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Chemical Properties of Native Savanna and Forest Soils in Central Brazil
Author(s) -
Cochrane Thomas T.
Publication year - 1989
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1989.03615995005300010026x
Subject(s) - soil water , subsoil , cation exchange capacity , context (archaeology) , vegetation (pathology) , soil ph , agronomy , environmental science , agroforestry , chemistry , geography , soil science , biology , medicine , archaeology , pathology
Recent research of the well‐drained cerrados (savanna) soils of Brazil suggests that poor root growth associated with inferior crop production is often caused by subsoil Ca deficiency rather than Al toxicity. The present study was conducted to re‐examine this hypothesis and to compare native soil vegetation patterns. Horizon samples from 48 representative soils of the Geo‐Economic region of Brasilia, an area covering 22‐million hectares of central Brazil, were analyzed for NH 4 NO 3 exchangeable cations, and cation and anion exchange capacity. Thirty eight of these soils were found under cerrados and 10 under the minor inclusions of native forests scattered throughout the predominantly savanna landscape. Calcium deficient soil conditions were only found in cerrados, although cerrados also occurred on high Ca soils. The Ca/Mg ratios were significantly higher in the forest vs. cerrados soils. Low Ca/K ratios and high anion exchange capacity/cation exchange capacity AEC/CEC ratios were common in cerrados soils. The Mg/K ratios were satisfactory in most of the soils. It is concluded that the Ca/Mg ratios of the cerrados soils should be examined in an agricultural context.