H A L B. REEVE AND ERNEST H. KIDDER1
This is a progress report on an experiment to determine the effects of supplemental irrigation on a soil-building rotation with sugar beets as one of the crops. The experiment is designed around a three-year rotation con- sisting of a small grain seeded to alfalfa, alfalfa used as a green manure crop with the first cutting left lying on the ground and second cutting allowed to grow through it with the entire growth, thus two cuttings being plowed under around August 15. Sugar beets are planted the following spring. Thus, one-third of the land area is devoted to the growing of alfalfa to be plowed under as a green manure crop.
For this experiment, an 1 8-acre area was divided into three six-acre fields. The soil was a Brookston loam, an excellent sugar beet soil. The field was tiled in 1949 at 4-rod intervals. Each field was again divided to compare rates of fertilization, the rates being 2,500 pounds of complete fertilizer on the high side and 1,250 pounds of complete fertilizer on the low side. The plots were further divided so that one-half of each fertilizer plot received supplemental overhead irrigation.
The fertilizer application by crops is shown in Table 1.
Small Grains (Seeded) H i g h Low 500 lbs. 500 lbs.
(4-16-16) (4-16-16)
T a b l e 1 Alfalfa (Green
H i g h 500 lbs.
( T o p Dressed) (0-20-20)
Manure) Low
0
Sugar Beets
H i g h Low 250 lbs. 250 lbs.
(4-16-16 + B)1 ( 4 - 1 6 - 1 6 + B ) 1250 lbs. 500 lbs.
(0-20-20) (0-20-20)
1 5 percent Borax
In 1953, the fertilizer application was changed so that additional fer- tilizer was applied on the small grain and less on the sugar beets as shown in Table 2.
Small Grai H i g h
ns (Seeded) Low
T a b l e 2.
Alfalfa (Green Manure) H i g h Low
Sugar Beets
H i g h Low 1500 lbs.
(5-20-20)
750 lbs.
(5-20-20)
500 lbs.
(0-20-20)
250 lbs. 250 lbs.
( 5 - 2 0 - 2 0 + B )1 ( 5 - 2 0 - 2 0 + B ) 250 lbs.
(0-20-20)
1 5 p e r c e n t Borax
Bouyoucos moisture blocks were placed at 5 inch and 10 inch depths in all crops. When these moisture blocks indicated an available soil moisture
1 A g r i c u l t u r a l i s t , F a r m e r s & M a n u f a c t u r e r s Beet S u g a r Association, Saginaw, M i c h i g a n , a n d Associate Professor, A g r i c u l t u r a l E n g i n e e r i n g , M i c h i g a n State College, East L a n s i n g , M i c h i g a n , respectively.
PROCEEDINGS—EIGHTH GENERAL MEETING 121 content of 50 percent or less, irrigation was applied with an overhead sprink- ling system as shown in Figure 1. In 1950, irrigations were made on the oats on J u n e 19-23 and July 9-11. Sugar beets were irrigated July 9-11 and August 24 and 25. It should be pointed out that each irrigation preceded a good rain by only a few days.
Figure 1.—Field layout.
-I
Oats were harvested with a combine and sack samples taken. Since there was no difference in treatment this first year, the irrigated plots were averaged together and yielded 57 bushels per ace, while the non-irigated plots averaged 67 bushels per acre. No visual difference could be noted in the standing grain with the possible exception of increased incidence of rust in the irrigated area.
Table 3.—Irrigation Statistical Summary for Sugar Beets, Rader Farm, 1950.
High Fertility Low Fertility
Difference Required for Significance at the 5% Level Tons/Acre
Sucrose Percent Gross Sugar
Tons/Acre Sucrose Percent Cross Sugar
Tons/Acre Sucrose Percent Gross Sugar
Higl Irrigated
19.30 16.38 6312
19.65 16.30 6410 Irrigated
18.66 16.22 6057 Fertility
Non-Irrigated 20.00 16.22 6509
19.05 16.21 6176 Non-Irrigated
20.04 16.29 6530 Low Fertili ty Irrigated Non-Irrigated
18.03 16.08 5802
20.08 16.35 6550
1.53 1.09 728
1.53 1.09 728
2.17 2.56 1033
122 A M E R I C A N S O C I E T Y O F SUGAR B E E T T E C H N O L O G I S T S
S u g a r beets w e r e h a r v e s t e d w i t h a Scott-Urschel s u g a r b e e t c o m b i n e in o n e - r o w strips for t h e l e n g t h o f each p l o t (1,090 f e e t ) . T h e statistical sum- m a r y i s p r e s e n t e d i n T a b l e 3 .
T h e yields o f alfalfa w e r e n o t t a k e n . I t was felt t h a t a n y benefit from t h e e x t r a fertilization o r i r r i g a t i o n o n t h e alfalfa s h o u l d b e m e a s u r e d i n terms of i n c r e a s e d yields in t h e f o l l o w i n g c r o p s of s u g a r beets a n d oats.
