A Rapid Method for the Routine Factory Analysis of Lactic Acid

R . F . O L S O N1

Received for publication June 14, 1963

Lactic acid d e t e r m i n a t i o n s i n sugar b e e t processing l i q u o r s have b e e n u t i l i z e d to m e a s u r e t h e e x t e n t of sucrose d e g r a d a t i o n (2, 4, 5)2. T h e m a j o r i t y of investigators use t h e c o l o r i m e t r i c m e t h o d , d e s c r i b e d b y B a r k e r a n d S u m m e r s o n (1). T h i s m e t h o d is a c c u r a t e a n d relatively s i m p l e , h o w e v e r it is l i m i t e d in its ability t o h a n d l e large n u m b e r s o f samples. Stark, G o o d b a n a n d Owens (3) p o i n t e d o u t t h a t p a p e r c h r o m a t o g r a p h y is a r a p i d , relatively a c c u r a t e m e t h o d b y w h i c h o r g a n i c acids c a n b e i d e n t i - fied. The p u r p o s e of this p a p e r is to p r e s e n t a n e w p a p e r c h r o m - atographic m e t h o d for d e t e r m i n i n g lactic acid. This m e t h o d is being used a t several factories w i t h confidence t h a t a n a c c u r a t e p i c t u r e of lactic acid c o n d i t i o n s is b e i n g r e c o r d e d .

Materials a n d Methods

A c h r o m a t o g r a m is o b t a i n e d in t h e following m a n n e r : a . W h a t m a n # 4 p a p e r — 1 81 / 4" X 2 21 / 2"

b . d e s c e n d i n g i r r i g a t i o n

c . r o o m t e m p e r a t u r e d e v e l o p m e n t

d. c a l c i u m lactate p e n t a h y d r a t e as s t a n d a r d e. solvent

A p a r a l l e l l i n e is d r a w n 14 cm from o n e e n d of p a p e r , each spot b e i n g s e p a r a t e d by 3 cm on this l i n e . The s t a n d a r d s a r e located i n t h e six m i d d l e positions a n d t h e u n k n o w n s a r e spotted on e i t h e r side. The v o l u m e of s a m p l e s p o t t e d is c o n t i n g e n t u p o n the lactic acid c o n c e n t r a t i o n . F o r h i g h c o n c e n t r a t i o n s of lactic acid, 15 l a m b d a a r e s p o t t e d a n d for low c o n c e n t r a t i o n s of lactic acid i n c r e m e n t s of 15 l a m b d a a r e spotted.

Extensive w o r k was d o n e in selecting a s u i t a b l e solvent. The solvent finally selected h a s t h e following m a k e - u p :

1. Stock S o l u t i o n

70 p a r t s isopropyl alcohol 25 p a r t s b e n z e n e

10 p a r t s n - b u t y l a l c o h o l 2. To 800 ml of stock s o l u t i o n a d d

200 m l distilled w a t e r 50 ml glacial acetic a c i d

.3 g b r o m c r e s o l g r e e n .1 g b r o m p h e n o l b l u e

1 Research Chemist, American Crystal Sugar Company, Rocky Ford, Colorado.

2 Numbers in parentheses refer to literature cited.

6 0 J O U R N A L OF T H E A. S. S. B. T.

T h i s y e l l o w - o r a n g e , n o n - c o r r o s i v e solvent has a p l e a s a n t o d o r a n d i s easily p r e p a r e d . I t does n o t leave i n t e r f e r i n g r e s i d u e s u p o n e v a p o r a t i o n . L a c t i c a c i d i s r e a d i l y s e p a r a t e d f r o m o t h e r c o n - s t i t u e n t s i n b e e t s u g a r p r o c e s s i n g l i q u o r s .

A f t e r s p o t t i n g , t h e p a p e r s a r e p l a c e d i n t h e s o l v e n t t r o u g h s a n d a l l o w e d t o r e m a i n for 1 t o 11 / 2 h o u r s ; t h e y a r e t h e n r e m o v e d f r o m t h e c a b i n e t s a n d a l l o w e d t o dry. T h e s o l v e n t r e m o v a l i s facilitated w h e n t h e c h r o m a t o g r a m i s e x p o s e d t o w a t e r v a p o r . T h i s can b e a c c o m p l i s h e d b y h a n g i n g t h e c h r o m a t o g r a m b e t w e e n sheets of w e t canvas in t h e d r y i n g o v e n or by c o n s t r u c t i n g a c a n - vas l i n e d frame i n w h i c h t h e c h r o m a t o g r a m i s p l a c e d . T h e c h r o m a t o g r a m d e v e l o p s q u i t e r e a d i l y if t h e canvas f r a m e is p l a c e d in a sink c o n t a i n i n g a small a m o u n t of h o t w a t e r . It is n o t e d t h a t s p r a y i n g o r d i p p i n g o f t h e c h r o m a t o g r a m has b e e n e l i m i n a t e d b y t h e a d d i t i o n o f t h e acid-base dyes t o t h e solvent.

The c h r o m a t o g r a m will h a v e a b l u i s h - g r e e n b a c k g r o u n d w i t h lactic acid as a yellow spot. T h e sensitivity of t h e m e t h o d is 1 g a m m a of lactic acid p e r 15 l a m b d a of v o l u m e .

Results a n d Discussion

A c o m p a r a t i v e analysis was m a d e b e t w e e n t h e c o l o r i m e t r i c a n d c h r o m a t o g r a p h i c m e t h o d s for t h e d e t e r m i n a t i o n o f lactic acid. T h e s a m p l e s w e r e o b t a i n e d from T h e G r e a t W e s t e r n S u g a r C o m p a n y ' s L o v e l a n d factory. T h e results w e r e :

Lactic Acid, p p m

Sample G . W . C o l o r i m e t r i c A.C.S. C h r o m a t o g r a p h i c Cossette Prses J u i c e 27 33 Diffusion J u i c e 64 58 Cell 3 72 66 Cell 5 85 83 Cell 7 75 100 Cell 9 89 108 Cell 11 93 95 Cell 13 77 116 Cell 15 79 71 Cell 17 88 71 P u l p Press W a t e r 63 47

T h e t i m e r e q u i r e d for t h e d e v e l o p m e n t o f c h r o m a t o g r a m s e n a b l e s t h e w o r k e r t o m a k e e v a l u a t i o n s t h r o u g h o u t t h e e n t i r e d a y a n d t h e d a t a w i l l reflect a large n u m b e r o f samples. T h e s i m p l i c i t y o f t h e p a p e r c h r o m a t o g r a p h i c m e t h o d h a s l e d t o t h e i n t r o d u c t i o n o f t h e a p p a r a t u s i n t o r o u t i n e factory analysis. T e c h - n i c i a n s a r e easily t r a i n e d t o s p o t a n d e v a l u a t e t h e c h r o m a t o g r a m s .

C e r t a i n p r e c a u t i o n s h a v e t o b e t a k e n i n o r d e r t o p r o v i d e a d e q u a t e c h r o m a t o g r a m s . T h e r o o m i n w h i c h t h e c h r o m a t o - g r a m s a r e s p o t t e d a n d d e v e l o p e d s h o u l d b e free o f e x t r a n e o u s

V O L . 13, N o . 1, A P R I L 1964 6 1

odors, d u s t a n d traffic. A m m o n i a fumes a n d l i m e d u s t a r e ex- tremely d e l e t e r i o u s to t h e d e v e l o p m e n t of a c h r o m a t o g r a m . An e x p e n d i t u r e of $100 or less will p r o v i d e t h e c o m p l e t e a p p a r a t u s necessary for t h e c h r o m a t o g r a p h y of lactic acid.

Summary

A c h r o m a t o g r a p h i c m e t h o d has b e e n d e s c r i b e d for t h e de- t e r m i n a t i o n of lactic acid in sugar b e e t processing l i q u o r s . T h e m e t h o d i s r a p i d a n d a d a p t a b l e t o r o u t i n e factory analysis.

L i t e r a t u r e Cited

(1) BARKER, S. B. a n d W. H. SUMMERSON. 1941. T h e colorimetric determ- ination of lactic acid in biological material. J. Biol. Chem. 138: 535- 554.

(2) N O R M A N , LLOYD W . a n d G U Y O . RORABAUGH. 1954. Studies of lactic acid in the Silver Diffuser. Proc. Am. Soc. Sugar Beet T e c h n o l . V I I I : 242-247.

(3) STARK, J . B., A. E. GOODBAN, a n d H . S. O W E N S . 1951. P a p e r c h r o m a t o - graphy of organic acids. Anl. Chem. 2 3 ( 3 ) : 413-415.

(4) STARK, J . B., A. E. GOODBAN a n d H . S. O W E N S . 1952. C o m p o s i t i o n of certain beet diffusion juices from the 1950 campaign. Proc. Am. Soc.

Sugar Beet T e c h n o l . V I I : 688-691.

(5) VERHART, M . L. A. a n d N . H . M . DE VISSER. 1959. Zeitschrift fur die Zucherindustries, p 446.

Beet Leafhopper a n d Curly-Top Disease Survey in W a s h a k i e County1

D A L E F U L L E R T O N2

Received for publication May J, 1963

S u g a r beets i n W a s h a k i e C o u n t y o f N o r t h e r n W y o m i n g h a v e b e e n seriously d a m a g e d b y c u r l y t o p o f s u g a r beets e a c h y e a r since 1960. Y i e l d losses h a v e b e e n h i g h t o g r o w e r s i n a n a r e a t h a t h a s b e e n a n d still i s e c o n o m i c a l l y d e p e n d e n t o n s u g a r beets.

Losses of 2 tons p e r a c r e in 1960, 4 to 5 tons in 1961, a n d 2 to 3 tons i n 1962 h a v e b e e n e s t i m a t e d b y c o u n t y a g r i c u l t u r a l officials.

W a s h a k i e C o u n t y i s w i t h i n t h e t e r r i t o r y o f H o l l y S u g a r C o r p - o r a t i o n , o n e o f t h e i r factories b e i n g l o c a t e d a t W o r l a n d , W y o - m i n g . R e s i s t a n t sugar b e e t seed h a s b e e n u s e d i n t h i s c o u n t y for m a n y years a n d u n t i l 1960 a p p e a r e d t o b e a d e q u a t e i n w i t h - s t a n d i n g c u r l y t o p disease.

T h e c u l t i v a t e d area o f t h e c o u n t y i s s i t u a t e d i n a n i r r i g a t e d valley f o r m e d b y t h e B i g H o r n R i v e r , t r a v e r s i n g t h e c o u n t y s o u t h t o n o r t h . C u l t i v a t e d l a n d s o n b o t h t h e west a n d east sides o f t h e r i v e r m e r g e w i t h a r i d r a n g e l a n d o n t h e west, east, a n d s o u t h sides o f t h e c o u n t y . T h e a r i d r a n g e l a n d i s c h a r a c t e r i z e d b y sparse v e g e t a t i o n .

