Corn production for grain or silage is possible on land reclaimed to modern standards after being surfacemined for coal in eastern and southeastern Ohio. Corn grain yields and silage production often are lower compared to production on unmined soil. A significant factor implicated in the lower yields is that rooting tends to be shallower and more restricted on mined soils than on unmined soils, magnifying adverse effects of any moisture stress that might occur.
Keys to successful corn production on reclaimed land include: (1) selection of an acceptable mined soil; (2) split application of nitrogen to improve N-use efficiency; (3) no-till planting into forage sod or stalk cover to conserve soil moisture; and (4) rotation of corn with forages and application of manure or organic amendments to improve soil physical properties. Given the sensitivity of the crop to moisture stress, success with corn on mine soils also depends greatly on the amount and distribution of precipitation, as well as an adequate hybrid selection best suited to the region and specific conditions.
Fairpoint, Farmerstown, and Morristown mine soils have proven most adaptable to corn production. In contrast, Bethesda is not recommended for corn. For corn, one should select only those sites where the mixed topsoilupper subsoil placed over the spoil is of silt-loam or siltyclay loam texture, avoiding surface layers with high clay content because they often produce poor stands.
Split application of nitrogen (one-half at planting and remainder sidedressed four to five weeks later) can double the efficiency of nitrogen fertilizer on mine soils. An opportunity for increased denitrification on mine soils (due to early season wetness) means that application of all N at planting time often promotes severe N losses. Fertilizing and liming according to soil test results provides corn with adequate phosphorus, potassium, calcium, and magnesium. No micronutrient problems have been identified for corn production on mine soils in Ohio.
Both conventional plow tillage and no-till planting have been used successfully on mine soils. No-till is preferable because retention of previous crop residue is valuable for conserving soil moisture on mine soils, which tend to be droughty after drying in the spring. Also, no-till decreases the number of rocks brought to the surface. A forage-sod mulch and no-till planting usually provide the best soil and water environment for corn.
Rotating corn with forages on mine soils is encouraged because soil structure rapidly improves under forage cover. Severe compaction sometimes occurs when the soil or topsoil material is moved when too wet during the reclamation process. Compaction restricts depth of rooting. Chisel-ripping may not alleviate problems. Severely compacted areas are best kept in continuous forage production.
Forages should be grown at least two seasons before beginning corn production. Heavy repeated applications of manure and/or municipal biosolids increase soil fertility and can enhance the structure of mine soils.
Very early planting is not recommended for mine soils because of their restricted internal drainage. Seed emergence may be delayed in wetter, cooler mine soils, similar to corn response on natural soils with poor internal drainage. When planting on mine soils, farmers should select high-yielding, adapted hybrids with strong emergence when grown on poor to moderately well-drained natural soils. Other desirable hybrid characteristics include good stalk strength and flexible ear size and number. Other aspects of corn production in mine soils should follow current Extension recommendations for these soils.
Seasonal precipitation can affect soybean yields significantly on both the light-colored, natural soils and mine soils in eastern Ohio. Farmers might expect soybean yields on mine soils to be about 65% of those obtained on unmined ones. With careful planting, plant densities should be similar to those obtainable on unmined sites. Narrow-row planting is recommended.
Farmerstown, Fairpoint and Morristown mine soils have proven more satisfactory for soybeans than the more acidic Bethesda mine soil. No consistent nutrient problems have been associated with the production of soybeans on properly managed mine soils. Mine soils likely will lack sufficient populations of Rhizobium bacteria, so seed inoculation usually will be necessary to ensure nodule formation and nitrogen fixation in soybean (and other legume) crops.