Posted June 1997
Ridge and Valley
Northern Piedmont
Coastal Plain
Southern Piedmont
The ridge and valley region stretches across the western part of Virginia. Bisected by the Shenandoah Valley, this region is bordered by the sharper, more irregularly shaped Blue Ridge Mountains to the east, and the more regular, washboard shaped Allegheny Mountains to the west. The valley reaches nearly 25 miles at its widest and is shaped by several major rivers, the north and south forks of the Shenandoah and the James Rivers. The climate here is cooler, supporting cool season grasses (i.e. bluegrass, white clover, orchard grass), and a shorter growing season for crops than other parts of the state.
Soils in this region range from deep, fertile soils with high clay content, to shallow soils over limestone, dolomite, shale or sandstone. Limestone out-croppings, subterranean caverns, and a landscape pot-marked with sinkholes are not uncommon. Alluvial, flood plain soils are also present along the rivers, providing flat areas with deep soil profiles. The capacity of the soil to retain nutrients against the forces of leaching is high along the uplands and in the flood plain soils. Although these high-clay soils are not highly leachable, fractured limestone bedrock underlies most of this area, meaning dissolved nutrients can move rapidly to ground water. These factors, along with the sloping landscape, dictate intense nutrient management programs to include such practices as split application of nitrogen on crops and cereal grain winter cover crops to trap residual soil nitrogen and reduce nitrogen loss to groundwater.
Agriculture systems in the ridge and valley region of Virginia are dominated by poultry, dairy and beef production which take advantage of the regions natural topography, economic infrastructure, and close proximity to large population areas. These factors have created profitable markets for these agricultural systems and there products. Poultry production is supported by the close proximity of processing facilities and contract growers in the Shenandoah valley. Feed is shipped in by rail from the Midwest and by tractor trailer from eastern Virginia. Beef production is primarily back-grounding stocker cattle, and cow-calf operations. These operations take advantage of abundant forage production and are a logical use for shallow, sloping soils not suitable for row crop production.
Dairy production is also a major agricultural system in the Shenandoah valley. A typical dairy operation utilizes a variety of conservation practices to improve profitability and maintain sustainability in the ridge and valley region of Virginia. In a year, one dairy cow can produce in excess of 20,000 pounds of milk, require up to 23,000 lbs. of forage and produce 10,000 gallons of manure. Maximizing profits requires intensive management of cropping systems, tillage practices, and utilizing on-farm nutrients.
Typical crops include a corn, alfalfa and some soybean rotation with a small grain, rye or wheat, cover crop. Rye or wheat is planted in the fall into corn stubble, and occasionally soybean stubble. The small grain cover serves two purposes of keeping the soil covered during the winter to prevent erosion and nutrient loss, and producing grain and forage which can be harvested in the spring for feed or sale, or turned under as additional organic matter for the soil. To break the disease cycle, corn is rotated a minimum of every two years with other crops such as alfalfa or soybeans. Corn is planted into mostly rye stubble, or occasionally soybean stubble, in the spring and harvested in the fall. Corn is a major feed component for livestock, especially dairy cattle, because of its high energy content and can be fed as corn silage or high moisture corn grain. Alfalfa, or a higher yielding alfalfa/orchard grass mix, is utilized in three year rotations, as a high quality forage for dairy cattle. As a legume, alfalfa will fix nitrogen in the soil which can be utilized by succeeding crops. In the Shenandoah valley, soybeans, also a legume, are used as a convenient rotational crop with wheat more than a major source of income. These rotational schemes enable dairy farmers to maximize on-farm feed production.
Preparing the soil for planting is a major factor in the success of the crop. Soil compaction is carefully monitored using a soil probe known as a penatrometer. Compaction of the soil can be caused by repeated usage of heavy equipment such as tractors or liquid manure spreaders over a field, or by traffic over a field when the soil is wet. Compacted soil inhibits the ability of the plant to grow an extensive root system, therefore effecting its ability to take-up nutrients and water. Compaction also inhibits air and water movement through the soil which can negatively impact plant growth. To prevent compaction, fields are "deep-tilled" at least every three years or when needed, based on penatrometer readings. Deep tillage utilizes an implement with long shanks to break the soil 16 to 18 inches deep and is followed by standard discs and rollers to smooth the surface for planting. This reduced tillage technique, also known as "ripping," is especially useful in keeping sub-surface soil loose while leaving up to 40% residue on the surface. No-till or reduced tillage are conservation practices in which the killed roots and stalks of the previous crop are left on the field and the current crop planted into the stubble. Leaving surface residue has many benefits such as preventing erosion, increasing the water holding capacity of the soil, increasing the organic matter content, and improving weed control.
Manure is a major by-product of dairy farms and is useful as a nutrient source for crop production. Utilizing these on-farm resources maximizes profits by recycling waste products back into crop production and minimizing outside inputs. Regular spring and fall soil and manure testing is needed to determine the nutrient content of homogenized manure and match the application rate to specific field needs.
The Northern Piedmont of Virginia is characterized by rolling foothill between the Blue Ridge Mountains to the west and the Coastal Plain to the east. The climate is similar to the valley region, but the piedmont is 600 feet lower in elevation. Common pasture grasses include orchard grass and fescue. The limestone bedrock from the valley changes to granite in the piedmont. The soils are a deep, rich red color. This color is indicative of soils containing high iron oxides. These soils also tend to be high in clay, but are also acidic and low in organic matter. There are also areas of Triassic soils which are thin, low fertility soils with perched water. The variability of the soil requires careful management to utilize each soil type to maximum potential.
