Article in Soil Science Society of America Journal · May 2015
DOI: 10.2136/sssaj2015.02.0051
Lingling Li
Gansu Provincial Key Laboratory of Aridland Crop Sciences Faculty of Agronomy Gansu Agricultural Univ. Lanzhou 730070 P.R. China
Francis J. Larney*
Lethbridge Research Centre Agriculture & Agri-Food Canada 5403 1st Ave. S.
Lethbridge, AB, T1J 4B1 Canada
Denis A. Angers
Soils and Crops Research and Development Centre Agriculture & Agri-Food Canada 2560 Hochelaga Blvd. Québec, QC, G1V 2J3 Canada
Drusilla C. Pearson
Robert E. Blackshaw Lethbridge Research Centre Agriculture & Agri-Food Canada 5403 1st Ave. S. Lethbridge, AB, T1J 4B1 Canada
Rapid expansion of irrigated row crop production, viz., potato (Solanum tuberosum L.), dry bean (Phaseolus vulgaris L.), and sugar beet (Beta vulgaris L.), in southern Alberta in the late 1990s provided the impetus for a 12-yr (2000–2011) study to evaluate cropping systems that maintained or improved soil quality. The study compared conservation (CONS) and conventional (CONV) management in rotations of 3- to 6-yr duration. Conservation management included reduced tillage, cover crops, feedlot manure compost addition, and solid-seeded narrow-row dry bean production. After 12 yr, particulate organic matter C (POM-C) and N (POM-N) showed >145% increases (POM-C, 2.2–5.8 Mg ha−1; POM-N, 0.20–0.49 Mg ha−1) with CONS management compared with 45 to 50% increases in total organic C and N (TOC, 10.2–15.3 Mg ha−1; TN, 1.06–1.53 Mg ha−1) and 20% increases in fine organic matter (FOM)-C and -N (FOM-C, 8.3–10.1 Mg ha−1; FOM-N, 0.87– 1.04 Mg ha−1). Aggregate stability of the pre-wet >1-mm fraction increased significantly from 13% under CONV to 21% under CONS management. Overall, the 5-yr CONS rotation (sugar beet–wheat (Triticum aestivum L.)– dry bean–potato–wheat) ranked highest for soil quality (100%), with CONV rotations substantially lower (33–38%). Adoption of CONS management enhanced a wide range of soil quality attributes that could safeguard sustainable expansion of irrigated specialty cropping in southern Alberta.
Abbreviations: AS, aggregate stability; CONS, conservation; CONT, continuous wheat; CONV, conventional; FOM, fine organic matter; MBC, microbial biomass carbon; MBCQ, microbial biomass carbon quotient; SOC, soil organic carbon; SOM, soil organic matter; POM, particulate organic matter; TC, total carbon; TN, total nitrogen; TOC, total organic carbon.