农田土壤微量元素含量的空间变异特征和影响因素

以浙江乐清市乐成镇为研究区域,采用地统计学和地理信息系统(GIS)相结合的方法,对土壤中有效态Fe、Mn、Cu、Zn和B含量的空间变异规律及其影响因素进行研究。描述性统计结果表明,土壤中微量元素Fe、Mn、B含量属于中等变异,Cu、Zn属于强变异。描述空间变异的半方差函数分析表明,Fe、Zn和B的最适模型是球状模型,Mn为指数模型,Cu为线性模型;Fe、Mn、Zn和B的块基比均小于25%,表明具有强烈的空间相关性,Cu的块基比大于75%,表明Cu含量具有较弱的空间相关性。土壤微量元素含量空间分布总体上呈现由东部向西部递减的趋势,其中Fe、Mn和B明显表现出连续分布的特点,Cu、Zn的分布没有明显的规律。土壤类型对Mn、Cu的含量有着显著影响,水稻土中Mn、Cu的含量显著高于红壤;土壤养分和微量元素的相关性分析可知,Fe与土壤pH、OM、全氮、碱解氮以及速效钾呈极显著相关,Mn、B与pH、速效磷和速效钾之间有显著或者极显著的相关性,Cu仅与速效钾显著相关,Zn的含量受土壤养分的影响较小,没有达到显著水平。     

植烟土壤有效态微量元素空间变异特征

基于GIS和GPS定位技术,结合网格取样,用地统计学方法研究了褐土烟区土壤有效态微量元素养分(速效Fe、速效Mn、速效Cu、速效Zn)的空间变异规律,并绘制了微量养分空间分布图。结果表明:土壤速效微量养分在整个研究区内均表现出中等变异水平,其变异性大小表现为:速效Zn速效Mn速效Cu速效Fe。除速效Mn外,其他微量元素都表现出很强的空间结构性,速效Cu、Zn变程较短,分别为182m和175m,速效Mn变程较长为850m。基于半方差函数模型,用普通克里格法对研究区土壤速效微量养分进行了克里格插值,结果表明:速效Fe在研究区内普遍缺乏,速效Mn、速效Cu含量中等偏高,而速效Zn含量在整个研究区表现出明显的差异性。     

西昌市土壤Fe、Mn、Cu、Zn有效性评价及其影响因素分析

在分析西昌市土壤微量元素Fe、Mn、Cu、Zn有效含量状况及其分布特征的基础上,从成土母质、土地利用方式、有机质和pH等4个方面探讨其对土壤微量元素有效含量的影响。结果表明:西昌市土壤有效Fe含量丰富,有效Cu和Zn略低且分布不均,有效锰有32.18%的土壤缺乏。成土母质是重要的影响因素,第四纪紫色洪冲积物发育的土壤Fe、Mn、Zn有效含量较高,二迭纪岩浆岩洪冲积物发育的土壤有效Cu含量较高,坡残积物发育的土壤4种微量元素有效态含量均较低;水田土壤各元素有效含量均大于旱地;有机质与有效Fe、Cu间显著正相关;pH值在中性偏碱时,有效Cu和Zn含量较低。     

吉林省黑土某些微量元素环境地球化学特征

根据吉林省第二次土壤普查资料 ,对黑土中微量元素B、Cu、Fe、Mn、Mo和Zn的全量、有效态含量、它们在土壤剖面中的迁移分布等环境地球化学特征及其影响因素进行了研究 ,得出如下结论 :①吉林省黑土B、Mn、Mo、Zn的全量缺乏 ,Cu、Fe的全量略低 ;②黑土B、Cu、Zn的有效态含量缺乏 ,其中Zn严重缺乏 ;③黑土剖面中 ,B、Cu、Fe、Mn、Mo、Zn等微量元素全量与有效态含量分布相似 ,均以淋溶层最低 ,表层和淀积层较高 (Mo的全量除外 )。微量元素有效态含量剖面分布中淀积层层次较深 ,表层富集程度稍强 ;④黑土中B、Fe、Mn、Mo、Zn的有效态含量与土壤有机质含量呈显著的正相关 ;B、Mo的有效态含量与 pH值呈显著正相关 ,而Cu、Fe、Mn、Zn的有效态含量则与pH值呈负相关 ;黑土B、Cu、Fe、Mn、Mo、Zn有效态含量与其全量均达到显著相关水平。根据吉林省黑土中微量元素全量和有效态含量分布的特点 ,需施用微量元素肥料 ,增加黑土中微量元素的含量 ,促进该地区农业的可持续发展     

