No description available.

No description available.

No description available.

No description available.

The present state and future prospect of the world's soil resources has prompted scientists and researchers to address the issue of soil quality and sustainable land management. Soil quality research has focused on intensively-managed agricultural and forest soils, but the concept and importance of soil quality is also pertinent to disturbed systems such as reclaimed mine soils. The restoration of soil function and mine soil quality is essential to long-term ecosystem stability. The objectives of this study were (i) to determine the comparative ability of topsoil, sawdust, and sewage sludge amendments, after 16 years, to positively affect mine soil quality using the following key soil quality variables: organic matter content, aggregate stability, and mineralizable nitrogen, (ii) to determine the effects of these key soil quality variables on plant productivity, and (iii) to determine the comparative ability of trees and herbaceous plants to persist and to conserve or maintain mine soil quality. In 1982, a mined site was amended with seven different surface treatments: a fertilized control (2:1 sandstone:siltstone), 30 cm of native soil + 7.8 Mg ha-1 lime, 112 Mg ha-1 sawdust, and municipal sewage sludge (SS) at rates of 22, 56, 112, and 224 Mg ha-1. Four replicates of each treatment were installed as a randomized complete block design. Whole plots were split according to vegetation type: pitch x loblolly pine hybrid (Pinus rigida x taeda) trees and Kentucky-31 tall fescue (Festuca arundinacea Schreb.). Soil analyses of composite samples for 1982, 1987, and 1998 were evaluated for changing levels of mine soil quality. The positive effect of these organic amendments on organic matter content, total nitrogen, and other soil parameters was most apparent and pronounced after 5 growing seasons. However, after 16 years, soil organic matter content and total nitrogen appear to be equilibrating at about 4.3 and 1.5%. There was a significant difference in organic matter content and nitrogen mineralization potential between vegetation types. Organic matter inputs by vegetation alone over the 16-yr period in the control plots resulted in organic matter and nitrogen mineralization potential values comparable to levels in the organically amended plots. The results suggest that about 15 years is needed for climate, moisture availability, and other edaphic features to have the same influence on overall organic matter decomposition, N accretion, organic nitrogen mineralization levels, system equilibrium, and overall mine soil quality as a one-time 100-Mg ha-1 application of organic amendment. Tree volume and biomass were measured as indices of the effects of organic matter content 16 years after initial amendment. Individual tree volumes of the sawdust, 22, 56, and 112 Mg ha -1 SS treatments retained 18 to 26% more volume than the control, respectively. Overall, fescue production was the same among treatments. Organic amendments improved initial soil fertility for fescue establishment, but it appears that they will have little or no long-lasting effect on plant productivity. / Master of Science

No description available.

No description available.

