Subject: Pesticide Carry Over Information

Herbicide carryover on new cropland acres bid into CRP is a major concern in new seedings. The attached Table I lists by crop, products that could require an additional cropping or fallow period for one or more years before seeding CRP grasses or legumes. These pesticides are used on corn, soybeans, grain sorghum, and small grain in Kansas.

In lieu of complying with the minimal rotation interval for the specific herbicide, a bioassay may be performed on the field(s) in question to determine whether carryover should be a concern. If a field bioassay is planned, contact the local chemical representative for information detailing bioassay procedures.

NRCS or the technical service provider will obtain at least two years of crop and pesticide application history on all new CRP acres offered under practices CP1, CP2, CP4B, CP4D, and CP25. Temporary seedings or residue management should be scheduled into the conservation plan of operations (CPO's) where products listed on Table 1 have been used and the months of carryover have not expired.

Table 1 is set up to indicate the number of months the pesticide will carry over and the cover crop(s) by label, that can be planted during this time period. Residue management through a fallow period can be used instead of an additional cover, only if the residue can be maintained until permanent cover can be established.

This list is not all inclusive. Please refer to the current Kansas State University Extension Publication "Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland," or contact the Kansas State University Department of Agronomy Extension Weed Specialist.

/s/ Michael D. Marshall for

HAROLD L. KLAEGE
State Conservationist

DIST: A, F, S, NPR, FSA(3), Benfer, T. Conway, G. Davis, Rice, Schroeder (KDWP)

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