湖北省柑橘园土壤养分分级研究

对湖北省柑橘主产区143个柑橘园0～30cm的土壤样品进行了测试分析。结果表明,全省有89.5%柑橘园土壤pH值适合柑橘生长;有59.4%的柑橘园土壤有机质含量偏低,土壤速效N、P、K缺乏分别为78.3%、44.1%和77.6%;中量元素养分Ca、Mg缺乏分别为39.1%和37.1%;分别有34.3%、20.3%、16.8%、63.6%、35.5%和77.4%的柑橘园缺乏有效Fe、Mn、Cu、Zn、Mo和B。土壤有效Ca、Mg、Fe、Mn、Cu、Mo含量在部分柑橘园存在过量现象,分别占柑橘园的9.8%、4.9%、7.7%、4.9%、3.5%和4.0%。柑橘园土壤pH值、有机质和各种有效养分含量呈现一定的地域性变化,如鄂南柑橘园土壤偏酸,而汉江流域(鄂北)土壤偏碱;鄂南Ca和Mg缺乏程度高,汉江流域含量相对较高,而有效Fe、Mn、Zn含量则相反。调查结果还表明,柑橘园土壤有效Cu和B含量受人为活动的影响非常明显。     

曲周县农田土壤有效微量元素含量空间变异特征及影响因素初探

以河北省邯郸市曲周县为研究区域,采用地统计学与地理信息系统相结合的方法,对曲周县农田土壤有效微量元素铁(Fe)、锰(Mn)、铜(Cu)、锌(Zn)含量的空间变异特征及其主要影响因素进行了初步研究和探讨。结果表明:土壤有效Fe、Mn含量的最优理论模型为指数型(R2为0.887和0.553),有效Cu含量为球状模型(R2为0.988),有效Zn含量为高斯模型(R2为0.977)。土壤有效微量元素含量的空间变异程度和空间相关性由大到小依次为:Zn> Cu> Mn> Fe,Fe> Zn> Mn> Cu。从空间分布来看,土壤有效Fe、Mn、Zn含量主要处于低水平,并且土壤有效Fe、Mn、Cu含量以片状分布为主,土壤有效Zn含量呈现由西向东逐渐递减的趋势。土壤有效Fe、Mn、Cu、Zn含量与土壤有机质含量均呈极显著正相关,与土壤pH间没有显著的相关,而土壤有效Cu含量则与土壤pH间存在显著正相关。总体而言,曲周农田土壤有效Fe,Mn,Zn含量相对较低,而有效铜含量相对较高。如果种植对铁锌敏感而且需求量相对较高的作物,应该考虑Fe、Zn肥的施用。     

甘肃省武威地区灌漠土微量元素的空间变异特征

用经典统计学与地统计学方法相结合,研究了甘肃省武威灌漠土耕层土样中B、Cu、Fe、Mn及Zn等5种微量元素有效含量的空间变异特征。结果表明:①99.17%土样缺乏有效Zn,93.33%的土样缺乏有效Fe。描述性统计所得变异系数在13.32%(有效Mn)~42.54%(有效B)之间。②球状模型和指数模型为土壤微量元素的最佳拟合模型,各元素的块金值、最大相关距及块金值与基台值之比C0/(C0+C)分别在0.001~0.429、192m~477m及0.126%~26.459%(有效B)之间。土壤微量元素含量的分形维数在1.804~1.947之间,土壤B的分形维数最低。③表征土壤微量元素空间变异的参数如变异系数、C0/(C0+C)及分形维数D之间均有一定的相关关系。④Kriging插值结果显示人为因素等表生作用对土壤有效B含量的空间分布影响较大,土壤Cu、Mn、Zn及Fe含量的空间分布则主要由成土母质与地形所决定。     