T h e same p r o c e d u r e s w e r e followed a n d t h e s a m e g e n e r a l results s e c u r e d i n 1951 a n d 1952. T h e yields w e r e t h e s a m e i n all t r e a t m e n t s . I n t h e sugar b e e t plots, h o w e v e r , it was observed t h a t m o r e disease in t h e form of r o o t r o t d u r i n g t h e s u m m e r was o c c u r r i n g i n t h e i r r i g a t e d p l o t s . T h i s disease was p r o b a b l y a factor in offsetting a n y yield benefits from t h e e x t r a fertilizer a n d / o r i r r i g a t i o n . T h e s t a n d o f s u g a r beets o n t h e i r r i g a t e d p l o t s a t h a r v e s t t i m e a v e r a g e d a b o u t 2 5 p e r c e n t less t h a n t h e n o n - i r r i g a t e d p l o t s .
In 1952, 1/2 inch of w a t e r was a p p l i e d to t h e sugar b e e t i r r i g a t i o n p l o t s p r i o r t o e m e r g e n c e d u e t o e x t r e m e l y d r y soil c o n d i t i o n s . T h e s e p l o t s e m e r g e d 10 days s o o n e r t h a n t h e n o n - i r r i g a t e d p l o t s .
I n 1952, i r r i g a t i o n was n o t a p p l i e d u n t i l t h e B o u y o u c o s m o i s t u r e blocks gave an i n d i c a t e d m o i s t u r e c o n t e n t of 20 p e r c e n t or less.
D u r i n g this three-year p e r i o d i t was f u r t h e r o b s e r v e d t h a t a t n o t i m e d i d t h e sugar beets a p p e a r to be suffering for t h e lack of m o i s t u r e even t h o u g h t h e soil m o i s t u r e c o n t e n t a t t h e 1 0 i n c h d e p t h g o t b e l o w t h e 2 0 p e r c e n t level.
In 1953, B o u y o u c o s m o i s t u r e blocks were p l a c e d at 6 i n c h , 12 i n c h , 24 i n c h a n d 3 6 i n c h d e p t h s . A d e q u a t e m o i s t u r e was r e c e i v e d u n t i l A u g u s t , followed b y a r a t h e r d r y A u g u s t a n d S e p t e m b e r . T h e r a i n f a l l for this p e r i o d is s h o w n in T a b l e 4.
T a b l e 4 . 1953
August 7 a n d 8 1.96"
12 .04 21 .07 T o t a l 2.07"
S e p t e m b e r 4 .45 6 .05 12 .56 19 1.20 26 .83
T o t a l 3.09"
O c t o b e r 4 .48 6 .30 27 .37 T o t a l 1.15"
C o n c l u s i o n
By t h e 20th of A u g u s t , m o i s t u r e blocks in t h e s u g a r b e e t p l o t s gave an i n d i c a t e d a v a i l a b l e m o i s t u r e c o n t e n t r e a d i n g of 0 p e r c e n t at t h e 6 i n c h d e p t h . By t h e 15th of S e p t e m b e r , all m o i s t u r e blocks in t h e s u g a r b e e t
PROCEEDINGS—EIGHTH GENERAL MEETING 123 plots read zero with the exception of the 36 inch depth. T h e moisture
reading at the 36 inch depth remained at a 100 percent level throughout the entire growing season. Again it was observed that at no time did the sugar beets show any symptoms of suffering for the lack of moisture throughout the 1953 growing season. No supplemental irrigation was applied to any crop during the 1953 season. Very little root rot was evident in the sugar beet plots in 1953.
From Table 4, you will note that during 1953 the last heavy rains oc- curred on August 7 and 8. A rainfall of 1.20 inches fell on September 19.
However, the ground was so dry that this moisture did not penetrate much below the 5 inch depth. Four rows in each treatment were harvested with a Marbeet Midget harvester and loaded directly into trucks to obtain yield results in 1953.
T h e yields obtained are shown in Table 5.
Table 5.
High Fertilization Low Fertilization
Tons/Acre 15.22 15.20 Tons/Acre 13.78 14.52 14.58 14.86
1. No increased yields have been secured to date from extra fertilization or supplemental irrigation.
2. Supplemental irrigation as applied to the sugar beets caused exces- sive root rot during the summer. Harvest stands in the irrigated plots were reduced by as much as 25 percent.
3. Early irrigations to get the beets up and off to a good start may be more important in normal years than late summer irrigations.
4. Sugar beets have the ability to draw moisture from the subsoil when no moisture is available in the surface area.
5. At no time during the growing season of 1950, 1951, 1952 and 1953 did the soil moisture get low enough to cause excessive wilting of the beet leaves as often occurs in the irrigated areas of the west.
6. It would appear that too much moisture may be more of a factor for decreased yields in this area than a lack of moisture when the soils are high in organic matter and adequate amounts of commercial fertilizer are used in the rotation.