CC23 Revised 1979 Emergency Flood Information...Improvement of Flood Damaged Cropland

Campaign Circular 23 This circular is about emergency flood information and how to improve flood damaged cropland

Pond Water Quality in a Claypan Soil

In many areas of the Midwestern United States, a safe and plentiful supply of groundwater is a primary concern. Groundwater is sporadic, unreliable, shallow, and often polluted, even though these same areas often have an annual rainfall in excess of 1 m. The pollution problems associated with these groundwater supplies are both chemical and bacterial. Older wells are often the most dangerous. Linings made of open brick near the surface, cracked casings and covers, and nearby privy, septic tank, and barnyard sites accentuate the problems in shallow groundwater aquifers. High levels of nitrates frequently present in the shallow domestic well water of Illinois were recognized as a health problem by Weart (1948). A preliminary study by Smith et al. (1970) in Washington County, Illinois, of 213 dug wells (2.1-9.2 m deep), 31 drilled wells, and 72 farm ponds showed that water from 73.4 percent of the dug wells exceeded the U.S. Public Health Standard of 10 mg/1 nitrate nitrogen. Only 19.3 percent of the drilled wells exceeded the standard for safe drinking water. All the ponds sampled were found to be well below the U.S. Public Health Standard for nitrate content. Pryor (1956) has reported that because of the geology of the area groundwater supplies in most of Washington County, Illinois, are inadequate. The geologic situation makes successful drilled wells almost nonexistent. Existing low-quality and low-yielding wells are being supplemented by cisterns, transported water, and some ponds. An economic analysis of farm water supplies in Washington County by Moore (1972) revealed that present well water systems are the least costly available, but the quality and quantity make most of these sources unreliable. Alternatives considered by Moore included farm ponds, municipal water supplies, transported water, and various combinations of these potential sources. Moore concluded that farm ponds with a treatment system could be one of the more satisfactory sources of water provided storage is available to meet demands during a prolonged drought. The data reported by Smith et al. ( 19 7 0) concerning nitrate levels in Washington County ponds were from samples collected during late spring. Hill et al. (1962) reported an average maximum level of 3.1 mg/1 of nitrate nitrogen occurred in 14 Ohio ponds with a mean value of 0.17 mg/1. Hill also reported that maximum values for some chemical parameters occurred during early spring months. The authors felt that ponds in Washington County could potentially exceed the public health limit for nitrate because contamination could occur from the same sources causing widespread groundwater contamination. Also, it was felt that differences in watershed types could influence the quality of pond water. Pryor (1956), Smith (1970), and Moore (1972) have shown that Washington County needs an alternate water supply to existing low-quality wells. A project was initiated in December 1970 to determine seasonal and monthly fluctuations of several water quality parameters in farm ponds having different watershed types. Additionally, the premise that Washington County farm ponds could provide water of acceptable quality to repace existing low-quality wells was considered

Maintaining a Septic Tank System

Once a septic tank and absorption field are installed, you can do several things to prolong their life, thus protecting an investment which may cost $2500 or more. Here are several tips you can follow. Often overlooked or neglected is the fact that septic tanks should be inspected at least once annually. In every properly functioning septic tank, sludge accumulates in the bottom. This sludge is composed of solid materials and must be removed periodically. If the sludge is not removed, the accumulated solids will build up in the septic tank and will begin to wash out into the absorption field. Allowing solids from the septic tank to wash out into the absorption field will eventually clog it to the point where a new field will be needed. Most authorities agree that for a typical three-bedroom home, a 1 ,000-gallon (3,800 I) septic tank will need to have the solids removed every three to five years. Smaller tanks must be pumped more often. Septic tank additives that clean the tank are available, but these are generally not recommended. Some additives may cause the solids to be flushed from the septic tank into the absorption field, causing clogging problems. Other compounds may produce a septic tank effluent which will destroy soil structure and cause premature failure of the soil absorption system. To determine if your septic tank needs pumping, the thickness of the sludge can be measured as illustrated in Figure 1. To measure the depth of the sludge, wrap a long stick with a piece of rough, white toweling and tie it securely. Lower the stick through the inlet tee (to avoid the scum) to the bottom of the tank. Wait about 30 seconds and remove the stick slowly and carefully. Black particles will cling to the towel indicating the depth of the sludge. The sludge should be removed if its depth is equal to one third or more of the liquid depth. Occasionally, a floating scum layer may develop in septic tanks. This scum layer can also cause clogging and should be checked annually. The scum layer thickness can be measured with a stick and hinged flap device (Figure 1). Push the stick through the scum until the hinged flap falls into the horizontal position. Raise the stick until you feel the bottom of the layer. Mark the stick to indicate the depth of the scum layer. Now use the same procedure to locate the lower end of the submerged inlet pipe. If the bottom side of the scum layer is within three inches (7.6 em) of the lower end of the submerged inlet, the septic tank should be pumped. Most communities have contractors who pump septic tanks. It may cost$50 or more, but it is necessary for maintaining the life of the absorption field. The contractors pump the contents into a tank truck and dispose of it at an approved treatment site or by proper land application. Be sure the workman who cleans your tank mixes the liquid, sludge and scum before pumping so that all of the material can be removed, not just the liquid. It is not recommended to wash, scrub or disinfect the septic tank when pumping. Similarly, it is not necessary to leave solids in the septic to start it again. Normally, as the septic tank fills, the natural processes begin. Products to seed the system with desirable bacteria are available, but they are also not necessary

