Soil Properties of an Irrigated Rotation Study with Sustainable and Conventional Management Practices

Francis J. Larney¹, Drusilla C. Pearson¹, Robert E. Blackshaw¹, Newton Z. Lupwayi¹, P. J. Regitnig² and Thomas A. Forge³

Abstract
Common irrigated crops in southern Alberta, Canada, such as potatoes (Solanum tuberosum L.), sugar beets (Beta vulgaris L.) and dry beans (Phaseolus vulgaris L.) produce little crop residue for return to the soil. Growing these crops in tight rotations may have long-term detrimental effects on soil quality.

An irrigated rotation study was initiated in 2000 to examine the impact of conventional and sustainable rotations on crop and soil response. The sustainable rotations (3 to 6 yr in length) were built around four specific soil management practices: (1) reduced tillage; (2) cover crops; (3) feedlot manure compost application and (4) where beans occurred in the rotation, solid-seeded narrow-row beans vs. conventional wide row beans.

Most soil parameters pointed to beneficial effects of sustainable soil management (e.g. increased soil organic carbon (SOC), microbial activity, and available water). Nematode populations were higher in shorter rotations. Sustainable management increased soil organic carbon on the 3- and 4-yr rotations by an average of 11% (0-15 cm depth) after 9 yr. In contrast, conventional management led to a 10% decline in SOC after 9 yr. The 3- and 4-yr sustainable rotations averaged 26% higher than their conventional counterparts for microbial biomass C in bulk soil.


Source
Proceedings of the Joint Conference of the Canadian Society of Soil Science and the Canadian Society of Agronomy, Beyond Organics session. Saskatoon, Saskatchewan. 20-24 June 2010.


Author Locations and Affiliations
(1) Agriculture & Agri-Food Canada, Lethbridge, AB
(2) Lantic Inc., Taber, AB
(3) Agriculture & Agri-Food Canada Agassiz, BC


Posted July 2010