Evaluating Oilseed Meals, Distillers Grains, Anaerobically Digested Fiber,

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Evaluating Oilseed Meals, Distillers Grains, Anaerobically Digested Fiber, and Mint Residue as Nitrogen Fertilizer Sources Amber Moore, Ashok Alva, Harold Collins, and Rick BoydstonUniversity of Idaho, Twin Falls, Idaho and USDA ARS, Prosser, Washington Introduction Amendment Characterization Results – 2007 Field Study in Paterson, Washington Results – 2008 Field Study in Paterson, Washington Results – 2009 Field Study in Kimberly, Idaho • Changing markets (ethanol and biodiesel) and practices (plug flow digestion) are changing waste materials that are available for crop field applications. • Mint residue (aka mint slugs) left over from mint harvest , limited uses • Agronomic properties poorly understood • Important to understand agronomic potential when applied to crops with high nutrient demands, such as potatoes • Great interest from organic and sustainable growers • Limited inexpensive, nitrogen-rich organic fertilizers in the Intermountain High Plain region of Idaho • Objective: Determine how field applications of new and unique waste materials impact tuber yields in potatoes, nitrate concentrations in the fourth petiole of the potato plant, and nitrogen mineralization rates. Table 1. Nutrient content of amendments. CM 267 kg N/ha MS 267 kg N/ha Control (No preplant N) MM 267 kg N/ha DG 92 kg N/ha Control (No preplant N) DG 169 kg N/ha • Application of DG at 92 kg N/ha increased yields by at least 11 tonne/ha • No yield response over 92 kg N/ha • Petiole nitrate concentrations significantly lower than recommended for conventional production at all rates • New petiole nitrate concentration recommendations may need to be developed for organic production • Slow release N fertilizers in other studies have shown lower petiole nitrate conc. with similar or greater yields Results – Incubation study Table 2. PAN % from organic N sources applied to a Quincy fine sand at 200 mg total N kg-1. Figure 3. Effect of amendment applications on tuber yield. Paterson, Washington, 2007, Conventional, Russet Ranger potatoes. Figure 7. Effect of DG applications on tuber yield. Kimberly, Idaho, 2009, Organic, Russet Burbank potatoes. Figure 5. Effect of amendment applications on tuber yield. Paterson, Washington, 2008, Conventional, Russet Ranger potatoes. • PAN is significant for MM and DG over growing season (Table 2), greater than poultry litter or dairy compost (data not shown) • Initial immobilization and delayed release of PAN in MM and DG treatments, likely related to allelopathic isothiocyanates (MM) and peptide compounds (DG) • ADF – greater PAN early in the season, immobilizes later in the season in closed incubation environment. C:N = 20:1, immobilization expected. (Table 2) Materials and Methods • Incubation study • Sealed polyethylene bags in dark growth chamber • Amendments applied to Quincy sand at a rate of 200 mg N kg-1 • Temperature changed biweekly to simulate Eastern Washington soil temperatures • 2007 field study in Paterson, Washington • Conventional production on a Quincy sand • Russet Ranger potatoes • Urea Ammonium Nitrate applied in-season to all treatments (107 kg N/ha, total) Figure 4. Effect of amendment applications on petiole nitrate concentrations over a growing season at the 133 kg N/ha rate. Paterson, Washington, 2007, Conventional, Russet Ranger potatoes. Limits based on Washington State University recommendations. Figure 8. Effect of amendment applications on petiole nitrate concentrations over a growing season. Kimberly, Idaho, Organic, Russet Burbank potatoes. Limits based on University of Idaho recommendations. • Study observations of PAN compared to Oregon State University Organic Fertilizer Calculator predictions (Figure 1) • OSU Organic fertilizer calculator assumes linear relationship between %N and PAN between 2 and 6 %N • Tuber yields similar for CM, MM, and DG at 89 & 133 kg N/ha rates. • For mustard meal, lowest tuber yield was at the highest rate of 178 kg N/ha . • Could be attributed to allelopathic isothiocyanates. • Lower yields and highest petiole nitrate conc. for urea in comparison to CM, MM, and DG at all rates. • Excess N likely stimulating tuber top growth, compromising tuber set and bulking thus lowering tuber yields. • Also, delayed release of N from MM and DG may be more plant available over the duration of the growing season than urea, which would also increase yields • 2008 field study in Paterson, Washington • Conventional production on a Quincy sand • Russet Ranger Potatoes • Urea Ammonium Nitrate applied in-season (107 kg N/ha, total) • 2009 field study in Kimberly, Idaho • Organic production on a Portneuf silt loam • Russet Burbank potatoes Figure 6. Effect of amendment applications on petiole nitrate concentrations over a growing season at the 178 kg N/ha rate. Paterson, Washington, 2008, Conventional, Russet Ranger potatoes. Limits based on Washington State University recommendations. Conclusion • PAN for DG, MM, and ADF amended soils directly related to %N • MS (2.9 %N) applied at rates above 178 kg N/ha greatly decreased yields • Amendments greater than 4 % (CM, MM, and DG) greatly increased yields at rates above 89 kg N/ha on sandy and/or silt loam soils • ADF (2.3 %N) increased yields slightly, especially at higher rates (>267 kg N/ha). • MM reduced yield slightly at rates greater than 133-178 kg N/ha , possibly due to isothiocyanate compounds in the meal • Petiole nitrate conc. recommendations may need to be altered for fertilizers containing organic N compounds • Tuber yield declines at 267 and 356 kg N/ha rates for MM trt (Figure 5) • Isothiocyanates in MM is known to be toxic to plants at high rates • Tuber yield rapidly and dramatically declines at 267 and 356 kg N/ha rate for MS trt (Figure 5) • Cause not yet determined • Minimal yield increase for CM and DG over 178 kg N/ha rate (Figure 5) • ADF yields steadily increase from 178 to 356 kg N/ha rates (Figure 5) • Petiole nitrate concentrations indicate N deficiency for ADF and MS Figure 1. Observed and OSU Organic Fertilizer Calculator predicted PAN for ADF, DG, and MM amended soil. Hand application of DG to field plots • Model efficiency (E) greater than 0.50, indicates that the OSU Organic Fertilizer Calculator is appropriate for predicting PAN in ADF, DG, and MM