滇西南亚热带山地主要植被类型下土壤微量元素状况研究

以滇西南澜沧县为研究区,研究了滇西南亚热带多年生常绿阔叶林、思茅松林和3 a生人工桉树林土壤中微量元素B,Cu,Zn,Fe,Mn的有效含量、分布规律,以及相似生境条件下三种植被类型对土壤微量元素的消耗状况及在土壤剖面中的垂直分布规律。结果表明：（1）不同植被类型的土壤中,有效Fe含量较为丰富,远高于临界值;而有效Zn,Mn,B含量很低,低于临界值,该地区属于Zn,Mn,B缺乏区;在常绿阔叶林和思茅松林下土壤中有效Cu的含量低于临界值,而在桉树林下土壤基本不缺Cu;（2）不同植被类型林下土壤微量元素的有效量有较大差异。常绿阔叶林下土壤中有效Fe,Zn的含量最高,有效Mn的含量最少;桉树林下土壤中有效Cu,Mn的含量最多,有效Zn的含量最少;松树林下土壤中微量元素都不多,其中有效Fe的含量最少;三种植被类型下土壤都缺少有效B元素;（3）相比较而言,在相似生境条件下,桉树林对有效Fe元素的消耗大于常绿阔叶林和思茅松林,但三种植被土壤中都不缺有效Fe;常绿阔叶林和思茅松林对有效Zn,Cu元素的消耗大于桉树林;常绿阔叶林对有效Mn的消耗大于桉树林,而桉树林对有效Mn的消耗大于思茅松林。且三种植被类型下土壤中都缺Zn,Mn,B,Cu微量元素;（4）各微量元素有效量在研究区土层中的分布规律因元素种类而异,少数元素与植被类型有关;在常绿阔叶林地中,随着土壤深度增加,有效Fe,Mn含量升高,有效Zn含量降低;而在生境条件相似的桉树林地中,随着土壤深度增加,有效Fe,Mn含量降低,其它元素则没有变化规律。在思茅松林地中,随着土壤深度增加,有效Fe,Mn含量降低;而在桉树林地中,随着土壤深度增加,有效Fe,Mn含量升高,其它元素则没有变化规律。     

三工河流域绿洲土壤微量元素有效含量特征分析

土壤微量元素的含量与分布特征是反映特定地区环境状况的一个重要因素,对土地资源的合理开发和利用具有重要意义.本研究以天山北坡三工河流域冲积平原型绿洲为研究区,选择盐土、潮土和灰漠土3种土壤类型,分析其B、Mn、Zn、Fe、Cu等微量元素的有效含量特征.结果表明:⑴以"全国农业系统的土壤速效微量元素丰缺指标"为标准,土壤有效Mn含量属于极低水平,有效Zn和Fe含量属于中等水平,有效Cu属于丰富水平,有效B属于极富水平;⑵三工河流域绿洲土壤中有效Mn、Zn、Fe、Cu含量与土壤pH呈负相关关系;土壤有机质对有效Fe、Cu含量影响很大;有机质和Mn的关系不明显,这和湿润地区研究结果存在显著差异;⑶不同的土壤类型对于土壤有效B、Zn和Fe的含量影响显著;潮土中微量元素的有效含量与盐土、灰漠土中含量相比有显著差异.     