C u r l y t o p i s a v i r u s disease t h a t d a m a g e s s u g a r b e e t s . T h e only k n o w n m e t h o d of t r a n s m i s s i o n is by t h e b e e t l e a f h o p p e r , Circulifer tenellus (Baker) ( l )3. In o t h e r s u g a r - b e e t - g r o w i n g r e g i o n s t h e b e e t l e a f h o p p e r o v e r w i n t e r s i n d e s e r t areas a n d m i - grates i n t o c u l t i v a t e d valleys i n t h e s p r i n g (2). H o w e v e r , its h a b i t s a n d b e h a v i o r a r e i n c o m p l e t e l y k n o w n , a n d t h i s lack o f i n f o r m a t i o n h a s c o n t r i b u t e d t o i n a d e q u a t e c o n t r o l a n d p r e v e n t i v e m e a s u r e s . I n f o r m a t i o n a s t o w h e r e a n d h o w t h e b e e t l e a f h o p p e r o v e r w i n t e r s a n d o n t h e t i m e o f m i g r a t i o n i s necessary t o i n i t i a t e c o n t r o l s . L i m i t s o f t h e insect's h o s t r a n g e w o u l d also b e o f v a l u e . T h i s survey was c o n d u c t e d t o d e t e r m i n e t h e e x t e n t o f c u r l y t o p i n f e c t i o n a n d t o a n s w e r s o m e o f t h e q u e s t i o n s p e r t a i n i n g t o t h e h a b i t s o f t h e b e e t l e a f h o p p e r . I t was h o p e d t h a t t h e s u r v e y w o u l d p r o v i d e a c l u e or s t a r t i n g p o i n t in t h e search for a b e t t e r u n d e r s t a n d i n g o f t h e b e e t leaf h o p p e r - c u r l y t o p r e l a t i o n s h i p i n W a s h a k i e C o u n t y .

1 Published with approval of the Director, Wyoming Agricultural Experiment Station as Journal Paper No. 207.

2 Instructor of Entomology, University of Wyoming, Laramie, Wyoming.

3 Numbers in parentheses refer to literature cited.

VOL. 13, N o . 1, APRIL 1964 63

Methods

Sugar b e e t fields in W a s h a k i e C o u n t y w e r e surveyed for t h e beet leafhopper on five occasions—April 17, May 8, J u n e 16, J u n e 2 1 , a n d J u l y 11, 1962. T h i r t y - e i g h t fields w e r e designated as check fields a n d each of these fields was e x a m i n e d d u r i n g every survey ( F i g u r e 1). Fifteen a d d i t i o n a l fields w e r e e x a m i n e d on each of t h e five surveys, u s i n g different fields each t i m e . T h e 38 p e r m a n e n t fields w e r e p i c k e d largely at r a n d o m ; however, a few were p i c k e d on t h e basis of c u r l y t o p infection in 1960 a n d 1961.

T w o m e t h o d s w e r e used to survey each field: (a) a s t a n d a r d insect n e t a n d (b) a square-foot sampler. T h e s a m p l e r is a m o d i - fication of t h e H i l l s S q u a r e F o o t S a m p l e r (3). It is a cage con-

SUGAR B E E T FIELDS SUGAR B E E T FIELDS USED

Figure 1.—Location of sugar beet fields used as checks in the survey tor beet leafhoppers.

6 4 J O U R N A L OF T H E A. S. S. B. T.

sisting of a c i r c u l a r f r a m e w r a p p e d w i t h c h e e s e c l o t h a n d is o p e n a t b o t h e n d s . W h e n a d e s i r e d p l a n t i s f o u n d , t h e o p e r a t o r places t h e s a m p l e r o v e r t h e p l a n t . T h e o p e r a t o r t h e n d i s t u r b s t h e p l a n t , c a u s i n g t h e leaf h o p p e r s t o j u m p t o t h e cheesecloth. T h e insects c a n b e c o u n t e d o r p i c k e d off t h e sides w i t h a n a s p i r a t o r , w h i c h c a n b e a n y f o r m o f s u c t i o n o r v a c u u m p u m p . T h e insects a r e t h e n r e m o v e d f r o m t h e a s p i r a t o r , c o u n t e d , a n d p r e s e r v e d .

Fifty square-foot s a m p l e s w e r e t a k e n a t r a n d o m l o c a t i o n s i n each f i e l d w i t h t h e s a m p l e r , a n d 200 sweeps w e r e t a k e n i n e a c h f i e l d w i t h t h e insect n e t . W e e d hosts o f t h e b e e t l e a f h o p p e r t h a t w e r e n e a r t o b e e t f i e l d s , o r b o r d e r e d t h e m , w e r e also e x a m i n e d , u s i n g b o t h m e t h o d s of survey.

X h e c u r l y t o p survey was c o n d u c t e d i n W a s h a k i e C o u n t y d u r i n g t h e week of A u g u s t 6 to 10, 1962, a n d was d e s i g n e d to i n c l u d e t h e e n t i r e sugar b e e t acreage i n t h e c o u n t y . A t o t a l o f 187 fields was e x a m i n e d , a few fields m a y h a v e b e e n missed because o f t h e i r h i d d e n o r u n s e e n l o c a t i o n .

A total of 1,000 p l a n t s was visually i n s p e c t e d by e x a m i n i n g 100 p l a n t s at each of 10 l o c a t i o n s selected at r a n d o m in e a c h field. The infected p l a n t s f r o m each of t h e l o c a t i o n s w e r e t h e n c o u n t e d t o give t h e t o t a l n u m b e r o f i n f e c t e d p l a n t s , t h u s d e t e r - m i n i n g t h e p e r c e n t a g e o f infected p l a n t s . E a c h f i e l d was g i v e n a d e g r e e of i n f e c t i o n r a t i n g based on a scale of five r a t i n g s as follows:

P e r c e n t infection D e g r e e of infection

0 n o n e 1-10 l i g h t 11-20 m o d e r a t e 21-50 severe 51-100 very severe

P l a n t s s h o w i n g q u e s t i o n a b l e c u r l y t o p s y m p t o m s w e r e n o t c o u n t e d . S y m p t o m s w e r e d e t e r m i n e d e n t i r e l y b y visual o b s e r v a - t i o n s i n t h e f i e l d . A m a p was c o n s t r u c t e d t o s h o w t h e l o c a t i o n o f t h e s u g a r b e e t f i e l d a n d t h e d e g r e e o f i n f e c t i o n i n e a c h f i e l d . N o a t t e m p t was m a d e t o show t h e l o c a t i o n o f h o s t p l a n t s o t h e r t h a n s u g a r beets. I t i s p r o b a b l e t h a t s o m e i n f e c t i o n o c c u r r e d after t h e s u r v e y was c o m p l e t e d , h o w e v e r , i t i s u n l i k e l y t h a t t h e s e new infections w o u l d a p p r e c i a b l y c h a n g e t h e g e n e r a l c o n c l u s i o n s .

R e s u l t s a n d Discussion

The first b e e t leaf h o p p e r s w e r e c o l l e c t e d d u r i n g a s u r v e y on J u l y 11. X h e f i r s t s y m p t o m s o f c u r l y t o p , f o u n d d u r i n g t h e survey c o n d u c t e d o n J u n e 2 1 , o c c u r r e d 2 1 days b e f o r e discovery o f t h e f i r s t b e e t l e a f h o p p e r s . N e i t h e r t h e b e e t l e a f h o p p e r s n o r s y m p t o m s o f t h e disease w e r e n o t e d i n surveys m a d e A p r i l 17, M a y 8 , o r J u n e 16. O n J u l y 11, w h e n t h e b e e t l e a f h o p p e r w a s f i r s t dis-

VOL. 13, N o . 1, APRIL 1964 6 5

covered, an average of t h r e e i n d i v i d u a l s p e r 200 sweeps w e r e taken. M o r e b e e t leafhoppers w e r e f o u n d at t h e e n d of t h e fields nearest to t h e desert area t h a n at t h e o p p o s i t e e n d . S y m p t o m s of curly t o p o c c u r r e d first in t h e e n d of t h e fields b o r d e r i n g t h e desert area i n d i c a t i n g t h a t m i g r a t i o n from t h e desert area t o cultivated areas h a d j u s t b e g u n .

T h e first s y m p t o m s of t h e disease a n d t h e first b e e t leafhoppers were n o t e d in fields b o r d e r i n g t h e desert area on t h e east side of t h e c u l t i v a t e d area. C u r l y t o p infection was n o t f o u n d on the west side of t h e Big H o r n R i v e r u n t i l 14 days after t h e first symptoms a p p e a r e d on t h e east side.

Figure 2.—Distribution of sugar beet fields and degree of curly top infection in Washakie County.

6 6 J O U R N A L OF T H E A. S. S. B. T.

A l l o f t h e s u g a r b e e t f i e l d s h a d some infected p l a n t s ; i n n o case was a field r a t e d a b s o l u t e l y free. T h e p e r c e n t a g e of p l a n t s infected in each field r a n g e d from 1.2 to 73.5 p e r c e n t . E i g h t fields or 4.3 p e r c e n t w e r e very severely infected, 17 fields or 9.1 p e r c e n t w e r e severely infected, 31 fields or 16.6 p e r c e n t w e r e m o d e r a t e l y infected, a n d 131 fields or 70 p e r c e n t w e r e con- sidered to h a v e a l i g h t infection.

T h e m a p ( F i g u r e 2 ) shows the d i s t r i b u t i o n o f s u g a r b e e t f i e l d s a n d t h e d e g r e e o f infection for each f i e l d . T h e m o s t heavily infected f i e l d s w e r e f o u n d o n t h e e x t r e m e b o u n d a r i e s , w h e r e t h e c u l t i v a t e d areas m e e t t h e a r i d r a n g e l a n d . M o s t o f t h e f i e l d s i n t h e c e n t e r o f t h e area h a d o n l y l i g h t infections. F i e l d s c o n - s i d e r e d t o b e very severely infected w e r e f o u n d i n t h e s o u t h - e a s t e r n c o r n e r o f t h e b e e t - g r o w i n g area. T h e r e a p p e a r e d t o b e a g r a d u a l decrease in t h e d e g r e e of i n f e c t i o n from t h e o u t e r b o r d e r s t o w a r d t h e c e n t e r o f t h e c u l t i v a t e d area.

Fields o n t h e east side o f t h e r i v e r h a d m o r e i n f e c t i o n t h a n those on t h e west side. F i v e fields on t h e west side of t h e r i v e r w e r e c o n s i d e r e d to be m o d e r a t e l y infected, o n e was severely infected, n o n e was very severely infected, a n d t h e rest h a d only light infections.

Conclusions

T h e fact t h a t beet leafhoppers w e r e n o t f o u n d u n t i l 2 1 days after d e t e c t i o n o f curly t o p i n f e c t i o n i n d i c a t e s t h a t t h e m e t h o d of survey a n d d e t e c t i o n m a y n o t h a v e b e e n as effective as d e s i r e d . It is a p p a r e n t t h a t small p o p u l a t i o n s of b e e t l e a f h o p p e r s d i d exist in t h e fields before d e t e c t i o n of t h e disease s y m p t o m s . M o r e i n t e n s i v e s a m p l i n g m a y h a v e p i c k e d u p t h e insects m u c h s o o n e r t h a n was r e p o r t e d . A s h o r t e r t i m e lapse in days b e t w e e n surveys m i g h t also have d e t e c t e d t h e b e e t l e a f h o p p e r b e f o r e t h e July 11 d a t e .

