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The effect of land use on the availability of soil nitrogen (N) was studied by separating total soil N into one labile and one stable fraction by oxidation and extraction of labile N with potassium permanganate. The nitrogen management index (NMI) was calculated according to Blair et al. (1995) f...


Westerhof, RVilela, LAyarza, Miguel AngelZech, W.[Labile N and the nitrogen management index of oxisols in the Brazilian cerrados]Labile N and the nitrogen management index of oxisols in the Brazilian cerrados

In the Cerrados, a large savanna region in Brazil, the effects of different land use on aggregation in Oxisols were studied, using laser diffraction grain-size analyses. The topsoil of plowed systems had significantly fewer macroaggregates (194-2000 micro m) and a significantly larger fraction of...


Westerhof, RBuurman, PGriethuysen, C. vanAyarza, Miguel AngelVilela, LZech, W.[Aggregation studied by laser diffraction in relation to plowing, soil organic matter, and lime in the Brazilian cerrados]Aggregation studied by laser diffraction in relation to plowing, soil organic matter, and lime in the Brazilian cerrados

The permanganate oxidation procedure is easily performed and may help monitor large areas for their soil organic matter (SOM) quality and nitrogen (N) availability. Knowledge of the chemical characteristics of fractions that are lost or remain after oxidation will help explain results obtained by...


Westerhof, RVilela, LAyarza, Miguel AngelZech, W.[Characterization labile and stable nitrogen]Characterization labile and stable nitrogen

In the Brazilian savannas, or Cerrados the rapid advance in agriculture and cattle ranching is affecting soils through, for example, accelerated erosion and depletion of soil organic matter (SOM). Changes in soil microbial biomass are good indicators of changes in SOM. We therefore assessed the e...


Renz, TENeufeldt, HenryAyarza, Miguel AngelResck, DVSZech, W.[Microbial biomass, microbial activity, and carbon pools under different land-use systems in the Brazilian cerrados]Microbial biomass, microbial activity, and carbon pools under different land-use systems in the Brazilian cerrados

Short-term changes in soil aggregation, total and particulate organic C and N were studied in cropping and pasture systems of the Brazilian savannas, also known as the Cerrados. Furthermore, the concepts of a hierarchical aggregate structure and of the interaction of soil structure with particula...


Freibauer, A.Westerhof, RAyarza, Miguel AngelSilva, J.E. daZech, W.[Short-term variation in aggregation and particulate organic matter under crops and pastures]Short-term variation in aggregation and particulate organic matter under crops and pastures

This study assessed the influence of land use (continuous cropping, CC; tree plantations, F; pasture, PG; and native savanna, NS) on P concentrations and partitioning in bulk soil and two aggregate size fractions of two Oxisols, one loamy and one clayey. The quantity and quality of physically pro...


Lilienfein, JWilcke, W.Neufeldt, HenryAyarza, Miguel AngelZech, W.[Phosphorus pools in bulk soil and aggregates of differently textured oxisols under different land-use systems in the Brazilian cerrados]Phosphorus pools in bulk soil and aggregates of differently textured oxisols under different land-use systems in the Brazilian cerrados

Soil organic matter quality is usually seen as a major attribute of soil quality. In this study, we extracted organic carbon with water (WEOC) or with potassium permanganate (PEOC). We assessed these extractions for their potential as sensitive indicators of the effect of land use on two importan...


Westerhof, RVilela, LAyarza, Miguel AngelZech, W.[Carbon fractions as sensitive indicators of quality of soil organic matter]Carbon fractions as sensitive indicators of quality of soil organic matter

Little is known about the sustainability of cultivation systems in the Brazilian savannas, also known as the Cerrados, despite its increasing significance for that country`s agriculture. To characterize management effects and follow alterations of organic compounds in different fractions, we stud...


Neufeldt, HenryResck, DVSAyarza, Miguel AngelZech, W.[Soil organic matter in oxisols of the Brazilian cerrados]Soil organic matter in oxisols of the Brazilian cerrados

The effects of land-use change on the structure of Oxisols in the Brazilian savannas (also known as the Cerrados) are still insufficiently understood. We therefore studied loamy and clayey Oxisols under natural savanna, crop, pasture, and reforestation to (1) quantify management-induced changes i...


Neufeldt, HenryAyarza, Miguel AngelResck, DVSZech, W.[Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados]Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados
Rao, Idupulapati M.Ayarza, Miguel AngelThomas, Richard J.Fisher, Myles J.Sanz Scovino, José IgnacioSpain, James M.Lascano, Carlos E.[Soil-plant factors and processes affecting productivity in ley farming]Soil-plant factors and processes affecting productivity in ley farming

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