The North Carolina Sedimentation Pollution Control Act was passed in 1973.  Agriculture and forestry were granted a blanket exemption.  In 1974, a Forest Practices study committee concluded that forestry practices were not major contributors of sediment and recommended that Voluntary Best Management Practices (BMPs) be used during forestry activities.  These voluntary BMPs were followed until the end of 1989.

 The 1989 North Carolina legislature amended the Sedimentation Pollution Control Act at the request of the forest industry and forestry community, which had tired of development interests claiming the forestry exemption as they pre-developed properties.  The amendment maintains the forestry exemption, conditional upon the use of recognized effective BMPs during forestry site disturbing activities.  Forest Practices Guidelines (15 NCAC 11.0101-0209) are mandated to maintain the forestry exemption.  These Guidelines were developed by a team of forestry and water quality experts, reviewed at public hearings, and approved by the Secretary of Environment, Health and Natural Resources.  The amendment became effective January 1, 1990.  Agencies, industries and private forestry companies cooperatively embarked on a major educational effort statewide, a Logger Education Advancement Program Grant (funded through the NC Cooperative Extension Service) funded the development of a logger education curriculum and the “Pro-Logger” education program emerged.

 Forest Practices Guidelines BMPs compliance surveys are conducted continuously by the NC Division of Forest Resources (NCFDR).  A limited survey in 1992 found overall compliance at 85%.  A survey of 196 sites in 1995 showed that overall compliance had risen to 92%.  Two hundred harvest sites and 23 site preparation sites across North Carolina were evaluated in 1996 with a compliance rate of 95%.

Riparian buffers are vegetated areas adjacent to water resources that provide protection from nonpoint source pollution, help with bank stabilization and provide a favorable environment for wildlife.  These buffers may be forested, grass or shrubs or combinations of these.  There is universal agreement by scientists that riparian buffers are very valuable for protection from nonpoint source pollution, particularly nitrogen and
sediment and phosphorus to a lesser extent.  However, it is much less clear how wide buffers should be, what type of vegetation should be planted or allowed to remain and what management practices should be used.  On April 8-10, 1997, a group of 26 scientists toured the Neuse River Basin and agreed on riparian buffer recommendations, which were designed to help protect water quality without limiting agricultural production.

The scientists agreed that a small percentage of the nonpoint source N in the Neuse was coming from the Piedmont area because of the limited area of crops and the presence of riparian buffers.  The recommended riparian buffers for cultivated areas was 25 feet of grass for removal of sediment and phosphorus and a 25 foot wooded area for removal of nitrogen and general stream health.

 There was also a consensus that water quality in the Lower Coastal Plain could best be protected from nonpoint source pollution by controlled drainage on field or collector ditches and riparian buffers on the larger streams.

 The middle and upper coastal plain is where the greatest amount of nitrogen
enters surface water from agricultural fields.  This is also the area where solutions are much less obvious.  Control of nonpoint source pollutants will need to be achieved by a combination of best management practices that include riparian buffers of varying widths depending upon conditions.  It was recognized that reduction of entry of nitrogen into surface waters cannot be achieved without both management and capital costs.

Farmers in the Neuse Basin have several combinations of Best Management Practices (BMPs) that can be implemented on their farms to reduce the agricultural contribution of nitrogen to the Neuse River. Controlled Drainage is one practice with widespread applicability in the middle and lower coastal plain regions of the basin.

Drainage has long been an important component of land management in the coastal plain and tidewater regions of North Carolina. On flat, poorly drained soils, drainage is necessary to facilitate most land based activities including transportation,
rural and urban development, and farming. The relative proportion of the landscape requiring drainage increases as one travels from west to east within the Neuse Basin. Nearly half of all cropland currently in production in North Carolina requires drainage
improvement for efficient production. Yet, the drainage intensity required for agricultural production is not the same in all years or all periods of the year. While wetness is the major concern, weather conditions vary such that crops periodically suffer from drought stresses in some years, even on traditionally wet soils.  Such was the case in 1997 where yields of many crops were less than 50 percent of average due to a drier than normal growing season. Intensive drainage systems that are necessary to satisfy production needs during extreme wet periods tend to remove more water than necessary during drier periods, leading to temporary "overdrainage."

Problems with drought on drained soils have resulted in a transition from conventional drainage methods to water table management. The latter utilizes water control structures, such as a flashboard riser, installed in the drainage outlet which allows
the water in the drainage outlet to be raised or lowered as needed making it possible to reduce overdrainage.  This water management practice has become known as controlled drainage. When the flashboards are lowered or removed, drainage occurs more quickly. When flashboards are added to the riser, the drainage rate is decreased and the height of the water level in the ditches and surrounding fields rise. Managing the field water level through the use of controlled drainage allows timely drainage but also maximum storage of water within the field for utilization by the crop.

Nitrogen and phosphorus not utilized by crops are transported from land based activities to receiving streams and estuaries by drainage of excess rainfall.  Field research conducted on several farms in eastern North Carolina has documented nitrogen losses in drainage water from the edge of fields to average about 20 pounds N/acre/year although
 amounts vary from site to site and year to year.  Factors causing variability include land use, type of drainage, drainage intensity, and variability in rainfall, soil, landscape position, fertilization rate, type of crop, and harvested crop yield.

