FAQs

Please navigate through the main categories below to view frequently asked questions and answers:

Maryland Department of Agriculture (MDA) Regulations and Policies

The following categories deal with the most frequently asked questions about MDA regulations and policies:

Account ID Numbers

  • Q: I am developing a nutrient management plan for a farm that was recently subdivided. As a result of the subdivision, several fields have multiple account ID numbers. Is it necessary to list all account ID numbers on the MDA Reporting Form or can I list just one? (Posted November 29, 2004)
    • A: If a single field encompasses multiple parcels, it could have multiple account ID numbers. In this case, all would need to be documented. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Annual Implementation Report (AIR)

  • Q: I received a letter from the MDA that included an Annual Implementation Report (AIR) which is due on March 1st of every year. Must I now submit my nutrient management plan before the growing season and then my AIR after the growing season? (Posted March 7, 2005)
    • A: No. The AIR was designed to limit the amount of paperwork you need to submit to MDA. If you have submitted a nutrient management plan to MDA in the past you don't need to do so again. You should maintain an updated nutrient management plan on your farm and only submit the AIR by March 1st every year.

Annual Income

  • Q: Is a nutrient management plan required in a situation where a producer has a number of small properties and doesn't make $2,500 on any individual property, however collectively makes more than $2,500? (Posted November 29, 2004)
    • A: An individual who receives annual farm income from one or several properties in excess of $2,500 must comply. The law relates to gross annual income, not parcel. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)
  • Q: A vegetable producer generates more than $2,500 gross income from his roadside stand. Some of the income (less than $2,500) is from crops he grows on his farm and some is from crops he purchases wholesale and resells. Does this producer need a nutrient management plan? (Posted November 29, 2004)
    • A: Yes. If you meet income requirements from an agricultural enterprise and are engaged in growing crops or raising animals, you must have a nutrient management plan. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Certified Farm Operator (CFO) Eligibility

  • Q: I work for a horse boarding operation and would like to develop a nutrient management plan for the operation. If I become certified as a certified farm operator can I develop the plan for my employer's operation? (Posted June 2, 2005)
    • A: The certification program for farm operators is exclusive to those who own, have an interest in a farm, or have responsibilities for operating a farm. If others, such as employees, want to provide nutrient management planning services they must attend the consultant training and become a certified nutrient management consultant.

Compost analyses from commercial compost facilities

  • Q: Clients who use commercial sources of compost are often able to get a compost analysis from the compost operator or company. Is an analysis of compost provided by the compost company acceptable to MDA for the development of nutrient management plans? (Posted April 2017)
    • A: Only a copy of the actual lab report is acceptable for use in a nutrient management plan. If the compost generator is not willing to provide the actual analytical report (not a secondary summary), the farmer must obtain a sample and analysis of the compost himself/herself. (Source: Bryan Harris, Maryland Department of Agriculture, April 2017)

CREP & CRP

  • Q: I enrolled a significant portion of my farm in the CREP Program a few years ago. I raise beef cattle and still have some pasture and hay fields; however, I am concerned that I may not have enough available ground for spreading the manure that accumulated over the winter. My nutrient management plan does not give any nutrient recommendations for the maintenance of CREP grasses. Can I spread manure on CREP ground? (Posted November 29, 2004)
    • A: Nutrient recommendations for maintenance of CREP cool-season grass stands should be addressed on a case by case basis. Most of these areas are buffers and should not be utilized for manure disposal. Application should be considered only when there is a maintenance problem. The NRCS specifications say that if the stand is not doing well the District Conservationist should be contacted for technical assistance. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)
  • Q: I don't actively farm my land; however, I receive more than $2,500 in income due to CREP payments. Do I still need a nutrient management plan? (Posted May 20, 2003)
    • A: No. MDA has developed an exemption form for situations such as this. Contact your regional MDA office and they can provide you with the form. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Definition of Animal Operations

  • Q: Are nutrient management consultants required to do plans for dog kennels and biomedical research facilities under the new regulations?
    • A: No. Dog kennels and biomedical research facilities are not considered "agricultural operations." Waste management for these types of facilities is under the jurisdiction of other agencies, not the Maryland Department of Agriculture. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)
  • Q: Does the 8,000 lb animal weight limit apply to any specific time of the year or any time during the year?
    • A: It is the maximum pounds of animal weight on the operation for any time during the course of the calendar year. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)
  • Q: What are slaughter/feed cattle?
    • A: The original language was taken from the EPA definition which governed at the time. The current wording is feed cattle meaning beef production as opposed to dairy cattle. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Educational Exemptions

  • Q: Many high school vocational agriculture programs have greenhouses for instructional purposes. They may also raise bedding plants for fundraising to help finance trips. Are these types of operations required to have a nutrient management plan? (Posted April 1, 2003)
    • A: Under MDA's regulations, any 4-H or FFA-type projects are considered exempt from the regulations. Ag educators who have greenhouses for instructional purposes would also fall under that category. The only thing they need to do, if called upon by MDA, is prove that what they are doing is for educational purposes. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Expiration of Soil Tests

  • Q: I’m developing a client’s plan for wheat so he can participate in the commodity cover crop program. His soil tests will be 3 years old in November.  Can I use these soil tests for this plan? (Posted August 9, 2011)
    • A: Soil test expiration should be treated the same way as nutrient management plans--a soil test informs the application of the nutrients ahead of time, and so cannot be expired when the planned nutrients go down.
    • For example: a soil test is 3 years old November 30, 2011. It may be used to plan the fall 2011 nutrient recommendation, but not for the spring 2012 nutrient recommendation (even though that application may be only nitrogen).
    • Consultants and producers will have to plan ahead to avoid having to update plans in similar cases by doing soil tests before the crop goes in. (Source: Jo Mercer, Nutrient Management Program, Maryland Department of Agriculture)

Justification for Additional N and P Applications

  • Q: A producer-client has always applied 60 pounds of phosphate to his vegetable fields. All of his vegetable fields have FIV-P's greater than 150. The crop removal is never as high as 60 pounds for any of the vegetable crops. What can I do? (Posted April 21, 2004)
    • A: Follow the UME recommendations and MD Nutrient Management Regulations. A certified consultant can recommend no more than the soil test-based recommendation, the starter recommendations, or crop removal, whichever is highest.
  • Q: Does there need to be justification for additional N applications beyond the original recommendations or can additional N applied just be documented?
    • A: Reasonable justification for additional N applications is needed and confirmed through tissue sampling and PSNT results. Unusual weather conditions and a description of plant deficiency that is noted visually is also acceptable. The challenge comes when all N recommendations were applied with manure at a time that was not optimum (fall/winter) and then N comes up short after the crop is planted. If no other extenuating circumstances exist, MDA to date has said that in these cases, no more N can be applied. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Manure Analysis and Utilization