D e t e c t i o n o f s y m p t o m s a n d b e e t l e a f h o p p e r s o n t h e east side o f t h e r i v e r before d e t e c t i o n o n t h e west side i n d i c a t e s t h a t t h e b e e t l e a f h o p p e r p o p u l a t i o n o r a t least t h e m a j o r i t y o f t h e p o p - u l a t i o n exists in t h e desert a r e a on t h e east side of t h e r i v e r .

L a r g e n u m b e r s o f b e e t l e a f h o p p e r s w e r e f o u n d o n t h e e n d o f t h e f i e l d s b o r d e r i n g t h e desert area, w h i c h i n d i c a t e s t h a t b e e t l e a f h o p p e r s m i g r a t e d f r o m t h e d e s e r t a r e a i n t o t h e c u l t i v a t e d a r e a . T h e m i g r a t i o n w o u l d also a c c o u n t for t h e most severe i n f e c t i o n i n f i e l d s o n t h e o u t e r edges o f t h e c u l t i v a t e d a r e a .

A d e c r e a s i n g d e g r e e of i n f e c t i o n o c c u r r e d from t h e o u t e r - m o s t fields i n w a r d , a n d f i e l d s i n t h e m i d d l e o f t h e valley h a d o n l y l i g h t infection. A p p a r e n t l y t h e b e e t l e a f h o p p e r s a r e e i t h e r o v e r w i n t e r i n g i n t h e d e s e r t area o r a r e m i g r a t i n g from o t h e r o v e r w i n t e r i n g g r o u n d s i n t o t h e desert area. M i g r a t i o n t o t h e c u l t i v a t e d a r e a occurs a s s u i t a b l e host p l a n t s b e c o m e a v a i l a b l e .

VOL. 13, N o . 1, A P R I L 1964 67

A larger p o p u l a t i o n of leafhoppers o c c u r r e d on t h e eastern side or t h e r i v e r t h a n on t h e western side. T h e most severely infected f i e l d s w e r e f o u n d southeast o f W o r l a n d a n d may i n d i - cate t h a t a m o r e dense p o p u l a t i o n of weed hosts are on t h e desert near these fields t h a n occurs a l o n g t h e b o r d e r s of t h e r e m a i n i n g fields. Visual observations before t h e survey showed t h a t t h e earliest signs of c u r l y t o p w e r e also f o u n d in this area.

Summary

A survey was c o n d u c t e d in W a s h a k i e C o u n t y on A p r i l 17, May 8, J u n e 16, J u n e 2 1 , a n d J u l y 11, 1962, to detect t h e earliest possible p r e s e n c e of t h e b e e t leafhopper. T h e first b e e t leaf- h o p p e r s w e r e f o u n d on July 11, or 21 days after t h e first s y m p t o m s of curly t o p a p p e a r e d .

T h e first i n d i c a t i o n of c u r l y t o p a n d t h e presence of beet leafhoppers o c c u r r e d on t h e east side of t h e Big H o r n R i v e r in fields b o r d e r i n g t h e desert area. A p p a r e n t l y t h e b u l k of t h e p o p u l a t i o n exists on t h e desert on t h e east side of t h e river.

A survey of sugar b e e t fields in W a s h a k i e C o u n t y to d e t e r m i n e the degree of curly t o p infection was c o n d u c t e d on A u g u s t 6-10, 1962. A total of 187 sugar b e e t fields w e r e surveyed, a n d 1,000 plants in each field w e r e e x a m i n e d visually.

T h e most severely infected f i e l d s w e r e f o u n d along t h e o u t e r edges of t h e c u l t i v a t e d areas adjacent to t h e a r i d r a n g e l a n d . T h e eastern edge was m o r e severely infected t h a n was t h e western edge. An area southeast of W o r l a n d h a d t h e most severely infected fields.

Seventy p e r c e n t of t h e fields h a d light infections, 16.6 p e r c e n t were m o d e r a t e l y infected, 9.1 p e r c e n t w e r e severely infected, a n d 4.3 p e r c e n t w e r e very severely infected.

L i t e r a t u r e Cited

(1) DOUGLASS, J. R. a n d W. C. COOK. 1954. T h e Beet Leafhopper. USDA Circ. 942: 1-21.

(2) Fox, D. E. 1938. Occurrence of the Beet Leafhopper and Associated Insects on Secondary P l a n t Successions in Southern Idaho. USDA T e c h . Bui. 607: 1-14.

(3) H I L L S , O. A. 1933. A new m e t h o d for collecting samples of insect p o p - ulations. J. Econ. E n t . 26: 906-910.

Redistribution of N i t r a t e in Soils and Its Effects on Sugar Beet N u t r i t i o n1

M Y R O N S T O U T2

Received for publication October 31, 1963

I n t r o d u c t i o n

N i t r o g e n n u t r i t i o n has b e e n s h o w n t o b e a n i m p o r t a n t factor in s u g a r b e e t yield a n d q u a l i t y (2,3,5,6,7,8)³. If n i t r o g t n is t o o low, u n p r o f i t a b l e yields r e s u l t , b u t if it is t o o h i g h at h a r v e s t , beets a r e low i n sucrose a n d p u r i t y . T h u s t i m i n g o f n i t r o g e n u p t a k e , as well as t h e t o t a l a m o u n t , is essential in successful s u g a r b e e t p r o d u c t i o n .

N i t r a t e n u t r i t i o n i s o n e o f t h e m o r e difficult p r o d u c t i o n v a r i a b l e s to c o n t r o l because it is i n f l u e n c e d by so m a n y e n v i r o n - m e n t a l c o n d i t i o n s . T h e i n c o r p o r a t i o n i n t o soil o f p r e v i o u s c r o p residues, t i m e of a p p l i c a t i o n of o r g a n i c or i n o r g a n i c forms of n i t r o g e n , t e m p e r a t u r e , a n d t h e m e t h o d a n d a m o u n t o f w a t e r a p p l i c a t i o n affect t h e a v a i l a b i l i t y o f n i t r a t e t o g r o w i n g c r o p p l a n t s .

Table 1.—Precipitation and Evaporation, Salt Lake Valley, 1959-1960 and Cache Valley, 1961.

Month April M a y June July August September October Total

Precipitation (inches) 19591

1.61 2.05 1.38 0.19 1.76 1.66 0.22 8.87

I9602

0.40 1.09 0.30 0.10 0.66 0.70 1.23 4.48

19613

0.69 0.66 0.59 0.53 0.72 1.89 1.64 6.72

Evaporation 19594

7.34 8.71 12.95 14.12 12.94 8.09 4.94 69.09

I9604

7.42 10.31 13.65 16.16 13.11 9.76 5.37 75.81

(inches) 19613

3.96 5.65 6.59 7.53 6.65 3.87 no data 34.25

1 Salt Lake Airport W. B. (Salt Lake Valley)

2 Midvale Station (Salt Lake Valley)

3 Greenville Farm, U.S.U. (Cache Valley)

4 Morton Salt Company (Salt Lake Valley)

T h e w i d e d i s c r e p a n c y b e t w e e n a m o u n t s o f r a i n f a l l a n d e v a p - o r a t i o n ( T a b l e 1) causes t h e r e d i s t r i b u t i o n of s o l u b l e salts in soils. T h i s results i n t h e b u i l d - u p o f h i g h surface c o n c e n t r a t i o n s a n d i s t h e p r i m a r y cause o f salinity p r o b l e m s i n a r i d c l i m a t e s . E x t e n s i v e r e s e a r c h has r e s u l t e d i n s o m e i n g e n i o u s p r a c t i c a l

1 T h e field studies involving deep vs. shallow furrowing were done in cooperation with members of the Research Staff of the Utah-Idaho Sugar Co.

2 Physiologist, Crops Research Division, Agricultural Research Service, United States Department of Agriculture.

3Numbers in parentheses refer to literature cited.

VOL. 13, N o . 1, A P R I L 1964 6 9

measures for m a n i p u l a t i n g t h e localization of h i g h salt c o n c e n t r a - tions (1). S o l u b l e p l a n t n u t r i e n t s , especially n i t r a t e , follow t h e same g e n e r a l p a t t e r n s of m o v e m e n t a n d c o n c e n t r a t i o n in soils.

T h e m o v e m e n t a n d localized p a t t e r n s o f r e d i s t r i b u t i o n o f n i t r a t e strongly affect n u t r i t i o n of t h e sugar b e e t c r o p .

T h e p u r p o s e o f this r e p o r t i s t o p r o v i d e a d d i t i o n a l i n f o r m a - tion on t h e e x t e n t of n i t r a t e m o v e m e n t in soils a n d to suggest some c u l t u r a l practices t h a t may alleviate some u n d e s i r a b l e effects from excess n i t r a t e s u p p l y at t h e w r o n g t i m e .

Chemical and Soil-Sampling Methods

Chemical. T h e c o l o r i m e t r i c p h e n o l d i s u l p h o n i c acid m e t h o d described by M. L. J a c k s o n (1958 e d i t i o n ) was used for soil n i t r a t e analyses. E i g h t g r a m s of screened (20 Mesh), well-mixed soil were l e a c h e d for 20 m i n u t e s by end-over-end r o t a t i o n in 50-ml test t u b e s w i t h 40 ml of d i l u t e C u S O4 s o l u t i o n a n d a small a m o u n t o f C a ( O H )2. T h e soil suspension was t h e n f i l t e r e d t h r o u g h close-textured filter p a p e r a n d an a l i q u o t of filtrate used for n i t r a t e e s t i m a t i o n .

Soil sampling and preparation. E x t r e m e g r a d i e n t s in con- c e n t r a t i o n of n i t r a t e u s u a l l y e n c o u n t e r e d in cultivated, a r i d soils make s a m p l i n g a n d sample h a n d l i n g u n u s u a l l y subject t o errors (4,5). T o r e d u c e errors, i t was f o u n d c o n v e n i e n t t o lightly press irregular soil surfaces a n d t h e n to use a flat-bottom scoop w i t h sides 1/4 inch h i g h to take t h e 0 to 1/2-inch surface samples. T h e soil t u b e was t h e n i n s e r t e d to t h e 6-inch d e p t h a n d any dry surface soil scraped away w i t h t h e scoop. T h e soil t u b e was t h e n rotated a n d pressed against t h e t o p sides of t h e h o l e to i n s u r e a r a t h e r conical-shaped, firm t o p before w i t h d r a w i n g t h e t u b e . If dry soil fell i n t o t h e h o l e , a n o t h e r 1/2-inch of core was re- moved a n d discarded before t a k i n g t h e n e x t sample.

T h e soil was m i x e d in p a n s (a separate p a n for each d e p t h i n c r e m e n t ) a n d a s a m p l e of a b o u t 60 to 100 g r a m s was sealed in small, w i d e - m o u t h bottles w i t h 2 to 3 ml of t o l u e n e . Soil samples w e r e d r i e d in m e t a l dishes at 65° C o v e r n i g h t , t h e n passed b e t w e e n steel surfaced rolls a n d lightly r u b b e d t h r o u g h a 20-mesh screen by m e a n s of a large r u b b e r stopper. T h e screened soil was t h e n r o l l e d t h o r o u g h l y a n d stored in p a p e r bags for analysis. T h e r a t h e r e x t r e m e p r e c a u t i o n s i n s a m p l i n g and sample p r e p a r a t i o n w e r e t a k e n because m o r e t h a n t h o u s a n d - fold differences i n n i t r a t e c o n c e n t r a t i o n s m a y b e e n c o u n t e r e d between surface 1/2-inch a n d lower layers of soil. F o r this reason, similar d e p t h - i n c r e m e n t s of different soil samples w e r e usually g r o u p e d a n d processed. T h e e q u i p m e n t was t h o r o u g h l y cleaned before p r e p a r a t i o n of a n o t h e r d e p t h - i n c r e m e n t g r o u p of samples.