Definitions of Tillage Systems for Corn

If tillage is defined as the mechanical manipulation of soil, it follows, then, that a tillage system would be the sequence of soil-manipulation operations performed in producing a crop. Today, however, such a definition is recognized as inadequate. We know, for instance, that the management of non-harvested plant tissue (i.e., residue) affects both crop production and soil erosion, and that field operations in which the soil is not tilled have a marked influence on soil condition. Therefore, in this publication, a tillage system is the sequence of all operations involved in producing the crop, including soil manipulation, harvesting, chopping or shredding of residue, application of pesticides and fertilizers, etc. But before describing and comparing the various tillage systems for corn, some terminologies and possible points of confusion need to be addressed. These have to do with primary vs. secondary tillage and the different ways in which similar tillage systems could be defined. PRIMARY AND SECONDARY TILLAGE For many tillage systems, the specific operations can be separated into primary and secondary. Primary tillage loosens and fractures the soil to reduce soil strength and to bring or mix residues and fertilizers into the tilled layer. The implements ( tools ) used for primary tillage include moldboard, chisel and disk plows; heavy tandem, offset and one -way disks; subsoilers; and heavy -duty, powered rotary tillers. These tools usually operate deeper and produce a rougher soil surface than do secondary tillage tools; however, they differ from each other as to amount of soil manipulation and amount of residue left on or near the surface. Secondary tillage is used to kill weeds, cut and cover crop residue, incorporate herbicides and prepare a seedbed. The tools include light- and medium -weight disks, field cultivators, rotary hoes, drags, powered and unpowered harrows and rotary tillers, rollers, ridge- or bed -forming implements, and numerous variations or combinations of these. They operate at a shallower depth than primary tillage tools and provide additional soil pulverization. Equipment that permits primary and/or secondary tillage plus planting in a single operation is also available

Slot Injection of Herbicides

Injection of thiocarbamate herbicides into a slot created by a coulter was evaluated during a 3-year study in southeastern Nebraska. Control of shattercane, the dominant weed, with the slot injector was similar to conventional double disk incorporation. In both tilled and untilled surface conditions, the slot injector placed the herbicide into the soil with minimal disturbance of the soil and residue. Herbicides which are normally broadcast applied were band applied, reducing chemical costs by two-thirds

G82-586 Effects of Agricultural Runoff on Nebraska Water Quality

This NebGuide discusses the effects of agricultural runoff on Nebraska water quality. Methods of controlling agricultural runoff are also examined. The Federal Water Pollution Control Act Amendments of 1972 and the Clean Water Act of 1977 were written in response to a national concern for decreasing surface and groundwater quality. These laws set 1985 as a target date for eliminating pollutant discharges into navigable waters. An interim goal of the acts calls for water quality which provides for the protection and propagation of fish, shell fish, and wildlife and provides for recreation in and on the water, where attainable, by July 1, 1983

Surface Cover from Corn Residue on Sandy Soils

Corn residue left as surface cover after land preparation and planting by various combinations of tillage implements and surface planters, respectively, was measured on four research/ demonstration sites with sandy soils in Nebraska. Surface cover ranged from 51 to 80% for the no-till treatments to 14 to 53% for the twice-disked treatments. The wide range in cover was due to the amount of antecedent residues from the previous crop and the soil type which ranged from sandy loam to tine sands. Other tillage implements included a rolling cultivator, sweep-plow, and mulch-treader

