RUSLE Screening Tool for Assessing the Need for Incorporation of Organic Nutrients March 2013

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1 Agricultural Nutrient Management Program Department of Environmental Science and Technology 0116 Symons Hall College Park, MD TEL FAX RUSLE Screening Tool for Assessing the Need for Incorporation of Organic Nutrients March 2013 Introduction The revised Nutrient Application Requirements published by MDA on October 15, 2012 mandate incorporation of organic nutrients within 48 hours of application with specific exceptions, including hay and pasture fields and highly erodible land (HEL). Recent guidance from MDA provides criteria for determining whether organic nutrients must be incorporated on fields that have traditionally been managed as no-till. The process requires a RUSLE calculation for each field on which a farmer wishes to apply organic nutrients without incorporation. If the RUSLE calculation indicates that soil loss (RUSLE A value) exceeds tolerable soil loss (T), incorporation is not required. Note: All organic nutrients applied in winter, starting in winter of , must be incorporated no exceptions. Purpose of Screening Process Performing a RUSLE calculation for each non-hel field on which a farmer wishes to apply organic nutrients without incorporation is a time consuming task. To minimize this time requirement, use the screening tool described below to make initial determinations. This screening tool will eliminate the need to make a field visit in situations where, using worst case conditions, the RUSLE A value is less than T. University of Maryland Extension programs are open to all citizens without regard to race, color, gender, disability, religion, age, sexual orientation, marital or parental status, or national origin.

2 Procedure Step Action 1 Identify each field where the farmer would like to avoid incorporation of organic nutrients and determine the dominant soil map unit for the field using the Web Soil Survey. a. Print the soil map and map unit information for inclusion in the nutrient management plan. b. Note the maximum slope in the slope range of the dominant soil map unit. 2 Use the following to determine the LS factor in NuMan Pro or RUSLE2. a. higher slope gradient associated with the dominant soil map unit b. a slope length of 400 feet 3 Using RUSLE2 or the C factor page in NuManPro*, calculate the RUSLE A for the cropping year. a. Choose the crop, type of manure application, chisel plow (#8 in the operation list) for incorporation method, planting date and harvest date. *Use of the C factor page in NuManPro is demonstrated in Appendix 1. 4 Note the RUSLE A value and the T-factor on Index Part A of NuManPro. Interpretation If RUSLE A is less than T RUSLE A is greater than T Then organic nutrients must be incorporated. a. conduct a site visit to determine the actual slope length and gradient of the field in the direction of surface water; b. recalculate RUSLE using the actual field slope data and tillage practices the famer indicates he is most likely to use. If RUSLE A is greater than T RUSLE A is less than T Then run RUSLE 2 using vertical tillage as the primary tillage operation. incorporation is required. 2

3 Required Documentation Documentation supporting your recommendation for organic nutrient application either with or without incorporation must be included in the nutrient management plan. Step Action 1 Create a new tabbed divider for the plan binder called No-Till Manure Evaluations. 2 Include HEL maps from the Farm Service Agency in this section. These maps support a surface application of organic nutrients without incorporation. No RUSLE evaluation of these fields is required. 3 Include Web Soil Survey maps for each field on which a RUSLE calculation was performed. 4 Include documentation of the RUSLE calculation in this section. If using NuMan Pro using RUSLE2 Then print out the RUSLE C-Factor Report and the RUSLE Report. select the AR RUSLE2 Profile Record Simple with Operations to print the RUSLE Erosion Calculation Record. 3

4 Appendix 1. Click here to access the RUSLE feature in NuMan Pro. If the PSI is turned off, click on the button to remove the red line. Note the slope range. Click on option 1. 4

5 Select the appropriate erosion factor for the field. Enter the maximum slope length (400 ft) and the higher slope gradient of the dominant soil map unit in the field. Enter a residue amount for the manure application. Select the crop that will be planted in the field and the practices described in Step 3 of the Procedure section of this document. Adjust the dates as appropriate. Table 1. Residue amounts provided by NRCS in Maryland RUSLE 2 Instructions & User s Guide, June Type of Manure Manure Characteristics Lbs. Dry Matter* Liquid % dry matter 1000 Solid and Semi-Solid, Moderate 6 25% solids 3000 Bedding Poultry 6 50% solids 3000 Semi-solid and Slurry 10 15% solids or % solids 3000 *These are maximum values. Do not use values greater than those listed.

6 This is the Tolerable soil loss value (T) for the field. This is the soil loss value (RUSLE A) for the field. In this example, Rusle A is less than T. Manure must be incorporated.