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Nutrient Management PracticesHow will this worksheet help?It will take you step by step through your nutrient management practices. It will help you rank your nutrient management practices according to how they may affect water quality on your farm. It will provide you with easy-to-understand rankings that will help you analyze the risk level of your nutrient management practices. It will help you determine which of your nutrient management practices are reasonably safe and effective, and which practices might require some modification to better protect your water resources. Arkansas nutrient management risk assessmentUse a pencil. You may want to make changes. For each category that is appropriate to your farmstead, circle the number that best describes conditions on your farmstead. Write the rank on the line on the right. Skip categories that don’t apply to your farmstead. See page 10 for scoring instructions. Allow about 15-30 minutes to complete the worksheet and figure out your risk ranking for nutrient management practices. Key: Evaluate your rankings for individual activities based on the following: 4's - Best: Low-risk practices 3's - Low-to-Moderate risk practices 2's - Moderate-to-High risk practices 1's - High risk practices Routine soil testingFrequency of routine soil tests 4's - Cropland fields are tested every year. 3's - Cropland fields are tested every 3 years; every other year for vegetable crops. 2's - Cropland fields are tested every 5+ years; every 3-4 years for vegetable crops 1's - No soil testing conducted. Sampling density 4's - At least 8 soil cores are collected from each 5 acres or less in a grid pattern and used to develop a map of the field. 3's - At least 10 soil cores are collected from 5 to 20 acres to form a composite sample. 2's - At least 10 soil cores are collected from 20 to 40 acres to form a composite sample. 1's - A composite soil sample is collected from 40 or more acres. Nutrient application rates 4's - Nutrient application rates do not exceed University of Arkansas recommendations.3's - Nutrient application rates exceed University of Arkansas recommendations by 10-25%. 2's - Nutrient application rates exceed University of Arkansas recommendations by 25-50%. 1's - Nutrient application rates exceed University of Arkansas recommendations by greater than 50%. Yield goal estimates 4's - For nitrogen recommendations, yield goals are not used (for example, nitrogen rates are based on the University of Arkansas recommendation program). For phosphate and potash recommendations, yield averages from 5 or more years are used for determining realistic yield goals for each field 3's - All fertilizer recommendations are based on yield goals using 3- to 5-year average yields. Soil nitrate testing for corn 4's - Soil nitrate tests are used when and where appropriate. Nutrient creditsManure Application rate 4's - Manure is applied to fields at rates not exceeding the nutrient need of the crop to be grown. Nutrient content 4's - Manure nutrient content is determined through laboratory analysis. 3's - Manure nutrient content is estimated using University of Arkansas laboratory averages (book values). 2's - Manure nutrient content used in determining manure nutrient credits is a “partial value from either a laboratory analysis or university book value. 1's - Manure nutrient content is unknown. Crediting 4's - Manure nutrient credits are confirmed through the use of a pre-sidedress soil nitrate test and fertilizer application rates are reduced accordingly. Legumes 4's - Legume nitrogen credits are calculated according to University of Arkansas guidelines and are fully deducted from nitrogen fertilizer application rates 3's - Legume nitrogen credits are confirmed through the use of a pre-sidedress soil nitrate test and nitrogen fertilizer application rates are reduced accordingly 2's - Legume nitrogen credits are partially deducted from fertilizer application rates. (At least 50% of the nitrogen credit is used.) 1's - Legume nitrogen credits are ignored. Fertilizer application rates are not adjusted Organic wastes (such as whey and sludge) 4's - Organic wastes are applied to fields at rates not exceeding the nutrient need of the crop to be grown 2's - Organic wastes are applied to fields at rates exceeding the nutrient need of the crop to be grown. Organic waste application rate to fields is unknown. Manure management Note: The following series of categories deals with management practices pertaining to the land application of manure. If you do not apply manure to your property, skip to the next section of this worksheet. Field selection 4's - Manure is applied to fields testing less than 100 lbs/A for soil test phosphorus (P). Animal units* to spreadable acres ratio 4's - Less than 0.5 animal units per acre of spreadable cropland. 3's - Between 0.5 and 1.0 animal units per acre of spreadable cropland 2's - Between 1.0 and 2.0 animal units per acre of spreadable cropland. 1's - More than 2.0 animal units per acre of spreadable cropland.
