Carbon contents and aggregation related
+ Models
STILL-2486; No of Pages 12
Available online at www.sciencedirect.com
Soil & Tillage Research xxx (2008) xxx–xxx
www.elsevier.com/locate/still
Carbon contents and aggregation related to soil physical and
biological properties under a land-use sequence in the
semiarid region of central Argentina
Elke Noellemeyer *, Federico Frank, Cristian Alvarez,
German Morazzo, Alberto Quiroga
Facultad de Agronomı´a, Universidad Nacional de La Pampa, C.C. 300, RA-6300 Santa Rosa, La Pampa, Argentina
Received 25 June 2007; received in revised form 11 December 2007; accepted 8 February 2008
Abstract
Land-use change affects vast areas of the semiarid region of central Argentina, where agriculture becomes predominant over
mixed farming systems, and large areas of permanent pastures (PAS) are being converted to agricultural land. This land-use change
causes loss of soil structure, but very little is known about the effect of changes in aggregate size distribution on soil physical,
chemical and biological properties. We decided to use dry sieved aggregates since this technique is commonly used in semiarid
regions. The study was carried out at Anguil, La Pampa, Argentina. The soil was a sandy loam Entic Haplustoll with a carbonatefree A-horizon. The PAS site had been under weeping love grass for more than 40 years. Parts of this PAS were turned to cultivation
in 1989 (CULT14) and in 2001 (CULT2). Sampling was carried out at 0.6 m intervals to 0.18 m depth. Bulk density (BD), organic
carbon (OC), and water holding capacity and infiltration were determined on these samples. Dry aggregate size distribution and OC
content of the size fractions were determined on large undisturbed samples. Samples of pooled aggregate size fractions >4, 1–4, and
4 mm) and 37% higher contents of very small (4,
1–4, and 8
4–8
3–4
2–3
1–2
STILL-2486; No of Pages 12
Available online at www.sciencedirect.com
Soil & Tillage Research xxx (2008) xxx–xxx
www.elsevier.com/locate/still
Carbon contents and aggregation related to soil physical and
biological properties under a land-use sequence in the
semiarid region of central Argentina
Elke Noellemeyer *, Federico Frank, Cristian Alvarez,
German Morazzo, Alberto Quiroga
Facultad de Agronomı´a, Universidad Nacional de La Pampa, C.C. 300, RA-6300 Santa Rosa, La Pampa, Argentina
Received 25 June 2007; received in revised form 11 December 2007; accepted 8 February 2008
Abstract
Land-use change affects vast areas of the semiarid region of central Argentina, where agriculture becomes predominant over
mixed farming systems, and large areas of permanent pastures (PAS) are being converted to agricultural land. This land-use change
causes loss of soil structure, but very little is known about the effect of changes in aggregate size distribution on soil physical,
chemical and biological properties. We decided to use dry sieved aggregates since this technique is commonly used in semiarid
regions. The study was carried out at Anguil, La Pampa, Argentina. The soil was a sandy loam Entic Haplustoll with a carbonatefree A-horizon. The PAS site had been under weeping love grass for more than 40 years. Parts of this PAS were turned to cultivation
in 1989 (CULT14) and in 2001 (CULT2). Sampling was carried out at 0.6 m intervals to 0.18 m depth. Bulk density (BD), organic
carbon (OC), and water holding capacity and infiltration were determined on these samples. Dry aggregate size distribution and OC
content of the size fractions were determined on large undisturbed samples. Samples of pooled aggregate size fractions >4, 1–4, and
4 mm) and 37% higher contents of very small (4,
1–4, and 8
4–8
3–4
2–3
1–2