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Fine-Tuning Corn Nitrogen Management. Quirine M. Ketterings, Joe Lawrence, Jon Klapwyk, Michele Wang, Miriam Goler, Karl Czymmek Nutrient Management Spear Program Department of Animal Science, Cornell University. Cornell Corn N Recommendations. Cornell corn N recommendations are based on:
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Fine-Tuning Corn Nitrogen Management Quirine M. Ketterings, Joe Lawrence, Jon Klapwyk, Michele Wang, Miriam Goler, Karl Czymmek Nutrient Management Spear Program Department of Animal Science, Cornell University
Cornell Corn N Recommendations • Cornell corn N recommendations are based on: • Yield potential • soil type and drainage • Soil N supply • soil type and drainage • N fertilizer uptake efficiency • soil type and drainage • N credits from sods • % legume/grass in the sod • N credits from manure • application method + timing
Cornell Corn N Recommendations in bushels/acre in lbs N/acre (yield potential * 1.2) – soil N – sod N N requirement = (fertilizer efficiency/100) in lbs N/acre in % - soybean N or manure N credits = soil series specific
Pre-Sidedress Nitrate Test (PSNT) 12 inch soil cores to when corn is 6-12 inches tall.
Pre-Sidedress Nitrate Test (PSNT) You really have to want to do this….
Pre-Sidedress Nitrate Test (PSNT) It can add to the work overload! Impractical timing for dairy farms.
Pre-sidedress Nitrate Test And there are many opportunities to make mistakes.
Illinois Soil N Test (ISNT) Test Method (Kahn et al., 2001) • 1 g soil + 10 mL of 2M NaOH in mason jar. • Add 5 mL of 4% boric acid to suspended petri dish. • Heat for 5 hours on hotplate griddles. • Titrate with sulfuric acid.
Illinois Soil Nitrogen Test (ISNT) Responsive Non responsive 225 ppm
Illinois Soil Nitrogen Test (ISNT) Main research questions in NY: Can this test separate responsive from non-responsive sites in New York? Can we use regular 8 inch cores instead of 12 inch cores? Can we sample before planting or after harvest? Can we determine N rates? No Yes [ ? ] [ ? ] [ ? ] [ ? ] [ ? ] [ ? ] [ ? ] [ ? ]
Four Project Phases • Fine-tuning the laboratory procedure • Initial field calibration • 0-8 or 0-12 inch samples? • Timing of sampling? • ISNT and manure N credits • ISNT use for corn in rotation
Phase 1: Laboratory Procedure Initial Observation: • High degree of day-to-day and within-griddle variability.
Phase 1: Laboratory Procedure Klapwyk and Ketterings (2005)
Phase 1: Laboratory Procedure • Temperature did not affect N recovery. • ISNT results increase with temperature. • Enclosing griddles resulted in: • Lower ISNT-N. • Lower CV. • Similar findings in Illinois led to modifications to include jar rotation at 1.5 and 3 h in Illinois. • Enclosed griddles at 50.6°C gave results directly comparable with Illinois.
Four Project Phases • Fine-tuning the laboratory procedure • Initial field calibration • 0-8 or 0-12 inch samples? • Timing of sampling? • ISNT and manure N credits • ISNT use for corn in rotation
Phase 2: Initial Field Calibration • 2002: • Albers • Barney • Bossard • Carey • Czymmek • Kilcer • T&R Center • 2004: • Albers • Barney • Bossard • Czymmek • Degni • Hunter • Kilcer • Miller/Stockin • Miner Institute • Tillapaugh • T&R Center • 2003: • Albers • Barney • Bossard • Czymmek • Degni • Kilcer • T&R Center Collaboration with local extension educators
Phase 2: Initial Field Calibration Klapwyk and Ketterings (2006)
Phase 2: Initial Field Calibration • Conclusions: • 8 inch samples ok • Samples could be taken outside growing season • Both ISNT and LOI were needed to predict responsiveness
Phase 2: Initial Field Calibration Loss-on-ignition (g kg-1)
Four Project Phases • Laboratory procedure • Initial field calibration • 0-8 or 0-12 inch samples? • Timing of sampling? • ISNT and manure N credits • ISNT use for corn in rotation
*** *** * * NS *** * *** *** *** *** NS NS NS *** *** *** ** *** *** *** ISNT Ammonium Nitrate Michelle Wang, 2005 Klapwyk et al. (2006)
Phase 3: ISNT and Manure N Credits • ISNT: • Part of the soil N pool • Increases with manure and compost addition • Reflects NH4+ peaks after manure application • So, for assessment of soil N supply potential: • Don’t sample within 5 weeks after manure application
Four Project Phases • Laboratory procedure • Initial field calibration • 0-8 or 0-12 inch samples? • Timing of sampling? • ISNT and manure N credits • ISNT use for corn in rotation
Phase 4: ISNT for Corn in Rotation 1st yr corn after sod • Small starter N • Forget about sidedress N. • Grass or alfalfa does not matter. • Late fall versus spring does not matter. • Stand needs to be sod, not weeds… Lawrence et al. (2008)
Phase 4: ISNT for Corn in Rotation 2nd+ yr corn or corn after soybean? Responsive: 8 sites, Nonresponsive: 10 sites
Phase 4: ISNT for Corn in Rotation Site A Overall Accuracy: 83% (15 of 18).
Phase 4: ISNT for Corn in Rotation Site B Overall Accuracy: 83% (15 of 18).
Phase 4: ISNT for Corn in Rotation Site C Overall Accuracy: 83% (15 of 18).
First year corn: Correct: 10 sites Incorrect: 6 sites 63% accuracy 2nd+ year corn: Correct: 15 sites Incorrect: 3 sites 83% accuracy
Phase 4: ISNT for Corn in Rotation ISNT in year 1 versus year 2… Samples taken at PSNT time… Measures soil organic N mineralization potential?
Phase 4: ISNT for Corn in Rotation A • Un-amended soil had constant ISNT. • ISNT follows ammonium release for both roots and shoots. • Nitrification gives flush of nitrate 4-6 weeks after alfalfa incorporation. • ISNT does not reflect nitrate N. ISNT NO3-N NH4-N B Miriam Goler, 2007
First year corn: Correct: 10 sites Incorrect: 6 sites 63% accuracy Sod N credits need to be added!! 2nd+ year corn: Correct: 15 sites Incorrect: 3 sites 83% accuracy
Conclusions for ISNT • ISNT is an accurate tool for predicting corn responsiveness (yes or no) to sidedress N in NY for 2nd+ year corn • Fits well with 3-year sampling protocol for general fertility However: • ISNT can capture ammonium release 1 – 5 wk after manure application or sod plowdown And: • 1st yr corn does not need N so no need to sample for ISNT Therefore: • Avoid sampling within about 5 weeks after manure application, sod/cover crop plowdown or chemical kill • Add manure N and cover crop N credits
Illinois Soil Nitrogen Test Main research questions: Can this test separate responsive from non-responsive sites in New York? Can we use regular 8 inch cores instead of 12 inch cores? Can we sample before planting or after harvest? Can we determine N rates? No Yes [ ? ] [ x ] [ ? ] [ x ] [ ? ] [ x ] [ x ] [ ? ]
Fine-Tuning Corn Nitrogen Management Questions? Cornell Nutrient Management Spear Program – qmk2@cornell.edu