  • Q: I heard from a colleague that manure can be applied on hay and pasture in the fall if the annual nitrogen recommendation has not been met? (Posted May 14, 2012)
    • A: As a matter of policy, manure may be applied in fall as the final application for the current year’s hay or pasture as long as the total recommended nitrogen rate for the year has not been exceeded. The fall rate is limited to 50 pounds of plant-available nitrogen (PAN) or the balance of the nitrogen recommendation for the year, whichever is less. (Source: Jo Mercer, Nutrient Management Program, Maryland Department of Agriculture)

Nutrient Management Plan Submission

  • Q: What information from the nutrient management plan do I need to send to MDA? (Posted July 6, 2009)
    • A: When the plan is developed, the operator needs to submit:
      • a signed MDA reporting form
      • a summary of nutrient recommendations which includes all fields and crops, crop yield goals, and nutrients to be applied
      • soil analysis information
      • a map or aerial photograph identifying location and boundaries of the agricultural operation, individual field boundaries, or management units and acreage
    • After the first submission, each operator needs to submit an Annual Implementation Report (AIR) every year by March 1st. The AIR summarizes the total acreage in each crop and the nutrient and manure usage per crop. (Source: MD Nutrient Management Regulations, COMAR 15.20.07.06)

Pastures

  • Q: Are soil tests required for pastures in situations where no fertilizer or lime is applied? (Posted June 6, 2003; updated February 4, 2020)
    • A: Yes, soil samples are needed as long as the pasture meets MDA’s definition of pasture (75% vegetation which is predominantly grass or a grass/legume mix). Essentially, nutrients are being applied in the form of manure from the animals. It is not necessary to generate a nutrient recommendation for pasture if an operator has no intention of applying additional nutrients.
    • No soil tests should be taken and no recommendations provided if the pasture does not maintain appropriate grass or grass/legume vegetative cover to meet the definition (weeds do not count as appropriate vegetative cover). (Source: Bryan Harris, MD Dept. of Agriculture)
  • Q: How should I report unmanaged/unimproved pasture on the MDA reporting form? This would be pasture land where animals graze but does not receive commercial fertilizer. (Posted May 20, 2003)
    • A: If it meets MDA's definition of pasture (75% vegetation which is predominantly grass or a grass/legume mix), it should be reported under “total farmed acres including pasture” on the Annual Implementation Form, regardless of whether fertilizer is added. (Source: Office of Resource conservation, Maryland Department of Agriculture)

Plan Requirements for Unusual Operations

  • Q: We produce microgreens in a greenhouse. We do not use fertilizers, only a compost-based organic potting soil mix. We do gross over the $2,500 a year in sales. Would we still need a greenhouse nutrient management plan?
    • A: Yes. If the operation grosses $2,500 or more, the fact that you do not apply fertilizer is irrelevant. (Source: Bryan Harris, Nutrient Management Program, Maryland Department of Agriculture, March 2016)

Rented/Leased Land

  • Q: I own farmland that I lease to farmers. Whose responsibility is it to get a nutrient management plan for this land?
    • A: The responsibility to get and implement a nutrient management plan rests with the operator (the person who is managing the agricultural operation). Owner/non-operators are not responsible for plan acquisition or implementation. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Setbacks for Nutrient Application - Documentation Required

  • Q: Can I take client’s word that there are no streams or ponds on his operation that would require a setback for nutrient application? (posted 11-13-17)
    • A: No. For each operation for which a plan is developed, nutrient management consultants must objectively determine if any surface water bodies (streams or ponds) exist within 35 feet of each fields or pasture.
      • During information collection, ask the farmer if there are any streams or ponds on the operation.  Note their location on the operation’s map. 
      • Use on objective source of information like Google Earth or QGIS to locate the water bodies and measure the distance from the edge of fields to the surface water. 
      • Printouts of the maps with measurements are part of clients’ files. 
      • Sometimes a client may indicate that no surface water exists on his/her operation or within 35’ of fields and pastures but an objective source indicates that water does exist.  Go with the objective source.  Make a note on MDA’s setback form that a disagreement exists between QGIS or Google and the client’s opinion.
      • Nutrient management consultants must always consult an objective source of information to determine if streams or other surface water exists near fields and pasture. (Source: Dwight Dotterer, Program Administrator, Nutrient Management Program, Maryland Department of Agriculture)

Timing of Nutrient Applications

  • Q: I heard from a colleague that manure can be applied on hay and pasture in the fall if the annual nitrogen recommendation has not been met? (Posted May 14, 2012)
    • A: As a matter of policy, manure may be applied in fall as the final application for the current year’s hay or pasture as long as the total recommended nitrogen rate for the year has not been exceeded. The fall rate is limited to the P-removal rate of the crop or the balance of the nitrogen for the year, whichever is less. (Source: Jo Mercer, Nutrient Management Program, Maryland Department of Agriculture)

Tissue Testing

  • Q: My client has several small blocks (about half an acre each) of perennial fruits in his orchard.  Are tissue tests required for each of these areas?
    • A: Effective December 2017, Maryland Department of Agriculture no longer requires tissue tests for perennial fruits in blocks less than 1 acre in size following the guidance below:
      • Blocks should be determined based on similar characteristics, including the same dominant soil, species, variety, age, and management. For more information about how to properly determine perennial fruit blocks, please view the document titled NM-5: Nutrient Management for Tree Fruits and Small Fruits on pages 6-7.
      • Additionally, nutrient recommendations in the absence of tissue tests are limited to an average nitrogen rate. If you believe you may have a deficiency of another nutrient based on visual symptoms or vigor, you must have a tissue sample before nutrients are applied. (Source: Bryan Harris of the Maryland Department of Agriculture, Posted 3/2/2019)

Maryland Department of the Environment (MDE) Regulations

Q: I have a CAFO client who is transferring ownership from himself to an LLC. I have been asked to develop a nutrient management plan for the LLC. What else is required by the client to meet MDE’s requirements (posted July 14, 2017)

  • A: Requirements for transfer of ownership differ for those registered under the current permit and those who are not yet registered under the current permit. 
  • If the original owner/operator is registered under the current permit and the new owner/operator will be managing the farm according to the current required plans (CNMP or NMP/CP), then they (both original and new operator) can fill out a transfer form (attached) and avoid public notice.
  • If current owner/operator is not registered under the current permit, then the current owner/operator should fill out a withdrawal form and a letter of modification. The new owner/operator should submit a new NOI and required plans. (Source: Gary Kelman, CAFO Program, Maryland Department of the Environment
  • Files:

NuMan Pro Software

Q: I would like to purchase a copy of the NuMan Pro software. Where can I get it? (Posted January 26, 2010)

  • A: You can download the order form or orders may be placed via credit card by calling the University of Maryland's Office of Technology Commercialization at (301) 405-3947.