The transport of nitrogen from drained fields can be minimized by managing the drainage system such that only the minimum drainage water necessary is allowed to exit the field. In numerous field studies controlled drainage has been documented to reduce the annual transport of total nitrogen at the field edge by 9 pounds per acre per year or 45 percent on average. Nitrogen reductions resulting from controlled drainage result from two processes.  Controlled drainage reduces the volume of drainage water leaving a field from 20 to 30 percent on average; although, outflow varies widely depending on soil  type, rainfall, type of drainage system and management intensity. Second, controlled
drainage provides a higher field water table level which promotes denitrification within the soil profile. (Denitrification is the process by which nitrate-nitrogen is converted to nitrogen gas by soil microorganisms when soil oxygen is low or absent.) In some cases, nitrate-nitrogen concentrations have been 10 % to 20 % lower in outflow from controlled systems compared to uncontrolled, free draining systems. The combined effect of reduced flow and reduced nitrate concentration results in the overall 45 percent reduction in nitrogen mass transport at the field edge. Controlled drainage has also been documented to reduce phosphorus transport by 0.1 pounds/acre or roughly 35 percent.

The successful utilization of controlled drainage rests on achieving a balance between two important objectives - production and water quality. General management guidelines have been developed that aim to achieve a balance between agricultural goals of optimum production efficiency and water quality goals of minimizing nitrogen transport.  Systems should be managed to minimize outflow which in turn will generally minimize nitrogen transport from fields to streams. Yet, maintaining fields "too wet", which can lead to crop stress, may not achieve water quality goals because crops undergoing stress do not uptake nutrients efficiently, thereby leaving more nutrients in the soil for transport in drainage water.  Under some conditions, productivity, water quality, or both goals may need to be mutually compromised to achieve an acceptable balance. Generalized management guidelines can be implemented that provide some benefit to both production and water quality. Once controlled drainage has been implemented, system monitoring should follow to develop a site-specific understanding of system performance.

Once installed and properly managed, producers can expect a modest increase in crop yield of up to 5 percent in most years with no additional fertilizer inputs.  These yield increases equate to better nutrient utilization by the crop resulting in less residue nitrogen remaining in the soil to be potentially transported in drainage water. Approximately 300,000 acres of controlled drainage are currently installed in North Carolina. Approximately one million additional acres are suited to controlled drainage
with roughly one fourth of this potential occurring within the Neuse Basin. Controlled drainage has the potential to reduce nitrogen transport from agricultural fields in the Neuse Basin by about two million pounds annually. Even though controlled drainage has
 been generally accepted by producers, is cost shared by the State, and recommended by both the Natural Resources Conservation Service and the North Carolina Cooperative Extension Service, there are still large areas, especially in the Neuse Basin, that could benefit from controlled drainage.

Nutrient management has the appeal of reducing inputs at the point of origin, while offering economic benefits to the producer in the form of reduced fertilizer costs.  It has been touted as one of the most cost-effective practices for reducing nutrient losses from agricultural fields.  Based on fundamental and familiar concepts such as yield response curves, soil productivity, soil testing and economic returns, nutrient
management is firmly rooted in traditional and proven agronomic practices.

In many crops, the application of economic analysis to yield response curves has shown that maximum economic returns occur at the point where nutrient uptake efficiency is maximized - usually at 90 to 95% of the maximum yield.   These analyses also indicate the point where potential losses to the environment begin to increase rapidly, and thus are important in managing for environmental quality as well.  However, the economic constraints against overuse of nutrients become negligible when fertilizers are cheap relative to the value of the crop produced, or when nutrients imported as feed for poultry and livestock are transformed into byproducts for disposal.  As a result, contemporary nutrient management deals with the agronomic and economic concerns, but within the context of protecting soil and water quality.   Thus, nutrient management attempts to maximize crop yields and nutrient uptake while minimizing nutrient losses from the root zone, and preventing excess accumulation of nutrients which may prove detrimental to subsequent crops or adjacent water resources.

What can we realistically expect from nutrient management?  Where commercial fertilizers are used, each nutrient can be applied at amounts based on agronomic, economic and environmental constraints.  The relative cost of fertilizer inputs to crop value currently allows the producers some leeway or "insurance" applications in the application of nutrients. Nutrient management could reasonably achieve a 10 to 15% reduction in N use in many fields without loss of yield, but could require additional cost for labor, equipment and management.  On farms producing poultry and livestock, substantial decreases in nutrient losses and savings in fertilizer costs have been documented in other states, and represent the major success on nutrient management implementation.  The value of these fertilizer savings is real only if the crop is harvested and sold at a profit. Most confined feeding operations in the basin currently are, or will shortly be required to have waste utilization plans (an N-only based subset of a nutrient management plan).   In the Chesapeake Bay, recent outbreaks of Pfiesteria have forced reexamination of N-based nutrient management plans.  Focus is now turning to phosphorus in regions of the Bay heavily populated with poultry farms, and phosphorus-based nutrient management plans appear to be inevitable.

The current Neuse River NSW rules mandate nutrient management educational programs for designated applicators.  Nutrient management is a complex process requiring integration of site characteristics with crop rotations, nutrient needs, source properties and economic constraints (including farm programs).   Many producers currently feel they are practicing a form of nutrient management if they soil test and apply locally common N recommendations and see no need to develop more extensive plans.  The North Carolina Cooperative Extension Service is in the process of finding ways to overcome these educational barriers. Over the last four years, we have provided training to many of the 400+ certified technical specialists in the state.  These training sessions were over 21 hours in length and targeted to an audience with considerable technical expertise.  Along with numerous cooperators, we have also designed programs and  trained over 5000 certified animal waste operators to implement their waste utilization plans. To provide meaningful training to farmers we need a clear, credible statement of the water quality problems to be addressed, and how nutrient management will effectively address those problems.  The remainder of the training will focus on the essentials of nutrient management planning for local regions and cultures, targeted commodity-oriented training modules, and user-friendly materials that provide the essential information required to develop plans.  There are a number of missing pieces in the technical database, and need for on-going demonstrations of the effectiveness of nutrient management in achieving source-input reductions.