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Guangxi Normal University (2008)

Studies on Characters of Fe-Mn Nodules and Pernicious Effect of Dryland Crops in Litang

Su Chun Tian

Titre : Studies on Characters of Fe-Mn Nodules and Pernicious Effect of Dryland Crops in Litang

Auteur : Su Chun Tian

Grade : Master’s Theses 2008

Université : Guangxi Normal University

Résumé partiel
In this paper, the key elements of the soil in the farmland ecosystems around the iron-manganese nodules - soil - element content in dryland crops and soil fertility, soil environmental quality, dryland crops edible part quality, Litang karst area, for example, to carry out sampling surveys, laboratory experiments and theoretical analysis, the results showed that : 1 soil in the study area is mainly siliceous earths, which is characterized by high silicon low sodium manganese. Soil mostly neutral, A layer of soil organic matter, total nitrogen, available nitrogen, total phosphorus, available phosphorus, potassium, cation exchange capacity, content and fertility indicators are generally higher than the B layer, phosphorus, full the potash force indicators overall performance and even the lack of its content can not meet the needs of normal growth of dryland crops, has become a major limiting factor for the growth of dryland crops. 2, the surface of the study area ferromanganese nodules Duocheng yellow-brown and smooth surface morphology is spherical, sub-spherical or ellipsoidal ; A, B layer of iron-manganese nodules oxide content are SiO2, Al2O3, Fe2O3-based, with high Fe low Mn as the main feature, compared with the soil, of ferromanganese nodules Fe2O3 and MnO has the obvious effect of enrichment and the Fe2O3 enrichment greater than of MnO, vertical, B layer of iron-manganese nodules of Fe2O3, MnO enrichment extent than the A layer. Iron-manganese nodules on the Si, Mg, Ca, Na, K, Ti and other elements having the effect of nuclear weakening effect of P elements having a specific adsorption. A B layer of iron-manganese nodules of heavy metals Pb, Co, Cr, Ni, Zn, Li content of more than the crustal elements Clarke value, the average content of heavy metals in order of Cr (VI) gt ; Zn gt ; Pb gt ; Ba gt ; Co gt ; Ni gt ; Li gt ; Hg, but the same heavy metals content in depth with the obvious differences, the B layer elements are generally abundant element content of the A layer of 1.5 times. A, B layer of iron-manganese nodules with some differences between the enrichment factor of heavy metal elements, vertical on the enrichment factor of the B layer of iron-manganese nodules are generally higher than the A layer, some differences in the size of the order of the enrichment factor, but iron the group elements (Cr, Co, Ni) and the pro-sulfur element (Zn, Pb) dominant, rock-forming elements (Ba, Li) subordination importance. Of Cr (VI), Co and Zn showed highly enriched, Pb showed high or moderate enrichment, Ni moderate enrichment Ba showed moderate or slightly enriched, Li showed slight enrichment . The elements of the correlation matrix of the enrichment of heavy metals associated with iron oxide, the factor analysis showed that iron-manganese nodules into nuclear enrichment effect, specific adsorption effects and nucleation easy leaching characteristics of effect.

Mots clés : Soil Ferromanganese nodules Heavy metal Poisoning Research Litang

Présentation (Dissertation topics)

Page publiée le 5 octobre 2014, mise à jour le 5 décembre 2017