Nutrient changes in direct-seeded submerged rice soils with varying nutrio-environments

Summary Nutrient changes in submerged rice soil were studied in soil-water-plant ecosystem in direct-seeded rice crop. Continuous removal of nutrients by the crop resulted in ultimate decrease in the availability of NH₄–N, P, K, Ca, Mg, Mn, Zn and Cu. However, there was a slight increase in Fe availability in soil with increase in period of submergence and crop growth. The data was subjected to statistical function fittings to study the nature of changes. Depending on the R²% values, quadratic type was the best fit for pH, available NH₄–N, K, Mg, Fe, Mn and Cu, whereas logarithmic type was the best fit for available P, Ca and Zn. No response was noticed to the application of P and K. Highest correlation coefficient between grain yield and NH₄–N in soil was obtained at the panicle initiation stage indicating that limiting nitrogen during this period might affect grain yield to the maximum extent compared to tiller initiation and maximum tillering stages.     

Effect of soil sodicity on the growth,yield and chemical composition of groundnut (Arachis hypogaea Linn.)

Summary A replicated field experiment was conducted to study the effect of exchangeable sodium percentage (ESP) on the yield, chemical composition, protein and oil content and uptake of nutrients by groundnut (Arachis hypogaea Linn.) variety M-13. ESP over 15 delayed germination and emergence of flowers. There was continuous decrease in dry matter yield at 30 and 60 days of growth, grain and straw yield after harvest and protein, oil and kernel percent with increase in soil ESP. A 50 per cent reduction in groundnut yield was observed at an ESP of 20. Increasing soil ESP, increased Na and decreased K, Ca and N contents, but had no effect on the Mg, P, S, Fe, Mn, Zn and Cu contents of the plant. Sodium content of the plant increased, while potassium and nitrogen decreased with age of the plant. The uptake of all the nutrients decreased with increase in soil ESP. The results showed that groundnut is a relatively sensitive crop to soil sodicity.     

Availability of iron,manganese, zinc and phosphorus in submerged sodic soil as affected by amendments during the growth period of rice crop

Summary Effect of amendments, gypsum (12.5 tonnes/ha), farmyard manure (30 tonnes/ha), rice husk (30 tonnes/ha) and also no amendment (control) on the availability of native Fe, Mn and P and applied Zn in a highly sodic soil during the growth period of rice crop under submerged conditions was studied in a field experiment. Soil samples were collected at 0, 30, 60 and 90 days of crop growth. Results showed that extractable Fe (1N NH₄OAC pH 3) and Mn (1N NH₄OAC pH 7) increased with submergence upto 60 days of crop growth but thereafter remained either constant or declined slightly. Application of farmyard manure and rice husk resulted in marked improvement of these elements over gypsum and control. Increases in extractable Mn (water soluble plus exchangeable) as a result of submergence and crop growth under different amendments were accompanied by corresponding decreases in easily reducible Mn content of the soil. Application of 40 kg zinc sulphate per hectare to rice crop could substantially raise the available Zn status (DTPA extractable) of the soil in gypsum and farmyard manure treated plots while the increase was only marginal in rice husk and control plots indicating greater fixation of applied Zn. Available P (0.5M NaHCO₃ pH 8.5) behaved quite differently and decreased in the following order with crop growth: gypsum>rice husk>farmyard manure>control.     

Distribution of N,P, K,Ca, Mg,S, Zn,Fe, Mn and Cu in groundnut

Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.     

