Protecting & Restoring Long Island's Peconic Bays
Example agricultural practice scenarios made available through NRCS (2021) for which nitrogen reduction benefits are available through CAST (Chesapeake Bay Program 2020) are described in this section. Practice scenario descriptions are provided below, and nitrogen reduction costs and benefits are summarized in Section 6.4.7. However, as noted above, practice scenarios, costs, and nitrogen reduction benefits are highly site-specific and vary greatly.
A Nutrient Management Plan (NMP) is a best management practice standard that allows qualified individuals to author and certify a site-specific management plan that is tailored to meet the land owner’s goals. A NMP provides guidance for an operation to manage on-farm nutrient use; specifically, the amount (rate), source (source of nutrients, type and or formulation of fertilizer), placement (method of application), and timing of plant nutrients and soil amendments to optimize efficient utilization of nutrients (Fixen 2020; NRCS 2012). The goal of a NMP is to 1) budget, supply, and conserve nutrients 2) minimize agricultural non-point source pollutants 3) properly utilize manure or organic byproducts as a source of nutrients, and 4) to maintain or improve the physical, chemical, and biological condition of soil. While all crops require nitrogen and other essential nutrients for growth and development, implementing nutrient management practices can increase crop nutrient use efficiency (NUE) and minimize environmental impacts. The SCSWCD and NRCS staff are available to assist in the development of NMPs. Additionally, SCSWCD, NRCS and CCE can provide science-based recommendations for BMPs related to nutrient management and NUE.
A nutrient budget that considers all potential sources of nutrients should be developed. Enhanced efficiency fertilizers (including controlled and slow-release nitrogen fertilizers) must be defined by the Association of American Plant Food Control Officers and accepted for use by New York State fertilizer official (NRCS 2012). Nutrient Management Plans must be reviewed and revised as needed with changes in farm practices or soil testing, and climate variability (NRCS 2012).
The primary goal of nutrient management planning is to minimize impacts from non-point source pollution to ground and surface waters (NRCS 2012). This practice helps agricultural producers address their resource concerns related to nutrients. Recommended nutrient application rates are based on several factors including crop type, crop rotation, crop age, soil types, NRCS-approved risk assessments, climate, and realistic yield goals (NRCS 2012). Nutrient management planning takes into account application timing, tillage and planting system, farm equipment, soil properties, crop, crop rotation, soil organic matter content, and resource concerns to produce a guidance document for producers to reach their voluntary stewardship goals. In addition, these plans identify and address site specific attributes such as soil type, crops grown, temperature, moisture levels, soil microbial activity, and farm management practices that impact nitrogen cycling and its fate in the environment (NRCS 2012). Nitrogen is essential for the growth of all crops; however, site specific nutrient management planning is critical to natural resource conservation.
The most successful cover crops are well-adapted to local climate/soil conditions, resistant to pests and diseases, and suppress or compete with weeds. Cover crops should be planted when there is adequate moisture to establish and more than one cover crop species should be planted, when possible, to provide additional agro-ecosystem benefits including attracting beneficial insects and pollinators, increasing soil biological diversity, trapping insect pests, and providing food and cover for wildlife habitat.
Cover crops that are compatible with the production system and well adapted to local climate and soils, be resistant to pests and diseases, and suppresses or competes with weeds, should be selected. Cover crops should be planted when there is adequate moisture to establish themselves. When possible, more than one cover crop species should be planted to attract beneficial insects and pollinators, increase soil biological diversity, trap insect pests, or provides food and cover to wildlife habitat.
The nitrogen reduction benefit of cover crops varies by soil type, cover crop species (legume versus non‑legume), if a single species or a cover crop mixture is planted, application rate of the cover crop, nitrogen application rate, climatic conditions, and management. A higher planting density will generally inhibit leaching of soil nitrogen into the groundwater. Traditional cover crops yield greater benefits than commodity cover crops that are harvested in the spring (Chesapeake Bay Program 2018). Winter cereals convert more nitrogen to plant biomass as soil nitrogen availability increases compared with after the summer harvest (Chesapeake Bay Program 2017). Fall applications of nutrients may enhance winter crop nitrogen uptake, but also increases the potential for nitrogen leaching (Chesapeake Bay Program 2017).