D e p t h of samples was u n i f o r m in all tests. T h e r e f o r e , to simplify p r e s e n t a t i o n a d e p t h code is u s e d in p r e s e n t i n g d a t a . D e p t h in-

70 J O U R N A L OF T H E A. S. S. B. T.

c r e m e n t s w e r e a s follows: A , 0 " t o 1 / 2 " ; B , 1 / 2 " t o 6"; C , 6 " t o 1 2 " ; D , 12" t o 2 4 " a n d E , 2 4 " t o 3 6 " .

E x p e r i m e n t a l R esult s Holden Plot Studies, 1959-1960

B o t h v e r t i c a l a n d l a t e r a l m o v e m e n t o f n i t r a t e w e r e s t u d i e d o n 40-inch d o u b l e - r o w b e d s u n d e r f r e q u e n t i r r i g a t i o n s d u r i n g l a t e s u m m e r i n 1959 a n d 1960. S t u d i e s w e r e m a d e o n a fine sandy l o a m p r e p a r e d a n d p l a n t e d t o sugar b e e t seed d u r i n g A u g u s t . I r r i g a t i o n furrows w e r e 4 0 i n c h e s a p a r t a n d a b o u t 2 t o 3 i n c h e s d e e p . T h e p l o t was u s u a l l y i r r i g a t e d a t i n t e r v a l s o f a b o u t f i v e days w i t h a small s t r e a m o f w a t e r . T h e r e was n o f l o o d i n g o f b e d s w h e r e n i t r a t e s t u d i e s w e r e m a d e . A f t e r p r e - l i m i n a r y o b s e r v a t i o n s s h o w e d a m a r k e d lateral m o v e m e n t of ni- t r a t e in t h e surface, s a m p l e s w e r e t a k e n to a d e p t h of 36 i n c h e s across t h e beds at f r e q u e n t spacings as s h o w n in tables 2 a n d 3.

P r e l i m i n a r y samples i n d i c a t e d m o r e t h a n a fourfold i n c r e a s e i n n i t r a t e c o n c e n t r a t i o n i n t h e c e n t e r o f t h e b e d w h e r e m o i s t surface zones b a r e l y coalesced in c o n t r a s t to a s i m i l a r l o c a t i o n w h e r e m o i s t u r e d i d n o t traverse so far. D a t a ( T a b l e 2) also

Table 2.—Vertical and lateral movement of nitrate in relation to irrigation, rainfall and evaporation. Fine sandy loam; 40-inch double beds. Holden plot, 1959.

Date

S e p t . 1 0 13 14 15

19 2 0 21 2 3 2 5 2 6 2 7 2 8 3 0

Rainfall*

inches

0 , 0 3 0 . 6 0 0 . 1 9

0 . 1 9 0 . 0 5 0 . 1 8 0 . 0 3 0 . 2 7 0 . 0 1 0 . 2 9 0.05

Depth code

A B C D E

p p m 3

3 10 9 7 4

2 2 2 2 11 5 4

2 3 3 2 2

Distance from Furrow ( 1 4 Nitrate N p p m

5 2 5

2 1 2 2 4

188 19 1 2 4 5 5 3 4 4

p p m 1570

8 8 8 2 5 11 7

4 6 0 6 6 15 10 6

5 5 0 186 2 5 7 7

inches) 2 0 ~

p p m 1800

6 5 7 2 9 12 8

1 9 0 0 1 1 8 1 8 10 4

1 7 0 6 9 16 7 5 1 Rainfall 7200 South 3rd East — 1.4 miles from plots

Irrigations September 1, 5, 9, and 14

VOL. 13, N o . 1, A P R I L 1964 71

indicate a p r o n o u n c e d lateral m o v e m e n t of n i t r a t e t o w a r d t h e centers of b e d s b e l o w t h e surface. R a i n f a l l a n d e v a p o r a t i o n p r o - duced s t r o n g effects on vertical m o v e m e n t of n i t r a t e . Surface c o n c e n t r a t i o n s of n i t r a t e in furrows w e r e p r o b a b l y m o r e de- p e n d e n t on l e n g t h of t i m e of s a m p l i n g after i r r i g a t i o n t h a n on other variables.

Date

Distance from Furrow (inches)

Rainfall1 Depth 0 10 20 10 0

inches code Nitrate N

A u g . 12

A u g . 19

A u g . 22 A u g . 23

A u g . 28 A u g . 30

Sept. 1 3 6 12

0 . 6 6

. A B C D E A B C D E

A B C D E F e r t i l i z e d i n b o t t o m o f f u r r o w s w i t h

0 . 1 3 0 . 3 9 0.01 0 . 0 4

A B C D E

p p m 1 1 4 11 16 3 1 3 11 15

1 2 2 11 4 a m m o n i u m

5 3 2 27 19 13

2 1 12 3 2 2 0 16

p p m 3 7 0 9 6 10 11 3 4 0 7 5 13 13

4 3 3 8 14 18 19 n i t r a t e ;

3 6 8 7 10 17 14

3 5 0 9 19 24 12

p p m 2 3 0 12 10 13 11 7 0 0 8 18 18

108 9 0 15 26 2 0

; t h e n i r r 4 6 4

37 11 2 0 16

1210 2 8 2 2 18 17

p p m 2 1 0 6 4 18 17 5 1 0 2 3 18 21

5 0 12 4 16 16 i g a t e d

5 0 4 4 5 18 15

4 7 0 2 4 14 17

p p m 1 1 3 15 13 3 1 2 11 10

1 1 1 7 19

3 11 5 6 10

6 4 10 12 14 1 Rainfall, Midvale, Utah

D a t a ( T a b l e 3) i n d i c a t e essentially t h e same p a t t e r n s of m o v e m e n t in 1960 as those in t a b l e 2 e x c e p t t h a t surface n i t r a t e c o n c e n t r a t i o n s w e r e h i g h e r in 1959. F i e l d l a b o r e r s a p p l i e d am- m o n i u m n i t r a t e t o t h e p l o t o n A u g u s t 28. I t i s e v i d e n t t h a t the u n a u t h o r i z e d a d d i t i o n of n i t r a t e to o n e furrow was twice

Table 3.—Vertical and lateral movement of nitrate in relation to irrigation, rainfall and evaporation. Fine sandy loan; 40-inch double beds. Holden plot, 1960.

72 JOURNAL OF THE A. S. S. B. T.

a s m u c h a s i n t h e o t h e r . T h e r a i n f a l l o f 0.66 i n c h , A u g u s t 2 2 o c c u r r e d d u r i n g a very s h o r t p e r i o d . T h i s h e a v y s h o w e r d i d n o t leach n i t r a t e from t h e surface n e a r l y s o c o m p l e t e l y a s t h e less r a p i d r a i n f a l l of S e p t e m b e r 13-15, 1959 ( T a b l e 2) or t h a t of O c t o b e r 8-12, 1960 ( T a b l e 6). S t u d i e s r e p o r t e d in T a b l e 3 w e r e t e r m i n a t e d by t h e a c c i d e n t a l c u l t i v a t i o n of surface soil after samples w e r e t a k e n S e p t e m b e r 12.

Effect of deep vs. shallow furrows on nitrate redistribution;, yield and quality

D e e p vs. shallow-cultivated strips w e r e c o m p a r e d o n t w o f i e l d s i n 1959. U n t i l a b o u t J u l y 1 , t h e f i e l d s w e r e u n i f o r m l y fertilized, c u l t i v a t e d a n d i r r i g a t e d . D e e p - f u r r o w e d s t r i p s w e r e m a d e a b o u t J u l y 1 at t h e t i m e of final c u l t i v a t i o n . B o t h fields w e r e i r r i g a t e d in t h e same a l t e r n a t e f u r r o w s all s u m m e r . T h e soil was h a r d a n d relatively d r y after A u g u s t 11. N o f l o o d i n g o c c u r r e d n e a r a n y s a m p l e d areas b u t t h e r e was l i t t l e difference i n d e p t h o f i r r i g a t i o n furrows a t harvest d u e t o w a s h i n g a n d s i l t i n g o f soil.

Soil a n d b e e t s a m p l i n g sites w e r e c h o s e n a b o u t 1/4 t h e d i s t a n c e from t h e t o p a n d 1/4 t h e d i s t a n c e from t h e b o t t o m of each field.

Because o f u s u a l differences i n yield a n d q u a l i t y b e t w e e n t o p a n d b o t t o m of i r r i g a t e d fields, c o m p a r i s o n s a r e possible o n l y be- t w e e n adjacent positions.

Soil b e l o w t h e surface was c o n s i s t e n t l y m o r e m o i s t a n d s a m p l i n g was easier i n d e e p l y - f u r r o w e d strips w h e r e w a t e r p e n e - t r a t i o n was b e t t e r . T h e s e differences a r e b e l i e v e d t o b e significant at least w i t h respect to differences in yield at harvest.

P r e s e n c e of an average of n e a r l y 400 p p m of n i t r a t e n i t r o g e n in relatively d r y surface soil after a series of r a i n s t h a t o c c u r r e d d u r i n g t h e s a m p l i n g p e r i o d seems very significant ( T a b l e 4).

F o l i a r p r o t e c t i o n o f this excess n i t r a t e i n t h e surface d u r i n g p r e c i p i t a t i o n s t o t a l i n g 3.25 i n c h e s m a y b e a n i m p o r t a n t factor in r e d u c i n g hazards of late rainfall in some r e l a t i v e l y d r y c l i m a t e s p r o v i d e d t h a t soils a r e n o t f l o o d e d b y p r e c i p i t a t i o n .

Soil samples w e r e t a k e n i n r i d g e d soil b e t w e e n f u r r o w s a n d b e t w e e n a p p r o x i m a t e l y n o r m a l l y spaced beets. D a t a ( T a b l e 5 ) i n d i c a t e t h a t t h e r e was a fairly c o n s i s t e n t difference in b o t h yield a n d q u a l i t y o f b e e t s b e t w e e n d e e p a n d s h a l l o w - f u r r o w e d s t r i p s of each field. T h e r e w e r e also c o n s i s t e n t differences in yield, s u g a r p e r c e n t a g e , a n d p u r i t y in favor of d e e p l y - f u r r o w e d strips. Differences i n a m i n o n i t r o g e n , s o d i u m , a n d p o t a s s i u m w e r e n o t sufficiently c o n s i s t e n t t o justify a n y definite c o n c l u s i o n s . T w o tests o n t h e effect o f d e e p vs. n o r m a l c u l t i v a t i o n w e r e r u n i n C a c h e Valley i n 1961. Surface c o n c e n t r a t i o n s o f n i t r a t e w e r e n o t s o g r e a t a s t h e y w e r e i n Salt L a k e Valley i n 1959 b e c a u s e

VOL. 13, N o . 1, A P R I L 1964 73 the e v a p o r a t i o n r a t e s a n d t e m p e r a t u r e s w e r e lower. Surface- n i t r a t e c o n c e n t r a t i o n was g r e a t e r in deeply-furrowed strips. A v e r - age yield of s u g a r p e r acre, t o n s of b e e t s p e r acre, sugar p e r c e n t - age, a n d p u r i t y values w e r e h i g h e r i n d e e p l y c u l t i v a t e d strips.

