Fertilizer costs, depending on the nutrients being considered, have increased up from 35 per cent to over 250 per cent (or over two and a half times) over the past year. Some producers have already started to purchase and store the fertilizer they will need for next spring to get out ahead of these continually rising costs. 

"With the high cost of fertilizers, it is even more important for producers to know exactly what nutrients are needed so they don't over or under fertilize," says Dr. Ross McKenzie, agronomy research scientist with Alberta Agriculture and Rural Development, Lethbridge. "Making informed fertilizer decisions starts with doing soil sampling and testing on fields. Assessing all fields to determine nutrient levels - which are deficient, which are marginal and which are adequate - is a critical step."

Soil testing and analysis can identify soil nutrient levels in their fields, which then helps producers make informed decisions about which fertilizer are required and which are not needed. Application rates can then be specifically determined for each nutrient for each field.

"The first thing producers need to do is select which fields will be tested, and how many fields should be tested so that the samples are representative of the entire operation," says McKenzie. "Ideally, all fields should be tested; however, this is not always possible, especially for producers with very large operations."

Timing of soil sampling is also an important factor. For producers in southern Alberta the optimum time is usually after the middle of October, and for producers in central and northern Alberta, after early October is the time when soil temperatures give the most reliable results.

"To get the best estimates of nutrient levels for nitrogen, phosphorus, potassium and sulfur, it's important to take soil samples when soil temperatures have cooled to less than 7ø C during the day," says McKenzie. "When soil is cooler, the activity of microbes in the soil will have slowed down and producers will be able to get better nutrient estimates from the sampling and analysis."

Whether producers are getting their fertilizer dealer to do the soil sampling or they are doing the sampling themselves, to get the most accurate nutrient analysis, three core depths are essential. The cores taken should include a 0 to 6 inch depth sample, a 6 to 12 inch depth sample and a 12 to 24 inch depth sample. A full 24 inch core can be broken up and separated so that all three depth samples can be taken from each core sample.

"Soil samples of only 0 to 12 inches are better than nothing; however, samples down to 24 inches are recommended to give the best decision making information possible," says McKenzie. "While soil sampling is important for all producers it is especially important for producers who are direct seeding. It is recommended to take between 15 and 20 core samples in each field being sampled. If only a few cores are taken in a field, the results may not truly be representative. And remember that each of these core samples should include soil taken from three core depths, 0 to 6 inches, 6 to 12 inches and 12 to 24 inches."

If possible, put samples into a cooler with ice packs and ship them off to the lab overnight. If this is not an option, producers should lay the samples on newspaper to air dry, then package the samples and send to the lab. Moist samples placed into plastic bags or samples that stay moist in a warm location for a couple of days will result in inaccurate analysis as biological activity is very likely to occur as the microbes in the samples will start breaking down the organic matter and change the nutrient readings in the sample.

The first thing producers should consider when looking at the soil analysis is the levels of nitrogen, phosphorous, potassium and sulfur. Farmers need to determine which nutrients are deficient and which are adequate in the soil. Most labs will provide general recommendations, but those recommendations will be just that - general. Alberta Agriculture and Rural Development has posted several fact sheets to the department website that include information which can be used to make decisions on fertilizer needs. Suggested fact sheets include:

"As well as the information provided in these fact sheets, another tool producers can use is the online program called Alberta Farm Fertilizer Information Recommendation Manager (AFFIRM)," says McKenzie. This downloadable program allows producers to input the soil test results, select the crop that will next be grown, input he fertilizer prices and the value per bushel of the intended crop. When this information is considered, producers can develop some very good fertilizer recommendations on their own that are based on soil analysis, fertilizer price and crop value to provide a good economic determination of fertilizer requirements. I strongly encourage farmers to consider using this program when making fertilizer decisions for next year."