Effect of nitrogen fertilization and topography on soft red winter wheat yield and protein content in two Ontario landscapes

2006 ◽  
Vol 86 (4) ◽  
pp. 729-739 ◽  
Author(s):  
Christopher J Denys ◽  
Ivan P O’Halloran ◽  
John D Lauzon

Identification of suitable management units for the variable application of fertilizer N is an essential component of a site-specific N management program. Topography and/or soil N test results are examples of two parameters that could potentially delineate N management units for improved grain yield or protein concentration. Field studies were conducted on soft red winter wheat (Triticum aestivum L.) to examine the effects of mineral soil N, soil organic carbon (SOC), and N fertilization on grain yields and protein concentrations in two variable landscapes in southwestern Ontario, Canada. Six N rates (0 to 145 kg N ha-1) were applied to plots (3 × 400 m long), arranged in a randomized complete split block design with four replicates. Sampling on a 3 × 20 m grid indicated slope position affected soil nitrate (NO3-N) and SOC levels at site 1, but not at site 2. The range of spatial correlation for NO3-N was 11.5 m at both sites and for SOC was 16.0 m and 32.4 m at site 1 and 2, respectively. Yields decreased and protein concentrations increased while moving upslope at both sites. Yield response to applied fertilizer N was characterized using a quadratic model. The most economic rate of N (MERN) for site 1 was 105 kg ha-1, and did not vary with topography. At site 2, yield response to applied fertilizer N varied with topography and MERN increased while moving downslope (91, 104, 120 kg N ha-1 for upper, mid, and lower, respectively). Protein concentration responses to applied N were fitted to cubic models, and the nature of the response to applied N did not vary with slope position. Based simply on grain yield, the potential to use topography and/or mineral N in the soil to identify management units for variable application of N was limited at these two sites; however, variably applying N may reduce the risk of exceeding the protein limits for export markets on the upper slope positions without sacrificing yield. Key words: Site-specific crop management, nitrogen application, N fertilizer, variogram, topography

2004 ◽  
Vol 84 (3) ◽  
pp. 307-316 ◽  
Author(s):  
I. P. O’Halloran ◽  
A. P. von Bertoldi ◽  
S. Peterson

Identification of management units for the variable application of fertilizer N is a critical component for the implementation of a site-specific N management program. Field studies were conducted to examine the spatial variability of soil nitrate levels, spring barley (Hordeum vulgare) and corn (Zea mays L.) yields and yield responses to fertilizer N applications on two sites in southwestern Ontario, Canada. Soil sampling on a 3 × 10 m grid indicated that soil NO3-N test values had a log-normal distribution and varied considerably at both sites with CVs exceeding 57% on the untransformed data. Ranges of spatial correlation varied from 20 to 95 m with 30 to 80% of the total variance of the ln-transformed data existing as either random or unsampled variance, and these parameters were not temporally stable. Although NO3-N tended to increase at lower slope positions in two of the 3 site-years, considerable within-slope variability of soil NO3-N levels was also observed. Spatial variations in soil N test levels, crop yields and crop yield responses to applied fertilizer N were not strongly related to one another indicating that it would be unlikely that either soil N test level or yield would adequately delineate management zones for the variable application of N fertilizer at these sites. Key words: Variogram, topography, site-specific crop management


2010 ◽  
Vol 100 (2) ◽  
pp. 160-171 ◽  
Author(s):  
P. A. Paul ◽  
M. P. McMullen ◽  
D. E. Hershman ◽  
L. V. Madden

Multivariate random-effects meta-analyses were conducted on 12 years of data from 14 U.S. states to determine the mean yield and test-weight responses of wheat to treatment with propiconazole, prothioconazole, tebuconazole, metconazole, and prothioconazole+tebuconazole. All fungicides led to a significant increase in mean yield and test weight relative to the check (D; P < 0.001). Metconazole resulted in the highest overall yield increase, with a D of 450 kg/ha, followed by prothioconazole+tebuconazole (444.5 kg/ha), prothioconazole (419.1 kg/ha), tebuconazole (272.6 kg/ha), and propiconazole (199.6 kg/ha). Metconazole, prothioconazole+tebuconazole, and prothioconazole also resulted in the highest increases in test weight, with D values of 17.4 to 19.4 kg/m3, respectively. On a relative scale, the best three fungicides resulted in an overall 13.8 to 15.0% increase in yield but only a 2.5 to 2.8% increase in test weight. Except for prothioconazole+tebuconazole, wheat type significantly affected the yield response to treatment; depending on the fungicide, D was 110.0 to 163.7 kg/ha higher in spring than in soft-red winter wheat. Fusarium head blight (FHB) disease index (field or plot-level severity) in the untreated check plots, a measure of the risk of disease development in a study, had a significant effect on the yield response to treatment, in that D increased with increasing FHB index. The probability was estimated that fungicide treatment in a randomly selected study will result in a positive yield increase (p+) and increases of at least 250 and 500 kg/ha (p250 and p500, respectively). For the three most effective fungicide treatments (metconazole, prothioconazole+tebuconazole, and prothioconazole) at the higher selected FHB index, p+ was very large (e.g., ≥0.99 for both wheat types) but p500 was considerably lower (e.g., 0.78 to 0.92 for spring and 0.54 to 0.68 for soft-red winter wheat); at the lower FHB index, p500 for the same three fungicides was 0.34 to 0.36 for spring and only 0.09 to 0.23 for soft-red winter wheat.