Table 4.—Nitrate nitrogen content of soil on two farms, deep vs. shallow furrows.

All samples taken between beets in the beds between furrows, 1959.

LESLIE JONES FARM

MELVIN JONES FARM

V O L . 13, N o . 1, A P R I L 1964 7 5 Table 6.—Nitrate nitrogen distribution in furrow-irrigated fields of sugar beets, Toppenish, Washington, 1960.

MACK HOUSTON FARM

Nitrate N at dates indicated Loca- Posi- Depth

t i o n tion code 5/14 6/30 7/19 8/5 9/8 10/17

Beet r o w

Furrow

Beet row

Furrow A B C D E A B C D E A B C D E A B C D E

p p m 340 81 82 17 6 370 119 90 19 8 260 88 68 16 7 620 107 65 17 14

p p m 840 36 133 51 39 260 11 15 11 7 290 34 76 46 16 160 10 10 5 4

p p m 3400

130 32 28 10 320 6 17 5 4 1650 112 56 33 53 33 5 3 4 2

p p m 2700

312 71 30 12 99 7 2 2 2 1900 24 107 6 7 81 8 3 2 25

p p m 4200

103 71 4 2 78 4 1 1 1 1110 17 11 1 1 94 14 1 1 1

p p m 1720

137 38 4 4 170 13 3 3 2 710 52 102 34 15 32 13 2 2 1

BILL PARRISH FARM

4/29 6/22 7/19 8/5 9/8

Beet r o w

Furrow

Beet R o w

Furrow A B C D E A B C D E A B C D E A B C D E

p p m 94 56 31 18 12 99 42 35 15 6 55 52 28 15 5 188 48 26 14 12

p p m 210 25 24 32 16 128 13 9 8 6 84 69 36 32 32 91 20 12 14 11

p p m 1250

25 19 10 4 240 5 3 20 4 1900 200 121 59 59 57 7 4 4 6

p p m 1400 93 21 37 18 90 7 3 3 7 1700 43 88 23 28 118 10 4 4 7

p p m 3650

55 6 9 6 36 4 2 3 5 1920 126 13 23 9 290 13 S 6 2

76 J O U R N A L OF T H E A. S. S. B. T.

Table 7.—Nitrate nitrogen distribution in sprinkler—irrigated sugar beet fields, Walla Walla, Washington, 1960.

FRANK RIZZUTE FARM

Nitrate N at dates indicated Loca- Posi- Depth

tion tion code 5/31 7/1 7/29 8/11 10/16

I B e e t r o w

F u r r o w A B C D E A B C D E

p p m 150 5 4 14 4

130 9 4 21 4 2

p p m 6 7 2 2 2 5 14 2 4 1 6 9 4 7 3 1

p p m 7 2

3 1 1

11 2 1 1 1

p p m 3 5

2 2 1 1 10 1 11 1 1

p p m 1 1 1 1 1 3 1 1 1

W. F. SCHIFFMAN FARM

5/31 7/1 7/27 8/11 10/16

1 N . S . — no sample

V O L . 13, N o . 1, A P R I L 1964 77

Soil Nitrate Studies on Sprinkler vs. Furrow-irrigated Sugar beet Fields

Soil samples w e r e t a k e n d u r i n g s u m m e r a n d early fall of 1960 o n t w o f u r r o w - i r r i g a t e d a n d t w o s p r i n k l e r - i r r i g a t e d sugar b e e t f i e l d s . T h e M a c k H o u s t o n a n d Bill P a r r i s h farms i n T o p p e n i s h , W a s h i n g t o n , w e r e f u r r o w - i r r i g a t e d , w h i l e those of W. F. Schiff- m a n a n d F r a n k R i z z u t i i n W a l l a W a l l a , W a s h i n g t o n , w e r e irrigated b y s p r i n k l i n g . S a m p l e s w e r e t a k e n i n b e e t rows a n d i n the furrows.

D a t a ( T a b l e s 6 a n d 7) i n d i c a t e large differences in surface n i t r a t e c o n c e n t r a t i o n r e s u l t i n g from t h e t w o m e t h o d s o f irrigation. C o n c e n t r a t i o n s of n i t r a t e in surface soils w e r e low w h e r e beets w e r e i r r i g a t e d b y s p r i n k l i n g a n d n e a r l y all n i t r a t e i n t h e soil was p e r i o d i c a l l y l e a c h e d to active r o o t zones of p l a n t s .

U n d e r f u r r o w i r r i g a t i o n , h i g h c o n c e n t r a t i o n s o f n i t r a t e w e r e found i n d r y surface soil w h e r e b e e t s c o u l d n o t use it. C o n c e n t r a - tions o f m o r e t h a n 4,000 p p m o f n i t r a t e n i t r o g e n w e r e observed o n t h e M a c k H o u s t o n F a r m . A l t h o u g h surface c o n c e n t r a t i o n s were m u c h g r e a t e r w h e r e s a m p l e s w e r e t a k e n t h a n i n furrows some idea of t h e a m o u n t s i n v o l v e d m a y be realized by t h e fact that only a l i t t l e m o r e t h a n 600 p p m of n i t r o g e n in a 1/2-inch layer of soil is e q u i v a l e n t to 100 p o u n d s of n i t r o g e n p e r acre.

If we e s t i m a t e s a m p l e d a r e a s to r e p r e s e n t 1/3 of the surface, m o r e t h a n 200 p o u n d s o f n i t r o g e n p e r a c r e m i g h t b e c o n c e n t r a t e d i n this area w h e r e it is n o t a v a i l a b l e to b e e t s unless a r a i n occurs to leach it i n t o t h e r o o t z o n e .

An e x t r e m e case of e v a p o r a t i v e r e d i s t r i b u t i o n of n i t r a t e in part of a 10-acre c o m m e r c i a l field of beets was observed in 1960.

T h e f i e l d h a d b e e n p l a n t e d t o g r a i n i n 1959 a n d a fairly heavy cover o f straw a n d s t u b b l e was p l o w e d u n d e r . N i t r o g e n was applied as a n h y d r o u s a m m o n i a at t h e r a t e of 135 p o u n d s of N per acre. P h o s p h a t e was also a p p l i e d in t h e fall w i t h t h e an- h y d r o u s a m m o n i a . A n early p l a n t i n g o f s u g a r b e e t s was frozen a n d t h e field was r e p l a n t e d A p r i l 22. A l t h o u g h t h e r e was a g o o d stand of s u g a r beets, they g r e w very slowly a n d w e r e obviously very deficient i n n i t r o g e n a s s h o w n b y tests w i t h d i p h e n y l a m i n e . T h e field was f u r r o w - i r r i g a t e d i n t h e same a l t e r n a t e furrows all season. A l t h o u g h furrows w e r e r a t h e r shallow, t h e r e was little or no flooding. A h e a v y surface a p p l i c a t i o n of a m m o n i u m n i t r a t e was m a d e t o t h r e e strips, crosswise t o t h e furrows, a b o u t J u l y 2 . T h e s e cross-strips w e r e a b o u t 10-feet w i d e a n d 200-feet long.

Response o f b e e t s t o a m m o n i u m n i t r a t e was very striking a n d sharply d e l i n e a t e d ( F i g u r e 1). Foliage of sugar beets in t h e fertilized cross-strips w a s m o r e t h a n k n e e h i g h a n d very d a r k g r e e n ,

7 8 J O U R N A L OF T H E A. S. S. B. T.

F i g u r e 1.—Sugar beets on t h e J o s e p h J. Schmidt f a r m , West J o r d a n , U t a h , O c t o b e r 17, 1960. Beets in f o r e g r o u n d h a v e b e e n harvested. The cross strip received a heavy a p p l i c a t i o n of a m m o n i u m n i t r a t e in J u l y . At harvest t h e r e was m o r e n i t r a t e in the surface of the a r e a w h e r e the beets were deficient b u t it was in the dry soil a n d u n a v a i l a b l e to t h e p l a n t s . w h i l e foliage o f a d j a c e n t beets d i d n o t cover m o r e t h a n half t h e 22-inch rows a n d w e r e only a b o u t a n k l e - h i g h . S y m p t o m s i n d i c a t e d a n e x t r e m e n i t r o g e n deficiency.

On O c t o b e r 8, soil samples w e r e t a k e n to a d e p t h of t w o feet i n i r r i g a t e d f u r r o w s a n d b e t w e e n f u r r o w s i n fertilized cross-strips a n d i n t h e n i t r o g e n - d e f i c i e n t sugar b e e t area. T h e soil was m o d e r a t e l y d r y w h e n s a m p l e d b u t a light, p e r s i s t e n t r a i n f a l l , a m o u n t i n g t o 1.23 inches, o c c u r r e d d u r i n g t h e p e r i o d o f O c t o b e r 8 t o 12. T h e s a m e a r e a s w e r e r e s a m p l e d o n O c t o b e r 12. I n a d d i - t i o n t o soil-profile samples, f o u r surface samples w e r e t a k e n be- t w e e n f u r r o w s w h e r e n i t r o g e n - d e f i c i e n t b e e t s w e r e l o c a t e d a n d f i v e surface s a m p l e s w e r e t a k e n i n fertilized cross strips w h e r e heavy foliage h a d p r o t e c t e d surface soil from r a i n f a l l . T h e s e

Table 8.—Nitrate nitrogen in soil profile before and after a prolonged light rainfall of 1.23 inches, J. J. Schmidt Farm, West Jordan, Utah, 1960.

V O L . 13, N o . 1, A P R I L 1964 79

latter s a m p l e s w e r e n o t t a k e n m i d w a y b e t w e e n rows, b u t closer t o beet r o w s w h e r e foliar c o v e r was b e t t e r .

D a t a ( T a b l e 8 ) s h o w t h a t b e f o r t t h e rainfall t h e r e was m o r e n i t r a t e i n surface soil w h e r e t h e deficient b e e t s w e r e located t h a n i n heavily fertilized cross strips. T h e 1260 p p m o f n i t r a t e n i t r o g e n observed in surface soil, w h e r e t h e deficient beets w e r e located, i s e q u i v a l e n t t o a b o u t 200 p o u n d s o f n i t r o g e n p e r a c r e — i n t h e top l/2-inch of soil. R a i n f a l l l e a c h e d all b u t 4 p p m i n t o lower layers of u n p r o t e c t e d soil, b u t , w h e r e t h e r e was g o o d foliar cover, 5 separate s a m p l e s h a d an a v e r a g e of 372 p p m t h a t r e m a i n e d in surface soil after p r e c i p i t a t i o n . T h e s e observations, c o n c e r n i n g protection b y g o o d foliar c o v e r i n p r e v e n t i n g l e a c h i n g surface n i t r a t e t o l o w e r levels, w e r e s i m i l a r t o o b s e r v a t i o n s i n 1959 ( T a b l e 4).

