A report at https://www.dtnpf.com/agriculture/web/ag/crops/article/2022/01/12/retail-fertilizer-prices-continue on January 12, 2022 indicated that the retail fertilizer prices compared to a year ago have increased significantly, with several having well over 100% price increases. 10-34-0 is now 71% more expensive, MAP is 72% higher, DAP is 79% more expensive, potash is 119% higher, urea is 148% more expensive, UAN32 is 171% higher, UAN28 is 179% more expensive and anhydrous ammonia is 204% higher compared to last year. What should I do? Can I minimize on my fertilizers input costs without compromising on the crop yields?
The answer is yes, you can! Among the fertilizer nutrients, nitrogen (N) is used in the highest amounts and therefore accounts for more cost than any other nutrients. If you haven’t tested your fields for nitrate N in the late fall, go for nitrate N test in early spring. Please remember that 1 ppm of N/or any other nutrient in a test means 4 kg of N/or any other nutrient. Therefore, you can reduce 4 kg N/ha for each ppm of nitrate N test from the recommended rate of N for crop production. If the soil test indicates 25 ppm nitrate N (= 100 kg nitrate N/ha), you can grow spring cereals without application of any N. If you are applying manure test manure for its nutrient contents and adjust the nutrients supplied by the applied manure from the recommended rates of nutrients. In the absence of a manure test, I have been reducing 10 kg N/ha for every 1000 gallons of liquid manure and 1 kg N/ha for every MT of solid manure. I have seen that this has worked well in our area. Legume contribution in our relatively colder area in a rotation could be taken as 40 kg N/ha. In the southern Ontario, this contribution can be taken as up to 80-100 kg N/ha. You can also reduce 40 kg N/ha from the recommended rate of N for a crop if that crop is grown after application of both manure and fertilizers. Research at LUARS has indicated that blending urea and ESN in 2:1 ratio on N basis could help lowering the N rate/or enhancing crop yields as compared to urea alone. Application of sulphur (S) and deficient micronutrients at recommended rates for each crop is a must to get optimum response to applied N. You will know about deficiency or sufficiency of essential nutrients in your fields from the appropriate soil tests.
You can do without application of P and K if the soil test rating is NR (No Response) or RR (Rare Response). This is when the soil P is excessive or highly excessive. If the rating is MR (Moderate Response), it would be sufficient to drill or side band MAP (11-52-0) @ 50 kg/ha at seeding to meet the phosphorus (P) requirements of crops. MR is obtained in soils medium in P. In case of MR rating for potassium (K), you can apply a nominal rate of 20 kg K2O/ha (=0-0-60 @ 33.33 kg/ha). You can reduce contribution of P and K from the applied manure from their recommended rates of application. However, please keep in mind that while most of the K from manure is available in the first year, only 40% of P from manure is available in the first year (http://www.omafra.gov.on.ca/english/crops/facts/13-043.htm; the link also gives nutrients contents in the different type of manures). You shouldn’t cut down on the recommended rates of P and K fertilizers if the soil test rating is HR (High Response). In such a case P and K would be deficient to highly deficient in the soil. Likewise, no compromise can be made on the rates of deficient secondary and micronutrients, failing which you will not get proper response to the applied major (N, P and K) nutrients.
Good Luck for Season 2022 and Always!