Crop rotations which differ in fallowing frequency, residues returned and fertilizer additions were hypothesized to have measurably altered the soil physical and biological properties that contribute to a quality soil. This study was initiated to evaluate the role of crop rotation in determining soil organic matter levels and concomitant changes in soil properties.<p> The rotation site was started in 1958 on a Black lacustrine soil at the Agriculture Canada Experimental Farm, Indian Head, Sk. Rotations of unfertilized fallow-wheat(FW), fertilized fallow-wheat-wheat(FWW(N+P;+straw)), fertilized fallow-wheat-wheat with straw baled (FWW(N+P; -straw)), unfertilized fallow-wheat-wheat-hay-hay-hay (FWWHHH), and fertilized continuous wheat (cont.W) were maintained in a modified randomized complete block design. Cultural practices were fairly consistent over time. Fertilizer additions, after 1977, increased to levels recommended by the Saskatchewan soil testing laboratory. However, the overall mean fertilizer additions from 1960 to 1984 varied only slightly among fertilized rotations.<p> Systematic transects across the experimental site revealed a major change in soil type occurring in the northern ranges, which was useful in determining a uniform sampling area. Ap horizon thickness and depth to carbonates suggested that topsoil was being removed from the plot areas and accumulating on the grassed roadways.<p> Continuous wheat and FWWHHH rotations maintained the highest organic C and N concentrations. Soils under FW and FWW rotations contained 13% less organic C and N on average than the cont.W or FWWHHH soils. The amount of light fraction (LF) organic matter and the C:H ratio of the LF were closely related to biological turnover, the LF is a readily available portion of the soil organic matter. Soils under cont.W and FWWHHH contained 1.5 to 2 times more of this active organic matter than those under FWW and FW. Baling straw, reducing fallow frequency, and adding fertilizer did not have a clear impact on total organic matter or the LF.<p> Mineralization of C, N, and S was statistically more sensitive to reductions in fallow frequency, improved fertility and residue removal. Nitrogen and S mineralization followed a ranking similar to organic C and LF-C contents, with cont.W = FWWHHH > FWW (N+P;+straw) > FWW (N+P;-straw) > FW. Soil biological properties in the 7.5 to 15 and 15 to 30 cm depths were not affected by long-term crop rotation, except for higher rates of C mineralization under cont.W and FWWHHH.<p> Soil aggregates were larger and more water stable in the less frequently fallowed cont.W and FWWHHH rotations. Soil organic matter and fertility characteristics were related to soil aggregation, likely through enhanced crop growth and production of roots and fungal hyphae. Sorptivity of water under suction was a sensitive indicator of pore structure. Soils in frequently fallowed rotations had the fewest large pores, whereas cont.W and FWWHHH soils had the most large pores. Long-term crop rotation did not affect soil aggregation below the 7.5 cm depth, except where rotations were sampled directly after forages.<p> Erosion, estimated by comparing 137Cs content in the topsoil, was highly variable but suggested that FW incurred the largest topsoil losses, followed by FWW and cont.W, with the FWWHHH rotation least eroded. Reconstruction of the Ap horizon also indicated that crop rotation had influenced the amount of soil lost. Forage periods and improved trash cover, associated with infrequently fallowed rotations, probably reduced wind erosion. Soil loss from frequently fallowed rotations may be exacerbated by tillage and lateral movement of soil from the plots onto the roadways. Loss of organic matter rich topsoil was negatively related to the level of 137Cs, implicating soil loss as an important process in depleting organic matter.<p> Soil quality as indicated by nutrient supply, soil organic matter content and lability, and soil tilth was best in the least eroded, most productive FWWHHH and cont.W rotations. Frequently fallowed FW or FWW rotations resulted in the lowest soil quality, with straw baling and inadequate fertilizer additions of lesser importance to the overall soil quality.