遵义市部分烟区烤烟中、微量元素含量及其空间分布

【目的】作为烟草生长发育所必需的营养元素,中、微量元素对于协调烟株生理机能、烤烟产量、品质的形成和增强抗病能力有着大量元素不可替代的作用。本研究基于野外取样与室内检测所获得的烟叶养分信息,旨在探求遵义市部分烟区烤烟烟叶中微量元素特征与空间分布情况,为该地烤烟生产养分分区管理、配方施肥技术和化肥减量提效提供科学参考。 【方法】运用经典统计学方法,初步对研究区烤烟烟叶中微量元素的丰缺状况进行分析评价,并结合 GPS 定位,以地统计学的半变异函数为工具,定量分析了研究区烟叶中微量元素的空间变异特征,采用 Kriging 插值法,得到烟叶中微量元素含量的空间分布格局。 【结果】1) 研究区 C₃F 等级烟叶 7 种中微量元素含量平均值分别为 Ca 20.3 g/kg、Mg 3.7 g/kg、Cu 4.42 mg/kg、Zn 34.85 mg/kg、Fe 229.81 mg/kg、Mn 205.43 mg/kg、Mo 0.25 mg/kg,含量范围分别为 Ca 14.7～27.3 g/kg、Mg 1.3～8.0 g/kg、Cu 1.69～8.83 mg/kg、Zn 12.31～56.11 mg/kg、Fe 141.62～339.00 mg/kg、Mn 66.21～426.11 mg/kg、Mo 0.06～0.60 mg/kg,各元素变异系数在 12.8%～48.7% 之间,均表现为中等强度变异;参照烟叶中微量营养元素分级标准,研究区烟叶适宜范围内钙占 95.2%,高水平锰含量占 65.1%,低水平镁、铜、锌、铁含量分别占 26.5%、55.4%、32.5%、20.5%,适宜水平镁、铜、锌、铁分别占 48.2%、25.3%、63.9%、79.5%,烟叶钼含量总体较缺乏。2) 研究区烟叶中 Ca、Mg、Zn 和 Fe 符合正态分布,Cu、Mn、Mo 经对数转化后均符合正态分布,分别选择指数模型作为 Ca、Cu、Fe、Mo 的最优拟合理论模型,Mg、Zn、Mn 为高斯模型,得出烟叶中 Ca、Mg、Cu、Zn、Fe、Mn、Mo 7 种元素各项异性比均大于 1,块金系数分别为 43.8%、26.9%、31.0%、58.4%、69.0%、32.6%、42.7%,变程分别为 148.099、137.407、15.554、18.723、25.624、88.770、74.749 km。 【结论】研究区烟叶 Ca 含量基本在适宜范围内,Mn 含量总体较高,Mg、Cu、Zn、Fe 含量基本在低–适宜水平,Mo 较缺乏。地统计分析表明:7 种元素均具有空间各向异性;空间变异指标块金系数大小顺序为 Fe > Zn > Ca > Mo > Mn > Cu > Mg,均为中等空间相关性;空间自相关范围由大到小依次为 Ca、Mg、Mn、Mo、Fe、Zn、Cu。采用地统计插值绘制的空间分布图,直观地反映了研究区烟叶中微量营养元素的含量分布状况。     

土壤微量元素含量及其影响因素的研究

论述了临沂市土壤中硼、锌、锰、铜、铁等5种主要微量元素的状况与其它因素的关系。有效硼含量0.09~3.67 mg/kg,平均0.35 mg/kg;有效锰22~572 mg/kg,平均244 mg/kg;有效锌0.15~4.02 mg/kg,平均0.53 mg/kg;有效铜0.09~5.78 mg/kg,,平均1.03 mg/kg;有效铁3.2~162 mg/kg,平均21.5 mg/kg;有效锰2.0~131.4 mg/kg,平均23.4 mg/kg。不同土壤类型的以上5种微量元素有明显差异,其特征是砂姜黑土缺锌,棕壤、水稻土富含铁、铜、锰、锌;成土母质是影响土壤微量元素的重要因素之一,发育在基性岩上的土壤一般含量较高,而由红土母质发育的土壤则含量较低。土壤有机质含量与土壤微量元素有明显正相关关系,其中速效锌、速效硼和速效铜与有机质的关系尤为显著。     

长期施肥对潮土耕层土壤和作物籽粒微量元素动态的影响

Micronutrient status in soils can be affected by long-term fertilization and intensive cropping.A 19-year experiment (1990-2008) was carried out to investigate the influence of different fertilization regimes on micronutrients in an Aquic Inceptisol and maize and wheat grains in Zhengzhou,China.The results showed that soil total Cu and Zn markedly declined after 19 years with application of N fertilizer alone.Soil total Fe and Mn were significantly increased mainly due to atmospheric deposition.Applications...     