Discussion

A p p l i c a t i o n o f t h e p r i n c i p l e s g o v e r n i n g salt m o v e m e n t a n d zones of c o n c e n t r a t i o n in soils to p l a n t n u t r i t i o n has received little a t t e n t i o n . M o s t c o n c e r n has b e e n d i r e c t e d t o w a r d solving adverse effects t h a t t h r e a t e n to cause a b a n d o n m e n t of soils. H o w - ever, some o f t h i s basic k n o w l e d g e c a n b e used i n u n d e r s t a n d i n g seasonal v a r i a t i o n s i n n u t r i e n t a v a i l a b i l i t y — a n d p r o b a b l y i n d e v e l o p i n g t e c h n i q u e s t o m o d i f y n u t r i e n t u p t a k e a n d t o m o r e nearly a p p r o a c h t h e o p t i m u m n e e d s o f s u g a r beets.

T h e e x t e n t o f r e d i s t r i b u t i o n p a t t e r n s o b s e r v e d i n a r i d soils u n d e r f u r r o w - i r r i g a t i o n or b e d - p l a n t e d beets offers a l u c i d ex- p l a n a t i o n o f t h e e r r a t i c s u g a r c o n c e n t r a t i o n a n d q u a l i t y o f sugar beets. F r e q u e n t h e a v y r a i n s before harvest can depress q u a l i t y of beets by c a u s i n g an u n f a v o r a b l e a b u n d a n c e of n i t r o g e n to become a v a i l a b l e a t t h e w r o n g t i m e . D r y p r e h a r v e s t c o n d i t i o n s may r e s u l t i n s u g a r c o n c e n t r a t i o n s t h r e e o r m o r e p e r c e n t h i g h e r t h a n w h e n w e t w e a t h e r o c c u r s b e f o r e harvest. T h e s e f l u c t u a t i o n s i n availability o f n i t r a t e m a k e i t difficult t o e s t i m a t e o p t i m u m a m o u n t s of n i t r o g e n fertilizers to a d d to soil even t h o u g h total a m o u n t s p r e s e n t m a y b e d e t e r m i n e d before p l a n t i n g . H o w e v e r , knowledge o f e v a p o r a t i v e r e d i s t r i b u t i o n p a t t e r n s , relative a m o u n t s , a n d e x t e n t o f foliar p r o t e c t i o n from r a i n s h o u l d b e useful i n d e v e l o p i n g c u l t u r a l m e t h o d s t o utilize these p h e n o m e n a t o i m p r o v e s u g a r b e e t c u l t u r e . S p r i n k l e r - i r r i g a t e d b e e t s a n d those i n areas w h e r e f r e q u e n t l a t e - s u m m e r a n d fall r a i n s o c c u r should b e h a n d l e d s o a s t o u t i l i z e n e a r l y all n i t r o g e n before harvest. I n s o m e o f o u r a r i d c l i m a t e s excess n i t r o g e n m a y b e relatively i m m o b i l i z e d i n d r y soil u n d e r a n a d e q u a t e p r o t e c t i v e foliar cover.

N e w p r o d u c t s a r e b e i n g i n t r o d u c e d t o r e d u c e m o b i l i t y o f nitrogen n u t r i e n t s b y e i t h e r r e d u c i n g t h e r a t e o f nitrification o f

80 J O U R N A L OF T H E A. S. S. B. T.

a m m o n i u m salts o r b y r e d u c i n g s o l u b i l i t y o f n i t r a t e b y incor- p o r a t i n g i t i n t o m o r e slowly s o l u b l e forms. T h e a u t h o r believes t h a t t h e d a t a p r e s e n t e d o n p a t t e r n s o f n i t r a t e m o v e m e n t i n t h e soil i n d i c a t e t h a t a n y s u p p l e m e n t a l n i t r a t e a d d e d t o r o w crops after t h e first i r r i g a t i o n s h o u l d b e p l a c e d b e l o w t h e b o t t o m o f i r r i g a t i o n f u r r o w s i n o r d e r t o l e n g t h e n t h e p e r i o d o f a v a i l a b i l i t y to p l a n t s before it r e a c h e s d r y surface layers of soil.

S u m m a r y

X h e n i t r a t e i o n m o v e s very freely w i t h m o i s t u r e i n soils. I t m a y b e easily l e a c h e d b u t i n a r i d o r semi-arid c l i m a t e s t h e m o v e - m e n t i s p r e d o m i n a n t l y t o t h e surface a s sub-surface m o i s t u r e m o v e s u p w a r d a n d e v a p o r a t e s . Surface c o n c e n t r a t i o n s o f n i t r a t e m a y be as m u c h as a t h o u s a n d t i m e s t h a t of subsurface c o n c e n t r a - t i o n s u n d e r f u r r o w i r r i g a t i o n . T h i s r e d i s t r i b u t i o n has a p r o f o u n d effect o n s u g a r b e e t n u t r i t i o n . B y d e c r e a s i n g n i t r a t e a v a i l a b i l i t y l a t e i n t h e season, s u g a r c o n c e n t r a t i o n a n d q u a l i t y o f t h e r o o t s i s i m p r o v e d . Late-season r a i n f a l l o r s p r i n k l e r i r r i g a t i o n u s u a l l y results i n l o w e r s u g a r c o n c e n t r a t i o n s a n d q u a l i t y .

Literature Cited

(1) BERNSTEIN, L E O N . 1959. Salt tolerance of vegetable crops in the west.

U. S. D e p t . Agr. Inf. Bull. 205. 5 p p .

(2) HADDOCK, J. L., et al. 1956. Nitrogen constituents associated with re- d u c t i o n of sucrose percentage a n d p u r i t y of sugar beets. J. Am. Soc.

Sugar Beet T e c h n o l . 9: 110-117.

(3) HADDOCK, J. L., et al. 1959. X h e influence of cultural practices on the quality of sugar beets. J. Am. Soc. Sugar Beet T e c h n o l . 10 (4) : 290- 301.

(4) NIELSON, R. F. a n d L. A. BANKS. 1960. A new look at nitrate move- m e n t in soils. U t a h Agr. E x p . Sta. F a r m a n d H o m e Science 21 (1) : 2-3, 19.

(5) STOUT, M Y R O N . 1961. A new look at some nitrogen relationships affect- i n g t h e q u a l i t y of sugar beets. J. A m . Soc. Sugar Beet T e c h n o l . 11: 288-298.

(6) U L R I C H , ALBERT. 1942. T h e relationship of nitrogen to the formation of sugar in sugar beets. Proc. A m . Soc. Sugar Beet T e c h n o l . 3: 66-80.

(7) U L R I C H , A L B E R T a n d F. J. H I L L S . 1960. Mineral nutrition a n d sugar beet quality. 1960 California Sugar Beet, p p . 36-37.

(8) W E N T , F. W. 1957. Climate a n d agriculture. Sci. Am. 1 9 6 ( 6 ) : 82-94.

Effectiveness of PEBC, D A T C , ond Endothall for Controlling W e e d s in Sugar Beets

in W e s t e r n Nebraska1 G . A . W I C K S AND F . N . A N D E R S O N2

Received for publication October 4, 1963

I n t r o d u c t i o n

O n e of t h e first selective h e r b i c i d e s u s e d on sugar b e e t s was a c o n c e n t r a t e d salt s o l u t i o n by B a k k e (3)³ in 1947; since t h e n m a n y chemicals h a v e b e e n t r i e d t o selectively r e m o v e weeds from sugar b e e t s (4,9,11). D a l a p o n ( 2 , 2 - d i c h l o r o p r o p r o n i c acid) has b e e n c o n s i s t e n t l y effective i n t h e c o n t r o l o f a n n u a l grasses i n sugar b e e t s w h i l e 3 , 6 - e n d o x o h e x a h y d r o p h t h a l i c acid ( e n d o t h a l l ) and t r i c h l o r o a c e t i c a c i d ( T C A ) h a v e given v a r i a b l e c o n t r o l o n a n n u a l grasses a n d b r o a d l e a f w e e d s (1,4). P r o p y l ethyl-n-butyl- t h i o l c a r b a m a t e ( P E B C ) h a s g i v e n a c c e p t a b l e weed c o n t r o l i n California, C o l o r a d o , W y o m i n g a n d M o n t a n a (2,5,8). A n o t h e r chemical 2,3-dichloroallyl d i i s o p r o p y l t h i o l c a r b a m a t e ( D A T C ) has proven t o b e a n e x c e l l e n t h e r b i c i d e for w i l d o a t c o n t r o l (9).

E x p e r i m e n t s w e r e i n i t i a t e d i n w e s t e r n N e b r a s k a a t H e r s h e y , Mitchell, a n d N o r t h P l a t t e , N e b r a s k a , t o d e t e r m i n e s u i t a b l e herbicides for c o n t r o l l i n g weeds in sugar beets.

Material and M e t h o d s

In 1961, e n d o t h a l at 2, 4, 6, a n d 8 l b / A , P E B C at 2, 4, a n d 8 l b / A t e r t - b u t y l d i - n - p r o p y l t h i o l c a r b a m a t e (R-1856) at 2.5, 5.0, a n d 10.0 l b / A , a n d D A X C at 1, 2, a n d 4 l b / A w e r e a p p l i e d pre- plant a s b r o a d c a s t t r e a t m e n t s a n d i m m e d i a t e l y i n c o r p o r a t e d o n April 12 a n d 13, A p r i l 14 a n d 15, a n d A p r i l 25 at M i t c h e l l , Hershey, a n d N o r t h P l a t t e , N e b r a s k a , respectively. Sugar beets were p l a n t e d A p r i l 13, 15, a n d 2 6 a t these p a r t i c u l a r locations.

In 1962, e n d o t h a l l at 2, 4, a n d 8 l b / A , P E B C at 2, 4, a n d 8 l b / A a n d D A T C a t 1 , 2 , a n d 4 l b / A w e r e a p p l i e d p r e p l a n t a n d soil i n c o r p o r a t e d as b r o a d c a s t t r e a t m e n t s A p r i l 12 a n d 13 at M i t c h e l l , a n d A p r i l 31 a n d M a y 1 at N o r t h P l a t t e . S u g a r beets w e r e p l a n t e d A p r i l 13 a n d M a y 4 at t h e r e s p e c t i v e locations. In- c o r p o r a t i o n to a d e p t h of 2 to 3 inches was a c c o m p l i s h e d w i t h i n one m i n u t e after s p r a y i n g i n 1961, a n d w i t h i n five m i n u t e s after spraying in 1962, by a p o w e r - d r i v e n r o t a r y t i l l e r m o u n t e d on a Gravely g a r d e n t r a c t o r .

1 Published with the approval of the directors as paper No. 1423, Journal Series Nebraska Agricultural Experiment Station.

2Assistant Professors of Agronomy, University of Nebraska Experiment Station at North Platte Mitchell, Nebraska, respectively.

3Numbers in parentheses refer to literature cited.

82 J O U R N A L OF T H E A. S. S. B. T.

E n d o t h a l l was a p p l i e d p r e e m e r g e n c e in 1961 at r a t e s of 2, 4, a n d 8 l b / A A p r i l 13, 19, a n d 27, respectively, at M i t c h e l l , H e r s h e y , a n d N o r t h P l a t t e . I n a d d i t i o n e n d o t h a l l was a p p l i e d p o s t e m e r g e n c e 26, 44, a n d 3 3 days after p l a n t i n g a t t h e respective locations. S u g a r beets w e r e in t h e 4- to 6-leaf stage at t h e t i m e of t h e p o s t e m e r g e n c e s p r a y i n g .