Soil health is defined as “the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans” (USDA-NRCS, 2018). Soil health emphasizes the integration of the biological, physical, and chemical properties of the soil in the management of an operation. Soil health enhancement is the implementation of BMPs specifically aimed at improving the functioning of agricultural soils, and are practices incorporated into the management of the overall operation. NMPs recommend BMPs that work in concert with each other to enhance the overall health of the soil for improved crop productivity, enhanced nutrient cycling, and support of greater microbial life.
The SCSWCD, NRCS and CCE all have programs to assist farmers in Suffolk County with understanding, monitoring, and implementing soil health building practices on their farms. These programs include, but are not limited to, the Comprehensive Soil Health Testing program and Soil Health Equipment Loan Program (Soil HELP). Below are some examples of Soil Health Enhancement BMPs (additional information is available on SCSWCD, NRCS and CCE websites).
This practice accounts for those crops that are planted and managed as a permanent living cover, such as switchgrass, to sequester carbon in the soil and improve water quality (Chesapeake Bay Program 2018). A permanent living cover, also called ‘continual living roots,’ is one of the five USDA NRCS Soil Health Building Principles. This practice promotes keeping the soil covered all year round by protecting it with living plants. This crop can be a cash crop or cover crop as long as the ground does not remain bare for long periods of time. This alternative crop practice does not apply to field borders, hedgerows, or riparian buffers (Chesapeake Bay Program 2018). Mowing and other measures to control weeds and invasive species may be required. In addition to climatic conditions, the previous crop, fertilizer practices, management strategies, soil type, and health of the soil will impact the nitrogen reduction benefit and the alternative crop that replaces them (Chesapeake Bay Program 2018).
This practice involves growing a diverse number of crops in a planned sequence to increase soil organic matter (SOM) and biodiversity, while controlling pest and disease cycles. Rotating crops on the same piece of land may also be part of a soil conservation management system to reduce soil erosion and enhance soil health (NRCS 2021). Crop rotations, when appropriate, should be integrated with the farming business; crop rotation typically means growing different species of crops in the same area throughout a given growing season and/or multiple growing seasons. Adjusting crop rotations to include both deep and shallow rooting crops can reduce soil compaction and improve water use efficiency (NRCS 2020).
Tillage is the physical manipulation of soil for crop production. It is a practice that began as a means of preparing the seedbed for planting, manage weeds, and incorporate organic amendments. However, it is also used for managing surface residues, minimizing crop diseases and pest issues, and regulating soil surface temperature. The implementation of conservation tillage or no-till management practices can reverse soil organic matter losses, enhance NUE, and lead to improvements in soil health (Al-Kaisi et al, 2005). However, different methods of tillage are used depending on the crop grown and soil conditions. There are many types of tillage methods available to farmers that occur on a continuum in terms of intensity of soil disturbance and percent crop residue remaining on the soil surface, for example, moldboard plow (greatest disturbance)® chisel plow ® strip till ® no till (least disturbance). The type of tillage used must consider soil type, crop type, crop rotation, and other management practices including fertilization practices. The nitrogen reduction benefits from implementing reduced or no-till practices can be seen over time. This practice may result in improved nutrient cycling, reduced soil loss, and increase in soil organic matter levels, which will allow the soil to retain greater amounts of nutrients when compared to conventional tillage practices.
Increasing SOM through the addition of soil amendments has a direct influence on the fate of nitrogen and other nutrients in the soil. SOM is the fraction of soil that consists of plant residues, animal remains, and microorganisms in various stages of decomposition. The retention of nitrogen in sandy soils is lower than finer textured soils, however both nitrogen retention and a soil’s capacity to retain water increases as SOM levels in soil increase. Every pound of organic matter can absorb nearly 20 lbs of water (Hoorman, 2009) and nutrients are taken up by plants from the soil solution. Nearly all the nitrogen in soil is retained in SOM, thus balancing the amount of nitrogen applied with the amount of nitrogen a growing crop needs is critical. Having adequate levels of SOM is essential for nitrogen to be retained in soil and serve as a reservoir of both water and nutrients. The quality and maturity of soil amendments is critical when considering its potential to improve soil health and nutrient management. This includes but is not limited to amendments including compost, mulches, manure, woodchips, biochar, etc. The amount of organic material needed to meet recommendations will vary by farm, but formulas provided by Cornell Waste Management Institute can help provide a perspective on quantities needs for a specific site to reach a specific stewardship goal.
