Side-Dressing Sugar Beets with Nitrogen
P R O C E E D I N G S — F O U R T H GENERAL. M E E T I N G 41 Table 1.—Effect of side-dressing of varying amounts of nitrogen on yield and
quality of sugar beets, 1944.
No manure Manured
Average fertility Low fertility Sucrose Treatment, Tons beets per acre Tons beets per acre percentage 82 pounds nitrogen
41 pounds nitrogen Check, no nitrogen
1945 Tests
In 1945 it was found impossible to purchase side-dressing equip- ment for use in large-scale tests. Therefore the American Crystal S u g a r Company built three machines: A three-row, a four-row, a n d a six-row machine. The four-wheel tractor was adjusted to s t r a d d l e three beet rows. With this a r r a n g e m e n t it was possible to use six openers a n d fertilize every center in the six-row p l a n t i n g s . To side- dress every middle with a three-wheel " F a r m a l l " t y p e tractor, it is necessary to straddle an even number of rows a n d to use an e x t r a opener. Both outside cans feed half speed and lap back each row, the same as when cultivating.
Several growers also built machines, most of which proved satis- factory. The most practical of these units was built on the r e a r b a r of the regular tractor cultivator and applied fertilizer as the tools on the front bar cultivated. Five openers were used on this four-row machine. The outside cans fed half as much fertilizer as the others, and the machine lapped back each r o u n d while cultivating. Several types of shoe and one disk opener were tried on these units, a n d the one adopted was similar to the shoe designed by Jones (4). It was found, however, t h a t even this narrow shoe, which was less than three- fourths of an inch thick, when travelling at speeds higher than 4 miles per hour moved enough d i r t 1o cover small beets 10 inches away.
Grinding off the two " l e f t w i n g s ' ' on the diamond point p a r t i a l l y cor- rected this, but it was necessary to shield the row when side-dressing very small beets. Covering of beets was not a factor with the ma- chines t h a t side-dressed as the operator cultivated, as it was not pos- sible to operate the cultivator at a high r a t e of speed. Less d i r t was moved when the shoe was placing the fertilizer 4 inches deep t h a n when it was adjusted for shallow operation. All fertilizer was drilled from 3 to 4 inches deep in the center between the beet rows.
To check the results obtained in 1944 a n d to t r y even h i g h e r r a t e s of application of nitrogen, one s t r i p test was conducted in 1945 on a field of good fertility. This field had been p l a n t e d to beets in 1944, and the beet tops plowed u n d e r in the fall. An application of 200 pounds of 6-30-0 was applied before seeding in 1945.
15.06 13.27 18.7 33.59 12.57 18.2 11.33 11.63 18.7
42 AMERICAN SOCIETY SUGAR-BEET TECHNOLOGISTS
In this test nitrogen was a p p l i e d in one application on M a y 30, after t h i n n i n g , ammonium, n i t r a t e being the source of nitrogen. Re- sults are given in table 2.
T a b l e 2.—Effect of s i d e - d r e s s i n g of v a r y i n g a m o u n t s of n i t r o g e n on yield of s u g a r b e e t s , 1945.
T r e a t m e n t T o n s p e r a c r e
201 p o u n d s n i t r o g e n 22.16 134 p o u n d s n i t r o g e n 19.90 67 p o u n d s n i t r o g e n 18.48 Check, no n i t r o g e n 16.20 At the time the s t r i p s were harvested t h e r e were three very dis-
tinct shades of green in the field, r a n g i n g from the very d a r k green of the heavy t r e a t m e n t to a light green in t h e s t r i p with the light appli- cation. The check was very yellow. The appearance of the two heavily t r e a t e d strips did not indicate t h a t all of the n i t r a t e h a d been used or leached t h r o u g h the soil.
M a n y of t h e growers who used side-dressing equipment to a p p l y nitrogen left an unfertilized check s t r i p t h r o u g h their commercial fields in 1945. In table 3 are given the acre yields of three of these fields, one being a field low in fertility, t h e second average, a n d the t h i r d high in fertility. Applications on these fields were made with ammonium n i t r a t e (33.5-0-0).
Table 3.—Grower tests of nitrogen fertilizer, 1045.
Yield in tons beets per acre
Low fertility Average fertility High fertility Treatment Unmanured Unmanured Manured 67 pounds nitrogen 5.48 12.81 22.46 Check, no nitrogen 4.23 11.10 21.28 Increase in tonnage 1.25 1.71 1.18 Percent increase 29% 15% 5%
Results of these trials indicate t h a t the farmer w i t h average fer- tility l a n d made a l a r g e r increase in tonnage t h a n t h e grower w i t h very low or very high fertility fields. The percentage increase was higher in the low fertility field, b u t the percentage r e t u r n on the fer- tilizer dollar invested was less.
