Effects of agricultural management on chemical and biochemical properties of a semiarid soil from central Spain

• Published in: Soil & tillage research 2013-11, Vol.134, p.49-55
• Main Authors: González-Prieto, S., Díaz-Raviña, M., Martín, A., López-Fando, C.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; C stock; Cropping systems. Cultivation. Soil tillage; Fallow; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; N stock; Soil enzymes; Soil science; Soil tillage; Tillage systems; Tillage. Tending. Growth control; δ 13C; δ 15N
• ISSN: 0167-1987; 1879-3444
• DOI: 10.1016/j.still.2013.07.007

•SOM sequestration reached a steady state after 15 years of conservation tillage.•Vertical gradients of most soil properties increased as tillage intensity decreased.•No effects of tillage systems on soil δ 13C were found.•Soil δ 15N showed that N cycling under fallow is more closed than in tilled soils. Long-term agricultural management may change soil C sequestration and alter soil C and N dynamics. The objective of this study was to investigate the impact of several tillage regimes with different intensity on C and N stocks in a Calcic Haploxeralf with a leguminous/cereal rotation under semiarid conditions after 15, 18 and 21 years of management. Seven chemical and biochemical properties (total C, total N, δ 13C, δ 15N, FDA hydrolysis, β-glucosidase and urease activities) were measured in a soil (0–5cm, 5–10cm, 10–20cm, 20–30cm) under the following agricultural management: fallow (F), no-tillage (NT), zone-tillage subsoiling with a paraplow (ZT), conventional tillage with mouldboard plow (CT), minimum tillage with chisel plow after NT (MTN) or CT (MTC). The results showed that soil reached a steady state of organic matter sequestration 15 years after starting the experiment and that C and N stocks varied greatly with agricultural management, particularly in the top 0–10cm, and followed the order: F≈NT≈ZT>MTN≈MTC>CT. Fallow and less intensively cultivated soils (NT, ZT) exhibited strong vertical gradients of most properties analyzed (total C, total N, FDA hydrolysis, urease and β-glucosidase activities) with values decreasing with depth, followed by minimum tillage treatments (MTN, MTC) whereas similar values along soil profile were observed in CT treatment. No significant differences in soil δ 13C values were detected among plots with different land use or tillage systems; however, the δ 15N values suggested that, although tillage system did not affect significantly N-cycling processes, a change from “open” to “closed” N cycling occurred when cultivated soils were set aside.