Formula:
Area to cover (ft2) x Rate of application (depth in inches) x 0.0031 = Volume (yd3)
Example: Farmer has a 10-acre field (435,600 ft2) and wants to apply 1” of compost to the entire field
435,600 ft2 * 1” * 0.0031 = 1,350.4 yd3 of finished compost required (~2,700 cu. yd. of raw materials)
Nitrogen reduction benefits vary greatly by crop and nitrogen load source (Chesapeake Bay Program 2018). In addition soil type and how crop residue is managed are also critical factors in this determination. For example planting perennial or annual legume crops in rotation can provide nitrogen for non-legume crops. Carbon to nitrogen ratios of 25:1 to 35:1 in crop residues can build a soil’s capacity to slowly release nitrogen while minimizing leaching. Further, including high-biomass annual or perennial crops for two-thirds of the crop sequence and high residue production crops for at least one-half of the sequence can also boost SOM and overall soil health (NRCS 2020).
The capital costs for NMP Development and Implementation assumes a 40-acre farm and includes the development of a NMP based on NRCS Practice 104, Scenario 17 along with per diem costs for a technical service professional and NRCS Practice 590, Scenario 5, and are combined with controlled release nitrogen fertilizer (CRNF). CRNF costs are based on the cost difference between controlled-release and conventional fertilizer (Liu et al. 2017a). Example costs for other potential agricultural nutrient management BMPs made available through NRCS (2021) and nitrogen reduction benefits made available through CAST (Chesapeake Bay Program 2020) are provided in Table 6-1 on a per acre basis. However, as noted above, costs and nitrogen reduction benefits are highly site-specific.
Nonpoint Source Control BMP Nitrogen Reduction Examples and Costs
| BMP | Description | Nitrogen Reduction (%) | Annual Nitrogen Removal (lb/yr) | Cost per Acre | Cost per Pound Nitrogen Removed |
|---|---|---|---|---|---|
| NMP Development and Implementation | Includes split application, variable N application, reduced rate, slow and controlled release fertilizers, etc. | 10–20 | 1.30–2.6 | $349 | $43–1,460 |
| Cover Crops | Legumes, brassicas, grasses, single species, mixtures | 5–45 | 0.4–4.5 | $80 | $18–201 |
| Alternative Crops | Warm season grasses, perennial crops, biofuel crops, etc. | — | 12 | $174 | $14 |
| Conservation Crop Rotation | Rotation of organic and non-organic crops; basic and specialty | 3–8 | 0.3 | $16–$42 | $51–$137 |
| CNRF | Potatoes | 14–29 | 25–50 | $29–$105 | $1–$4 |
The SCSWCD, the Suffolk County Department of Economic Development and Planning, and the USDA NRCS developed costs to implement nutrient management practices for farming in Suffolk County (Suffolk County 2016). Funding for implementation of these practices is available from the NRCS EQIP, as well as the New York State Agricultural Nonpoint Source Abatement and Control program. Similarly, as of the 2016 revision, the Peconic Bay region community preservation funds can include non-point source abatement and control program projects pursuant to section 11b of the Soil and Water Conservation Districts Law, depending on the East End town in question (New York Consolidated Laws, Town Law – TWN § 64-e). Thus, a portion of the costs associated with implementation of nutrient management practices can be offset by these programs. Reduction of pesticide loading to groundwater, as well as irrigation practices that minimize water use resulting in groundwater conservation, are potential benefits that result from implementing nutrient management practices. Further, adopting practices on farms that improve soil health lead directly to improved nutrient management and can result in a net cost savings (see the American Farmland Trust). The Soil Health Testing and Equipment Loan Programs lead by CCE and the SCSWCD are further incentive programs for farmers improve soil health on their farms and encourage better nutrient management.
Sign up for News, Events and Information straight to your inbox.