Agricultural systems shift to beef or dairy cattle operations due in part to the soil variability. Handling of manure waste using nutrient management plans are paramount due to the sloping and variable soils. These plans include methods of storing manure, testing the nutrient value of the manure, and matching soil and crop needs with manure application rates. This type of nutrient management utilizes available on-farm nutrients while preventing nutrient loss to the environment. No-till or reduced tillage practices and equipment are often used to prevent soil erosion, increase organic matter, and increase water holding were soil is suitable for crops. Wheat or barley with a double crop soybean and corn are common crops along with various forages. Crops are utilized on-farm for feed, or sold for profit.
Agriculture in this region is supported by local businesses, Virginia Cooperative Extension, and cooperatives which provide technical knowledge, materials and application equipment. These businesses work closely with farmers to determine fertilizer, herbicide, and pesticide needs. Certified crop advisors will make on-farm visits, test soils and manures, and make recommendations to optimize yield. Commercial fertilizers can be mixed into "prescription fertilizer," and applied more often at low rates to maximize effectiveness and improve yields. This technique can cut costs to farmers and prevent potential pollution.
Atlantic coastal plain soils generally have deeper profiles than valley or piedmont soils, with alluvial areas along terraced flood plains. Soils can be fertile, but can also be high in sand in areas, low in clay, and organic matter, and prone to drought. The low clay and organic matter content of the soils also indicates decreased capacity to hold nutrients against the forces of leaching. Nutrients will leach more readily through the soil, creating the need to apply split applications of fertilizers. Farms are generally larger in size and consist almost entirely of cash grain crops. Crop rotations of small grains, corn and double crop soybeans are common, with increasing interest in grain sorghum which is more drought tolerant than corn. This region of Virginia also supports diverse crops such as: strawberries, pumpkins, peas, asparagus, and the more common wheat, barley and soybeans.
Tillage techniques vary from no-till to conventional tillage. No-till has advantages on the light, sandy soils because the corn or soybean stubble holds water, adds organic matter, controls weeds, and prevents erosion. However, this region has a warmer climate, and no-till can increase disease and pest problems in crops planted in soybean or corn stubble, creating the need for more fungicides and insecticides. Conventional tillage reduces these pest and disease problems, but the benefits, especially added water holding and increased weed control, are lost. The timing of planting is also important. Early planting, especially of soybeans, can reduce insect problems, and the crop matures earlier, before the hottest part of the summer.
Large farm sizes in this region places added importance on accurate and time-saving practices. Tilling, planting and harvesting equipment is larger in this region than other parts of the state. Combines can be fitted with stripper headers for small grains which remove only the grain and leave the chaff standing in the field. This enables the farmer to harvest at a faster speed and therefore, one person can cover more acreage. Global positioning systems track yields across fields as the combine is harvesting. This system is also utilized for site specific management, allowing variable rate fertilizer application. Applying fertilizer at varying rates to fit the soil types, and yield potentials for the crop planted, can be money saving for the farmer and prevent loss of nutrients through leaching in the light soils. Farmer rely more heavily on services, such as Virginia Cooperative Extension, for reports on local weather, soil, insect and disease conditions to alert them of problems they need to look for in their own crops.
The large acreage of crops planted, and the volume of grain produced in this area supports many industries and businesses. Retail farm equipment dealerships, seed, ag-chemical and custom application businesses are numerous. Grain, mostly corn and soybeans, can be marketed at large grain elevators. The proximity of navigable waterways in this region means grain can be shipped out by barge. New grain elevators for sorghum have increased the acres planted of this drought tolerant crop because a convenient market is now available.
The Southern Piedmont of Virginia is more rural than the Northern Piedmont. The soils have deep profiles, but are generally sandy, and drought prone. The climate is mild and supports a long growing season. Field sizes are smaller, with farmland is intermingled with forest. The light soils are excellent for growing tobacco, peanuts, and in recent years, cotton.
Tillage in this region varies from conventional, with some areas of no-till corn, soybeans and cotton. However, tobacco and peanuts are susceptible to disease and insects in this warm climate. Therefore, tobacco and peanuts are grown almost exclusively using conventional planting and tillage.
Flue-cured tobacco is a traditional crop in this region, and labor intensive. Seeds are started in open seed beds or in greenhouses. These seedlings are then transplanted by hand to a tobacco planter where they are set in the ground. The leaves are most often harvested by hand by picking the lower, more mature leaves. The leaves are then stacked and cured.
Cotton has become a popular alternative to soybeans because it is more profitable, and as an alternative to corn because it is more drought tolerant. However, cotton requires intensive management and regular field scouting. Cotton is susceptible to numerous pests and requires regular application of pesticides. This plant is a tropical perennial, and requires application of growth regulators to prevent excess vegetative growth, and promote boll formation.
Farms in this region rely on high value crops on less acreage. Each crop, tobacco, cotton and peanuts, requires more intensive management, labor, and special equipment to plant and/or harvest or prepare for the market. This means many farms must invest more overhead in equipment and labor, and rely on the local knowledge base of businesses and services such as Virginia Cooperative Extension. Utilizing the knowledge, equipment and labor most efficiently is often the difference between profit and loss.
