Dividing fields for winter spreading activities

Dividing fields for winter spreading activities

When is a field not a field?  Answer: When it’s a subfield. 


In conversations with farmers and agencies, it has become clear to me that complying with the spirit of the new Illinois Title 35 regulations requires a big dose of common sense.  None of us wants to expose surface water to pollutants, yet there are things in Parts 501 and 502 of the Illinois Pollution Control Board regulations that defy mother wit.


One of the fine points in the regulation that has always bothered me a bit is the IPCB’s use of the word, “field.”  The Definitions section of Part 501 does not include a definition of a field.  There are plenty of other definitions, but none for a field.  The term “field” is used in the regulation in several places, but by far the most occurrences are in the sections applying to NPDES permits.  If we apply the word “field” in its broadest sense, i.e. the boundaries shown on an FSA map, then the regulations in Title 35 that affect prohibitions or restrictions on spreading manure affect management of that land resource all the way out to those boundaries.  On the other hand, should one choose to draw boundaries within a field to artificially divide the area into logical management zones, the regulation does not prohibit such divisions. 


I believe there are many cases where, to preserve perfectly acceptable land area for manure application, dividing a field into subfields makes sense.  Some fields need to be managed by parts.  That takes some effort, because a producer needs to know where, when, and how manure nutrients were applied, and be able to show to an agency a good faith effort to follow the details of the law.  Furthermore, if manure is applied according to a seasonal restriction (like spreading on frozen or snow-covered ground), one wants to be able to come back to the right place with the manure spreader or fertilizer applicator when finishing the job later in the year.


Those producers who are unpermitted Large CAFOs and who want to maintain eligibility to claim the Ag Stormwater Exemption are required to follow some sections of Part 502 of the regulation (502.510(b) and 502.630).  Applying manure on frozen or snow-covered ground is particularly cumbersome insofar as the burden of documentation.   Look at the section at 502.630, “Availability of Individual Fields for Winter Application.”  There are six paragraphs with language that restricts where you can apply manure.  However, there are confusing discrepancies in the language.  For example, in paragraph 3, the wording is “Application on land with slopes greater than 5% is prohibited.”  It doesn’t say “on fields” but “on land.”  In paragraphs 4, 5, and 6 the language is “on sites”, “the slope of the field”, and “For fields with slopes of less than 2 percent”.  So where the regulation speaks of a field, it really refers to a portion of an FSA field that has been either naturally bounded, say by surface water or a property line, or artificially bounded by the manager for the purpose of regulatory compliance.


I believe that our industry can easily make the case for dividing fields into subfields for manure management, as long as we have a defensible system for drawing the boundaries.  One might consider slope, soil type, crop residue, distance from surface water and/or conduits to surface water, depth to underlying fractured bedrock or other sensitive material, or tile drainage.  The key is to have good documentation and a rationale for subdividing fields.  For documentation, one may want to use GPS based as-applied field maps, boundaries aligned with permanent features such as terraces, or perhaps flags that will be left in place until spring planting. 


This winter’s early heavy rains are doubtlessly wreaking havoc with some producers’ manure management activities.  Weather happens, and the manure keeps on piling up.  Let’s make sure that winter spreading is done on land that is suitable and safe for such applications, and use a system that carefully and accurately documents the boundaries—by field or sub-field.