E 

 sod ar 

 the ap 

 duced 

 di sapp 

 1 n g of 

 greate 

 kill in 

 m" t r g 

 e s p e c i 

 2.40'X 

 2.42 t 

 shoots 

 the n i 

 b i 1 i ty 



ffect 

 e i nd 

 plica 

 a spr 

 eared 



gras 

 r tha 

 g not 

 en , b 

 ally 

 N. I 

 2.5 



and 

 troge 



i s u 



s of d 

 i cated 

 t i n 

 e a d in 



in 19 

 ses an 

 n vi su 



only 

 ut dea 

 as ref 

 n 1970 

 7% N, 

 in sho 

 n meta 

 nder s 



i c h 1 b e 

 by 1 ea 

 f diffe 

 1 eaf n 

 69. We 

 d dove 

 al appe 

 reduced 

 th of p 

 1 ected 

 , all t 

 and pro 

 ot 1 eng 

 b 1 ism 

 tudy , 



nil 

 f ni 

 rent 

 i tro 



be! 

 rs i 

 aran 



gra 

 1 ant 

 at t 

 rees 

 duce 

 th. 

 of t 



stuntt 

 trogen 



rates 

 gen th 

 ieve t 

 n the 

 c e i n d 

 ss-clo 

 s i n c r 

 he 1 ow 



i ncre 

 d a 1 a 



Wheth 

 hese t 



ng or 

 val u 

 of f 

 at CO 

 he am 

 early 

 i cate 

 ver c 

 eased 

 es t n 

 ased 

 rge i 

 er or 

 rees 



killi 

 es in 

 erti 1 i 

 nti nue 

 ount 



summe 

 d. Th 

 ompeti 



the a 

 i troge 

 1 eaf n 

 ncreas 



no t d 

 is not 



ng th 

 Table 

 zer n 

 din 

 f stu 

 r of 

 is 19 

 tion 

 V a i 1 a 

 n tre 

 i trog 

 e i n 

 i chl 

 know 



e grass- 



1 . By 

 i trogen 

 1968, bu 

 n t i n g an 

 1969 was 

 69 stunt 

 for aval 

 bl e ni tr 

 atment, 

 en from 

 both num 

 b e n i 1 in 

 n . This 



clover 

 1967, 

 had pro- 

 t had 

 d kill- 



much 

 i n g and 

 lable 

 ogen , 

 2.23 to 

 about 

 bers of 

 f 1 uenced 



p s s i - 



TABLE 1 



LEAF NITROGEN 



1964 



1965 



1967 



1968 



1969 



1970 



Low Ni trogen 1 .88 

 Medium Nitrogen 2.05 

 High Nitrogen 2.04 



Prior to application of treatments. 

 Conclusions : 



1. Continued annual applications of dichlobenil or similar 

 herbicides may injure the tree. 



2. Use of herbicides that stunt the grass-clover sod will 

 reduce grass-sod mineral nutrient competition with the apple tree 

 roots . 



3. Use of herbicides that kill the grass-clover sod will 

 result in a release of mineral nutrients in the year sod is killed. 



4. Unless the sod is re-established, loss of mineral nutrients 

 by leaching will require careful re-evaluation of the mineral fer- 

 tilizer program and will probably require an increase in fertilizer 

 appl ication . 



*************** 



