PDFWAC 16-302-535
Isolation requirements for white clover and trefoil seed certification.
Isolation requirements for the production of white clover and trefoil seed crop are as follows:
(1) White clover or trefoil fields for certification must be isolated from all other fields of the same variety not meeting varietal purity requirements for certification as follows:
Class Being Produced | Fields less than five acres | Fields five acres or more |
Foundation | 900 feet | 600 feet |
Registered | 450 feet | 300 feet |
Certified | 165 feet* | 165 feet |
* | 330 feet required for trefoil. |
(2) Isolation between different classes (generations) of the same variety of white clover or trefoil is as follows:
Class Being Produced | Distance Required from Fields Planted with: | Fields less than five acres | Fields five acres or more |
Foundation | Foundation or Registered | 225 feet | 150 feet |
Registered | Registered or Certified | 115 feet | 75 feet |
Certified | Certified | 75 feet | 45 feet |
(3) In cases where an adjoining field is planted with a different variety, or of a lower class, isolation may be obtained by measuring off the required strip in the certified seed field. This isolation strip may be mowed for hay or it may be harvested for uncertified seed under the following conditions:
(a) The grower must apply for certification of the entire white clover or trefoil field and clearly stake off the isolation strip. The entire field must pass all certification requirements, except for isolation, at time of inspection. The field report will show rejection due to lack of isolation.
(b) The grower must harvest and deliver to a department approved conditioning plant the seed from the certified portion of the field separately from the seed from the isolation strip. After the seed is weighed and lotted in the weight of the seed from the isolation strip is to be reported to the seed program. At this time the seed program records will indicate the field has passed certification.