Soil-sodicity-induced zinc deficiency in maize

Summary Maize (Zea mays L. cv. Ganga-2) plants were grown in pot culture on a loamy alluvial soil of Lucknow district (India) alkalinized to graded levels of ESP (Exchangeable Sodium Percentage) ranging from 15.5 to 55.3. Before sowing maize seeds the soil was fertilised with NPK, Fe, Mn and Cu. At and above ESP 34 Zn-deficiency symptoms first appeared at 30 days. The symptoms gradually became pronounced with increase in age and at 60 days they were found even at ESP 15.5. The severity of symptoms was related to increase in sodicity. Alkalinization of soils depressed available soil Zn and tissue Zn and increased tissue ratios of Na/Zn and P/Zn. It also decreased the total plant content of Zn, Fe, Mn, Cu and even Na. Increase in soil sodicity increased both tissue concentration and total content of P in plants upto ESP 34 beyond which it decreased it. Among different extractants, 0.1N HCl, DTPA pH 7.3 and EDTA-(NH₄)₂ CO₃ pH 8.6, for measuring available soil Zn the latter showed best correlations with soil ESP (−), tissue P (−), P/Zn ratio (−), dry matter yield (+) and tissue Zn (+). Tissue Zn was related to yield (+), tissue Na (−) and soil ESP (−). Mild, moderate, severe and very severe Zn deficiency in maize was induced by soil ESP levels, 18, 25, 33 and 45, respectively.     

Chemical composition of whole plant and grain and yield of nutrients in grain of five barley cultivars

Summary twenty seven field experiments were conducted to determine if there were differences between five barley cultivars in their ability to utilize soil nutrients. There were significant differences among cultivars in yield of grain and in concentration of all macro and micro nutrients examined in both the whole plant and grain.Gateway ranked the highest for the concentration of Na, Mn, and Cu in the whole plant and was among the cultivars with highest concentration of Ca, Fe, and Zn. Centennial had generally the lowest concentration of all the nutrients determined in the whole plant. For the concentrations of Na, Mg, and Cu in grain Gateway ranked highest, but ranked third for the concentrations of K, Ca, Fe, Mn, and Zn in grain. Galt had the highest K and Mg concentration and lowest Mn, Cu and Zn concentration in grain. Except for K concentration in grain, Centennial had the lowest concentrations of all other cationic nutrients in grain.Yield of grain rather than nutrient concentration was the most important criteria in determining the ranking of nutrient yields per hectare. Because of its high grain yield, Bonanza produced the largest yield of micronutrient cations and was second to Galt in production of macronutrient cations, although it was lowest in macronutrient cation concentration. Similarly, Bonanza and Galt had the lowest protein concentration, but produced the highest yield of protein per hectare.The implications for animal nutrition of different levels of nutrients between cultivars are discussed.     

Release of Fe,Mn and P in a calcareous vertisol and yield of upland rice as influenced by presowing soil water treatments

Summary A field experiment was conducted on a calcareous vertisol at Mahatma Phule Agricultural University, Rahuri to study the release of Fe, Mn and P in soil and yield of two rice cultivars due to different soil water treatments for 15 days prior to sowing. Soil saturation (daily two irrigations) for 15 days prior to sowing increased the supply of Fe, Mn and P in soil at sowing as a result of reduction in pH and Eh. Dry matter yield at different growth stages as well as grain yields of Karjat 184 (dwarf) and Tuljapur 1 (tall) also increased due to presowing soil saturation treatment. Tuljapur 1 yielded more than Karjat 184 when grown under upland conditions. Laboratory incubation studies showed reduction in soil pH (from 8.6 to 7.5) and Eh (from +501 to +362 mv) at the end of 15 days under soil submergence treatment. Availability of Fe, Mn and P was also found to be increased.     

Mineral Elements in Root of Wild Saposhnikovia divaricata and Its Rhizosphere Soil

