In-Row Rotary Tilling for Orchard 

 Weed Control 



James Schupp and John McCue 

 Highmoor Farm, University of Maine 



Weeds compete with fruit trees for water and 

 nutrients making weed control necessary to produce 

 optimum yields of quality fruit. Uncertainty about 

 the future of herbicide registrations suggests that 

 alternative methods of weed control should be inves- 

 tigated. The use of in-row rotary tilling may be a 

 substitute for the use of herbicides in orchards, so a 

 study was designed to test the usefulness of this 

 technique, by itself, and in 

 combination with other 

 methods, for weed control 

 in New England orchards. 



growth and fruit size similar to the herbicide treat- 

 ment. The rotary till alone and in combination with 

 herbicide resulted in similar yield to the herbicide 

 treatment; however, the rotary till plus living mulch 

 treatment yielded less than the herbicide treatment. 

 Fruit from the herbicide treatment had higher 

 starch index values (riper), lower soluble solids, and 

 less red blush, while fruit from the untreated trees 



Methods 



Three-tree plots of 

 mature 'McIntoshVM.7 

 trees were assigned one of 

 the following weed control 

 treatments: 1) untreated 

 control; 2) herbicide spray 

 (Gramoxone™ plus 



Surflan™) applied at tight 

 cluster; 3) rotary tilling 

 (Weed Badger™) applied 

 at tight cluster, mid-June, 

 and late July; 4) rotary 

 tilling plus Surflan; and 5) 

 rotary tilling plus a living 

 mulch (oats), sown in Au- 

 gust. 



Results 



The untreated control 

 resulted in less tree 

 growth than all other 

 treatments and lower yield 

 than the herbicide treat- 

 ment (Table 1). The un- 

 treated controls also had 

 significantly fewer large 

 fruit than the herbicide 

 treatment. The rotary till 

 combinations resulted in 



Table 1. Growth and yield of Mclntosh/M.7 apple trees with five 

 different weed control methods in 1989. 



Treatment 



Untreated 

 Herbicide 

 Rotary till 

 Till + herbicide 

 Till + live mulch 



*Means within columns not followed by the same letter are signifi- 

 cantly different at odds of 19:1. 



Fruit Notes, Winter, 1991 



29 