Q: Where can I find updates to the NuMan Pro software?

  • A: When NuMan Pro is updated, updates can be found on our Downloading NuMan Pro - Installation and Updates web page.

Q: I purchased a new printer and I am no longer able to print any NuMan Pro outputs. What do I need to do so I can print? 

  • A: You’ll need to communicate with NuMan Pro to choose a new printer. 
  1. Open NuMan Pro and go to toolbar at the top of the page. 
  2. Choose “File” then print setup.   
  3. All the printers to which you have been given access will show up in this list. Choose the one you want. 
  4. If the printer you want to use is not in the list, the printer must be installed.  

Nutrient Management Plan Development

The following categories deal with the most frequently asked questions about nutrient management plan development:

Analytical Labs and Issues

  • Q: I have a liquid manure analysis where the lab has stated the nutrient content in parts per million (ppm). How do I convert this information to percent (%) so I can enter the information correctly into NuMan Pro? (Posted June 5, 2008)
    • A: A percent is 10,000 parts per million. In order to express the results as a percent, divide the nutrient content (which is expressed in ppm) by 10,000. For example, if the reported value for P2O5  is 2,690 ppm, the calculation to convert to percent would be: 2,690 ppm ÷ 10,000 = 0.269%.
  • Q: I'm developing a nutrient management plan using a food processing waste as a nutrient source. A note on the bottom of the lab's analytical report says the information is reported on a dry weight basis. Is it correct to enter the percent nutrient information in NuMan Pro? (Posted May 13, 2008)
    • A: NuMan Pro is designed to calculate application rates when waste nutrient content information is entered on an "as-is," "as-received," or wet-basis. However, the nutrient content expressed on a dry-weight basis can be used as long as either the moisture content or percent solids is also given in the report and the data are first converted to an "as-received" basis before entering into NuMan Pro.
    • See the worksheet "Converting Nutrient Content of Wastes from a Dry-Weight Basis to an As-Received, (or Wet) Basis." Note: Most waste analyses show P and K elementally; however, you must convert P and K to their oxide form (P2O5 and K2O). Be sure to include a copy of this worksheet and a copy of the lab report in the nutrient management plan. 
  • Q: I notice your web site has information about various labs that perform plant, manure, and compost analyses; however, you do not indicate how someone can convert lab data for plant tissue or manure into the form a nutrient management planner would need to develop a plan. (Posted July 9, 2004)
    • A: Unlike soil testing where different extractants are used from lab to lab, procedures used to analyze plant tissue, manure, and composts are more standardized. Labs use a procedure (usually a mix of very strong acids or very high heat) to break down the organic matrix followed by analysis such as ICP spectometry that can quantify elemental concentrations. For practical purposes, the differences between labs are insignificant, so no conversion is necessary.
  • Q. Results occasionally come back on soil and manure/compost analyses that are confusing or potentially flawed. Where can I find examples of these types of analyses so I know when to contact the lab or how to enter the results? (Posted on March 2, 2018)
    • A: See the Nutrient Management Planning Tools Handbook, where there are links in both Chapter 2 and Chapter 3 for the “Problematic results and flawed analyses” page. There is a list of scenarios with example analyses and guidance for how to proceed on this page. If you are still confused or have an unusual result that is not listed, feel free to call or email our Nutrient Management Specialists for additional guidance.
  • Q: Why isn’t nitrate included in the average manure composition table on the ANMP website? (Posted March 16, 2018)
    • A: Very few laboratories serving agricultural clientele analyze for nitrate in manure and other organic samples submitted to them, so we have insufficient data for reliable averages of nitrate in various animal manures.
    • In addition, in the manure analyses where nitrate is reported, it is markedly less than the ammonium concentration, usually by an order of magnitude or more (the exception to this is waste water treatment plan effluent, where most of the total N is often in the nitrate form). Providing nitrate concentrations would require an addition analytical procedure. This would increase the time and cost of analysis and for most manure and compost samples would provide little useful additional information. (Source: Agricultural Nutrient Management Program)

Basis of Nutrient Management Plans

  • Q: Can a consultant ever recommend a nitrogen-based application of manure? 
    • A: Yes, under two circumstances:
      • if the FIV-P is less than 150, an N-based recommendation is allowed for organic nutrient sources;
      • if the FIV-P is greater than or equal to 150 and the P risk assessment required for the operation in the year the plan is being developed allows it. 
    • (Source: Maryland Nutrient Management Regulations, COMAR 15.20.08)

Biosolids

  • Q: A client has asked me to develop a nutrient management plan using a local biosolid (sewage sludge) as the nutrient source. He brought me a copy of a recent analysis. I checked the Maryland Department of the Environment (MDE) Summary of Plant Available Nitrogen Calculations table and was not able to find the treatment facility listed. Should I use the data from the analysis to develop the plan? (Posted January 16, 2008)
    • A: NO! In Maryland, a biosolid may not be used as a nutrient source until it has been approved for land application by MDE. Once it has been approved by MDE, it will be added to the Summary of PAN Calculations table. Authorities at the waste water treatment plant must seek this approval from MDE. (Source: Nazeeh Freij, Maryland Department of the Environment, Waste Management Division)

Crop Code Clarification

  • Q: I’m confused by the new crop codes for wheat and barley in NuMan Pro 4.2. Can you provide some clarification? 
    • A: Changes in the last several years have necessitated new crop codes for these crops. First, based on research by Dr. Bob Kratochvil, fall and spring nutrient recommendations have been separated. Second, State of Maryland nutrient management regulations now require a Fall Soil Nitrate Test (FSNT) to justify fall nitrogen application on wheat and barley grown for grain. Third, regulations allow manure usage on fall-seeded crops to supply phosphorus on fields where phosphorus is recommended based on soil test. There is a 50 pound of plant-available nitrogen (PAN) limit in these situations.  
    • Crop Crop Code Appropriate use of crop code Comments