Mineral elements are important components of medicinal herbs, and their concentrations are affected by many factors. In this study, Ca, Mg, Na, K, Fe, Mn, Cu, and Zn concentrations in wild Saposhnikovia divaricata and its rhizosphere soil collected from seven locations at two different times in China were measured, and influences of rhizosphere soil on those minerals in plant were evaluated. The results showed that mean concentrations of eight minerals in plant samples decreased in the order: Ca > Mg > Na > K > Fe > Zn > Mn > Cu, and those in the soil samples followed the following order: Na > Fe > Ca > K > Mg > Mn > Zn > Cu. Mean concentrations of Ca, Na, Mg, and K in plants were higher than those in soils, while higher mean concentrations of the other four minerals were found in soils. It was found that there was a positive correlation of Mg, Na, and Cu concentrations in the plant with those in the soil respectively, but a negative correlation of Mn concentration in plant with that in the soil. Except Ca, K, and Mn, the other five minerals in plant were all directly affected by one or more chemical compositions of soil. The results also indicate that pH value and concentrations of total nitrogen, Mg, Mn, and Cu in soil had significant correlations with multimineral elements in plant. In a word, mineral elements uptake of S. divaricata can be changed by adjusting the soil fertility levels to meet the need of appropriate quality control of S. divaricata.     

川东红池坝地区红三叶和鸭茅人工草地土壤和植物营养元素含量特征的研究

川东红池坝地区红三叶（Ｔｒｉｆｏｌｉｕｍｐｒａｔｅｎｓｅ）和鸭茅（Ｄａｃｔｙｌｉｓｇｌｏｍｅｒａｔａ）人工草地土壤和植物营养元素的含量特征如下：（１）土壤中的元素含量以铁、钾和镁较高,钠、钙、氮、锰和磷较低,硫、锌、硼、铜和钼微少;（２）从元素的富集特征来看,该区土壤中的钙、硫为重度淋溶元素,钾、磷、镁、锌、钠为中度淋溶元素,铁、铜属轻度淋溶元素,锰属富集元素;（３）根据元素的生物吸收系列,红三叶属氮－钙型植物,鸭茅属氮－钾－磷型植物。（４）两种牧草的生物吸收系数,均以钙、硫、磷较高,钠、铁较低,其余７种元素介于二者之间。     

Responses of Wheat Yield,Macro- and Micro-Nutrients,and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn.     

Contribution of mineral nutrients from source to sink organs in rice under different nitrogen fertilization

The pot experiment with three treatments of nitrogen (N) topdressing was performed with the japonica rice cultivar viz. Huaidao 5. Remobilization of nine mineral nutrients including N, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) was measured from the source organs including bracts, leaf, and sheath to sink rice grain. Experimental results showed considerable contribution of bracts to grain for N, Mg, and Zn, with the averages contributions of 5.96, 12.56, and 12.34%, respectively, indicating a positive role of rice bracts in N, Mg, and Zn remobilization during grain filling. By contrast, minor contribution of bracts to grain P, K, and Cu was revealed, with the contribution rate being 0.99, 3.90, and 3.05%, respectively. Further, a net increase in Ca and Fe concentrations of bracts was detected, implying that bracts function as a sink of these mineral nutrients. In addition, grains produced at a moderate level of N topdressing had higher Fe and similar Zn concentration in comparison with those at high N level, suggesting the possibility of N management for maintaining Fe and Zn level under high yielding conditions.     

Accumulation of Minerals by Leccinum scabrum from Two Large Forested Areas in Central Europe: Notecka Wilderness and Tuchola Forest (Pinewoods)

Leccinum scabrum sporocarps and associated topsoils from two areas in Poland have been characterized for contents and bioconcentration potential of Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn. Topsoil and fruitbody element composition varied between the two study sites, most likely as a result of local soil geochemistry. Element content of the labile fraction in topsoil from both sites followed the ‘pseudo‐total’ fraction and median values (mg kg^?1 dry matter) were: K 380 and 340, Mg 760 and 840, P 1100 and 920, Al 3800 and 8100, Ag 0.31 and 0.28, Ba 28 and 37, Ca 920 and 790, Cd 0.23 and 0.23, Co 2.0 and 1.7, Cu 3.2 and 3.6, Fe 2800 and 6300, Mn 280 and 180, Na 99 and 110, Ni 7.8 and 8.8, Pb 12 and 18, Rb 1.3 and 2.1, Sr 4.8 and 4.0 and Zn 22 and 19, respectively. Only for some elements such as K, Mg, Al, Ag, Ca, Co, Mn, Na, Ni, Sr and Zn we found concentration differences between the two study sites for the caps of sporocarps. With the exception of Al, Mn, Na and Pb, stipes showed a similar tendency. Caps had a higher concentration of K, Rb, P, Mg, Al, Ag, Cu, Fe, Zn, Cd, Pb and Ni compared to stipes, while Na, Ba and Sr contents were higher in stipes. The comparison of soil and fruitbody concentrations indicates that L. scabrum bioconcentrate some elements while others are bioexcluded.     

