NDSU Extension - Williams County


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Soil Fertility after a Drought - November 2, 2017

County Agent Update

Danielle Steinhoff


Soil Fertility after a Drought

Every week the Carrington Research Extension Center puts out a little article, rotating between their specialists, called Center Points. Recently an article was written by Jasper Teboh, Research Soil Scientists, wrote an article called Soil Fertility Concerns Following Haying of Crop Fields. As we know, this past year was once of the driest years on record, many who ranch have had to find additional feeds. Many of those additional feeds were baled crops, removing much of the residue that would have been left on the soil. Removing the residue or stubble from fields could have a difference in snow capture and water conservation, or erosion control, but many had to salvage what they could for this year.

Here are some notes that were pointed out in that article;

  • Crop residues, left in the field, are major sources of soil organic carbon and soil nutrients which enhance microbial activity, improve soil structure and water retention.
  • The most visible effect from removal is soil erosion, which is worsened by annual residue removal.
  • To determine the amount of nutrients removed from the field when a crop is baled, follow procedures to take a sample of the bale for analysis, weigh the bale, and determine dry weight (moisture content) of the bale.

So a question I have had come into my office is; If farmers baled their fields this year, should they be concerned about nutrient deficiencies for the next cropping season?

The answer is no, only if farmers test their soils to know what the current nutrient levels are, even if the soil test levels were high in spring of 2017. Without soil test results, farmers should be concerned especially about macro nutrients like potassium (K) and phosphorus (P) that are sometimes not included in the farmer’s regular fertilization plans. Without soil sampling and testing adequate fertilizer recommendations cannot be made.

K and P fertilizer application may be necessary following residue removal

  • Application of K fertilizer will surely be required for soils that had medium to low levels of K (120 ppm or 240 lbs or less in the top 6 inches) at the start of the 2017 cropping season because of high K content in residues.
  • Wheat contains a relatively higher proportion of K in the residue than in the grain (about 400% more). For example: a 35-bushel wheat yield removes about 11 lbs of K2O/ac with the grain and will leave about 55 lbs K2O in the residue. When residue is baled, soil K levels can drop significantly.  
  • Loss of top-soil through wind erosion can cause a reduction of both P and K in the soil.

Soil testing is a great tool that can be implemented in any farming operation, the test are relatively inexpensive. Your operation could have hundreds or thousands of dollars on fertilizer bills every year, or you can figure out what exact nutrients your soil needs to produce high quality and high yielding crops.



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