Studies begun in 1970 were continued in 1971 under the co-leadership of and Bauer and Keith Cassel. Aspects of management under investigation include evaluation of the effect of fertilizers on crop yields and quality aspects, movement of nitrate nitrogen under different crops and water regimes, water use and water use efficiency by crops, measurement of the plant rater status of crops and evaluation of irrigation scheduling methods.
Two small plot irrigators were built and used in one sugarbeet trial in 1971. Expansion of work involving effect of water levels on other crops is planned for 1972.
Table 1 provides information on the date and amount of irrigation water application. The reader is referred to the section by Dr. J. I. Ramirez for precipitation data.
Two trials involving sugarbeets were conducted in 1971. One was a rate of nitrogen-sugarbeet variety trial - a continuation of the 1970 study - and the other was a rate of nitrogen-level of water study.
The nitrogen--variety trial was planted on May 6 in 22-inch rows with plants spaced an average of 9 inches within the row. Irrigation water was applied by the sprinkler system provided for the site.
The nitrogen-water level trial was planted to Holly variety beets on May 7 in 24-inch rows with plants spaced an average of 9 inches within the row. Irrigation water was applied with small plot irrigators. Plot size irrigated at each setting was 24 feet by 38 feet.
About 400 pounds 0-33-17 was broadcast prior to spring plowing. Fertilizer nitrogen, ammonium nitrate, was broadcast after planting. Plots receiving 100 pounds nitrogen (N) or less were treated on May 10, but plots treated with 200 pounds received a split application of 100 pounds each on May 10 and July 7. The plots were hand weeded.
Both trials were harvested October 8. Samples for sugar content and impurity were analyzed by the American Crystal Sugar Company at Rocky Fort, Colorado.
Precipitation received during the growing season was about 12.85 inches (See J. 11. Ramirez Agroclimatic Report). Irrigation water applied to the nitrogen-variety trial was about 15 inches (See Table 1). On the nitrogen water level trial, the irrigation water applied to treatment W1 was none, to W2 5 inches and to W3 11 inches.
Table 2 provides a summary of the significance of variance sources for both Sugarbeet trials. 1971.
Data for beet yield, % sucrose, impurity index and sugar yield for the rate of nitrogen-variety trial and the rate of nitrogen-water level trial are presented in Table 3 and Table 4, respectively.
In the rate of fertilizer nitrogen variety trial (Table 3) only the % sucrose and impurity index were affected by fertilizer nitrogen rate. The % sucrose was decreased and the impurity index increased by fertilizer nitrogen applied at 200 pounds N per acre. The 200 pounds of fertilizer nitrogen applied in this trial was much more than needed for the highest yield.
In the rate of fertilizer nitrogen-variety trial (Table 3) the odds are 90 out of 100 that the Holly variety yielded more beets than the other two varieties. However, the odds are less than 90 out of 100 that sugar yield was different among the varieties.
In the rate of fertilizer nitrogen-variety trial the impurity index was not affected in the same manner among the varieties at the four nitrogen rates applied. (Significant variety x nitrogen interaction). Where no fertilizer nitrogen was applied the impurity index of Beta 95.1 was lower than of Beta 96 and at the 200-pound rate the impurity index of Beta 95.1 was higher than Beta 96.
Irrigation water had an effect on all factors evaluated in the rate of nitrogen-water level trial (Table 4). When averaged over all fertilizer nitrogen rates, irrigation water increased beet and sugar yield and reduced the % sucrose and impurity index at either or both water levels.
When averaged over all water levels some fertilizer nitrogen rates increased yield of beets and sugar, decreased the sucrose and increased the impurity index. The 50-pound rate increased beet yields, but rates in excess of 50 pounds did not increase yields over that of the 50 pound rate. The largest sugar yields were obtained with the 50 pound rate; also at this rate the sucrose and impurity index did not differ from the check treatment.
The water level x nitrogen rate interaction was significant for yield of beets and sugar, and for impurity index. Beet yields were not increased by fertilizer nitrogen at the low (W1) and intermediate (W2) water level, but they were increased at the high (W3) water level. Sugar yield per acre was similarly affected as the beet yield in that sugar yield was increased by fertilizer nitrogen only at the high (W3) water level. The impurity index of the beets growing at the low (W1) water level was increased by the 100-pound fertilizer nitrogen rate, but at the other two water levels it was not increased until 200 pounds N was applied.
Data of water use efficiency (WUE) are presented in Table 5 for the rate of nitrogen.-water level trial. Water use efficiency is defined as the yield of beets per inch of water that could not be accounted for at the end of the season.
Application of irrigation water improved the efficiency of utilization of the precipitation.
The efficiency of utilization of irrigation water was highest for the intermediate (W2) water level.
Nitrate movement studies under irrigated corn and second year alfalfa were continued 9 in addition, nitrate movement under irrigated soybeans and sugarbeets was investigated.
Sugarbeets
Solution samples were not collected from treatment W1 (low water level) because of the difficulty encountered in obtaining samples from dry soil. A significant amount of nitrate moved down to the 3-foot depth for treatment W3 (high irrigation rate). The nitrate apparently remained at this depth until extracted by beet roots as little downward movement of nitrate below 3 feet was detected. Leaching of nitrate for treatment W2 (medium water treatment) would be expected to be less than for treatment W3.
1970 Tissue Samples
Tissue samples of sugarbeets were analyzed for various nutrients at four dates in 1970. The purpose of the analysis was to determine potential fertility problems (Table 15).
The concentration of phosphorus, zinc, manganese and copper tended to decrease as season advanced while potassium and calcium tended to increase.
The concentration was sufficiently high to be adequate for 25 ton beet yields. (See 1970 report).
The sugarbeet tissue samples were analyzed also for nitrogen and sulfur. Data are presented in Table 16.
Nitrogen (N) concentration ranged from 4.17 to 5.20%. The concentration at a specific sampling date was usually highest where fertilizer nitrogen was applied.
The nitrogen (N) to sulfur (S) ratios ranged from 5.8 to 9.0. Ratios larger than 17 are considered to indicate sulfur sufficiency.
1971 Sugarbeet Research and Extension Reports. Volume 2, pages 49 - 56.