      Wheat

      Barley

      25

      26

      Typical grain production situations Fall N rec is based on FSNT results and included in Note 41

      Wheat/Double Crop Soybeans

      Barley/Double Crop Soybeans

      15

      16

      Typical double crop situations Fall N rec is based on FSNT results and included in Note 41

      Wheat; Fall P-based

      Barley; Fall P-based

      326

      327

      1) Allows manure utilization up to 50 # PAN when

      2) P is recommended based on soil test and

      3) FSNT allows fall N

      1) Only useful if FIV-P is less than 90; 

      2) must choose "Phosphorus" on scenario page (top of page) at Rec Base

      Wheat/Barley; Fall organic utilization, low FSNT 21

      1) Wheat or barley for grain production and

      2) FSNT allows fall N (30 # PAN) and

      3) Client wishes to use manure to meet N rec

      Only appropriate for fields where a fall manure application is planned

       

Duration of Plan

  • Q: My client has less than 20 animal units, so I know that we can use book values for the manure nutrient content rather than requiring a manure sample. She would like a multi-year plan, but isn’t sure on which fields she’ll end up applying the manure. Is it ok to develop a plan with multiple field options for manure application for multiple years?
    • A: Yes, a multi-year plan may be developed for this client, as long as they understand that a manure credit must be taken for every field that manure may potentially be applied. If the operator is ok with potentially limiting the N recommendation for fields where they did not actually make a manure application in the previous year, the advisor may proceed in developing a multi-year plan through the expiration of the soil analyses.
    • If the farmer is very concerned about max production and the nitrogen recommendations to sustain it, but does not know where manure will be spread over the 2-3 year duration of the plan, then a 2-3 year plan is not suitable for this operation. (Source: Agricultural Nutrient Management Program; Published: August 9, 2018)

Manure Issues

  • Q: My client has horses and does not spread any manure. The manure is put in a pile near the barn where it decomposes. Some of the manure is applied to the family garden and the neighbors take the rest. Is it necessary to address manure in the plan? (Updated 5-15)
    • A: Yes, manure must be addressed in the plan. You will need to determine the quantity of manure deposited on the pasture and also the quantity of manure collected. If some will be used on a family garden and some will be exported, an estimate of both quantities is needed in the plan. In the manure management paragraph, indicate the following:
      • 1) estimate the amount of collected manure that can be applied on the home garden (see Using Manure from Operations Requiring Nutrient Management Plans on Operator’s Home Garden to estimate this);
      • 2) estimate the quantity of manure available for export from the operation (quantity collected minus quantity used on family garden); and 
      • 3) list names and town of the persons who will be utilizing the rest of the manure. 
    • The client should keep a sign-up sheet handy and ask those exporting  manure from the operation to record their name, address, phone number, and amount of manure taken (just in case there is ever a question during an MDA inspection).
    • If the pile of manure is outside of a storage structure (stockpiled), MDA regulations require that stockpiled organic nutrient sources “be land applied in the first spring season after the placement of the stockpile.”
  • Q: Are manure applications allowed on soybeans? (Posted August 2015)
    • A: Yes, use crop code 9, soybeans with P or K-based manure application. As long as FIV-P is less than 150, manure can be applied to supply the P-removal of the crop up to a cap of 50 pounds of PAN per acre.
    • Choose reg P rem at the bottom of the scenario page in NuMan Pro.
    • Bottom line - the manure rate is capped at the P-removal rate or 50 pounds of PAN per acre, whatever comes first. (Source: Bryan Harris, Nutrient Management Program, Maryland Department of Agriculture, updated May 2016)

Nitrogen Credits

  • Q: Several clients of mine plant oats-crimson clover or oats-hairy vetch cover crops. How much of a nitrogen credit do crop combinations warrant? (Posted February 10, 2009)
    • A: Typically the oats will winter-kill and form a vegetative mat under the crimson clover or hairy vetch. The nitrogen credit for the crimson clover and hairy vetch will depend on the amount of above ground biomass present at the time the crop is killed. This in turn is a function of how long the crimson clover or hairy vetch is allowed to grow. Consult the table below for nitrogen credits based on typical spring weather in Maryland.
    • Nitrogen credits (pounds N per acre) for legume-oat combinations as a function of kill date
    • Kill Date Hairy Vetch Crimson Clover
      Before Mid-April 0 0
      Late April 75 50
      May 100 75
    • (Source: Dr. Les Vough, Associate Professor Emeritus & Extension Specialist, Forage Systems Maintenance, Department of Plant Sciences and Landscape Architecture, UMCP)
  • Q: Many farmers suffered serious drought this year and their soybean crop is only a fraction of what they normally produce. Is it appropriate to take a nitrogen (N) credit when soybean yields are poor? What is a reasonable N credit? (Posted November 8, 2007)
    • A: The range of credits in the University of Maryland Extension guidance assumes a "respectable" soybean crop. If the soybean crop yield was low due to environmental factors such as drought, flooding, disease, or insect infestation, it can be assumed that the N credit should be less. If the soybean yield was less than 20 bu/a, the N credit would be zero. (Source: Dr. Frank Coale, Department of Environmental Science and Technology, UMCP)
  • Q: I have a client who uses Chilean nitrate. What kind of N credit should I take for it? (Posted July 9, 2004
    • A: Chilean nitrate is nothing more than sodium nitrate, a highly soluble inorganic compound. All of the N will be available the year of application, and therefore no N credit should be taken in subsequent years.
  • Q: Last year a farmer had a field planted in 50% forage soybeans and 50% sudangrass. The crop was taken off as silage. Should any nitrogen credits be taken for the beans? (Posted April 21, 2004)
    • A: Given that the cover crop is mixed grass-legume AND is harvested, no credit is recommended.
  • Q: My client raises vegetables. Do I need to give nitrogen credits for green beans? (Posted June 6, 2003)
    • A: No. Green beans are a short season crop that receive nitrogen fertilizer at planting. The N fertilization suppresses the plants' ability to fix nitrogen; therefore a nitrogen credit is not taken.
  • Q: I am writing a nutrient management plan for a farm that received biosolids last year. I know that I need to enter this information into the NuMan Pro history so that the appropriate nitrogen (N) credits are assigned. The biosolids applicator provided a list of all of the materials applied to each field. Which organic N value should I enter if biosolids from multiple treatment plants were used on the same field?
    • A: There are a few things to remember when entering biosolids information into the NuMan Pro history.
      • 1) The application rate must be entered in the dry weight basis.
      • 2) You must use the organic N information from the Maryland Department of Environment PAN Rates Table rather than the PAN rate provided by the biosolids applicator.
      • 3) If only two biosolids products were applied to the field and one was obviously applied at a heavier rate, enter the product applied at a heavier rate into the history.
    • If multiple biosolids products were applied, use the following process to determine which biosolids product to enter into the history:
      • Enter each of the biosolids into the organics list in NuMan using the organic N from the MDE PAN Rates Table.
      • Apply each biosolid on the field at the N-based rate.
      • The biosolid that can be applied at the highest application rate is the one you would enter into the history. (This will be the product that provides the least amount of N credit on the field. This product is selected to minimize the potential for applying inadequate N in any part of the field for the growing crop.)

