Farmers are constantly reminded of the importance of timeliness. Fall typically demands many hours to harvest, haul and store grain. Using those hours to avoid unpredictable weather extremes or lapses in common sense can be challenging and frustrating.

Several harvest-time incidents recently cost area farmers bushels and time tabulating losses. Learning about their misfortunes might help others avoid similar experiences.

A hail storm that followed a rather narrow path in our area on Sept. 16 was devastating to several soybean fields awaiting the combine. A couple of farmers estimated somewhere between 25-30 bushels of soybeans were on the ground due to hail.

We all know how fast the crop dried down this year, bringing multiple fields/crops to harvest ready moisture at almost the same time. As one of the reporting soybean producers mentioned, “I wish we had combined that field the day before,” lamenting the fact that the yield went from 55 down to 25 bushels per acre, compliments of “frozen” rain balls.

While working at the Farm Science Review, I received a call from a different farmer, needing information on losses incurred as a result of a neighbor’s mismanaged trash fire. As dry as our section of Ohio has been, the thought of burning trash on a windy day defies logic.

Nevertheless, approximately 20 acres of standing corn went up in smoke. While the loss of the grain can be calculated fairly easily, determining a value for the burned residue is somewhat more difficult.

Of the major nitrogen (N), phosphorus (P) and potassium (K) mineral nutrients, only N is volatilized and lost when plant material burns. Phosphorus and K remain and return to the ground with ash. However, P and K could be blown from the field site during or after the fire if ash leaves the field.

Assigning a value to lost organic matter is difficult because there are no standard values for crop residue or soil organic matter. Compared with organic matter levels in soils, the amount that would normally remain after residue decomposition from one crop is very small (long-term, approximately 10 percent of the carbon in crop residue remains as soil organic matter). Additionally, loss of surface residue may be a short-term issue in some fields for erosion control.

What about the effect on N need when corn follows soybeans? A large reason corn rotated after soybeans needs less N fertilization compared with corn after corn has to do with differences between the crops in the amount of residue, relative N concentration and timing of residue decomposition. This is more important (especially on a short-term basis) than simply the return or loss of soybean residue in a field.

Research conducted at the University of Wisconsin showed that when soybean residue was removed after harvest from an area, the N need of the following corn crop was essentially the same as in areas where the residue was left (and similar where the soybean residue was doubled).

Therefore, a suggestion is to not apply extra N for corn that will be planted next year in a burned soybean field.

There is no one answer to the question, “What is lost when my field burns?” Evaluation of each field is required to arrive at the best estimate. Also, as is often the case, entire fields do not burn but only irregular areas; thus, an estimate of the affected area, as well as the crop or residue components lost, is required.

Iowa State University has an excellent online resource with more information at www.ipm.iastate.edu/ipm/icm/2000/10-23-2000/dryfallfires.htm

The views and opinions expressed in this column are those of the author and not necessarily those of Farm World. Readers with questions or comments for Roger Bender may write to him in care of this publication.