The level of plant available N greatly affects sugarbeet (Beta vulgaris L.) quality, sucrose production, and the amount of lower quality crown ussue produced. The response of several sugarbeet cultivars to N fertilization was studied in 1977 and 1978 to determine: i) what level of available N was needed by each cultivar to maximize sucrose production; ii) if each cultivar would respond similarly to N fertilization; and iii) if crown tissue production varies with cultivar. Nitrogen rates from 0 to 448 kg/ha were used as main plots with three to five commercially‐grown sugarbeet cultivars as subplots in the study. Root and sucrose yield, sucrose content, clear juice purity, and crown tissue production were determined for each treatment. All sugarbeet cultivars tested responded similarly to increasing levels of available N with crown tissue growth increasing linearly, sucrose content and clear juice purity decreasing linearly, and whole root yield increasing curvilinearly. Addition of some N fertilizer was needed to maximize sucrose production; however, as the level of N fertilization increased above the N level needed for maximum sucrose production, sucrose production decreased. Root tissue growth and sucrose production were maximum at the same N level, but maximum sucrose production did not coincide with maximum whole root yield. Sucrose production was maximum at the same N level for all cultivars. Thus, sugarbeet producers need not vary N fertilizer rates for each sugarbeet cultivar grown. However, total amount of sucrose production per unit area and crown growth did vary with cultivar. At optimum N fertilization, crown tissue accounted for 12 to 17% of the whole root yield, depending on year and cultivar grown. Results of this study indicate that N fertilization influences sugarbeet quality, crown tissue production, and level of sucrose production more than does sugarbeet cultivar.

Over the past 4 decades, sucrose content of sugarbeets (Beta vulgaris L.) has decreased while root yield has increased. Reasons reported include processing of more crown material, because mechanical harvesting removes less crown tissue than hand‐topping methods, and incre ased use of N fertilizer. Our objective was to determine the relationship between N application rate and sugarbeet crown tissue production, and its effects on processing quality of sugarbeets. Reported are the results of two studies conducted in 1975 and one in 1976, each using a different sugarbeet cultivar and seven N rates. Green petiole material was removed before each sugarbeet was sectioned into root and crown tissues for yield and quality analyses. Crown tissue increased linearly as rates of N application increased. Root tissue and recoverable sucrose yields were near maximum when spring soil NO3‐N or soil NO3‐N plus added N reached 200 to 225 kg/ha. At higher N levels, crown tissue yield increased and sucrose content in both root and crown tissues decreased, offsetting any potential benefits from increased whole beet yield. When N was adequate for maximmn sucrose production, crown tissue contributed approximately 20% of the total recoverable sucrose per ha. As N rate increased, sucrose concentration, extractable sucrose per metric ton, and purity decreased whereas Na, K, amino‐N, invert sugar, and imaturity index values increased for both root and crown tissues. Root tissue always had higher levels than crown tissue of extractable sucrose and purity and lower levels of Na, amino‐N, invert sugar, and impurity index. Crown tissue production can be minimized, and processing quality of sngarbeets can be improved by conservative use of N fertilizer.

Application of excessive N to sugarbeet‐producing soils has caused a deterioration in sugarbeet (Beta vulgaris L.) quality resulting in decreased sucrose production. The objective of the present work was to determine what rates of N fertilizer would produce maximum sucrose without sacrificing quality. Influences of repeated applications of sugarbeet yield and various quality factors, in a longtime organic and inorganic N sources and rates since 1953 on irrigated sugarbeet‐small grain rotation, were investigated in 1972 at Sidney, Montana. Nitrogen treatments included barnyard manure (22.4 and 67.2 metric tons/ha), green manure (alfalfa and biennial sweetclover), ammonium nitrate (O, 56, 112, 168, 224, 336, 448, and 560 kg N/ha) and a combination organic and inorganic N treatment (67.2 metric tons barnyard manure plus 112 kg inorganic N/ha). Highest sucrose production (7.9 metric tons/ha), obtained with 22.4 metric tons/ha of manure, was accompanied by root yields of 47.5 metric tons/ha, with sucrose percentage of 16.6 and petiole NO3‐N concentration (about 6 weeks before harvest) of 663 ppm. For the inorganic N treatments, highest sucrose yield (7.6 metric tons/ha) was obtained with 112 kg/ha of N, with similar results obtained for the green manure treatments. Inorganic N rates greater than 112 kg/ha caused progressive decreases in sucrose yields, sucrose percentage, and dry matter root weights. Dry matter root/top ratios of two or greater coincide with maximum sucrose yields. Increasing the rate of organic or inorganic N applied decreased dry matter root/top ratios. Results of this study indicate that either barnyard or green manure can be used successfully as a source of N for quality sugarbeet production.

