Soil Testing A Valuable Practice

To grow good crops, most farmers need to fertilize. To be sustainable, farmers need to fertilize to replace nutrients removed by crops.

“Fertilizing increases crop yield, and the improved crop growth maintains and even builds soil structure and the quality of the soil. If things aren’t done properly, however, there can be negative impacts,” says Ross McKenzie, agronomy research scientist with Alberta Agriculture and Food, Lethbridge. “Over fertilizing with nitrogen, for instance, can potentially lead to nitrate leeching into the ground water, or erosion can cause phosphorus to enter surface water. Environmental considerations and the high cost of nitrogen and fertilizers have made it even more important for farmers to use good management practices.”

Soil testing, at least on key fields, is a really good way to keep an eye on soil nutrient levels and provide a base for making fertilizer recommendations and determining fertilizer requirements.

Producers can use soil testing as a check on a number of different things, such as:

-primary nutrient levels

-nitrogen, phosphorus, potassium and sulfur levels (low, marginal, high or very high)

-micronutrient levels

-soil pH

-soil salinity

-soil organic matter

Once collected, soil samples are sent to a lab for analysis. Sending soil samples in to an Alberta lab is recommended as local labs use Western Canada-based research data to make their fertilizing decisions. Labs are not in the business of making fertilizer recommendations; they analyze soil. Their analysis and available research information will, however, determine when a fertilizer is needed.

“You may not want to sample every field every year and farmers may not need to test for all nutrients each time,” says McKenzie, “Testing key, uniquely different fields every year is a good way to see where the nutrient levels are at. Phosphorus and potassium don’t change much from year to year, but nitrogen and sulfur can change more dramatically. The lab analysis will not only show the nitrogen and sulfur levels, but will provided information on other nutrients as well. Soil testing is a valuable tool that helps farmers make informed decisions so that the optimum amount of soil nutrients is provided and waste is minimized.”

Further information on soil sampling and testing is available on the Alberta Agriculture and Food website.