Effect of salinity,alkalinity and iron application on the availability of iron,manganese, phosphorus and sodium in pea (Pisum sativum L.) crop

Summary The effect of the salinity, alkalinity and Fe application on the dry matter yield and availability of Fe, Mn, P and Na were studied in the greenhouse on pea (Pisum sativum L.) crop. The highest dry matter yield was recorded in normal soil which decreased with the increase in the salinity and alkalinity, minimum being at 40 ESP. Alkalinity was more harmful to pea crop than salinity.Fe at 10 ppm increased the dry matter yield significantly. Highest Fe concentration (408.12 ppm) was recorded in 40 ESP soil followed by 20 ESP (395.2 ppm). Salinity alongwith marginal or higher alkalinity reduced harmful effect of alkalinity. The uptake of Fe was the highest in normal soil due to the high dry matter yield. All the three sources increased the concentration of Fe and its uptake than the control in all the soils but did not show much distinction among themselves.The concentration of Mn decreased more with the increase in alkalinity than salinity but salinity with alkalinity improved Mn concentration. Similarly uptake of Mn also decreased sharply with the increase in salinity and alkalinity. The application of Fe sources decreased Mn concentration but increased the uptake. The highest decrease was caused with FeSO₄ and lowest with Fe rayplex.Like Mn the concentration and uptake of P decreased with the increased levels of salinity and alkalinity. The addition of Fe decreased the concentration of P, highest depression being with Fe KE-MIN.Increase in ESP increased the concentration and the uptake of Na greatly. Addition of Fe through all the sources increased Na concentration and uptake significantly but sources did not differ much in their effect on Na.     

Accumulation and Distribution of Nutrients in Fruits of Castor Bean (Ricinus communis L.)

The nutrition of developing fruits of Ricinus communis was studiednear Perth, Western Australia, where the species grows as aweed on poor sandy soil. Fruits required 60 days to mature anddehydration of the capsule began 20 days before the seeds ripened.Mature seeds accumulated 49 per cent of the fruit dry matterand over 80 per cent of its P, Zn and Cu, 50–80 per centof its Mg, N, Fe and Mn, 41–46 per cent of its S and Caand 11–21 per cent of its K and Na. Losses of nutrientsfrom capsules during fruit ripening were: Zn, 73 per cent, P,42 per cent, Cu, 23 per cent and Mn, 8 per cent. Dry matter,N, K, S, Ca, Mg, Na and Fe were not withdrawn from capsules.Apparent retranslocation from capsules could have provided from6–28 per cent of the Zn, Mn, P and Cu in mature seeds.Seeds from plants on poor sandy soil were small but had adequatelevels of nutrients when compared with those from plants growingon a fertile loam. Concentrations of all nutrients except P were higher in youngcapsules than in young seeds, but levels of N, P, Mg, Fe, Znand Cu were higher in mature seeds than in mature capsules.The intake of most nutrients by fruits was out of phase withdry matter accumulation, especially in capsules, and the elementsappeared to accumulate in fruit parts independently of eachother. Glutamine accounted for over 85 per cent of the amino-Nin phloem sap destined for fruits. Potassium made up over 90per cent of the inorganic cations in phloem exudate. Of theminor elements in the exudate, Fe was present at highest concentrationand Cu at the lowest. The results showed that retranslocation from the capsule madea very small contribution to the nutrition of seeds. It is suggestedthat R. communis would require a sustained supply of soil nutrientsto ensure maximum seed yield, partly due to the restricted retranslocationof most nutrients from capsules. Ricinus communis L., castor bean, mineral nutrition, translocation, retranslocation     