Pasture and Forage Crop Issues

  • Q: I'm writing a plan for a horse boarding operation. The operation has 13 horses on 2 acres of land. The owner says that the horses are on pasture 24/7, except for cold weather months (November through February) when they are confined overnight. He calls the area "pasture" but I'm not so sure. When I visited the farm in April there was not much growing; however, the owner claims that in the summer the area is covered with grass. Should I assume the area is a pasture and provide a nutrient recommendation for grass for this client? (Posted August 12, 2008)
    • A: The rule of thumb for stocking density for horses is 2 to 3 acres of pasture per horse. Stocking rates considerably higher than that can lead to loss of vegetated cover, particularly if the horses have continuous access to the area. Such areas would be considered heavy-use areas or sacrifice areas, not pastures. As such, no nutrient recommendation would be made. (Source: Dr. Les Vough, Forage Crops Specialist Emeritus, Department of Plant Science, UMCP)
  • Q: Are soil tests required for pastures in situations where no fertilizer or lime is applied? (Posted June 6, 2003; updated February 4, 2020)
    • A: Yes, soil samples are needed as long as the pasture meets MDA’s definition of pasture (75% vegetation which is predominantly grass or a grass/legume mix). Essentially, nutrients are being applied in the form of manure from the animals. It is not necessary to generate a nutrient recommendation for pasture if an operator has no intention of applying additional nutrients. 
    • No soil tests should be taken and no recommendations provided if the pasture does not maintain appropriate grass or grass/legume vegetative cover to meet the definition (weeds do not count as appropriate vegetative cover). (Source: Bryan Harris, MD Dept. of Agriculture)
  • Q: When giving nutrient recommendations for a spring-seeded perennial forage crop, should I also include maintenance recommendations for the same growing season?
    • A: The pre-plant fertilizer recommendations sustain the crop through the first cutting.  After the first cutting, maintenance recommendations should be provided.  Thus, if the crop code/yield goal maintenance recommendation provides a green-up fertilizer recommendation, these should be disregarded and crossed out in the recommendations section of the NMP, as shown in the example of the annotated recommendations printout from NuMan. (Source: Dr. Les Vough, Forage Crops Specialist Emeritus, Department of Plant Science & Landscape Architecture, UMCP; Posted 12/03/2018)

Recommendations for Fruit Crops

  • Q: I have a client who is growing some new cultivars of apples not listed in NM-5, "Nutrient Management for Tree Fruits and Small Fruits." Can you tell me what cultivar category (soft, fresh market, or processed) the following cultivars would be classified as: GingerGold, HoneyCrisp, Pink Lady? (Posted November 8, 2007)
    • A: New cultivars are constantly being introduced into Maryland. The table below summarizes the information about the new cultivars that is needed to develop a nutrient recommendation. (Source: Dr. Christopher Walsh, Extension Specialist, Fruit Crops, Department of Plant Sciences and Landscape Architecture, UMCP)
    • Apple Cultivars Cultivar Category Background Information
      GingerGold (early season, ripens in August) Fresh Market Originated from a chance seedling of Golden Delicious found in Virginia.
      HoneyCrisp (ripens in September) Fresh Market Bred in Minnesota; Maryland is at the southern end of its production range.
      Pink Lady (ripens in late October or early November) Fresh Market An Australian variety with little record in the U.S.; susceptible to fireblight.
  • Q: A client of mine grows currants. I do not see a recommendation for currants in NM-5, "Nutrient Management for Tree Fruits and Small Fruits." Can you advise me as to how I can develop a recommendation for currants? (Posted November 8, 2007)
    • A: Currants (Ribes) are similar in growth habit and fertility requirements to brambles. Tissue samples should be analyzed and nutrient recommendations made using the bramble tissue norms and fertility recommendations in NM-5, "Nutrient Management for Tree Fruits and Small Fruits." (Source: Dr. Joe Fiola, Extension Specialist, Viticulture and Small Fruit, UME)
  • Q: I am writing a nutrient management plan for a client who is growing Asian pears. NM-5, "Nutrient Management for Tree Fruits and Small Fruits," does not include recommendations for Asian pears. Should I use the recommendations for pears? (Posted November 8, 2007)
    • A: Asian pears are quite different from European pears in their management. Asian pears need to be pruned and hand-thinned for large, high quality fruit. More than 50 varieties have been propagated, and they differ in their susceptibility to fireblight. Choose cultivars that have some resistance to fireblight and fertilize them like fireblight-resistant European pears. The fireblight status of some common Asian pear varieties is listed below. (Source: Dr. Christopher Walsh, Extension Specialist, Fruit Crops, Department of Plant Sciences and Landscape Architecture, UMCP)
    • Asian Pear Cultivar Fireblight Status
      Hosui Susceptibe*
      Olympic Tolerant
      Chojuro Somewhat susceptible
      Niitaka Somewhat susceptible
      Shineseiki Somewhat susceptible
      20th Century (Nijiseki) Somewhat susceptible
    • * Although considered susceptible, it is much less susceptible than Bartlett pears and usually survives an infective event.

