The pre-tillage code caused very high soil loss and P Index values for some crop and tillage combinations in previous versions of SnapPlus (before 20.4).

 

This code problem may be present for a rotation if checking pre-tillage causes soil loss to jump significantly, or annual P index values to be unreasonably high for some crop years. The problem was most likely to occur on fields with spring manure applications and "Spring cultivation" or "Fall chisel, no disk" selected for tillage. It was not present in corn and soybean crops, but was in the alfalfa seeding and other legume forage seeding crops along with some less common crops and double crops. We believe we have found and adjusted all the crop and tillage combinations that were incompatible with the code that added pre-tillage to the rotation, but if you see unexpectedly high soil loss or P Index values with pre-tillage, please contact SnapPlus Support so we can make sure it is not caused by something we missed.

 

In addition, please be aware that the pre-tillage compliance checks built into SnapPlus 20 do not work for some double crop or cover crop scenarios. For example, even though pre-tillage would be possible in these situations, checking pre-tillage with a fall application before a disked cover crop or a summer application after wheat harvest before a tilled forage crop will generate the following message:

 

This field is likely to have Silurian dolomite within 20 ft of the surface and liquid manure applications should be injected or incorporated with pre-tillage. The tillage or season selected for this application is not consistent with the pre-tillage requirement. Please modify the application or the tillage selection.

 

In these situations, the SnapPlus team recommends writing an explanation for the planned legitimate pre-tillage operation in the box for explaining non-compliant applications.

 

A different type of error occurs with double crops that can have one crop no-till and the other crop tilled, such as Winter Rye (forage) to Corn Silage, 30 inch row with crop 1:No-till, crop 2: Cult selected as tillage. In this scenario, the software will allow you to incorporate a manure application with pre-tillage into the no-till crop without giving a warning message that manure incorporation with pre-tillage is incompatible with no-till. These problems with double crops and pre-tillage are a result of adding the pre-tillage checks on to the existing SnapPlus2 crop management database structure. SnapPlus3 is being designed so that the crop and tillage sequences will be compatible with the guidelines for pre-tillage whenever it is required on soils with less than 20 ft of soil over Silurian bedrock.Enter topic text here.