Flooding- type, flat-fan nozzles are becoming more popular for broadcasting herbicides. 

 They have large round openings that are less likely to clog, and they can be spaced 

 farther apart on the boom. When applying herbicides, a nozzle spacing of no more 

 than 40 inches is recommended. The boom height can be adjusted or the nozzles can be 

 rotated to give double coverage for best distribution. Flooding-type nozzles produce 

 a satisfactory distribution pattern for herbicide application, but do not expect dis- 

 tribution to be as complete or as uniform as with the regular, flat-fan nozzles. 



The spray from flooding-type nozzles has less of a tendency to drift than that from 

 other types of nozzles. Flooding-type nozzles should be operated at a pressure of 15 

 to 25 p.s.i. Pressures as low as 5 p.s.i. can be used to achieve drift control. 



Some herbicides must be incorporated soon after application. If such herbicides are 

 applied in front of the incorporation tool, either the regular, flat-fan nozzles 

 (mounted on a boom or on the tractor) or the flooding-type nozzles are recommended. 

 Flooding nozzles are easier to mount directly on the incorporating tool. 



Always select nozzle tips for your particular application needs. Select the nozzle 

 type according to the uniformity required and the need for drift control. The nozzle 

 size should be based on the recommended application rate, ground speed, operating pres- 

 sure, and nozzle spacing involved. 



Finally, take time to calibrate the sprayer before going into the field to apply a pes- 

 ticide. For information on calibrating sprayers, write for Illinois Circular 1038, 

 available from the Of f ice of Agricultural Publications, 123 Mumford Hall, Urbana, Illi- 

 nois 61801. 



INCORPORATING HERBICIDES 



Herbicides can be satisfactorily incorporated by using several tools. University of 

 Illinois studies indicate that the tandem disk harrow is better than the field culti- 

 vator as an incorporating tool. These studies also show that two passes with a disk 

 will provide more uniform incorporation than a single pass. 



A light tandem disk with 18-inch blades operating about 5 inches deep was used in these 

 studies. After two passes, most of the surface -applied material was incorporated in 

 the upper three inches of soil. If a larger, heavier disk is used and operated at 

 greater depths, the herbicide may be diluted with too much soil for good weed control. 



Incorporation improves with higher ground speeds. Disking twice in the same direction 

 is just as good as cross-disking the second time. Relatively uniform incorporation 

 will occur to a depth of about 1-1/2 inches less than the operating depth. Herbicides 

 that need incorporation work best when they are incorporated twice with a disk harrow 

 or with a disk harrow followed by a field cultivator, according to the UI tests. 

 Herbicides that are not normally incorporated may benefit from it when rainfall is lim- 

 ited after application. 



If wet soil conditions continue to delay field operations, it may be necessary to in- 

 corporate herbicides where excessive plant residues have been left on the surface be- 

 cause the soil has been turned with a moldboard plow. Also, incorporation might be 

 attempted on soils that are extremely cloddy. You should anticipate less than satis- 

 factory herbicide performance in either situation. 