One grower side-dressed 67 p o u n d s of n i t r o g e n in two applica- tions. The first application of 331/2 p o u n d s was applied j u s t after t h i n n i n g , a n d the second application of a like a m o u n t was applied in t h e final cultivation. Although no d a t a from t h i s grower test was obtained, it a p p e a r s reasonable t h a t in using very large a m o u n t s of nitrogen p e r acre, especially in the form of ammonium n i t r a t e , two lighter applications should be made d u r i n g the growing season r a t h e r t h a n one heavy early application. Carlson (2) a n d G a r d n e r a n d Rob-
P R O C E E D I N G S — F O U R T H G E N E R A L M E E T I N G 43 ertson (3) both concluded t h a t beets make their g r e a t d e m a n d for ni- t r a t e in A u g u s t and September and assimilate more n u t r i e n t s d u r i n g those 2 months than d u r i n g a n y other similar period. It is i m p o r t a n t to have adequate n i t r a t e available d u r i n g J u l y a n d A u g u s t , a n d this could be accomplished by spreading the side applications of n i t r o g e n over a longer period, of time.
Discussion
The results of preliminary tests indicated increased yields could be obtained by a moderate application of nitrogen fertilizers. These tests stimulated such wide interest among growers t h a t in 1945 about 3,000 acres of beets were side-dressed, mostly with ammonium n i t r a t e , at an average rate of 67 pounds of nitrogen per acre. This represents a substantial portion of the Missoula factory acreage.
Although purities on individual fields were not obtained, the in- dications are t h a t nitrogen applied d u r i n g the 1945 season did not have a detrimental effect on the quality of the beets. P u r i t y of juice was 88.4 in 1945 as compared to the 8-year factory average of 88.7.
The average sugar percentage for the Missoula factory was the high- est of the five factories in the state of Montana, a n d was 0.19 percent above the past 8-year factory average.
In the light of the foregoing it is of interest to note the conclu- sions of Ulrich (5) : " I n some environments, beets high in nitrogen may also be high in sugar, and likewise in another environment beets low in nitrogen could be low in sugar. The conditions which favor the storage of sugar by beets, even when the nitrogen supply is high, would occur in localities where sunlight is intense, the days w a r m to hot, a n d the nights cool. Under these conditions, photosynthesis would be at a maximum, and respiration would be at a minimum, thus r e s u l t i n g in the formation of sugar faster t h a n it can be utilized to form new tissues (leaves and roots), even when large amounts of nitrogen are available for growth. (Other n u t r i e n t s are assumed to be a d e q u a t e ) . " These qualifications all apply to western Montana, where t h e r e are cool nights and long, warm days with intense sunlight.
Looking ahead to 1946, there is a strong possibility t h a t well over half of the beet acreage for the Missoula factory will be side-dressed with nitrogen fertilizers. In the B i t t e r Root Valley the percentage will be much higher. F o r 1946 experimental work it is planned, to conduct tests with both ammonium n i t r a t e a n d ammonium sulphate as to the most efficient source of nitrogen a n d the timeliness and r a t e of application. Tests with other fertilizer combinations will also be made.
44 AMERICAN SOCIETY S U G A R - B E E T TECHNOLOGISTS S u m m a r y a n d Conclusions
A nitrogen deficiency exists in many beet fields in western Mon- t a n a in the lighter-textured soils. Field tests conducted in 1944 dem- onstrated applications of more t h a n 20 p o u n d s nitrogen p e r acre p r o - duced the most profitable increases in beet yield. In 1945 about 3,000 acres of beets were side-dressed with ammonium n i t r a t e or ammonium sulphate, the average application being 67 p o u n d s nitrogen per acre.
W i t h the greater availability of side-dressing equipment, nitrogen will be applied in lesser amounts in two or three applications d u r i n g the early part of the growing season to reduce losses due to leaching a n d to make for a more balanced feeding of the plant. Nitrogen applied to fields of low, average, and high fertility levels produced largest in- creases in beet yields from fields of average fertility. The percentage sucrose a n d p u r i t y were not affected adversely because of nitrogen fertilization. A very material increase in the use of nitrogen will be made in the fertilization of t h e beet crop in western Montana in 1946.
L i t e r a t u r e Cited
1. Afanasiev, M. M. a n d Morris, H. E. 1941 F e r t i l i z e r T r e a t m e n t s of B i t t e r Root Cooperative Tests. ( U n p u b l i s h e d ) .
2. Carlson, W. E. Mineral Assimilation of S u g a r Beets. Proc.
Amer. Soc. Sug. Beet Tech., 81-88. 1942.
3. Gardner, Robert a n d Robertson, D. W. The Nitrogen Require- ments of Sugar Beets. Colo. E x p . Sta. Tech. B u l . 28. 1942.
4. Jones, R. A. Methods a n d E q u i p m e n t for Fertilizing Row Crops.
Proc. Amer. Soc. S u g . Beet Tech., 283-286. 1942.
5. Ulrich, Albert. The Relationship of Nitrogen to the F o r m a t i o n of S u g a r in S u g a r Beets. Proc. Amer. Soc. Sug. Beet Tech., 66-80.
1942.