Nitrogen Requirements of Winter Wheat (Triticum aestivum, L.) Varieties ‘Blueboy’ and ‘Redcoat’¹

Abstract

In 1970–71, five N‐rate field experiments were conducted with fall‐seeded soft red winter wheat (Triticum aestivum, L.) on limestone‐derived soils in Pennsylvania. Varieties ‘Blueboy’ and ‘Redcoat’ were compared at two locations. At three locations, only Blueboy was grown. Redcoat is widely grown in Pennsylvania, but Blueboy was only recently introduced. The relative nitrogen requirements of these varieties, therefore, was essentially unknown when these studies were begun. Fall and spring applications of 0, 34, 67, 101, 135, and 168 kg/ha of N as ammonium sulfate were compared at each location. The nitrogen content of grain plus straw associated with maximum attainable yield of dry matter was similar among locations and varieties, the mean percent N and its standard deviation being 1.38 ± 0.06%. Yields of grain invariably were depressed when nitrogen in grain plus straw exceeded the mean value of 1.22 ± 0.06% (S.D.). The latter value is considered to represent the internal N requirement of the wheat associated with optimum production of grain, and it corresponds to the percent N in grain plus straw associated with 95 to 98% of total dry matter production. Recovery of fertilizer N was significantly greater for spring than for fall applications, although differences were small (means were 56 and 48%, respectively, for all locations). Yields of Blueboy were substantially greater than those of Redcoat at locations where these varieties were compared. Interactions of rate and time of N application on yields of grain and dry matter and N yields were not significant. Total uptake of N required per unit of wheat grain for maximum attainable yield is almost twice that required for corn.

Predicting Nitrogen Fertilizer Needs for Sugarbeets from Residual Nitrate and Mineralizable Nitrogen

“…The Ef value can be expected to range from 0.5 to 0.7, depending on management practices (13), and was previously found to be 0.65 in this area (5). After harvest, the yield response to N can be evaluated by substituting Ymax for YE in Equation [2b1.…”

“…Ef can be evaluated by determining total N uptake from about 4 rates of Nf (0, 0.5, 1.0, and 1.5 to 2 times the rate needed For optimum production) or by assuming a value between 0.5 to 0.7 (13). When evaluating Ef', the method and time of fertilizer application normally used by the growers should be used.…”

Relationship of nitrogen management to winter wheat yield and grain protein in South Dakota

“…Nitrogen management in wheat is also important since excess N can reduce yields because lodging and pathogen pressure increase. However, some varieties exhibited a yield reduction as N applications exceeded optimum rates for grain production even before lodging was observed (Stanford and Hunter, 1973). Lower grain yields were also observed when higher than optimum N levels were applied (McDonald, 1992) presumably because N stimulated higher vegetative growth (Schleuber and Tucker, 1967) which did not translate into yield increases.…”

“…Lower grain yields were also observed when higher than optimum N levels were applied (McDonald, 1992) presumably because N stimulated higher vegetative growth (Schleuber and Tucker, 1967) which did not translate into yield increases. This occurred because the optimum N requirement for maximum straw production is higher than the N requirement for optimum grain yields (Stanford and Hunter, 1973).…”

Analysis of Wheat Cultivar Differences in Grain Yield, Grain Nitrogen Yield and Nitrogen Utilization Efficiency.

“…trait would be useful in selecting genotypes Both fall and winter nitrogen (N) appli-with high yield potential and yield stability, cations can affect wheat yields but results dep-The objective of this study was to evaluate the end on the environment. Generally, when N influence of N fertilizer and application timing availability in the soil was low, grain yields on the importance of the various component increased with N application until yield was traits to determine the variability in grain yield, maximized (STANFORD andHUNTER 1973, grain N yield andN utilization efficiency FREDERICK andMARSHALL 1985, BRUCKNER among four wheat cultivars grown under field and MOREY 1988). The results of split N appli-conditions in a Mediterranean climate, cation are contradictory.…”