Recommendations for Minor Crops

  • Q: Where can I find information about nutrient management plans for Christmas trees? (Posted July 9, 2009)
    • A: The NuMan Pro software contains pre-plant nutrient recommendations for Christmas trees (these recommendations are for the year in which the trees will be planted). For established trees, follow the nutrient recommendations provided in Section I-B4 of the Maryland Nutrient Management Manual or in the Agricultural Nutrient Management Program's Information Sheet (NM-2) entitled "Nutrient Recommendations for Commercial Christmas Tree Production."
  • Q: A client plants oats as a nurse crop for spring-seeded alfalfa. Should I use the alfalfa recommendations or the spring oats recommendations? (Posted July 9, 2004)
    • A: Emphasis should be placed on meeting the alfalfa's nutrient needs because as a perennial crop, it is a longer-term investment. Therefore, use the spring-establishment alfalfa recommendations. (Source: Dr. Frank Coale, Chair, Department of Environmental Science and Technology, UMCP)
  • Q: Where can I find information about nutrient recommendations for turfgrass? (Posted June 6, 2003)
    • A: Planners can find nutrient recommendations in the University of Maryland Turfgrass Technical Update, March 2003, TT-114 entitled "Nutrient Management Guidelines for Sod Production". Recommendations can also be found in the University of Maryland Turfgrass Technical Update, March 2003, TT-115 entitled "Nutrient Management Guidelines for State Property and Commercially Managed Turfgrass" and the August 2005 TT-116 entitled "Nutrient Management Guidelines for Commercial Turfgrass Seeding." Recommendations for a number of sod crops are now in NuMan Pro.
    • Other publications addressing turfgrass fertility can be found on the Maryland Turfgrass Council website.

Record Keeping

  • Field Management Records Booklet
    • This booklet is a free tool to help make crop, pesticide and nutrient management recordkeeping easier. It contains space to record crop information, management practices and nutrient applications on a field-by-field basis. Also contained in the booklet are common seeding rates for some agricultural crops and yield calculation formulas.
    • To order your recordkeeping booklets, please e-mail Elizabeth Abebe or call (301) 405-1318 and leave your name, mailing address, and the number of booklets needed.

Soil Sampling and Testing

  • Q: I have heard that arsenic mimics P in soil tests and can falsely elevate P levels in results. Is this true? (Posted March 18, 2008)
    • A: At one time the ascorbic acid-molybdate blue method was a popular choice for assessing P levels in soil samples. If samples were not specifically treated to remove arsenic, then yes it would interfere with accurate P determinations. However, most labs now use the inductively coupled plasma (ICP) spectrometer and interference is not an issue.
  • Q: Is it good practice to take soil samples on fields that have recently received organic or commercial fertilizer applications? (Posted May 26, 2005)
    • A: Sampling after manure or fertilizer application, especially in no-till or pasture situations, will make soil analyses highly variable and usually result in highly inflated soil test numbers. The rule of thumb is to wait 6 months before soil sampling. (Source: Dr. Frank Coale, Professor, Department of Environmental Science and Technology, UMCP)
  • Q: How deep should I collect soil samples? The UME guidance says 8 inches (plow layer depth) but the labs that some of my clients use indicate different depths. (Posted March 15, 2004)
    • A: Collect soil samples to a depth of 8 inches; this is consistent with the sampling depth guidance we have been using in the University of Maryland Extension.
    • We rely upon equations generated in a soil sample exchange to convert soil test output from cooperating regional soil testing labs to equivalent UME output in FIVs. The soil samples used to generate the equations were collected to an 8-inch depth. Therefore, to use the soil test lab conversion information appropriately, all samples should be collected to a depth of 8 inches.
    • Soil test submittal sheets should indicate that the samples were collected from plow layer depth. If there is no entry for sampling depth on the submittal form, write "plow layer depth sample" on the form.
    • Soil test output will be in error if, for example, a lab calculated output for a pasture assuming the sample was collected to a depth of 4 inches when in fact the sample was collected to an 8-inch depth. Clear communications with analytical labs are imperative.
  • Q: Who is responsible in the case where the farmer takes the soil samples? (Posted June 6, 2003)
    • A: Ultimately the farmer is liable for both proper implementation of the plan, and if he has taken the samples, for the use of proper sampling techniques. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)
  • Q: Are soil tests required for pastures in situations where no fertilizer or lime is applied? (Posted June 6, 2003)
    • A: Yes, soil samples are needed. Essentially, nutrients are being applied in the form of manure from the animals. It is not necessary to generate a nutrient recommendation for pasture if an operator has no intention of applying additional nutrients. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)

Unusual Land Uses

  • Q: A client is receiving cost-share for pollinator habitat establishment and was told that the area needed to be included in his nutrient management plan. How do I handle this? (posted 12-1-14)
    • A: Pollinator habitats are addressed by USDA NRCS in Conservation Cover (Code 327). Under most circumstances, the plant species mixture for pollinator habitats would include a legume, thus a nitrogen application at establishment would not be recommended.  No fertilizer additions are assumed after establishment. 
    • Acknowledge the area on the cover sheet in brief description section as well as on the map and indicate that the area is being managed under the guidance of Conservation Cover, Code 327 (Source: James Myers, District Conservationist, USDA-NRCS)

Unusual Nutrient Sources

  • Q: A client of mine wants to purchase some Perdue® pelletized poultry litter to use as a nitrogen source. How do I integrate that product into a nutrient management plan? Its fertilizer guarantee is 4-2-3. (Posted December 4, 2007)
    • A: The following are preliminary data from current research projects taking place in Maryland and Delaware on pelletized poultry litter.
    • Composition: First, like raw poultry litter, the nitrogen (N) in pelletized poultry litter is predominantly organic and must undergo mineralization before it is plant-available. The label does not indicate how much of the N in pelletized manure is ammonium nitrogen (NH4-N) but preliminary research indicates that NH4-N is approximately 8% of the total N. So, until further data are available, assume the following about nitrogen composition for Perdue® pelletized poultry litter:
      • N (total) - 4.0%
      • NH4-N - 0.3%
    • Mineralization: Until future research indicates otherwise, assume that pelletized poultry litter mineralizes like raw poultry litter.
    • (Source: Dr. Josh McGrath, Soil Fertility Specialist, Department of Environmental Science and Technology, UMCP; Dr. Trish Steinhilber, Ag. Nutrient Mgmt. Program Coordinator, Department of Environmental Science and Technology, UMCP)