太湖地区不同土壤-森林生态系统中林木生长对微量元素的反应及反馈效应

Vector analysis technique and ecological sequential comparison methods were adopted to study tree growth response to the micronutrients,B,Mo,Cu,Zn,Fe,and Mn,in soils derived from various parent materials in the forest area of Tailhu Lake region in southeast China,The results showed that the dry weight of individual current-year needle of Chinese fir(Cunninghamia lanceolata) grown on the soil derived from granite parent rock was increased by 8% and 13% in comparison with that grown on the soils derived from sandstone and ash-tuff parent rock,respectively.And such dry weight of loblolly pine (Pinus taeda) grown on the soil derived from sandstone parent rock was increased by 21% in comparison with that on the soil derived from ash-tuff parent rock.One of the reasons for those results was that micronutrients content in the soil derived from ash-tuff parent rock were not sufficient to meet the requirement of the growth of Chinese fir and loblolly pine ,i.e.,micronutrients in soil were deficient and/or induced defiient.The amounts of Cu,Zn,Fe,and Mn uptake by Chinses fir and loblolly pine were in agreement with the contents of available micronutrients in soil respectively,except for B and Mo.Meanwhile,there might exist and “antagonism“ between the uptake of B versus Mo by trees,although more studies are needed to confirm it .Regression analysis indicated that amount of a soil available micronutrient was correlated to the type of parent material and its total amount in the forest floor, except for B.The F test identified that the correlation of each equation reached the significant level to different extents,respectively,The t test confirmed that amount of available forms was mainly depended on the type of parent material for Mo,Cu,Zn and Mn but on the forest floor for ,Fe,There was a feedback effect of forest stand on the amount of soil available micronutrients.The ability of accumulating available micronutrients in soil was better by the sawtooth oak(Quercus acutissima) stand than by the Chinese fir stand (except for B).The ability of accumulating available Zn,Fe,Mn and Mo in soil was better by the Chinese fir stand than by the loblolly pine stand ,while as for available B and Cu,by the latter was better than by the former,When discussing the efect of forest stand on the amount of soil available micronutrients,not only the amount of micronutrient in the forest floor and the parent materials but also the amount of micronutrient taken up by current-year needles have to be considered.     

Micronutrients distribution in salt-affected soils of the Punjab in relation to soil properties

Salt-affected soils in arid and semi-arid tracts of the Indian Punjab are prone to deficiency of micronutrients. Nine profiles from alluvial terraces, sand dunes and palaeochannels in the southwestern Punjab were investigated for total and diethylenetriamine-penta-acetic acid (DTPA) extractable Zn, Cu, Mn and Fe. Soil physiography exerted significant influence on the spatial distribution of micronutrients. Total contents varied from 20–78 for Zn, 8–32 for Cu, and 88–466 mg kg^?1 for Mn and 0.82–2.53% for Fe. DTPA-extractable contents varied from 0.10–0.98 for Zn, 0.14–1.02 for Cu, 0.54–13.02 for Fe and 0.82–9.4 mg kg^?1 for Mn. Total contents were higher in fine-textured soil than in coarse-textured soils. Concentration of micronutrients in the surface layer was low and there occurred more accumulation in the Cambic horizon. Organic carbon, pH, clay, silt and calcium carbonate exerted strong influence on the distribution of micronutrients. DTPA extractable Zn, Cu, Mn and Fe increased with increasing organic carbon but decreased with increase in pH and calcium carbonate content. Total micronutrient contents increased with increase in clay, silt and calcium carbonate contents and decreased with increase in sand content.     

Changes in soil properties and the availability of soil micronutrients after 18 years of cropping and fertilization

Micronutrient deficiencies are common in many parts of China's Loess Plateau. The objective of this experiment was to study the effects of long-term cropping and fertilization practices on soil properties and micronutrient availability in this region. The field plot experiment began in 1984. It included five cropping systems and four fertilizer treatments. In September 2002, soil samples were collected and soil pH, organic matter content, available P, and CaCO₃ were measured. Total and available Zn, Cu, Mn, and Fe were also determined. The relationship between soil properties and available micronutrients was determined by correlation and path analysis. After 18 years, soil pH and CaCO₃ levels were lower in the cropped and fertilized treatments compared to the fallow treatment. In contrast, soil organic matter and available P levels were higher in cropped compared to fallow treatments. A comparison of unfertilized treatments indicated that available Zn and Cu levels in cropped treatments were lower compared to the fallow treatment, probably due to the removal of these micronutrients from the system through crop uptake and harvest. In contrast, available Mn and Fe levels were higher in cropped treatments compared to the fallow treatment. The impacts of fertilization on available micronutrients varied with cropping systems. Generally, available Zn and Fe were higher in fertilized compared to unfertilized treatments, but available Cu was not significantly influenced by fertilization. Fertilization tended to increase available Mn in continuous wheat and maize, but reduced available Mn in continuous clover and the crop–legume rotation. The total (plant available + unavailable) micronutrient contents were lower in the four cropped-treatments compared to the fallow treatment. The addition of manure or P fertilizer increased total Zn, Fe, and Mn, but had no significant effect on total Cu. The results of correlation analysis and path analysis indicated that soil organic matter exerts a significant and direct effect on the availability of Zn, Mn, and Fe, but has little influence on available Cu. The effects of available P, CaCO₃, and pH on micronutrient availability were indirect, passing through soil organic matter. The results of this study suggest that long-term cropping and fertilization altered several important soil properties and increased the plant available micronutrient content of this loess-derived soil.     