Crop rotations which differ in fallowing frequency, residues returned and fertilizer additions were hypothesized to have measurably altered the soil physical and biological properties that contribute to a quality soil. This study was initiated to evaluate the role of crop rotation in determining soil organic matter levels and concomitant changes in soil properties.<p> The rotation site was started in 1958 on a Black lacustrine soil at the Agriculture Canada Experimental Farm, Indian Head, Sk. Rotations of unfertilized fallow-wheat(FW), fertilized fallow-wheat-wheat(FWW(N+P;+straw)), fertilized fallow-wheat-wheat with straw baled (FWW(N+P; -straw)), unfertilized fallow-wheat-wheat-hay-hay-hay (FWWHHH), and fertilized continuous wheat (cont.W) were maintained in a modified randomized complete block design. Cultural practices were fairly consistent over time. Fertilizer additions, after 1977, increased to levels recommended by the Saskatchewan soil testing laboratory. However, the overall mean fertilizer additions from 1960 to 1984 varied only slightly among fertilized rotations.<p> Systematic transects across the experimental site revealed a major change in soil type occurring in the northern ranges, which was useful in determining a uniform sampling area. Ap horizon thickness and depth to carbonates suggested that topsoil was being removed from the plot areas and accumulating on the grassed roadways.<p> Continuous wheat and FWWHHH rotations maintained the highest organic C and N concentrations. Soils under FW and FWW rotations contained 13% less organic C and N on average than the cont.W or FWWHHH soils. The amount of light fraction (LF) organic matter and the C:H ratio of the LF were closely related to biological turnover, the LF is a readily available portion of the soil organic matter. Soils under cont.W and FWWHHH contained 1.5 to 2 times more of this active organic matter than those under FWW and FW. Baling straw, reducing fallow frequency, and adding fertilizer did not have a clear impact on total organic matter or the LF.<p> Mineralization of C, N, and S was statistically more sensitive to reductions in fallow frequency, improved fertility and residue removal. Nitrogen and S mineralization followed a ranking similar to organic C and LF-C contents, with cont.W = FWWHHH > FWW (N+P;+straw) > FWW (N+P;-straw) > FW. Soil biological properties in the 7.5 to 15 and 15 to 30 cm depths were not affected by long-term crop rotation, except for higher rates of C mineralization under cont.W and FWWHHH.<p> Soil aggregates were larger and more water stable in the less frequently fallowed cont.W and FWWHHH rotations. Soil organic matter and fertility characteristics were related to soil aggregation, likely through enhanced crop growth and production of roots and fungal hyphae. Sorptivity of water under suction was a sensitive indicator of pore structure. Soils in frequently fallowed rotations had the fewest large pores, whereas cont.W and FWWHHH soils had the most large pores. Long-term crop rotation did not affect soil aggregation below the 7.5 cm depth, except where rotations were sampled directly after forages.<p> Erosion, estimated by comparing 137Cs content in the topsoil, was highly variable but suggested that FW incurred the largest topsoil losses, followed by FWW and cont.W, with the FWWHHH rotation least eroded. Reconstruction of the Ap horizon also indicated that crop rotation had influenced the amount of soil lost. Forage periods and improved trash cover, associated with infrequently fallowed rotations, probably reduced wind erosion. Soil loss from frequently fallowed rotations may be exacerbated by tillage and lateral movement of soil from the plots onto the roadways. Loss of organic matter rich topsoil was negatively related to the level of 137Cs, implicating soil loss as an important process in depleting organic matter.<p> Soil quality as indicated by nutrient supply, soil organic matter content and lability, and soil tilth was best in the least eroded, most productive FWWHHH and cont.W rotations. Frequently fallowed FW or FWW rotations resulted in the lowest soil quality, with straw baling and inadequate fertilizer additions of lesser importance to the overall soil quality.

Since 1982, the state of Illinois has afforested over 100,000 acres of abandoned or marginal cropland. Afforestation, the planting of trees on land not in forest cover, is a sustainable forest management practice that has been shown to store carbon, increase plant diversity, improve soil and water quality, and assist in flood abatement. Our research seeks to develop practical soil and vegetative indicators that can be used by researchers and land managers alike to accurately assess changes to ecosystem function following land use shifts. To assess forest restoration success in terms of ecological function, seven ecological indicators were measured across a chronosequence of 50 afforested sites and 20 mature forested sites. Soil indicators: bulk density, aggregate stability, total nitrogen, total carbon, and labile carbon, and vegetation indicators: forest productivity and stocking density were assessed for each site. Additional sampling was completed on 25 nearby agriculture fields for each of the five soil indicators. Our data were analyzed using an analysis of variance test with multiple comparisons to examine differences among indicator values by land use category. Overall, soil indicator bulk density significantly decreased across afforested sites with stand age, whereas indicators aggregate stability, labile carbon, and total carbon significantly increased across afforested sites with stand age. Linear regression analyses were used to assess the change in indicator values with stand age. Additional linear regression analyses were used to assess the change in indicator values with site index, and significant results were recorded for 3 out of the 5 soil indicators. Indicator bulk density displayed a significant negative relationship with site index, and indicators aggregate stability and total carbon displayed a significant positive relationship with site index. Overall, our results indicated that four out of the five soil parameters measured were successful indicators of restored ecological function in afforested sites. Furthermore, we believe that the inclusion of vegetation indices forest productivity and stocking density provides vital information into forest succession and a better understanding of how productive sites benefit soil quality.