Tartós műtrágyázás hatása a talajok nehézfém felhalmozására = Effect of long-term fertilization on accumulation of heavy metals in soils

Az Országos Műtrágyázási Tartamkísérletek (OMTK) lehetőséget nyújtanak a tartós műtrágyázásnak a talajok nehézfém tartalmára gyakorolt hatásának vizsgálatához. Vizsgálataink kiterjedtek a talajminták különböző oldhatóságú (cc.HNO3+cc.H2O2, 0,1M, KCl + 0,05M EDTA és NH4-acetat+EDTA oldható) Cu, Zn, Mn, Cd, Pb, Cr, Ni tartalmának meghatározására. A talaj-növény rendszerbeli mobilitás tanulmányozására tenyészedényes kísérleteket állítottunk be. A talajok KCl+EDTA oldható Zn és Mn tartalmára a műtrágyakezeléseknek nem volt matematikailag igazolható hatása. A tápanyagkezelések hatására a kísérleti talajokban nőtt a KCl+EDTA a Mo tartalom, ezzel ellentétben a műtrágya adagok növelésével a B tartalom csökkenése volt megfigyelhető. A kísérleti eredmények azt mutatták a 8 kísérleti helyen, hogy a talajok toxikus nehézfém (Cd, Pb, Ni) tartalmát nem befolyásolta a 28 évig tartó műtrágyázás. A keszthelyi műtrágyázási tartamkísérlet talajmintáiban a vizsgált cc.HNO3+cc.H2O2 oldható elemek a következő emelkedő sorrendben fordultak elő: CdCd>Zn>Ni>Mn>Pb>Cr; saláta:Cd>Cu>Mn>Zn>Ni>Cr>Pb, ami a növényi elemkoncentráció és a talaj összes elemtartalma közötti összefüggést mutatja. | The National Long-Term Fertilization Trials provide excellent possibilities to examine the effect of long-term fertilization on the heavy metal content of soils. Our experiments involved the specification of the different soluble (cc.HNO3+cc.H2O2; 0,1M KCl + 0,05M EDTA and NH4-acetat+EDTA) Cu, Zn, Mn, Cd, Pb, Cr, Ni content of soil samples. In order to study the mobility of heavy metals in a soil-plant system we set up a pot experiment. The fertilization treatment did not have any mathematically justifiable (significant) effect on the KCI+EDTA soluble Zn and Mn content of soils. As a result of the fertilization treatments the KCI+EDTA soluble Mo content increased in the soils under examination. The increased doses of fertilizers caused the decrease of soluble B content. The experimental results show that 28-year old long-term fertilization treatments did not result higher values than the accepted concentration level, even they did not approach it in eight different agro-ecological regions. In the soil samples of long-term fertilization trials carried out in Keszthely the cc.HNO3+cc.H2O2 soluble elements turned up in the following rising order: CdCd>Zn>Ni>Mn>Pb>Cr; lettuce: Cd>Cu>Mn>Zn>Ni>Cr>Pb

Testing of available heavy metal content of soils in Long-Term Fertilization Trials with ryegrass (Lolium perenne L.)

A greenhouse pot experiment was set up to study the Cd and Cr uptake of ryegrass (Lolium perenne L.) from the National Long-Term Fertilization Trials (NLFT) in Keszthely. The soil used was Eutric cambisol. Soils samples were taken in October 2000 in the 34th years of the experiment. Ryegrass was grown for four weeks and the plants were cut above the soil. Fresh and dry biomass weight and Cd and Cr concentrations were measured. The "total" (cc. HN03 + cc. H2 02 soluble) Cd and Cr contents of the NLFT soils were determined. The "total" Cd content of the experimental soils ranged between 0.18-0.21 mg kg1 soil. The Cd concentration in the aboveground ryegrass parts was 0.14-0.27 mg kg-1 dry matter. The Cd content of plants was 76-141% of the soils' Cd content. It was found that the "total" Cr content of soils was 37.9-40.3 mg kg-1 soil. The Cr content of ryegrass was 2.68-6.09% of the soils' Cr content. The concentration of the examined toxic heavy metal in soils was only a fraction of the valid Hungarian maximum permissible quantity. No connection was found between fertilization and the amounts of elements

Trace element content of several weed seeds

Although there is a potential contamination of cereal grains by weed seeds, an evaluation of microelement and potentially toxic element content of weed seeds concerning the potential contribution to the culture plant grains is still lacking. In our study, 30 seed samples from different weed families were analysed for some potentially toxic elements (Al, Cr, Hg, Pb) and microelements (Fe, Mn, B, Zu, Cu, Ni, Co, Se). Taking consideration the fact that even at low level of weed seed contamination of the cereal grains (1% m/n) increased significantly the toxic element concentrations of that, Al and the Sr can be ragarded as potentially harmful elements concerning to the food chain. There is a significant increase of Al concentration at 5% contamination level; the concentration was nearly two-fold companing to the ingenious concentration, while for Sr the final concentration of the grain+weed seed mixture is higher by 166.7% than the initial concentration. In case of microelements, the modifying effect of the weed seeds on it was more moderately. There was 1.9-21.2% increase for Cu, 0.2-47.9% for Mn and 0.5-7.8% for Zn