Amounts and forms of micronutrient cations in a group of loessial grassland soils of New Zealand

The status of micronutrient cations Fe, Mn, Zn, Cu and Co was examined in a group of soils from beneath undisturbed grassland sites. The soils were selected such that factors of soil formation besides loess accumulation and rainfall remained relatively constant. In a previous study these two factors were found to have a large effect on the K status of the soils, but results from this study showed that there had been little effect on micronutrient content. With decreasing loess accumulation the total and HCl- and EDTA-extractable micronutrient content of soils tended to decrease, but rainfall had no consistent effect. Extractable levels of Cu and Co in A horizons tended to decrease from high to potentially deficient values with decreasing loess accumulation.HCl- and EDTA-extractable Fe, Mn, Zn and Cu were clearly higher in A than B horizons although total contents tended to be lower in A horizons. A chemical fractionation procedure demonstrated that there were greater quantities of pyrophosphate- and oxalate-extractable Zn and Cu and acetic acid-extractable Zn in the A than B horizons.With the exception of HCl-extractable Cu, extractable micronutrients were significantly correlated with the organic matter content of the HCl or EDTA extracts. There were no significant correlations between extractable micronutrients and soil pH or oxalate-extractable Al or Fe.Acetic acid-extractable Co was not significantly correlated with any measured soil property. It is concluded that the cycling of nutrients and the build-up of organic matter, which characteristically occur under grassland conditions in New Zealand, were the major factors influencing the micronutrient status of the soils.     

长期不同施肥对南方黄泥田水稻子粒与土壤锌、 硼、 铜、 铁、 锰含量的影响

在福建黄泥田长期定位施肥试验的第26年,研究了不同施肥模式对水稻子粒与土壤微量元素含量的影响。结果表明,与不施肥（CK）相比,化肥+牛粪（NPKM）、 化肥+秸秆还田（NPKS）及单施化肥（NPK）处理的水稻子粒Zn、 B、 Cu含量均有不同程度的提高,并尤以NPKM处理最为明显,三种微量元素含量分别提高14.3%、 25.1%、 465.2%,均达差异显著水平。NPKM与NPKS处理还不同程度地提高了子粒Mn含量,但各施肥处理的子粒Fe含量均显著降低。各施肥处理尤其是NPKM与NPKS均显著提高了子粒微量元素吸收量。NPK处理的土壤有效B、 Fe、 Zn、 Cu含量与CK相比均呈下降趋势,且有效Zn、 Mn含量较试验前土壤分别降低了36.4%与24.6%,而NPKM与NPKS处理缓解了下降趋势,且NPKM处理的土壤有效Zn、 B、 Mn含量分别较CK提高46.6%、 52.0%、 43.0%,均达差异显著水平。土壤有机质与子粒B、 Cu、 Zn含量呈显著正相关,子粒必需氨基酸、 粗蛋白与子粒Zn含量呈显著正相关。以上结果说明,长期化肥配施牛粪或秸秆还田有利于提高水稻子粒Zn、 B、 Cu等微量元素含量和产量,改善子粒营养品质,一定程度上又可缓解土壤有效微量元素含量的下降,是适合南方黄泥田的施肥模式。     

Micronutrient Soil-Test Levels and Eucalyptus Foliar Contents

Eucalyptus is the most widely planted forest species in Brazil (～3.4 million hectares). Ongoing rotations and high yields lead to the occurrence of copper (Cu), manganese (Mn), iron (Fe), and zinc (Zn) deficiency symptoms. The objectives of this work were to identify the most appropriate extractant for evaluating micronutrient availability in commercial Eucalyptus plantations and to evaluate the influence of soil properties on Eucalyptus foliar micronutrient contents. Soil micronutrient contents were extracted by Mehlich 1, Mehlich 3, and diethylenetriaminepentaacetic acid (DTPA). Mehlich 1 and Mehlich 3 extracted the greatest amounts for all micronutrients analyzed. Foliar Cu, Mn, and Zn contents showed significant and positive relationships with soil Cu, Mn, and Zn contents extracted by the three solutions. Soil organic carbon (SOC), soil clay content, and soil pH improved significantly the power of regression models in estimating foliar micronutrient contents. The improvement was greater for Mehlich 3 and DTPA extractants than for Mehlich 1.