H a n d w e e d i n g a t weekly i n t e r v a l s a n d check ( n o w e e d control) w e r e u s e d a s t r e a t m e n t s i n 1961 a n d 1962. W e e d s w e r e r e m o v e d from t h e n o w e e d c o n t r o l p l o t s f o l l o w i n g w e e d harvest.

I n 1961 t h e c u l t u r a l p r a c t i c e o f t h e c o o p e r a t i n g f a r m e r was in- c l u d e d a s a t r e a t m e n t . T h e f a r m e r ' s o p e r a t i o n s a t M i t c h e l l in- c l u d e d t w o c u l t i v a t i o n s ; a t H e r s h e y e n d o t h a l l was a p p l i e d a n d soil i n c o r p o r a t e d in a b a n d a h e a d of t h e p l a n t e r a n d t h e s u g a r b e e t s w e r e c u l t i v a t e d f i v e t i m e s . T h e N o r t h P l a t t e l o c a t i o n i n c l u d e d p r e p l a n t a n d soil i n c o r p o r a t e d a p p l i c a t i o n o f e n d o t h a l l a n d t w o c u l t i v a t i o n s . T h e f a r m e r ' s practices a t t h e t h r e e loca- t i o n s w e r e h a n d w e e d e d a n d t h i n n e d b y M e x i c a n l a b o r e r s .

A r a n d o m i z e d block design w i t h f o u r r e p l i c a t i o n s was used at each l o c a t i o n in 1961 a n d a split-plot d e s i g n w i t h five replica- t i o n s was used at each l o c a t i o n in 1962. In t h e split-plot design, one-half o f each m a i n p l o t received t h e f i r s t c u l t i v a t i o n a t t h e t i m e t h e s u r r o u n d i n g f i e l d was c u l t i v a t e d a n d t h e o t h e r half r e c e i v e d all c u l t i v a t i o n s e x c e p t t h e f i r s t . T h e plots t h a t received t h e f i r s t c u l t i v a t i o n a r e r e f e r r e d t o a s n o r m a l , t h e o t h e r s a r e called d e l a y e d . T h e f a r m e r ' s t r e a t m e n t s i n 1961 w e r e c o m p o s e d o f t h r e e strips six r o w s w i d e , o n e o n each side a n d o n e d o w n t h e m i d d l e o f t h e e x p e r i m e n t a l a r e a . Plots t o b e i n c l u d e d i n t h e e x p e r i m e n t w e r e selected a t r a n d o m from t h e strips.

I n 1961, visual n o t e s w e r e t a k e n 4 3 , 47, a n d 3 8 davs after p l a n t i n g a t M i t c h e l l , H e r s h e y , a n d N o r t h P l a t t e , respectively.

I n 1962, c o u n t s w e r e t a k e n from t w o p e r m a n e n t l y m a r k e d areas.

1 ft by 9 ft, d i r e c t l y o v e r t h e s u g a r b e e t r o w , 36 a n d 53 davs after p l a n t i n g a t M i t c h e l l a n d 3 6 days after a t N o r t h P l a t t e . Also a n a r e a .5 ft by 18 ft (9 sq ft) was c o u n t e d over t h e r o w at M i t c h e l l 6 8 days after p l a n t i n g . T h e l a t t e r c o u n t o c c u r r e d 5 days after b e e t s w e r e t h i n n e d o n c e by m e c h a n i c a l t h i n n e r . A dry s e e d b e d p r e v e n t e d susrar b e e t seed g e r m i n a t i o n s o t h e y w e r e i r r i g a t e d t h e f i r s t w e e k o f M a y a t M i t c h e l l . R a i n o n M a y 1 3 was sufficient for s u g a r b e e t seed g e r m i n a t i o n a t N o r t h P l a t t e .

W e e d yields w e r e o b t a i n e d i n 1961 a n d 1962 b v h a r v e s t i n g a b o v e g r o u n d p o r t i o n s f r o m 6.5, 9 , a n d 1 8 scmare feet. W e e d h a r v e s t o c c u r r e d 69, 65, a n d 58 davs after plantino- r^s*>ectivelv.

a t M i t c h e l l , H e r s h e y a n d N o r t h P l a t t e i n 1961. T h e 1962 harvest o c c u r r e d 83 a n d 59 to 60 davs after p l a n t i n g , respectively, a t M i t c h e l l a n d N o r t h P l a t t e . W e e d s w e r e s e p a r a t e d a s t o grasses

VOL. 13, N o . 1, A P R I L 1964 83

a n d broadleaf w e e d s in 19.61, a n d in 1962 they w e r e s e p e r a t e d b y species a t w e e d h a r v e s t . W e e d s w e r e o v e n - d r i e d a n d r e p o r t e d as p o u n d s p e r a c r e . A t r a n s f o r m a t i o n of log (x + 1) was used o n weed c o u n t s a n d w e e d w e i g h t s . T h e d a t a w e r e analyzed a n d expressed as g e o m e t r i c m e a n s . In 1962 weeds w e r e harvested only from t h e d e l a y e d c u l t i v a t e d plots. All p l o t s w e r e w e e d e d following w e e d h a r v e s t a n d k e p t weed-free t h e rest of t h e season.

T h e n o r m a l c u l t i v a t e d p l o t s w e r e w e e d e d a t t h e t i m e o f t h e first c u l t i v a t i o n .

In 1961 plots w e r e located on t h e following soil types:

B r i d g e p o r t l o a m a t N o r t h P l a t t e a n d M i t c h e l l , a n d B r i d g e p o r t sandy clay l o a m a t H e r s h e y . T h e 1962 p l o t s w e r e located o n t h e following soil types: B r i d g e p o r t l o a m a t M i t c h e l l , a n d H a l l loam a t N o r t h P l a t t e .

Results Climatology

T h e soil t e m p e r a t u r e ( d e p t h — t h r e e inches) a t t h e t i m e o f a p p l i c a t i o n a n d i n c o r p o r a t i o n of t h e p r e p l a n t t r e a t m e n t s in 1961 was 4 5 ° F a t M i t c h e l l , 4 9 - 6 1 ° F a t H e r s h e y , a n d 54-58°F a t N o r t h Platte. T h e soil t e m p e r a t u r e in 1962 at t h e t i m e of a p p l i c a t i o n a n d i n c o r p o r a t i o n of t h e p r e p l a n t t r e a t m e n t s was 44-56° F at Mitchell a n d 46-58°F a t N o r t h P l a t t e .

T h e soil m o i s t u r e i n t h e t o p t h r e e i n c h e s o f t h e soil a t t h e time p r e p l a n t t r e a t m e n t s w e r e m a d e i n 1961 was 1 7 . 4 % a t Mitchell, 1 7 . 9 % a t H e r s h e y , a n d 1 9 . 7 % a t N o r t h P l a t t e . T h e soil m o i s t u r e in 1962 at t h e t i m e of t h e p r e p l a n t t r e a t m e n t s was 1 2 . 2 % a t M i t c h e l l a n d 9 . 8 % a t N o r t h P l a t t e .

Table 1.—Accumulative precipitation in inches for 42 days following planting of sugar beets at experimental locations in 1961 and 1962.

84 JOURNAL OF THE A. S. S. B. T.

T h e average m i n i m u m a n d m a x i m u m a i r t e m p e r a t u r e s for o n e a n d t w o w e e k s after p l a n t i n g , respectively, i n 1961 w e r e 2 8 - 5 8 ° F a n d 31-61°F a t M i t c h e l l , 33-65°F a n d 3 4 - 6 3 ° F a t H e r s h e y , a n d 34-58°F a n d 4 0 - 5 6 ° F a t N o r t h P l a t t e . T h e a v e r a g e m i n i m u m a n d m a x i m u m a i r t e m p e r a t u r e s i n 1962 for o n e a n d t w o weeks after p l a n t i n g , respectively, w e r e 37-75°F a n d 41-74°F a t M i t c h e l l a n d 54-88°F a n d 53-78°F a t N o r t h P l a t t e .

The p r e c i p i t a t i o n d a t a , from p l a n t i n g to 42 days later, a r e p r e s e n t e d in T a b l e 1 for 1961 a n d 1962.

Effect on prethinning sugar beet stands

I n 1961 P E B C a t 4 a n d 8 l b / A r e d u c e d sugar b e e t s t a n d s b e l o w t h e check b y 2 0 a n d 3 9 % . D A T C a t 2 a n d 4 l b / A r e d u c e d s t a n d s b y 1 7 a n d 3 3 % . S t a n d losses o n p l o t s t r e a t e d w i t h R-1856 a t 5 a n d 1 0 l b / A w e r e 5 a n d 1 1 % . E n d o t h a l l a p p l i e d p r e p l a n t at 4 a n d 8 l b / A r e d u c e d s t a n d s by 5 a n d 1 7 % ; all m e t h o d s of a p p l i c a t i o n w e r e a b o u t t h e same. I n 1962 p l o t s t r e a t e d w i t h P E B C a t 4 a n d 8 l b / A lost 1 9 a n d 5 2 % o f t h e p r e t h i n n i n g s t a n d , D A X C at 2 a n d 4 l b / A lost 11 a n d 2 7 % a n d s t a n d loss o n t h e e n d o t h a l l a t 8 l b / A plots was 1 0 % .

Annual grass control

X h e a n n u a l grasses i n 1961 a n d 1962 w e r e p r e d o m i n a t e l y Setaria s p p . Visual r a t i n g s t a k e n in 1961 a r e s h o w n in T a b l e 2.

Visual c o n t r o l w i t h P E B C a t t h e t h r e e l o c a t i o n s r a n g e d from 7 5 t o 9 4 % w i t h 2 l b / A , 9 5 t o 1 0 0 % w i t h 4 l b / A , a n d 1 0 0 % w i t h 8 l b / A . P e r c e n t c o n t r o l w i t h D A T C r a n g e d from 3 2 t o 8 2 % w i t h 1 l b / A , 6 5 t o 9 5 % for 2 l b / A , a n d 9 8 t o 1 0 0 % for 4 l b / A . C o n t r o l o b t a i n e d w i t h R-1856 was a s follows: 3 5 t o 6 8 % w i t h 2.5 l b / A , 7 2 t o 9 9 % w i t h 5.0 l b / A , a n d 9 2 t o 9 8 % for 10.0 l b / A . Visual c o n t r o l w i t h e n d o t h a l l a p p l i e d p r e p l a n t was a s follows: 0 to 9 2 % for 2 l b / A , 15 to 9 8 % for 4 l b / A , 28 to 9 8 % for 6 l b / A , a n d 2 2 t o 1 0 0 % for 8 l b / A . R e s u l t s a t M i t c h e l l w e r e e x c e l l e n t , a t H e r s h e y c o n t r o l was fair; a t N o r t h P l a t t e , i t was p o o r .

C o n t r o l w i t h e n d o t h a l l a p p l i e d p r e e m e r g e n c e r a n g e d from 0 t o 5 8 % for 2 l b / A , 15 t o 7 4 % for 4 l b / A , a n d 70 to 8 8 % for 8 l b / A . X h e r e was l i t t l e difference b e t w e e n c o n t r o l a t M i t c h e l l a n d H e r s h e y , a t N o r t h P l a t t e i t was p o o r , e x c l u d i n g t h e 8 l b / A r a t e .