青藏高原掌叶大黄和丽江大黄及其土壤的主要元素含量

采集掌叶大黄（Ｒｈｅｕｍ ｐａｌｍａｔｕｍ）和丽江大黄（Ｒｈｅｕｍ ｌｉｋｉａｎｇｅｎｓｅ）根茎、叶及根部土壤,应用ＩＣＰ测定主要元素含量特征,研究了２种大黄及其土壤的元素含量特征。结果表明,２种大黄土壤Ｐ含量远低于大黄根茎和叶,Ｆｅ含量则为土壤〉根茎〉叶,其中根茎与叶相差不大,但它们与土壤相差５０～１１０倍;Ｎａ、Ｍｎ、Ｃｕ含量在２种大黄中都表现为土壤〉叶〉根茎,Ｃａ含量在掌叶大黄中为土壤〈叶〈     

An elemental correlation study in cancerous and normal breast tissue with successive clinical stages by neutron activation analysis

Influence of trace elements in body metabolism and their physiological importance in various diseases have motivated their accurate and quantitative determination in biological tissues and fluids. Instrumental Neutron Activation Analysis (INAA) using short and long term irradiation has been employed to determine five minor elements (Cl, K, Na, Mg, P) and 15 trace elements (As, Br, Co, Cr, Cs, Cu, Fe, Hg, Mn, Rb, Sb, Se, Sc, Sr, and Zn) in cancerous and normal breast tissue from 30 patients of four clinical stages. Several elements show enhancement in cancerous breast tissue. Selenium shows maximum enhancement of 94.7% followed by K (81.6%), Sc (66.7%), Cu (58.2%), Na (48.5%), P (44.4%), and Zn (39.2%). Some element, such as Fe, Cr, and Mn, are depressed by 30.8, 30.1, and 12.8%, respectively. These elements compete for binding sites in the cell, change its enzymatic activity and exert direct or indirect action on the carcinogenic process accelerating the growth of tumors. This is further evidenced by histopathological examination of cancerous cells showing poor cytological differentiation. An attempt has been made to correlate trace element concentrations of Se, Cu, Zn, Rb, Br, Hg, As, Co, Fe, Cr, and Mn and the ratios of Se/Zn, K/P, Cu/Zn, Na/K, and Se/Fe with the clinical stages of cancer. Inhibition of enzymatic activity caused by variation in trace element concentrations results in immunological breakdown of the body system.     

Influence of washing on elemental analysis of leaves of fieldgrown crop plants

Summary Information is limited on soil contamination of leaves from field-grown row crops, especially with respect to aluminum (Al) analyses. The objective of this study was to determine the influence of washing leaf samples with either deionized water or detergent solution on elemental analyses for several agronomic crop plants. The crop plants sampled were corn (Zea mays L.), soybean (Glycine max L. Merr.), grain sorghum (Sorghum bicolor L. Moench), and wheat (Triticum aestivum L.). The crops were grown on a range of soil types, soil pH values, and tillage practices. Samples of upper leaves and lower leaves were collected separately. The samples were either not washed, washed with deionized water, or washed with detergent solution. After drying, grinding, and digesting, the samples were analyzed for Al, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). For all crop plants and conditions studied, there was no effect on measured N, P, K, Ca, Mg, Mn, Zn, or Cu concentrations, but measured Al and Fe concentrations were influenced by washing. In general, washing had a greater effect on Al analyses than on Fe analyses. Soybean samples were most affected by washing, while wheat samples seemed to be least affected. The results reflected greater contamination of lower leaves than upper leaves. Decontamination procedures appear necessary prior to Al and Fe analyses of field-grown crop plants.     

