A Soil Quality Assessment within the Iowa River South Fork Watershed

作者：Stott Diane E^*; Cambardella Cynthia A; Tomer Mark D; Karlen Douglas L; Wolf Roger

来源：Soil Science Society of America Journal, 2011, 75(6): 2271-2282.

DOI：10.2136/sssaj2010.0440

Soil quality assessment is a proactive process for understanding the long-term effects of crop and soil management practices within agricultural watersheds. Fields with both well-developed and poor (N-deficient) corn (Zea mays L.) canopy growth were identified within the Iowa River's South Fork Watershed. Our objectives were to quantify several soil quality indicators, including the near-surface soil organic carbon (SOC) content, and determine if the Soil Management Assessment Framework (SMAF) could distinguish between the well-developed and poor corn canopy areas. Four sites, three representing the major soil series in the well-developed canopy areas and one in the poor area, were identified and sampled (0-10 cm) within 50 fields. There were no significant differences between performance zones when analyzed collectively. Using SMAF indicator scores, SOC, bulk density (D(b)), water-filled pore space (WFPS), electrical conductivity (EC), and microbial biomass carbon (MBC) were significantly lower in the poor canopy areas; however, no single indicator scored significantly less across all 50 fields. When separated by landscape position (hilltop, sideslope, toeslope, or depression), only SOC was significantly different between performance zones across each position. Other indicators that differed in at least one slope position included D(b), WFPS, MBC, EC, P, Fe, Cu, Zn, or potentially mineralizable C. A majority of fields had multiple indicators with SMAF ratings at least 0.10 lower in the poor areas than in the corresponding well-developed canopy areas. Soil quality assessment on a field-by-field basis thus provides an approach for identifying potential specific soil-based causes for the poor canopy development.

• 出版日期2011-11