Introduction

The Colonial District Agricultural Program has defined the organization over its many years, as soil and water conservation districts were born from the unsustainable agricultural practices of the Dust Bowl era. Today, even though the local trend is transitioning out of agricultural land-uses and into suburban and residential uses, the District’s agricultural programs are still very important. While it is true that the crops produced on our fields help feed the population, it should be noted that the scope of agriculture within the Colonial District and even the entire state is miniscule when compared to other areas of the country such as the Midwestern corn-belt. As an example LaSalle County Illinois produces twice as much corn as the entire state of Virginia (Ag Census 2007). That isn’t to say that our agricultural lands aren’t important. In fact, they are more important now than ever. Virginia’s farm lands offer the most cost effective means to achieve large scale water quality improvements through the installation and implementation of conservation practices, which is exactly what the District’s agricultural program focuses on: getting the best possible performance (both agronomically and environmentally) out of our agricultural lands.

Virginia Agricultural Cost Share Program

One of the core responsibilities of the Colonial SWCD is the administration of the Virginia Agricultural Cost Share (VACS) Program. Funded through the efforts of Virginia’s Department of Conservation and Recreation (DCR), the program offers financial assistance and/or state tax credits to agricultural producers implementing conservation practices on their farms.

The Continuous No-Till BMP (SL-15A) pays farmers to stop tilling the soil. Eliminating tillage reduces erosion by increasing crop residue on the soil’s surface and improves the soil’s structure by increasing organic matter.	Winter cover crops such as this field of cereal rye have been identified as one of the most cost effective BMPs for improving water quality in the Chesapeake Bay. Cereal cover crops scavenge residual or “left over” nitrogen while legumes fix or “make” nitrogen.

These conservation practices, collectively known as Best Management Practices (BMPs), aim to improve water quality through the reduction of pollutants entering local water ways such as nutrients and sediment. Since the program’s inception in 1985, the Colonial District has distributed over $1.5 million to its farmers. Currently, there are approximately 70 BMPs from which to choose. Click here to learn more about the VACS Program.

Research & Demonstration

The Colonial SWCD is not a research institution, however, over the years the District has partnered with many different organizations in an effort to quantify environmental benefits resulting from the implementation of agricultural BMPs in our region (i.e. the Mid-Atlantic Coastal Plain). Beginning in 1999, District staff secured a grant to pilot a Cost Share practice to encourage the implementation of continuous no-till. Local farmers received financial incentives to implement the no-till practice on about 1,500 acres for a period of 5 years. At that time, statewide estimates were that approximately 8,000 acres were being managed with the continuous no-till system. Today, a decade later, estimates are that approximately 500,000 acres have adopted the continuous no-till management system across the Commonwealth. The level of effort exerted by the Colonial District to facilitate such a movement was immense, as well as expensive. Thankfully, the District was the recipient of several grant awards which helped fund some of the following projects: Rainfall Simulator demonstration on no-till cropland at the 2000 Virginia Ag Expo; creation of the Innovative Cropping Systems (ICS) No-Till video; and hosting a USDA/SARE Professional Development Training showcasing continuous no-till.

In addition to the no-till effort, the Colonial District staff and directors have dedicated time, talents, and resources to the following research and/or demonstration initiatives: Winter Cover Crop Study, GreenSeeker™ Study, Soil Carbon/Nitrogen Leaching Study, and Nitrogen Injection Study. Please follow the links to learn more about each subject.

Winter Cover Crop Study

From a water quality standpoint, elimination of fallow periods in a crop rotation is very important due to a growing crop’s ability to cycle nutrients, provide soil stabilizing root systems, and supply a leafy canopy to intercept raindrops, diffusing their energy, before hitting the ground. Thanks to a 2004 USDA Conservation Innovation Grant (CIG), the Colonial SWCD in conjunction with Virginia Cooperative Extension conducted an evaluation of winter cover crop species which could fit into the double-crop rotation commonly found in the coastal plain. Consisting of corn, small grains, and soybeans – followed by a four month fallow period – the crop rotation doesn’t offer an opportunity for cover crops until late in the growing season after the soybeans are harvested: usually around mid November.

The three year cover crop study has yielded a bounty of information, including the virtues of using cereal rye and hairy vetch as winter cover crops – both individually and also together in a mixture, as shown in the graphs below.

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Due to the very promising cover crop results, especially the amount of nitrogen being produced by the vetch, the partnership evaluated corn yields which followed a vetch cover crop. As the graph below identifies, harvested corn yields following a vetch cover crop exceeded 140 bu/ac with no commercial nitrogen applied.

GreenSeeker™ Study

For coastal plain farmers the application of nutrients to their crops is a relatively expensive, but necessary proposition due to the high cost of “chemical” or commercial fertilizers containing nitrogen, phosphorus, and potassium. Annual costs for growing an acre of corn can top $400 with approximately half of that attributed to applications of nutrients. Needless to say, reducing fertilizer inputs is in the farmer’s best interest. Thanks to a 2004 USDA Conservation Innovation Grant (CIG), the Colonial SWCD in conjunction with Virginia Cooperative Extension conducted an evaluation the GreenSeeker™ sensor based variable rate nutrient application technology in an effort to improve water quality by reducing nitrogen inputs on cropland.