2008 ◽  
Vol 88 (5) ◽  
pp. 837-848 ◽  
Author(s):  
S J Steckler ◽  
D J Pennock ◽  
F L Walley

The Illinois soil N test (ISNT) has been used to distinguish between soils that are responsive and non-responsive to fertilizer N in Illinois. We examined the suitability of this test, together with more traditional measures of soil fertility, including spring nitrate-N and soil organic carbon (SOC), for predicting yield and N fertilizer response of wheat (Triticum aestivum) on hummocky landscapes in Saskatchewan. The relationship between ISNT-N and wheat yield and fertilizer N response was assessed using data and soils previously collected for a variable-rate fertilizer study. Soils were re-analyzed for ISNT-N. Our goal was to determine if ISNT-N could be used to improve the prediction of crop yields. Although ISNT-N was correlated with both unfertilized wheat yield (r = 0.467, P = 0.01) and fertilizer N response (r = -0.671, P = 0.01) when data from all study sites were combined, correlations varied according to landscape position and site. Stronger correlations between nitrate-N and both unfertilized wheat yield (r = 0.721, P = 0.01) and fertilizer N response (r = -0.690, P = 0.01) indicated that ISNT-N offered no advantage over nitrate-N. Although both tests broadly discriminated between sites with high or low N fertility, few relationships were detected on a point-by-point basis within a field. Stepwise regression equations predicting yield and yield response did not include ISNT-N, due in part to the high degree of collinearity between ISNT-N and other variables such as SOC, suggesting that ISNT-N alone was not a key indicator of soil N supply. Key words: Illinois soil nitrogen test, potentially available N, soil N, fertilizer N recommendations


Plant Disease ◽  
2015 ◽  
Vol 99 (10) ◽  
pp. 1434-1444 ◽  
Author(s):  
K. T. Willyerd ◽  
C. A. Bradley ◽  
V. Chapara ◽  
S. P. Conley ◽  
P. D. Esker ◽  
...  

Standard foliar fungicide applications in wheat are usually made between flag leaf emergence (Feekes [FK] 8) and heading (FK10.5) to minimize damage to the flag leaf. However, over the last few years, new fungicide programs such as applications prior to FK8 and split half-rate applications have been implemented, although there are few data pertaining to the efficacy of these programs. Eight experiments were conducted in Illinois, Indiana, Ohio, and Wisconsin from 2010 to 2012 to compare new programs to standard FK8 and FK10 programs in terms of disease control and yield response. The programs evaluated consisted of single full-rate applications of 19% tebuconazole + 19% prothioconazole (Prosaro) or 23.6% pyraclostrobin (Headline) at FK5 (pseudostem strongly erected), FK8, or FK10, or split half rates at FK5 and 8 (FK5+8), plus an untreated check (CK). Leaf blotch (LB) severity and yield data were collected and random effects meta-analytical models fitted to estimate the overall log odds ratio of disease reaching the flag leaf ([Formula: see text]) and mean yield increase ([Formula: see text]) for each fungicide program relative to CK. For all programs, [Formula: see text] was significantly different from zero (P < 0.05). Based on estimated odds ratios (OR = exp[[Formula: see text]]), the two FK8 programs reduced the risk of LB reaching the flag leaf by 55 and 75%, compared with 62 and 69% and 67 and 70% for the two FK10 and FK5+8 programs, respectively, and only 32 and 37% for the two FK5 programs. [Formula: see text] was significantly different from zero (P ≤ 0.003) for all FK8, FK10, and FK5+8 programs, with values of 233 and 245, 175 and 220, and 175 and 187 kg ha−1 for the FK10, FK5+8, and FK8 programs, respectively. Differences in mean yield response between Headline and Prosaro were not statistically significant (P > 0.05). The probability of profitability was estimated for each program for a range of grain prices and fungicide application costs. All FK8, FK10, and FK5+8 programs had more than an 80% chance of resulting in a positive yield response, compared with 63 and 67% for the two FK5 programs. The chance of obtaining a yield increase of 200 kg ha−1, required to offset an application cost of $36 ha−1 at a grain price of $0.18 kg−1, ranged from 44 to 60% for FK8, FK10 and FK5+8 programs compared with 22 and 25% for the two FK5 programs. These findings could be used to help inform fungicide application decisions for LB diseases in soft red winter wheat.


Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1683
Author(s):  
Ammar Al-Zubade ◽  
Timothy Phillips ◽  
Mark A. Williams ◽  
Krista Jacobsen ◽  
David Van Sanford

Soft red winter wheat (SRW) is characterized by high yield and relatively low protein content. In Kentucky, there is growing demand from local artisan bread bakers for regionally produced flour, requiring production of grain with increased protein content and/or strength. The objective of this two-year field experiment was to evaluate the effect of nitrogen (N) management on five cultivars of winter wheat on yield and bread baking quality traits of modern and landrace SRW cultivars (Triticum aestivum L.). All five cultivars were evaluated using two N application rates in conventional and organic production systems. All traits measured were significantly affected by the agricultural production system and N rate, although plant height and other quality traits varied by study year. Significantly higher yields were achieved in the conventional system at a relatively low N rate (67.2 kg ha−1) in both study years (2017–2019) (p < 0.01). Results were variable by cultivar and a locally bred, high-yielding cultivar (Pembroke 2014) had the highest lactic acid solvent retention capacity score and thousand kernel weight of the cultivars evaluated. In addition, a landrace cultivar (Purple Straw) had the highest grain N and plant height. A French soft wheat, Soissons, had the highest sedimentation value and Pembroke 2016 achieved the highest yield. The findings from this study suggest the possibility of attaining a desirable grain with quality traits of SRW wheat that meets the needs of local bread wheat production in Kentucky through improving the optimization of cultivar selection, N management and specific considerations for conventional and organic systems.


2004 ◽  
Vol 96 (1) ◽  
pp. 124 ◽  
Author(s):  
Michael Flowers ◽  
Randall Weisz ◽  
Ronnie Heiniger ◽  
Deanna Osmond ◽  
Carl Crozier

2009 ◽  
Vol 89 (2) ◽  
pp. 113-132 ◽  
Author(s):  
B J Zebarth ◽  
C F Drury ◽  
N Tremblay ◽  
A N Cambouris

There is increasing public pressure to reduce the environmental impacts of agricultural production. Therefore, one key challenge to producers is to manage their crop production systems in order to minimize losses of nitrogen to air or water, while achieving crop yield and quality goals. Many strategies have been developed in recent years to meet this challenge. These include: development of new tools to measure crop N status in order to refine in-season fertilizer N management, development of new soil N tests to improve prediction of soil N supply, development of new fertilizer N products with release patterns more closely matched to crop N uptake patterns, and development of site-specific N management strategies. We review the opportunities and limitations to these new strategies within different arable crop production systems under the humid and sub-humid soil moisture regimes present in eastern Canada. Future research opportunities to improve the efficiency of fertilizer N utilization include development of practical methods to predict the magnitude of soil N mineralization; refinement of decision-making processes which take into consideration the crop N status and soil properties as a basis for variable rate fertilizer N application; development of affordable controlled-release fertilizer N products with improved N release characteristics; development of practical methods for capturing and recycling nutrient-laden drainage water; development of gene expression profiling based techniques to identify crop N stress; and application of crop genomics and molecular breeding techniques to accelerate the development of new cultivars with increased N use efficiency. Key words: Soil N tests, plant N tests, nitrogen fertilizers, nitrogen cycling


2020 ◽  
Vol 56 (3) ◽  
pp. 397-406
Author(s):  
Arun Shankar ◽  
R. K. Gupta ◽  
Bijay-Singh

AbstractField experiments were conducted to standardize protocols for site-specific fertilizer nitrogen (N) management in Bt cotton using Soil Plant Analysis Development (SPAD) chlorophyll meter. Performance of different SPAD-based site-specific N management scenarios was evaluated vis-à-vis blanket fertilizer N recommendation. The N treatments comprised a no-N (control), four fixed-time and fixed N doses (60, 90, 120, and 150 kg N ha-1) including the recommended dose (150 kg ha-1), and eight fixed-time and adjustable N doses based on critical SPAD readings of 45 and 41 at first flowering and boll formation stages, respectively. The results revealed that by applying 45 or 60 kg N ha-1 at thinning stage of the crop and critical SPAD value-guided dose of 45 or 30 kg N ha-1 at first flowering stage resulted in yields similar to that recorded by applying the recommended dose of 150 kg N ha-1. However, significantly higher N use efficiency as well as 30–40% less total fertilizer N use was recorded with site-specific N management. Applying 30 kg N ha-1 at thinning and SPAD meter-guided 45 kg N ha-1 at first flowering were not enough and required additional SPAD meter-guided 45 kg N ha-1 at boll formation for sustaining yield levels equivalent to those observed by following blanket recommendation but resulted in 20% less fertilizer N application. Our data revealed that SPAD meter-based site-specific N management in Bt cotton results in optimum yield with dynamic adjustment of fertilizer N doses at first flowering and boll formation stages. The total amount of N fertilizer following site-specific management strategies was substantially less than the blanket recommendation of 150 kg N ha-1, but the extent may vary in different fields.


Crop Science ◽  
1982 ◽  
Vol 22 (4) ◽  
pp. 871-876 ◽  
Author(s):  
Allen W. Kirlies ◽  
Thomas L. Housley ◽  
Abdallah M. Emam ◽  
Fred L. Patterson ◽  
Martin R. Okos

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