Yield Goals

  • Q: I have a client who has pastures and he has no idea what the typical yield is of those fields. How can I obtain yield information for situations like this where the producer has no records of yield?
    • A: Yield estimates (based on soil map units) embedded in Web Soil Survey have replaced all other sources of published yield information. MASCAP and published hard copies of soil surveys all contain outdated information.
    • Directions: Finding Yield Goals in Web Soil Survey
  • Q: I have a new client growing summer annuals as forage for grazing his cattle. He has no idea what his yields have been and data on summer annual forages does not exist in Web Soil Survey? What is a reasonable yield for summer annual forage crops? 
    • A: In research at both University of Maryland Central Maryland Research and Education Center in Clarksville (Piedmont location) and the University of Maryland Wye Research and Education Center (Eastern Shore location), the typical yield of summer annual forages is 3 tons per acre. (Source: Dr. Les Vough, Extension Forage Specialist Emeritus; Posted July 25, 2018)
  • Q: I have many clients growing small grains for silage or grazing. They have no idea what their yields have been and data on small grains harvested for forage production does not exist in Web Soil Survey. What is a reasonable yield for these crops?
    • A: In multi-year research at both University of Maryland Central Maryland Research and Education Center in Clarksville (Piedmont location) and the University of Maryland Wye Research and Education Center (Eastern Shore location), the typical yield of small grains as forages is 4 tons per acre. (Source: Dr. Les Vough, Extension Forage Specialist Emeritus; Posted July 25, 2018)
  • Q: I have a client who has grown wheat in the past and who wants to grow barley this year.  My client has no yield records for barley and Web Soil Survey does not provide typical yields for barley.  How should I proceed?  (Posted April 4, 2018)
    • A: According to Dr. Bob Kratochvil, Cropping Systems Specialist in the Plant Science and Landscape Architecture Department of UMCP, barley yields at 10-20 % higher than wheat.  So, if your client knows his typical wheat yield, multiply it by 1.2 to get a typical barley yield. If the client does not have wheat yield records, the same conversion may be done with the Web Soil Survey wheat yield rating for the dominant map unit of the field. (Sources: Dr. Bob Kratochvil and the Agricultural Nutrient Management Program)

University of Maryland Phosphorus Management Tool (UM-PMT) and Phosphorus Site Index (PSI)

The following categories deal with the most frequently asked questions about the Phosphorus Site Index (PSI), and apply to the UM-PMT, which will eventually replace the PSI:

Erosion Estimates (A value)

  • Q: Both the UM-PSI software and the UM-PMT software require the RUSLE A value. Where is this information in a RUSLE printout?  Is it also indicated in a soil conservation plan? 
    • A: In soil loss estimation tools (USLE, RUSLE and RUSLE2), “A” is the average annual soil loss in tons per acre per year. On RUSLE2 printouts, the Soil loss for cons. plan value is the same as the RUSLE A value.
    • The A value may not be specifically indicated in a soil conservation water quality plan (SCWQP).  While a SCQWP typically indicates a cropping management scheme (crop rotation/tillage/residue management) to keep soil erosion to a tolerable level, the actual soil loss estimate is often not explicitly stated in a SCWQP. 

Field Slopes

  • Q: Can I use the slope given in the soil survey or do I need to measure it myself?
    • A: The slope should be measured for each field for which you are calculating a P risk assessment (PSI/PMT). The range of slopes in the soil survey may not represent what is actually occurring in a particular field.
  • Q: When taking slope measurements for the P risk assessments (PSI/PMT), does it matter whether I measure up the slope or down the slope?
    • A: No, it doesn't matter. One should get a similar measurement either way you measure. (Source: Mickey Shockley, USDA, NRCS)
  • Q: If there is a slope that is forested above a cropped field, where do I start to measure the slope length?
    • A: If the forest is undisturbed and not grazed, do not include the forested area in the measurement of the slope length. If the forest is grazed, include the forested area in your measurement of the field length. Likewise, if there is a cropped field upslope from the field in question, include it in the measurement for slope length. (Source: Mickey Shockley, USDA, NRCS)
  • Q: Is the slope that I measure for soil loss the same slope that I use for the runoff matrix?
    • A: Yes. It is also the slope across which the row grade is measured if there is contouring. (Source: Mickey Shockley, USDA, NRCS)