Biomass and chemical composition of fertilized and/or irrigated Pinus resinosa Ait. plantations

Estimates were made of the above-ground biomass and contents of ash, N, P, K, Ca, Mg, Na, Mn, Al, Fe, Zn, and Cu by plant components for a 40-year-old Pinus resinosa Ait. plantation growing on a known K-deficient site and treated with KCl fertilizer and/or irrigation. Regression equations were developed from sample-tree data, obtained by total tree analysis techniques, for each tree component on each treatment. After an examination of analytical techniques, it was determined that the contents of the fertilized trees increased more than 140 per cent K, 70 per cent Mn, and 50 per cent N compared to the nonfertilized trees, while the increases in contents of the other elements were more closely related to the 22 percent increase in the biomass of the fertilized trees. The approximate ratio of contents of elements in the total above-ground biomass, expressing Cu=1, was Ca 1000, N 800, K 260, P 90, Mn 90, Mg 75, Al 50, Na 20, Fe 15, Zn 8, Cu 1. The 75 kg per ha more K in the above-ground biomass of the fertilized trees compared to nonfertilized trees was about 15 per cent of the total K applied in the fertilizer. The influence of irrigation on the biomass and chemical composition of the trees was minimal.     

Accumulation, Partitioning and Redistribution of Dry Matter and Mineral Nutrients in Ixia flexuosa L., with Special Reference to its Cormaceous Habit

The seasonal dynamics of uptake, partitioning and redistributionof dry matter, N, P, K, S, Ca, Mg, Na, Cl, Fe, Zn, Mn and Cuby the cormaceous plant Ixia flexuosa were studied in pot cultureat Perth, Western Australia. Dry matter and P, N, K, Zn andCu were redistributed from the mother corm with about 90 percent net efficiency: there was no net redistribution of Ca,Na, Fe or Mn. The efficiency of redistribution from the leafyshoot to fruits and the new season's corm was 80 per cent forN and P, 24–49 per cent for K, Cu and Zn, and 0–15per cent for Na, Fe, Ca, Mn, Cl, Mg, S and dry matter. Redistributionfrom the mother corm and vegetative organs could have suppliedthe replacement corm, cormlets and fruits with 32–53 percent of their S, K, P, N, Cu and Zn, and 11–25 per centof their Ca, Cl, Mn, Mg and dry matter. The mature replacementcorm had over 60 per cent of the plant's N and P, 25–50per cent of its dry matter, Zn, Cu, Mg, K and Cl, but less than20 per cent of its Ca, Na, Fe and Mn. Each plant produced anaverage of 12 cormlets; these had 35 per cent of the dry matterand 23–47 per cent of the amount of a particular nutrientin the new season's corms. Fruits had less than 16 per centof the dry matter and each mineral in the mature plant. Ratesof mineral intake by Ixia were much lower than reported forcrop plants, and may be related to the long growing season ofthe species. Ixia polystachya L., corm, nutrition, mineral nutrients, nutrient redistribution     

Macro- and trace element concentrations in blood plasma and cerebrospinal fluid of dairy cows exposed to electric and magnetic fields.

Eight multiparous, nonlactating pregnant Holstein cows (at 198 +/- 35 days of gestation and weighing 608 + 24 kg) and seven nonlactating nonpregnant ovariectomized heifers (weighing 370 + 29 kg) were confined to wooden metabolism crates in an electric and magnetic field chamber. Subarachnoidal catheters were inserted before the activation of the electric and magnetic fields. For 30 days, cows and heifers were continuously exposed in separate trials to electric and magnetic fields (60 Hz, 10 kV/m, and 30 microT). Blood plasma and cerebrospinal fluid samples were collected for 3 consecutive days before the exposure period, the last 3 days of the exposure period, and for 3 days starting 5 days after the exposure period. Concentrations of Ca, Mg, Cu, Zn, Fe, Mn, Na, P, and K in blood plasma and cerebrospinal fluid were determined. Exposure to electric and magnetic fields resulted in decreased concentrations of Mg in blood plasma and in increased concentrations of Ca and P and decreased concentrations of Fe and Mn in cerebrospinal fluid.