ONTARIO GRAIN FARMER CROP SIDE 13 EVALUATING AVAILABLE OPTIONS In a scenario where fertilizer prices are high, a producer might explore organic amendments to supplement fertilizer. Current options include dairy or poultry compost and pelleted, ashed or pH-enhancing biosolids (i.e., N-Viro/N-Rich). The target is to fulfill phosphorus needs for corn production while enhancing overall nutrient balance and soil organic matter. Each of these products can supply the phosphorus needs of the crop, but their differences matter. Think about other goals depending on soil test levels—extra organic matter to build soil, or a product that also adds micro-nutrients or helps raise pH. Watch nutrient balance, too. Biosolids often have very little potassium, potentially requiring supplementing with commercial fertilizer. Some biosolids also contain high levels of calcium, aluminum or iron, which can tie up phosphorus and make it less available, especially in low or high soil pH conditions. As a rule of thumb, assume only about 20 per cent of the phosphorus in biosolids is available in the first year, and use a starter fertilizer to make sure the crop gets what it needs. Over time, the rest will become available, but this can take months or even years depending on soil characteristics, including pH, microbial activity, moisture, and temperature. Cost and logistics can also influence product choice. The dairy compost in the example in this article can’t economically meet phosphorus needs. But reducing application to 5 ton/ac would provide similar soil health benefits, and can be complemented with commercial fertilizer to match crop nutrient needs. Ashed biosolids Table 1: Comparing Products Dairy compost Poultry compost Biosolids pellets1 Ashed biosolids2 N-Viro (N-Rich) Dry matter % 35 70 96 70 77 ~Available N-P2O5-K2O (lbs/ton) 4 – 4 – 13 - 1 (S) 12 – 37 – 28- 7 (S) 35 – 64 – 7 - 10 (S) 0.2 – 218 – 13 – 3 (S) 4 – 15 -79 – 59 (S) C:N ratio 22:1 8:1 7:1 15:1 21:1 Organic matter (lbs/ton as-applied) 125 311 1,400 17 432 Ca- Al - Fe (lbs/ton) 21 – 0.5 - 2 81 – 6 - 11 39 – 8 - 37 113 – 37 - 180 322 – 28 – 15 (ag index 23) Rate to meet corn P2O5 target 21 tons 2.25 tons 1.3 tons 0.4 tons 5.6 tons N-P-K applied at target rate 84 – 84 - 273 27 – 83 - 63 46 – 83 - 9 0 – 87 - 5 22 – 84 – 442 ~ Cost/ton 3 $40 $110 $95 $120 $105 ~ Cost/ac3 at target rate $800 $250 $123 $48 $600 1 This example uses Detroit pellets (Toronto pellets ‘NutriPel’ ~50 – 120 – 2 – 22S -77Ca – 6Al - 118Fe lbs/ton) 2 Phosphorus content will vary by location of origin. 3 Cost will vary with distance for transporting materials would economically build phosphorus but with limited benefit to improving overall soil health. With so many choices, it's important to focus on farm needs, what each product adds (or lacks), and the cost and logistics. Picking the option that fits best will give the greatest return.• Greenbin and yardwaste compost application demonstration near North Gower (photo courtesy Christine Brown).
RkJQdWJsaXNoZXIy MTQzODE4