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Soil water depletion by profile depth increments and total water usage were measured yearly under either small grains or corn (Zea maysL.) over a 4‐yr period on undisturbed Williams loam (fine‐loamy, mixed Typic Argiborolls) and soil reclaimed following simulated stripmining. The reclaimed soil had topsoil thicknesses of either 0.23, 0.46, or 0.69 m respread over nonsaline, nonsodic spoil materials whose textures were gravelly loamy sand with and without a clay loam subsoil, clay loam, or silty clay loam. Total water usage and soil water depletion (for profile depths of 0 to 0.6 m and 0.6 to 1.5 m) were consistently greater, but essentially significant (P = 0.10) only in 1 yr, for the undisturbed compared to the reclaimed soil (averaged over topsoil thickness or spoil texture). Grain or biomass yields were significantly higher for the undisturbed compared with the reclaimed soil when growing‐season precipitation was inadequate or poorly distributed. Shallower rooting depths and thus lesser soil water depletion even though the reclaimed soil had similar amounts of plant‐available soil water at planting for 3 of the 4 yr resulted in water stress conditions and reduced potential productivity in inadequate precipitation years on the reclaimed soil. Similar water‐use efficiency values were found for both the undisturbed and reclaimed soils for all 4 yr. If amounts of available soil water at planting and soil water depletion values had been more uniform between the undisturbed and reclaimed soils, the reclaimed soil most likely would have met the reclamation law requirement of “equal or better than” productivity present prior to mining (undisturbed soil productivity) for all 4 yr.

Stripmining of coal drastically disturbs agricultural land and may alter many of the plant‐soil‐water relationships of undisturbed land. Plots were established on leveled moderately sodic clay loam mine spoil to evaluate topsoil thickness and P on crop production and soil moisture in a semiarid environment. A nonsodic sandy loam topsoil was replaced on the spoil at thicknesses of 0.05, 0.15, 0.30, and 0.60 m. Prior to topsoil placement, P was broadcast on the leveled spoil at rates of 0, 34, and 100 kg P ha−1. Phosphorus at rates of 0, 11, and 34 kg ha−1was applied annually for 4 yr to plots seeded to hard red spring wheat (Triticum aestivumL.) using a drill attachment and by banding to corn (Zea maysL.). In the last 2 yr, P broadcast rates of 0, 12, and 12 kg P ha−1on wheat and 0, 18, and 18 kg P ha−1on corn were substituted for the drilled and banded P treatments. Corn silage and wheat grain yields in most years were significantly higher on 0.15‐, 0.30‐, and 0.60‐m topsoil compared to 0.05 m. The clay loam spoil was not as drought prone as the sandy loam topsoil and therefore, as the thickness of topsoil increased, the ability of the profile to continuously supply water to the growing crop decreased. The relationship between wheat yield and total water use was similar to undisturbed soils in the Northern Great Plains. Responses of wheat and corn to the one time broadcast application of P to the topsoil‐spoil interface or annual applications were generally small and occurred at the low rate of P.

Eight trenches were excavated to a depth of 4.6 m and filled with one of three different textures of spoil to evaluate topsoil and subsoil thickness requirements for crop production on nonsaline, nonsodic spoil material. Yields of wheat (Triticum aestivumL.) in 1979 and 1982, barley (Hordeum vulgareL.) in 1980, and corn (Zea maysL.) in 1981 and 1983 were compared on plots with 0.23, 0.46, or 0.69 m of topsoil replaced over loamy sand spoil with and without subsoil, over clay loam spoil, or over silty clay loam spoil. Crop yields increased with increasing thickness of replaced topsoil, especially on trenches filled with loamy sand spoil. Crop yields were greater when subsoil was replaced than when no subsoil was replaced on loamy sand spoil at a given topsoil thickness. Average yields from the trenches were equal to or better than average yields from undisturbed plots in 1979 and 1983. On irrigated plots in 1983, response of silage and corn grain to subsoil/spoil treatments was similar to the nonirrigated plots. Wheat grown on irrigated plots in 1982 did not respond significantly to topsoil thickness or subsoil/spoil treatments. At least 0.69 m of topsoil plus subsoil was required to achieve highest yields on nonsodic, nonsaline, loamy sand spoil, but 0.46 to 0.69 m of topsoil was sufficient for highest yields on clay loam and silty clay loam nonsaline, nonsodic spoil. Crop yields were not increased by broadcast applications of N and P fertilizer.

The study was conducted to determine the effect of fertilizer N and P on a grass‐legume mixture grown on land reclaimed following strip‐mining. Phosphorus was broadcast at rates of 0,6,17,50, and 150 kg P/ha in the fall of 1974. One‐third of the plots which received 6, 17, or 50 P/ha received no additional P during the course of the study; one‐third received an additional broadcast application of 6, 17, or 50 kg P/ha, respectively, in the spring of 1976 and one‐third received 6,17, or 50 kg P/ha, respectively, in the spring of each year from 1976 to 1981. Nitrogen was applied annually in the spring, on the same plots, beginning in 1975, at rates of 34,67, and 134 kg N/ ha. Fertilizer N applied at 134 kg/ha increased total forage yield from 11 to 45% compared to 34 kg N/ha. ‘Lincoln’ smooth bromegrass (Bromus inermusLeyss.) and wheatgrass sp. yields were increased 30 and 37%, respectively, in 1981 while botanical composition on a percent by weight basis increased 15 and 19%, respectively. Compared to the 34 kg N/ha rate, yield and percent composition of ‘Vernal‘ alfalfa (Medicago sativaL.) were decreased by the 134 kg N/ha rate. Total forage yields were not increased by fertilizer P. Yield and percent composition of wheatgrass increased with increasing additions of P, while the percent composition of smooth bromegrass decreased. Yields of smooth bromegrass and wheatgrass were highly correlated with the cumulative P applied 4 to 6 years prior to the 1981 harvest. Fertilizer recommendations based on soil test values accurately predicted response to N and P fertilizer.