Phosphorus Assessment Tool Worksheet

USDA-NRCS-NM 7/7/2008 PHOSPHORUS INDEX WORKSHEET for New Mexico Client Name: Planner: Soil Permeablity (in/hr): Site Characteristic Soil Test P Level Phosphorus (P2O5) Application Rate Organic Phosphorus Source Application Method Field(s): Location: Date: Crop: Slope (%): Planned/Exist.: Place an X in the approprate box for each of the Site Characteristic listed Sub Total below. Very Low <8 ppm Low 8-15 ppm Moderate >15-23 ppm High >23-30 ppm Very High >30 ppm >150 lbs/ac P2O5 None Applied <30 lbs/ac P2O5 30-90 lbs/ac P2O5 >90-150 lbs/ac P2O5 Incorp. >3 Mo. Before Planting or Surface Applied <3 Mo. before Planting Incorp. >3 Mo. Before Planting or Surface Applied <3 Mo. before Planting High 30-200 feet High >5-15 t/ac None Applied Injected Deeper than 2 inches Incorporated Immediately before Planting Surface Applied >3 Months Before Planting Phosphorus Fertilizer Application Method Proximity of Nearest Field Edge to Named Stream or Lake Soil Erosion (wind & water) Runoff Class (Runoff Class Table 2) Incorporated Placed with Planter None Applied Immediately before Deeper than 2 in. Planting Surface Applied >3 Months Before Planting Very Low >1000 feet Very Low <1 t/ac Low >500-1000 feet Low 1-3 t/ac Medium >200-500 feet Medium >3-5 t/ac Very High <30 feet Very High >15 t/ac Very Low or Negligible Low Medium High Very High Irrigation Erosion (See QS note) Tailwater Recovery Not Irrigated or or QS<6 for very QS>10 for erosion No Furrow erodible soils or resistant soils Irrigation QS<10 for resistant soils QS>10 for erodible soils QS>6 for very erodible soils Grazing Management Not Grazed Graze Crop Residues Pasture <30% Dry Pasture 30 to 80% Dry Pasture 80 to 100% Matter as Matter as Dry Matter as Supplemental Feed Supplemental Feed Supplemental Feed Vegetative Buffer > 100 ft wide >65-100 ft wide 20-65 feet wide < 20 feet wide No Buffer P Hazard Class: Phosphorus Application Classification: Notes: Total Index Points: Comments: USDA-NRCS-NM 7/7/2008 Phosphorus Index Rating for New Mexico Weighting Factor Times the Column Factor Site Characteristic Wt. Factor 1 None or Very Low 0 Very Low <8 ppm 0 None Applied 0 None Applied 0 Low 1 Low 8-15 ppm 1 <30 lbs/ac P2O5 1 Injected 3-6 inch below surface 1 Medium 2 Moderate >15-23 ppm 2 30-90 lbs/ac P2O5 2 Incorporated Immediately before Planting 2 High 4 High >23-30 ppm 4 >90-150 lbs/ac P2O5 Very High 8 Very High >30 ppm 8 >150 lbs/ac P2O5 8 Soil Test P Level Phosphorus (P2O5) Application Rate Organic Phosphorus Source Application Method 1 1 4 Incorporated >3 Months Before Planting or Surface Surface Applied Applied <3 Months before Planting 4 8 Incorporated >3 Months Before Planting or Surface Surface Applied Applied <3 Months before Planting 4 High 30-200 feet 6 High >5-15 t/ac 6 High 6 8 Very High <30 feet 12 Very High <15 t/ac 12 Very High 12 Phosphorus Fertilizer Application Method 1 Placed with Incorporated Planter Immediately None Applied Deeper than 2 before Planting in. 0 1 Low >500-1000 ft 1.5 Low 1-3 t/ac 1.5 Low 1.5 2 Medium >200-500 feet 3 Medium >3-5 t/ac 3 Medium 3 Proximity of Nearest Field Edge to Named Stream or Lake Soil Erosion (WEQ & RUSLE) Runoff Class (Runoff Class Table) 1.5 Very Low >1000 feet 0 Very Low <1 t/ac 0 Negligible & Very Low 0 1.5 1.5 Irrigation Erosion 1.5 Tailwater Recover or Not Irrigated QS>10 for QS<6 for very erosion or No Furrow erodible soils or resistant soils Irrigation QS<10 for other soils QS>10 for erodible soils QS>6 for very erodible soils 0 Not Grazed 0 1.5 Only Graze Crop Residues 0.5 >65-100 feet wide 1.5 3 Pasture <30% Dry Matter as Supp. Feed 1 20-65 feet wide 3 6 Pasture 30 to 80% Dry Matter as Supplemental Feed 2 < 20 feet wide 6 Grazing Management 0.5 12 Pasture 80 to 100% Dry Matter as Supp. Feed 4 No Buffer 12 Vegetative Buffer 1.5 > 100 ft wide 0 QS Note: Q=flow rate of water introduce into the the furrow (in gallons per min). S= furrow slope (in ft/100ft, percent). Q is mutliplied by S. For example: 5 gpm X 2%=10. Phosphorus Index Classification P Hazard Index Pts. Class 0-10 Very Low 10-17 Low 17-27 Medium 27-37 High 37-47 Very High >47 Excessive P Application Classification N Based N Based N Based P Based (1.5 x crop removal) P Based (at crop removal) No P application allowed USDA-NRCS-NM 7/7/2008 Runoff Class Based on Field Slope and Permeability Class Very Rapid >20 (in/hr) N N N VL VL L Rapid 20-6 (in/hr) N N N VL VL L Moderately Moderately Rapid Slow Slow Moderate 6-2 2-0.6 0.6-0.2 0.2-0.06 (in/hr) (in/hr) (in/hr) (in/hr) N N VL L L M N N L M M H N L M H H VH N M H VH VH VH Very Slow 0.06-0.0015 (in/hr) N H VH VH VH VH 1 Slope % Level or Concave >0 to 1 1 to <5 5-<10 10-<20 >20 Impermeable <0.0015 (in/hr) VH VH VH VH VH VH Note: Adapted from the National Soil Survey Handbook. 1 Based on the most restrictive horizon above 20 inches. If the most restrictive horizon is between 20 and 40 inches, the runoff estimate should be reduced by one class (e.g., medium to low). If the most restrictive layer in the soil is below 40 inches, use the lowers class that occurs above 40 inches. Runoff Classes: N-negligible, VL-very low, L-low, M-medium, H-high, VH-very high Special Rule 1 - A soil horizon that has a seasonal water table is assumed to have very slow permeability. Special Rule 2 - Runoff is rated as "negligible" (N) if the soil is in a depression, regardless of the permeability. Assumptions: 1. Soil Permeability based on bare soil surface. 2. Low water retention due to ground surface irregularities. 3. Steady ponded infiltration rate. 4. Bulk density of upper 10" is within normal range for the soil.