For example, 60 milk cows=84 animal units (60x1.4=84 animal units). If the farm has 120 acres of spreadable cropland, the animal unite to spreadable acres ratio is 0.7 (84 animal units/120 acres=0.7). Slope 4's - Manure is applied to fields with slopes of 0-2%. Field History 4's - Manure applications are made to fields that have been in corn production for three or more years with alfalfa, corn, or some other high nitrogen demanding crop to be grown the next year. Distribution 4's - Manure is applied only to fields with optimum or lower soil test phosphorus values at rates not exceeding crop nutrient need. Timing and method of application 4's - Fall and/or spring manure applications of manure are injected or incorporated within three days of application. Uniformity of applications 4's - Manure is applied uniformly across fields over a short period of time (1-2 days) when emptying a storage facility. Application rate 4's - Manure application rate is estimated by a custom manure applicator using calibrated equipment. Application strategy 4's - Manure is applied at rates to meet the phosphorus (P) need of crop to be grown. Field characteristics/site considerations 4's - No cropland acres have physical characteristics that would limit their suitability for receiving manure. Nitrogen (N) fertilizer applicationsSandy soils Timing of N fertilizer applications 4's - Single sidedress or multiple delayed applications of N. Cover crops 4's - Cover crops are established in the fall after the primary crop is harvested on all sandy soil fields. 3's - Fall cover crops are established on the majority of sandy fields. 2's - Fall cover crops are established on the minority of sandy fields. 1's - Fall cover crops are not used. Source of N 4's - Anhydrous ammonia or ammonium sulfate forms of N fertilizer are used. 3's - Ammonium nitrate, urea, or N solution (28%, 32%) forms of N fertilizer are used. 1's - Potassium nitrate or calcium nitrate forms of N fertilizers are used. Medium- and fine-textured soils Timing of N fertilizer applications Preplant of split (preplant and sidedress) applications of N are made. Sidedress application(s) of N are made. Fall applications of N with a nitrification inhibitor are made. The majority or all of N is applied in the fall without a nitrification inhibitor. Phosphorus (P) and potassium (K) fertilizer applications Timing of P and K applications 4's - Immediate incorporation of broadcast applications. Or Band application (such as starter fertilizer). Irrigation Scheduling 4's - The University of Arkansas Irrigation Scheduling Program is followed. 3's - Some type of irrigation scheduling program us used that utilizes weather information and field measurements of evapotranspiration. 2's - Irrigation performed when judged necessary by land manager. Decision is based on past experience combined with some field measurements. 1's - Irrigation frequency is not based on any measure parameters. Starter fertilizer rates 4's - Starter fertilizer applications on medium- and fine-textured soils that have soil test values for phosphorus(P) and potassium(K) of optimum or less. Application rates deliver approximately 10 lb of N, 20 lb of P2O5, 20 lb of K2O (such as 100 lb of 9-23-30). 3's - Starter fertilizer applications on medium- and fine-textured soils that have soil test values for P and K of high or excessively high. Application rates deliver approximately 10 lb of N, 20 lb of P2O5, 20 lb of K2O (such as 100 lb of 9-23-30). 1's - Starter fertilizer applications in excess of 10 lb of N, 20 lb of P2O5, 20 lb of K2O on soils testing high or excessively high for P and K. Calibration of fertilizer application equipment 4's - Application equipment is adjusted and calibrated at least once a year. 3's - Application equipment is adjusted and calibrated every other year. 2's - Application equipment has not been calibrated in the last 5 years. 1's - Application equipment has never been calibrated. Recordkeeping 4's - Crop nutrient management decisions are based on detailed field history records (yield, manure applications, crop rotations, etc.). 1's - Field history records are not kept. Soil conservation 4's - A farm conservation plan is being followed that does not allow tolerable soil loss (T) to be exceeded for any cropland fields. 3's - A farm conservation plan is being followed only on designated highly erodible land (HEL) acres. These acres are planned to not exceed T. 2's - A farm conservation plan is being followed, but the plan allows erosion in excess of T (for example, a plan includes alternate conservation systems). 1's - No farm conservation plan is being followed. Visible evidence of soil erosion. Crop rotation 4's - Rotation with more years of deep-rooted legume crops (alfalfa and/or soybean) than row crops. 3's - Rotation of row crops with a deep-rooted legume crop at least one out of every three years. 2's - Rotation of row crops with small grain (oats, wheat, etc.) crops. 1's - Continuous corn or other high intensity row crop(s). What do your rankings mean?Assess the number of categories that you have given a high risk or moderate to high risk. The more high and moderate to high-risk ratings you have, the greater your risk for contributing to water-quality problems. To avoid potential problems, you should look for ways to improve your rankings in the high-risk categories. To assess your rankings of individual activities, use these guidelines: Low-risk practices (4s) are ideal and should be your goal. Low-to-moderate-risk practices (3s) provide reasonable protection of water quality. Moderate-to-high-risk practices (2s) provide inadequate protection of water quality in most circumstances. High-risk practices (1s) indicate a high potential for degrading water quality. To fully interpret your potential for harming drinking-water quality through your nutrient management practices, you may also wish to consider a site assessment. The Site Evaluation Worksheet (worksheet 11) ranks soil and subsurface geologic materials and their ability to protect groundwater and surface-water quality. Any site that falls in a category higher than low risk has a reduced ability to attenuate contaminates--that is, in those settings even low- to moderate- or moderate-to-high-risk practices that have the potential to degrade water quality. If your farm is located on a high- or moderate-to-high-risk site, you should view the groundwater risk as being one category of risk higher than your rankings indicate, and you should develop a plan for implementing practices to enhance groundwater protection. Read the companion University of Arkansas Extension publication A3557, Nutrient Management: Practices for Arkansas Corn Production and Water Quality Protection, and consider how you may modify your nutrient management practices to better protect water quality on your farm. Additional information on any of the agricultural practices discussed in the assessment worksheet can be obtained from your county University of Arkansas Extension office. Work Sheet 9b - Cropland Pest Management Practices • Fact Sheet 9 - Assessing Your Cropland |
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