RESIDUE MANAGEMENT TO CONTROL SOIL EROSION BY WATER

The Erosion Process Erosion of topsoil begins when water detaches individual soil particles from clod and other soil aggregates. A single raindrop may seem insignificant, yet collectively, raindrops strike the ground with surprising force. During an intense storm, rainfall can loosen and detach up to 100 tons of soil per acre and can be especially erosive when residue mulch or vegetation are not present to absorb their impact. Two problems often occur during rainstorms. The rate of rainfall can exceed the rate at which water can enter the soil and raindrop impact forces can partially seal the soil surface. In the first in distance, the excess water either collects on or runs off the soil surface and in the second, less water can infiltrate into the soil, causing more runoff. This runoff will travel downhill, carrying soil particles with it. Runoff from steeper areas flows at greater velocities and may transport considerable amounts of soil. Further, longer slopes have greater flows because water is concentrated from a larger area. As runoff flow across unprotected soil surfaces, additional soil particles are dislodged, thus creating even more soil erosion. Residue Reduces Erosion Crop residue helps protect the soil surface from raindrop impact. It. also reduces surface crusting, sealing and rainfall-induced soil compaction, all of which increase water runoff by reducing infiltration. In addition, runoff is reduced because pieces of residue form a complex series of small dams and obstructions that slow the runoff. Years of research show that no-till planting systems, which leave the greatest amount of residue cover, can reduce soil erosion by 90 to 95 percent of that occurring from cleanly tilled systems. As little as a 30 percent residue cover can reduce erosion by 65 percent as shown in the illustration. Prior land use, crop canopy and surface roughness also influence erosion from different tillage and planting systems, but residue cover is the single most important factor

Soil Compaction I Where, how bad, a problem

Soil compaction is a more common problem now than it was 15 years ago, regardless of the tillage system used. Producers now use heavier tractors, larger implements, bigger combines, earlier spring tillage, reduced tillage, and no-till planting systems. While all of these have a potential to increase compaction, the major cause of the problem is conducting field operations when the soil is too wet. Most think about tilling wet soils in the spring as being the major problem, but harvesting a too-wet field in the fall can cause just as much compaction. Large combines and auger wagons can have loads exceeding 20 tons per axle. Continuous no-till has also created concerns regarding soil compaction and potential yield decreases. A study in Minnesota that compared no-till and other tillage systems used for 10 years on a clay loam soil showed the greatest soil density for the no-tilled soil. A study in Illinois indicated more compaction with no-till and other reduced tillage systems than with moldboard plow or chisel systems. Generally speaking, no-till is undesirable on a fine textured soil which has poor internal drainage or on a soil that has marginal tilth at the outset. On top of the soils themselves, the residue cover with no-till conserves moisture and slows soil drying, which can further complicate the problems of compaction when no-till is used on poorly drained soils. Soils with good structure, high organic matter, and good internal drainage are less likely to have compaction problems. Also, in low-rainfall areas, such as the Great Plains, compaction is less likely to be a problem than it is in areas of more moisture. The biggest single cause of compaction is the degree of wetness in a field when work is performed in or on that field. Defining compaction Compaction can be defined as the moving of soil particles closer together by external forces exerted by humans, animals, equipment, and/or the impact of water droplets. Packing the soil particles together results in the loss of pore space within the soil. This, in turn, leads to poorer internal drainage and aeration. Under many soil conditions compaction leads to slower water infiltration, which results in greater runoff and soil loss from both rainfall and irrigation. Compaction effects on the crop include reduced plant growth, especially root development, decreased crop yield , and delayed maturity

Tillage Systems for Row Crop Production

Selecting the tillage system best suited to a particular farming situation is an important management decision. Formerly, the traditional system was a moldboard plow operation followed by several secondary tillage operations before planting. This system can be appropriate for poorly drained soils having little or no slope and low erosion potential. However, plowing has several disadvantages . The potential for soil erosion is high on sloping lands, and labor and fuel requirements can be substantially higher than with other tillage and planting systems. Today, conservation tillage systems are used to reduce preplant tillage operations, thus reducing soil erosion and moisture loss while saving labor and fuel. The label conservation tillage represents a broad spectrum of farming methods, and is most often defined by the amount of residue cover remaining on the soil surface. The minimum amount recommended is 20 to 30 percent after planting. Research in Nebraska and other Midwestern states has shown that leaving at least this much residue will reduce erosion by more than 50 percent of that occurring from a cleanly tilled field. To achieve effective erosion control, this minimum residue cover should be maintained during the critical soil erosion period between spring seedbed preparation and crop canopy establishment. Conservation tillage does not necessarily require new equipment. Most conventional farm implements can be used. For corn, grain sorghum, or wheat residue, one or two passes with a field cultivator, disk, or chisel plow will usually leave more than the 20 percent minimum cover. Additional operations reduce the amount of residue, and thus reduce erosion control. Other tillage and planting systems such as ridge-plant (till-plant) and no till leave even more residue, and thus offer greater erosion control. However, no-till planting is the only method that consistently leaves the minimum surface cover in the more fragile and less abundant soybean residue. No single tillage system is best for all situations at all times. Selecting the best tillage system for a particular soil and cropping situation requires matching the operation to the crop sequence, topography, and soil type. Rotating systems to coincide with crop rotations often provides an excellent combination. For example, a no till system could follow soybeans while a chisel or disk system might follow corn. This tillage rotation provides the best erosion control following soybeans, and provides an opportunity for some tillage in the less fragile and more abundant corn residue