General UM-PMT and PSI Questions

  • Q: Can animals be pastured on fields with FIV-P ≥ 150?  Is P risk assessment required? 
    • A: Based on MDA policy put forth in MDA’s Nutrient Management Guidance for Certain Animal Operations (2000) there is no restriction on pasturing animals on fields whose FIV-P ≥ 150.  A P risk assessment is not required unless additional manure or P-bearing fertilizers will be applied by the operator.  
  • Q: I have a client who applies horse manure on her pastures.  The FIV-Ps on the pastures are greater than 150 and she’s in TM1 in 2019. How can I determine the P removal rate of forage in a horse pasture?
    • A: No P is removed by grazing horses in fields that are used exclusively for pastures. So, when a client transitions into PMT (TM1, TM2 or full implementation of PMT) no more P may be applied in any form. If there is no removal, there can be no P application. 
    • Because horses are typically fed supplemental forage or grain produced elsewhere, horse pastures are typically net importers of phosphorus (and other nutrients). 
    • There is no restriction on grazing animals in such areas nor is there a restriction on the application of nitrogen fertilizer to maintain forage production. The restriction is on the addition of more phosphorus when none is being removed. (Source: MDA, Dwight Dotterer, Nutrient Management Program; Posted 10/1/2018)
  • Q: There are several wheat fields on a farm that have FIV-P's in the excessive range (>100) and several others where the FIV-P is in the optimum range (51-100). No P is recommended for the fields in the excessive range; however, the farmer would like to apply the same rate of P-fertilizer to all the fields. (Posted May 30, 2007)
    • A: In order to apply P-fertilizer to fields where no P is recommended,  P risk assessments (PSI/PMT) are required. Depending upon the year and the P loss rating of the P risk tool in effect that year, a P application up to P-removal may be allowed.
      • If the P-recommendation for the fields in the optimum range is greater than the P-removal rate, the P-removal rate can be applied to all fields.
      • If the P-recommendation is less than the P-removal rate, the recommended rate can be applied to all fields.
  • Q: A producer has a corn field where the FIV-P is 129. He wants to apply more than the 20-30 lbs/A starter P recommended in the NuMan Pro crop notes. The yield goal for this field is 150 Bu/A. (Posted May 30, 2007)
    • A: P risk assessments (PSI/PMT) are required if the producer wants to exceed the recommended rate for starter P-fertilizer.
  • Q: A producer wants to apply P as a starter fertilizer, but there is no recommendation for starter fertilizer on the crop he is growing. Can he add P-fertilizer? (Posted May 30, 2007)
    • A: P risk assessments (PSI/PMT) are required if the producer wants to add P-fertilizer where none is recommended. A phosphorus loss rating of low or medium would allow a total P-fertilizer application up to the crop P-removal rate.
  • Q: Is it necessary to do  P risk assessments (PSI/PMT) if a client wants to use starter fertilizer on my corn? (Posted May 20, 2003)
    • A: If the soil test FIV-P for the field is 150 or greater, then P risk assessments (PSI/PMT) will be required for the field even if the operator only intends to use a starter.
  • Q: Soil tests for a field indicate that the FIV-P is greater than 150. The operator does not plan on adding manure or commercial P fertilizer. Are P risk assessments (PSI/PMT) required for this field?
    • A: P risk assessments (PSI/PMT) are required for fields whose FIV-P is 150 or greater only if the operator wishes to apply additional P-bearing sources. (Source: Louise Lawrence, Office of Resource Conservation, MD Dept. of Agriculture)
  • Q: Many vegetable growers utilize trickle irrigation. Should trickle-applied phosphorus be treated the same as injected-banded, incorporated, or surface-applied? One school of thought is that if a surface-applied fertilizer is irrigated into the soil or is applied before a rain, it should be treated like injected since the water moves into the soil. (Posted April 1, 2003)
    • A: Incorporation involves mechanical tillage. Injection means that the fertilizer is placed at least 2 inches below the surface at the time of application. Materials that are applied to the soil surface are surface-applied. (Source: Dr. Frank Coale, Professor, Department of Environmental Science and Technology, UMCP)
  • Q: How does one determine the dominant map unit of a field? 
    • A: Detailed directions for Using Web Soil Survey to Determine Dominant Map Units can be found on our website. A soils map and the map unit legend both provide the information. The map unit legend gives the estimated percentage of each soil type in the field.
    • The dominant map unit is the soil type that makes up the highest percentage of a field. If more than one map unit of the same soil series exist in a field, sum up the percentages of the map units from the same series and use that for the determination. For the P risk calculations themselves, use the soil properties associated with the soil map unit that is more potentially erosive.   
    • For example, if a field is GgA – 30%, GgB – 30%, and MaB – 40%, then Gg (Glenelg) makes up 60% of the field.  Choose GgB in the P risk assessment software for the associated soil properties. 
    • Both the map and the map unit legend for each field requiring a P risk assessment should be printed and kept in the client’s file.  
  • Q: Is it necessary to do a P risk assessment (PSI/PMT) for crops grown in high tunnels? The soil test FIV-P is >150 and the crops are planted in the soil; however, the high tunnel sheds the rain which eliminates potential for erosion and runoff. (Posted 11-11, revised 10-16
    • A: Due to the controlled nature of management operations, no, it is not necessary to perform  P risk assessments (PSI/PMT) for crops grown in high tunnels as long as the high tunnel is in place 365 days a year. But, a PSI must be done if the high tunnel is not in place 100 percent of the year. (Renato Cuizon and Bryan Harris, MDA)

Soil Drainage

  • Q: If a field has tile drains in only a portion of the field, should it be considered as having "artificial subsurface drainage?"
    • A: If any part of a field is drained, consider the entire field drained when calculating UM-PMT. (Source: Dr. Joshua McGrath, Associate Professor, Department of Environmental Science and Technology, UMCP)

Surface Water

  • Q: Is a water lead or a shovel ditch considered "surface water?" (Posted April 1, 2003)
    • A: No. For the sake of the  P risk assessment tools (PSI/PMT), surface water is defined as any permanent, continuous, physical conduit for transporting water. Shovel ditches and water leads are not permanent. (Source: Dr. Frank Coale, Professor, Department of Environmental Science and Technology, UMCP)
  • Q: Are ponds considered "surface water?" (Posted April 1, 2003)
    • A: If water has never been known to exit the pond via an overflow or spillway, the pond is "isolated" (as opposed to "continuous") and does not have to be considered as surface water. If water exits the pond at any time, it is considered surface water. If in doubt, call it surface water. (Source: Dr. Frank Coale, Professor, Department of Environmental Science and Technology, UMCP)
  • Q: Is a grassed waterway considered surface water?
    • A: No. A grassed waterway is not considered surface water. (Source: Dr. Frank Coale, Professor, Department of Environmental Science and Technology, UMCP)
  • Q: Does a ditch that runs into the woods have to be considered as surface water?
    • A: Yes. Unless a ditch that drains a field empties into a sediment pond, it must be considered surface water. (Source: Dr. Frank Coale, Professor, Department of Environmental Science and Technology, UMCP)
  • Q: Is a marsh or wetland considered surface water?
    • A: Yes, it is considered surface water. (Source: Dr. Frank Coale, Chair, Department of Environmental Science and Technology, UMCP)

Revised Universal Soil Loss Equation (RUSLE)

The following categories deal with the most frequently asked questions about the Revised Universal Soil Loss Equation (RUSLE):

C Factor 

  • Q: One of my producers does not know which of several crops he will plant next year. What should I use to determine the C factor? The most erosive crop? The average of all possible crops he may grow?
    • A: If a producer does not know which of several crops he will grow, choose the most erosive possibility. The producer should be advised that choosing the most likely crop could work in his favor. (Source: Mickey Shockley, USDA, NRCS)

P Factor 

  • Q: When calculating the P factor in RUSLE, I noticed that at times, two Hydrologic Soil Groups (HSG) are listed in the table or the computer program. Which HSG do I use?
    • A: The two columns or choices of data for Hydrologic Soil Group correspond to drained and undrained conditions. If a producer has tile drains or ditch drains in a field, use the information for "drained". If there are neither tile drains nor ditch drains in a field, use the information for "undrained." (Source: Mickey Shockley, USDA, NRCS)
  • Q: Is it true that the P factor for contouring can be used only if the contours are engineered contours?   
    • A: No. The contouring P factor is used to show the effects of tillage/planting operations that reduce or direct runoff. Depending upon site conditions, the contouring P subfactor can substantially reduce erosion. In general, some erosion reduction is achieved if tillage/planting operations are less than or equal to a 45 degree angle to the hillside slope. (Source: Mickey Shockley, USDA, NRCS)
  • Q: I have a strip cropped field that has been treated as two management units (a management unit for the corn strips and a management unit for the grass strips). It is however all one field. Can I generate the soil loss on the whole field and the PSI on the two management units?
    • A: Absolutely. RUSLE was designed to be used for the field or system, not each strip. If the strips are different management units, the PSI must be done on each management unit.

QGIS

PDF document addressing Frequently Asked Questions for QGIS (with pictures)