The effect of crop-pasture rotations on the C, N and S contents of soil aggregates and structural stability in a volcanic soil of south-central Chile

• Published in: Acta agriculturae Scandinavica. Section B, Soil and plant science Vol. 57; no. 3; pp. 255 - 262
• Main Authors: Sandoval, Marco A., Stolpe, Neal B., Zagal, Erick M., Mardones, María
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01-01-2007
• Subjects: Andisol; annual crops; Medicago sativa; pastures; Trifolium repens; Chile
• ISSN: 0906-4710; 1651-1913
• DOI: 10.1080/09064710600925836

The effects of six crop-pasture rotations were evaluated on properties of soil aggregates in a volcanic soil (Humic Haploxerand) of south-central Chile. Rotations that included intensive cropping without pastures, and crops with short- or long-term pastures were maintained for 12 years after which soil samples were taken at 0-5 and 5-10 cm depths for analysis of the C, N and S contents in the different grades of water-stable aggregates. The mean weight diameter of the aggregates was also determined as an indicator of structural stability. The results showed that the rotations which included long-term pastures of alfalfa (Medicago sativa L.) or white clover (Trifolium repens L.) had higher contents of C, N and S in soil and there was a higher concentration of these elements in macro-aggregates (>0.5 mm) than in micro-aggregates (<0.5 mm). Additionally, the rotations with pastures also produced greater structural stability of the soil aggregates. Consequently, crop rotations that included pastures, particularly those of longer duration, improved the soil and were therefore a more sustainable use of the soil resource compared to the more intensive rotations. Additionally, there was evidence of hierarchical organization of the soil structure, which is a previously non-described feature of volcanic soils.