Submitted to: International Journal of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2018
Publication Date: 4/26/2018
Citation: Merrill, S.D., Liebig, M.A., Hendrickson, J.R., Wick, A. 2018. Soil quality and water redistribution influences on plant production over low hillslopes on reclaimed mined land. International Journal of Agronomy. Vol. 2018, Article ID 1431054, 12 pages. https://doi.org/10.1155/2018/1431054.
Interpretive Summary: Understanding interactions among plant growth, soil quality (SQ), and landscape hydrology can serve to guide management decisions for optimizing ecosystem services on agricultural landscapes. In this study, we applied both SQ assessment and an index of water redistribution to resolve the influence of soil and land factors on plant productivity for mined land reclamation sites in central North Dakota. At one site near Zap, North Dakota, cool-season forage grasses were more influenced by hillslope water redistribution while spring wheat yield showed influence of SQ and depth in the lower part of the hillslope and water redistribution in the upper part of the hillslope. At the site near Stanton, North Dakota, perennial forages and spring wheat showed similar patterns of growth response, with SQ and depth effects lower on the hillslope and water redistribution effect on the upper part. Results of this study suggest plant community and soil characteristics on reclaimed, disturbed lands can alter the relative influence of SQ factors and water distribution effects on hillslope production patterns. This outcome is relevant to not only land managers dealing with reclamation of disturbed lands, but to agricultural producers in general.
Technical Abstract: A basic part of soils’ delivery of ecosystem services is the interaction between plant growth response to soil quality (SQ) factors at point scale and water redistribution effects at hillslope scale. To study the influence of SQ-indicator properties and water redistribution, we examined hillslope production patterns of perennial forage species and spring wheat (Triticum aestivum), and the relationships of such yield patterns with respread soil depth (RSD), SQ index (SQI) and hillslope wetness from catchment area (HW(a)) within two mined land reclamation experiments in central North Dakota USA (Zap and Stanton). At Zap, yield of cool-season forages crested wheatgrass (CWG: Agropyron cristatum) and Russian wildrye (Psathyrostachy juncea) increased about 10% with increasing RSD from toeslope to about 10 m upslope, and then declined by greater amounts further upslope. These hillslope patterns appeared dominated by water redistribution effects, reflecting response of cool-season forages to springtime water availability. Forage species at Stanton included alfalfa (Medicago sativa), native grass mix (two Bouteloua spp.), and CWG. Growth of these increased 70% from toe to midslope, and then decreased 20% towards summit, indicating a greater response to RSD and SQ factors downslope and lesser response to water redistribution upslope. Hillslope patterns of spring wheat seed yields at both sites were similar to those of forages at Stanton, showing greater response to SQ metrics. Factors likely to be involved in production patterns at Stanton exhibiting greater response to SQ measures than at Zap were, (a) indications that hydraulic conductivity in the mine spoil at Stanton was lower than at Zap, and (b) Stanton had south aspect only, while Zap had north and south aspects. Regressions of perennial biomass yields vs. soil characteristics were consistent with hillslope production results, with positive responses to HW(a) and negative responses to RSD and SQI for forages at Zap, but positive responses to SQ measures for forages at Stanton (p =< 0.006). Results indicate that plant community and soil characteristics on reclaimed, disturbed lands can cause a shift in the relative influence of SQ factors vs. water redistribution on hillslope production patterns.