Chemistry and mineralogy of acid sulfate soils and potential utilization of green manures as acid soil amendments.

摘要

The growth and acidity tolerance of four legumes (Cajanus cajan, Sesbania aculeata, S. rostrata and S. speciosa) were studied in a greenhouse experiment for potential green manure sources. Two acid sulfate soils (Typic Sulfaquents, Bang Pakong (Bg) series; and Sulfic Tropaquepts, Rangsit (Ra) series) were adjusted to four pH levels: 3.8 or 4.0 (original soil pH), 4.5, 5.5 and 6.5 (amended with lime). Based on green manuring criteria of high biomass production and high N content, C. cajan and S. aculeata were better suited to the acid sulfate soils than S. rostrata and S. speciosa. C. cajan tolerated nearly three times the level of Al as the Sesbania species: Critical Al concentrations in shoots (for 10% dry matter reduction) were 80 mg kg;A greenhouse experiment was conducted to quantitatively compare the effects of two green manures (0-80 Mg ha;An incubation study for 90 days was conducted to determine changes in the solid, solution, and mineralogical properties of representative acid sulfate soils following lime (CaCO