Field studies were conducted from 1979 through 1982 on a furrow irrigated silty clay loam soil (Typic Argiboroll) to determine if sugarbeet (Beta vulgaris L.) sucrose production levels could be maintained with reduced seedbed tillage. Tillage treatments were: a) conventional tillage (CT)—complete fall incorporation of surface residues; b) strip tillage (ST)—fall incorporation of surface residues in 18‐cm wide bands located 56 or 61 cm apart; and c) no‐tillage (NT)—no incorporation of surface residues. Herbicides were fall applied for weed control. Sugarbeets were seeded 10 or 15 cm apart to eliminate need for thinning. Sugarbeet stands before cultivation averaged 3.7 sugarbeets/meter of row over the 4‐year period. Tillage treatment had no significant effect on spring soil temperatures and on sugarbeet stand, root yield, sucrose content, gross sucrose yield, and recoverable sucrose yield when averaged over the 4‐year period. Sugarbeet quality, in terms of clear juice purity, tended to be better in the reduced tillage treatments than in the CT treatment. This difference in clear juice purity probably resulted from the higher levels of spring soil NO3‐N found under CT than under reduced tillage plots. The results indicate that sucrose production under reduced seedbed tillage conditions can be maintained at levels comparable with conventional seedbed tillage conditions. Potential advantages of reduced seedbed tillage for sugarbeets are wind erosion control, reduced soil crusting problems, better soil water conditions in the seedbed for germination, reduced energy requirements, and reduced production costs.

Field experiments requiring 15N enriched fertilizer are costly, thus microplot techniques are generally used. Placing physical barriers around microplots to contain the 15N may introduce artifacts that affect N recovery by crops, limit types and numbers of measurements, and cause other restrictions. The purpose of this experiment was to determine minimum microplot size (without the use of barriers) for accurately measuring enriched 15N uptake into a winter wheat crop, while using normal field cultural practices. Winter wheat (Triticum aestivum L.) was seeded into KNO3 fertilized (56 and 112 kg N ha−1) plots (4.57 m by 3.05 m) on a Platner silt loam soil (fine montmorillonitic mesic Aridic Paleustol). Within each larger plot, four microplots (2.29 m by 1.83 m) were fertilized with 10 atom % 15N enriched KNO3 at the same rate as for main plots. Nitrogen‐rate treatments were replicated four times in a randomized block design. Above ground plant material was harvested (0.3 m of row) from six adjacent rows at flowering (Feeke's scale = 10.5). Three rows were harvested from inside (15N enriched KNO3 added) and three from outside (15N enriched KNO3 not added) of the microplots. Plant uptake of total N into plant tops was not significantly different across any of the six harvested rows. Dry matter yields and total‐N uptake were significantly larger for the 112 than for the 56 kg N ha−1 fertilizer rate, as were the 15N uptake and atom 15N % values in plant material within the microplots. In rows adjacent to microplot borders, concentrations of 15N in plant material changed rapidly; but there were no differences beyond 0.46 m inside or outside the microplots. These results indicate that minimum microplot size for studies with fall‐applied 15N on winter wheat grown in the Great Plains is 1.5 by 1.5 m.