The p o s t e m e r g c n c e t r e a t m e n t of e n d o t h a l l g a v e c o n t r o l of 5 t o 5 5 % a t 2 l b / A , 48 t o 8 0 % for 4 l b / A , a n d 70 t o 9 8 % for 8 l b / A . E x c e p t for t h e l o w r a t e s a t N o r t h P l a t t e , c o n t r o l was a b o u t t h e s a m e for t h e t h r e e locations.

The grass yields at t h e t h r e e l o c a t i o n s ( T a b l e 2) s h o w e d t h a t several t r e a t m e n t s c o m p a r e d favorably t o h a n d w e e d i n g a t w e e k -

1 Number of days after planting.

2 Numbers followed by the same letter do not differ significantly at the 5 percent level using Duncan's multiple range tests.

Table 2.—The effect of various herbicides on annual grasses as measured by visual estimations and oven dry weights at Mitchell, Hershey, and North Platte, Nebraska in 1961.

86 J O U R N A L OF T H E A. S. S. B. T.

ly intervals. T h e s e w e r e : 2, 4, a n d 8 l b / A of P E B C , 5.0 a n d 10.0 l b / A of R-1856, 2 a n d 4 l b / A of D A T C , a n d p o s t e m e r g e n c e t r e a t m e n t of e n d o t h a l l at 8 l b / A .

Grass c o u n t s a n d yields for 1962 a r e p r e s e n t e d i n T a b l e 3 . C o u n t s 3 6 days after p l a n t i n g a t M i t c h e l l show t h a t t h e r e was n o significant r e d u c t i o n i n t h e n u m b e r o f a n n u a l grasses b y P E B C a n d D A T C t r e a t m e n t s . C o u n t s t a k e n 5 3 days after p l a n t - i n g s h o w e d significantly fewer p l a n t s o n t h e D A T C a t 2 a n d 4 l b / A a n d 2 , 4 , a n d 8 l b / A o f P E B C t h a n o n t h e check. Grass yields o n t h e D A T C a n d P E B C t r e a t m e n t s w e r e e q u a l t o o r l o w e r t h a n t h e h a n d w e e d t r e a t m e n t .

A t N o r t h P l a t t e w h e n c o u n t s w e r e t a k e n 3 6 days after p l a n t - i n g P E B C a n d D A T C h a d e l i m i n a t e d significantly m o r e a n n u a l grasses t h a n t h e check. C o n t r o l was still effective 60 days after p l a n t i n g .

R e s u l t s w i t h e n d o t h a l l w e r e o u t s t a n d i n g from t h e f i r s t read- i n g a t M i t c h e l l , b u t b y t h e second r e a d i n g t h e r e was a n i n c r e a s e i n p l a n t n u m b e r s o t h a t t h e r e was n o significant difference be- t w e e n e n d o t h a l l t r e a t m e n t s a n d t h e check. T h e N o r t h P l a t t e c o u n t s s h o w n o difference b e t w e e n check a n d a n y e n d o t h a l l t r e a t m e n t . T h e r e was n o significant difference b e t w e e n check a n d e n d o t h a l l t r e a t m e n t s i n t h e grass yields h a r v e s t e d 8 3 t o 6 0 days after p l a n t i n g a t M i t c h e l l a n d N o r t h P l a t t e , respectively.

Grass yields for l o c a t i o n s show t h a t all rates o f D A T C a n d P E B C w e r e s i m i l a r t o t h e h a n d w e e d t r e a t m e n t . T h e r e was a h i g h l y significant l o c a t i o n X t r e a t m e n t i n t e r a c t i o n c a u s e d by b e t t e r p e r f o r m a n c e o f e n d o t h a l l a t M i t c h e l l .

Broadleaf w e e d control

P r i n c i p l e b r o a d l e a f species in 1961 w e r e : k o c h i a (Kochia scoparia L.) a n d r o u g h p i g w e e d (Amaranthus retroflexus L.).

K o c h i a was p r e d o m i n a t e a t M i t c h e l l a n d N o r t h P l a t t e , a n d r o u g h p i g w e e d a t H e r s h e y . I n 1962, k o c h i a a n d r o u g h p i g w e e d w e r e t h e p r e d o m i n a t e b r o a d l e a f w e e d s a t M i t c h e l l a n d N o r t h P l a t t e . S e e d l i n g alfalfa was p r e s e n t i n sufficient q u a n t i t y t o c o u n t . Black n i g h t s h a d e (Solanum nigraum L.) was p r e s e n t at t h e N o r t h P l a t t e site.

V i s u a l r a t i n g s w e r e t a k e n i n 1961 a n d r e s u l t s a r e s h o w n i n T a b l e 4 . P E B C a t 2 l b / A c o n t r o l l e d 3 0 t o 9 5 % , 4 l b / A con- t r o l l e d 8 8 t o 9 8 % , a n d 8 l b / A c o n t r o l l e d 9 2 t o 1 0 0 % . C o n t r o l w i t h R-1856 r a n g e d f r o m 0 t o 1 8 % for 2.5 l b / A , 0 t o 6 2 % for 5.0, a n d 2 5 a n d 8 1 % for 1 0 l b / A . C o n t r o l for D A T C r a n g e d f r o m 0 t o 4 5 % for 1 l b / A , 2 0 t o 6 5 % for 2 l b / A , a n d 5 2 t o 9 4 % for 4 l b / A . O n l y P E B C a t 8 l b / A was e q u a l t o h a n d - w e e d i n g a t weekly i n t e r v a l s for b r o a d l e a f w e e d c o n t r o l .

Table 3.—The effect of various herbicides on annual grasses as measured by plant counts and oven-dry weights at Mitchell, and North Platte, Nebraska in 1962.

1 A nine square foot area was harvested, counted and over-dried 83 days after planting at Mitchell and 60 days after at North Platte for the delayed cultivation. Normal was counted 68 days after planting.

2 Numbers followed by the same letter do not differ significantly at the 5 percent level using Duncan's multiple range tests.

Table 4.—The effect of various herbicides on broadleaf weeds as measured by visual estimations and oven-dry weights at Mitchell, Hershey, and North Platte, Nebraska, in 1961.

1 Number of days after planting.

2 Numbers followed by the same letter do not differ significantly at the 5 percent level using Duncan's multiple range tests.

VOL. 13, N o . 1, A P R I L 1964 89

E n d o t h a l l a p p l i e d p r e p l a n t a n d soil i n c o r p o r a t e d , c o n t r o l l e d 0 to 9 1 % for 2 l b / A , 12 t o 9 8 % for 4 l b / A , 18 t o 1 0 0 % for 6 l b / A , a n d 3 8 t o 9 8 % for 8 l b / A . P r e e m e r g e n c e a p p l i c a t i o n s o f e n d o t h a l l c o n t r o l l e d 10 to 4 9 % for 2 l b / A , 8 to 7 2 % for 4 l b / A , a n d 40 to 9 0 % for 8 l b / A . P o s t e m e r g e n c e a p p l i c a t i o n s of en- d o t h a l l c o n t r o l l e d 0 to 4 5 % for 2 l b / A , 0 to 6 0 % for 4 l b / A , a n d 1 2 t o 9 2 % for 8 l b / A . T h e p r e p l a n t soil i n c o r p o r a t e d a n d the p r e e m e r g e n c e m e t h o d o f a p p l y i n g e n d o t h a l l p e r f o r m e d best a t M i t c h e l l b u t t h e p o s t e m e r g e n c e t r e a t m e n t was best a t H e r s h e y . T h e w e e d yields show t h a t t h e o n l y s t r i k i n g results w i t h en- d o t h a l l w e r e w i t h t h e p o s t e m e r g e n c e t r e a t m e n t s a t H e r s h e y .

T a b l e 5 shows t h e d a t a t a k e n o n r o u g h p i g w e e d a t M i t c h e l l a n d N o r t h P l a t t e i n 1962. P E B C was m o r e effective b y t h e second c o u n t i n g a n d all r a t e s w e r e significantly b e t t e r t h a n a n y o t h e r t r e a t m e n t . T h e t w o areas c o u n t e d o v e r t h e r o w a t M i t c h e l l 5 3 a n d 6 8 days after p l a n t i n g r e s p o n d e d similarly. T h e N o r t h Platte c o u n t s s h o w e d P E B C t o b e t h e o u t s t a n d i n g h e r b i c i d e for c o n t r o l of r o u g h p i g w e e d . W e e d yields w e r e c o m p a r a b l e to the h a n d w e e d t r e a t m e n t at b o t h locations. P E B C at 4 a n d 8 l b / A w e r e s u p e r i o r t o h a n d w e e d i n g a t weekly intervals m e a s u r e d b y D u n c a n ' s m u l t i p l e r a n g e tests o n l o c a t i o n m e a n s .

C o u n t s a n d w e e d w e i g h t s t a k e n a t b o t h locations i n d i c a t e that D A T C was ineffective i n c o n t r o l l i n g r o u g h pigweed.

E n d o t h a l l a t 8 l b / A was very effective i n c o n t r o l l i n g r o u g h pigweed a t t h e first o b s e r v a t i o n a t M i t c h e l l . T h e r e was n o significant difference b y t h e second r e a d i n g b e t w e e n t h e check a n d the e n d o t h a l l t r e a t m e n t s o n t h e 12-inch w i d e a r e a over t h e row. T h e r e was a significant difference b e t w e e n t h e check a n d e n d o t h a l l t r e a t m e n t s o n t h e 6-inch w i d e area. W e e d yields o n the 4 l b / A p l o t s w e r e significantly less t h a n t h e check. T h e e n d o t h a l l t r e a t m e n t s a t N o r t h P l a t t e w e r e n o t significantly different t h a n t h e c h e c k a t a n y t i m e . M o s t o f t h e h i g h l y significant location X t r e a t m e n t i n t e r a c t i o n was c a u s e d by b e t t e r e n d o t h a l l p e r f o r m a n c e a t M i t c h e l l .

T a b l e 6 shows t h e d a t a t a k e n o n k o c h i a a t M i t c h e l l a n d N o r t h P l a t t e i n 1962. P E B C a n d D A T C d i d n o t c o n t r o l kochia at e i t h e r l o c a t i o n . E n d o t h a l l gave g o o d c o n t r o l of k o c h i a at M i t c h e l l a s i n d i c a t e d b y t h e f i r s t w e e d c o u n t s , a n d b y t h e c o u n t s a n d w e e d w e i g h t s 8 3 days after p l a n t i n g . T h e second r e a d i n g d i d n o t a p p e a r a s g o o d a s t h e f i r s t o r t h a t t a k e n 1 5 days l a t e r o n t h e 6-inch a r e a . C o n t r o l o f k o c h i a a t N o r t h P l a t t e w i t h e n d o t h a l l was p o o r , a l t h o u g h t h e r e was a significant r e d u c t i o n i n w e e d w e i g h t s b u t n o n e for c o u n t s . A g a i n t h e highly significant l o c a t i o n X treatment interaction was due to better endothall performance at Mitchell.

Dalam dokumen J O U R N A L of the (Halaman 65-111)