Simply stated, GreenSeeker™ is a modern marvel. Imagine hi-tech light emitters and sensors mounted to the boom of an agricultural spray rig. As the machine passes through the field, the light emitters send down two beams of light – one visible and one near infrared. As the lights reach the crop canopy, some light gets absorbed by the plant while some light bounces off or “reflects”. Reflected light is received by the sensor – overhead and attached to the spray boom. The amount of light absorbed by the plant (light emitted – light reflected = light absorbed) is directly related to the amount of chlorophyll located in the plant, the level of which is an indicator of plant health. A signal is sent from the sensor to the on-board rate controller of the spray rig – telling the on-board computer how much nitrogen to apply to the plant below. This process is repeated thousands of times across the field with variable rates of fertilizer being applied based upon the plant’s need.

GreenSeeker™ reads chlorophyll levels as the sprayer crosses the field and records data in numeric terms called NDVI (normalized difference vegetative index). Each colored dot represents a sensor’s reading which occurs about every 10 feet	The sensor’s NDVI reading is translated into a specific rate of nitrogen applied to the growing crop. This map depicts the rates of nitrogen applied to specific places in the field. Application rates are in gals/ac.

The GreenSeeker™ technology has been demonstrated on winter wheat as well as corn. The tables below demonstrate the potential of GreenSeeker™ as a viable agronomic practice:

To learn more about GreenSeeker™ follow the link to the NTech website.

Soil Carbon/Nitrogen Leaching Study

A 2004 Conservation Innovation Grant (CIG) award funded the Colonial District and its partners to evaluate leaching tendencies of fields under long term continuous no-till management. The evaluation compared fields under no-till management to fields which received tillage treatments prior to planting small grain. The study was conducted on three different soil types commonly found within the coastal plain: Altavista fine sandy loam, Emporia fine sandy loam, and Bojac sandy loam. Over the course of the project, water samples were collected from lysimeters placed under four feet below the surface of an undisturbed soil profile.

		Far left: Vertical holes were drilled to install the lysimeters. Top left: A forty eight inch pipe supported the lysimeter housing for all 24 sites. Bottom left: A horizontal shaft was dug to place the lysimeter directly under the row. Below: Normal farming operations are conducted above the lysimeters.

A 2004 Conservation Innovation Grant (CIG) award funded the Colonial District and its partners to evaluate leaching tendencies of fields under long term continuous no-till management. The evaluation compared fields under no-till management to fields which received tillage treatments prior to planting small grain. The study was conducted on three different soil types commonly found within the coastal plain: Altavista fine sandy loam, Emporia fine sandy loam, and Bojac sandy loam. Over the course of the project, water samples were collected from lysimeters placed under four feet below the surface of an undisturbed soil profile.

The full project report, published by Dr. John Spargo can be viewed by following the link. Summarizing the report, the continuous no-till cropping system sequesters nitrogen in the soil – about 20 lbs N/year – through the increase of organic matter, which amounts to a nitrogen savings account for the farmer. The nitrogen in this “account” is fairly stable and may become available to the plant under the right environmental conditions including adequate moisture and temperature. The savings account can also be robbed of its valuable commodity (nitrogen) if the farmer tills his field, as tillage instigates a feeding frenzy of soil microbes which consume soil organic matter, thereby converting the stable nitrogen into a plant available and/or environmentally susceptible form. From a practical standpoint, this study’s findings suggest that, over time, utilizing continuous no-till may allow famers the ability to reduce fertilizer nitrogen inputs to their crops.

A companion study looked at Carbon sequestration rates in both continuous not-till fields, as well as fields which implemented tillage practices before the planting of small grains. The study found that the continuous no-till management system sequesters just shy of ½ ton ac/year CO2 equivalent. Applications of organic material sources such as bio-solids were found to increase soil Carbon to an even greater level, however it is difficult to justify the application of bio-solids as a true “sequestration” technique. This is not to say that increasing soil Carbon isn’t a good thing – because it’s a very good thing. By increasing soil Carbon (soil organic matter), soil aeration and porosity is improved, soil water holding capacity is improved, and nutrient cycling is improved.

Additional findings from these studies found that the primary period of nitrate leaching – when looking across the two year double crop rotation – occurs during the fallow period between soybean harvest and corn planting. This finding suggests that the intensive nutrient management techniques employed – particularly on the corn and small grain crops – is extremely effective in keeping nitrogen in the field as opposed to losing it to the environment.

Nitrogen Injection Study

Injection of sidedress nitrogen in corn is a technology that was adopted nearly 30 years ago, however, it fell out of favor with farmers due to the slow ground speeds and its time consuming nature. Undeniably, nitrogen lost to the environment is reduced by injecting the material into the ground, but until recently, the relatively low price of nitrogen meant time was the limiting factor for the farmer not the possible loss of nitrogen.

This 8 row nitrogen injector was leased by the Colonial SWCD to demonstrate its ability to reduce commercial nitrogen inputs to corn.	Farm field day events offer excellent opportunities for farmers, academics, agri-business, and agency people to witness new technologies.

In an effort to continue the evaluation and demonstration of agricultural management techniques to improve water quality, the Colonial SWCD leased a nitrogen injector with the intent to catalog its relevance and perhaps generate a renewed interest in its ability to reduce nitrogen inputs. The injection rig has been showcased at several events including the Four Rivers Small Grains Field Day and the Virginia Ag Expo.

Demonstration plots have been positioned around the Coastal Plain and proven the injector’s ability to reduce nitrogen application rates by up to 30 lbs per acre – resulting in a reduction of input costs of up to $20 per acre. If adopted widely by Virginia grain producers, this management approach could result in a nitrogen reduction of 14.4 million lbs annually. A reduction of this magnitude would achieve the targeted agricultural N reduction goal set by the Virginia Tributary Strategy Initiative.