主要是黃土和黃河沖積物發(fā)育的各種土壤，包主要是黃土和黃河沖積物發(fā)育的各種土壤，包括括塿塿土、黃綿土和黃潮土等。土、黃綿土和黃潮土等。新建及河西走廊地區(qū)氣候干旱，蒸發(fā)量大于降水量，鹽分在土壤表層累積，是我國的高硼區(qū)。而東北、華北及黃土高原地區(qū)有大面積的缺硼土壤。估計缺硼及可能缺硼的土壤占耕地面積的70%左右(余存祖等，2004)。Effects of soil pH on availability of micronutrientsTransformation of micronutrien

56、ts in soil 我國土壤缺乏微量元素的面積種類ZnBMoMnCuFe億畝7.294.926.683.040.980.71占耕地%51.534.546.5土壤臨界值（mg/kg）550.25 ppm)，會引起牲畜中，會引起牲畜中毒，患毒，患“堿質(zhì)病堿質(zhì)病(alkali disease)”和和“盲跚病盲跚病”。世界上約有世界上約有110多個國家的多個國家的10億人口患有此病。我億人口患有此病。我國患病人口分布在國患病人口分布在20多個省市區(qū)，人口約多個省市區(qū)，人口約4.25億億。（2 2）地方性缺碘?。┑胤叫匀钡獠? (甲狀腺腫大病甲狀腺腫大病) )地方

57、性甲狀腺腫是世界上流行最廣泛的一種地方病俗稱地方性甲狀腺腫是世界上流行最廣泛的一種地方病俗稱“大粗脖大粗脖”，以甲狀，以甲狀腺腫大為主要特征。腺腫大為主要特征。我國貴州的都勻市、黔西縣屬高度缺碘地區(qū)我國貴州的都勻市、黔西縣屬高度缺碘地區(qū), ,發(fā)病率相當(dāng)高。發(fā)病率相當(dāng)高。碘由陸地進(jìn)入海洋，由海洋逸出進(jìn)入大氣，再通過降水進(jìn)入陸地，形成了一碘由陸地進(jìn)入海洋，由海洋逸出進(jìn)入大氣，再通過降水進(jìn)入陸地，形成了一個大循環(huán)。個大循環(huán)。土壤土壤植物植物人體人體水水大氣大氣動物動物巖石巖石圖圖 碘的生物地化循環(huán)碘的生物地化循環(huán)碘的生物地化循環(huán)碘的生物地化循環(huán)碘非?；顫?，遷移性強。土壤中的碘易隨水遷移。碘非?；顫姡?/p>

58、遷移性強。土壤中的碘易隨水遷移。碘分布特性碘分布特性： “山區(qū)少于平原，平原少于沿海，沿海少于海洋山區(qū)少于平原，平原少于沿海，沿海少于海洋”我國自然土壤碘含量平均我國自然土壤碘含量平均4.22 ppm，在世界土壤正常范圍，在世界土壤正常范圍(1-5 ppm)。但黃土高原。但黃土高原土壤全碘含量低。土壤全碘含量低。褐土褐土 1.59 ppm灰鈣土灰鈣土 2.74 ppm供應(yīng)含碘食鹽，即食鹽中加供應(yīng)含碘食鹽，即食鹽中加KIO3。預(yù)防措施：預(yù)防措施：是長期攝入高氟水、糧食等而引起的一種慢性氟中是長期攝入高氟水、糧食等而引起的一種慢性氟中毒疾病。主要表現(xiàn)為毒疾病。主要表現(xiàn)為氟斑牙氟斑牙和和氟骨癥氟骨癥

59、。(3)(3)地方性氟中毒地方性氟中毒過量的氟在體內(nèi)與鈣結(jié)合成氟化鈣，使人體內(nèi)鈣磷過量的氟在體內(nèi)與鈣結(jié)合成氟化鈣，使人體內(nèi)鈣磷代謝平衡受到破壞，血鈣因而降低，導(dǎo)致溶骨細(xì)胞代謝平衡受到破壞，血鈣因而降低，導(dǎo)致溶骨細(xì)胞活性增強，促進(jìn)溶骨作用和骨的吸收。活性增強，促進(jìn)溶骨作用和骨的吸收。伊朗村病是缺少微量元素伊朗村病是缺少微量元素鋅鋅而引起的地方性侏儒癥而引起的地方性侏儒癥, , 因因1958 1958 年在伊朗錫拉茲地區(qū)年在伊朗錫拉茲地區(qū)發(fā)現(xiàn)，故得名。發(fā)現(xiàn)，故得名?！耙晾蚀宀∫晾蚀宀　笨诜每诜肸nSOZnSO4 4 和和V VB B 做成的復(fù)合鋅片進(jìn)行預(yù)防和治療效果良好。我國衛(wèi)生部門批準(zhǔn)做成的

60、復(fù)合鋅片進(jìn)行預(yù)防和治療效果良好。我國衛(wèi)生部門批準(zhǔn), ,在食品加工中添加硫酸鋅、葡萄糖酸鋅、乳酸鋅，還有氨基酸鋅，這些均是有效的在食品加工中添加硫酸鋅、葡萄糖酸鋅、乳酸鋅，還有氨基酸鋅，這些均是有效的鋅制劑。鋅制劑。Welch R M. The impact of mineral nutrients in food crops on global human health. Plant and Soil 247: 8390, 2002.Furthermore, micronutrient-rich fruit and vegetable production has not kept pace with popula