End-of-Season Corn Stalk Test for Excess Nitrogen in Silage Corn

Hooker, Beth; Morris, Thomas F.

doi:10.2134/jpa1999.0282

Cited by 26 publications

(35 citation statements)

References 17 publications

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“…The corn stalk nitrate test (CSNT) was developed to provide an assessment of the N status of corn at the end of the season (Binford et al, 1990(Binford et al, , 1992cHooker and Morris, 1999;Fox et al, 2001;Forrestal et al, 2012). This test was developed to take advantage of the fact that corn plants store nitrate in the lower stalk when excess N is available during the growing season.…”

Section: Corn Stalk Nitrate Testmentioning

confidence: 99%

Strengths and Limitations of Nitrogen Rate Recommendations for Corn and Opportunities for Improvement

et al. 2018

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A gronomy J our n al • Volume 110 , I ssue 1 • 2 018 1 T he goal of an N recommendation system is to accurately estimate the gap between the N provided by the soil and the N required by the plant. Accurately estimating this gap depends on the ability of the recommendation system to accurately estimate fi eld or subfi eld specifi c economically optimal nitrogen rates (EONR). Current recommendation systems are not as accurate as needed to provide consistently reliable estimates of N needs across years at the fi eld or subfi eld scale. Uncontrollable factors like temperature, rainfall timing, intensity and amount, and interactions of temperature and rainfall with factors such as N source, timing and placement, plant genetics, and soil characteristics combine to make N rate recommendations for an individual fi eld or rates for subfi elds a process guided as much by science as by the best professional judgement of farmers and farm advisors.Substantial evidence has accumulated that EONRs can vary widely across fi elds, within fi elds and over years in the same fi eld for a wide range of crops and geographies. Examples ABSTRACTNitrogen fi xation by the Haber-Bosch process has more than doubled the amount of fi xed N on Earth, signifi cantly infl uencing the global N cycle. Much of this fi xed N is made into N fertilizer that is used to produce nearly half of the world's food. Too much of the N fertilizer pollutes air and water when it is lost from agroecosystems through volatilization, denitrifi cation, leaching, and runoff . Most of the N fertilizer used in the United States is applied to corn (Zea mays L.), and the profi tability and environmental footprint of corn production is directly tied to N fertilizer applications. Accurately predicting the amount of N needed by corn, however, has proven to be challenging because of the eff ects of rainfall, temperature, and interactions with soil properties on the N cycle. For this reason, improving N recommendations is critical for profi table corn production and for reducing N losses to the environment. Th e objectives of this paper were to review current methods for estimating N needs of corn by: (i) reviewing fundamental background information about how N recommendations are created; (ii) evaluating the performance, strengths, and limitations of systems and tools used for making N fertilizer recommendations; (iii) discussing how adaptive management principles and methods can improve recommendations; and (iv) providing a framework for improving N fertilizer rate recommendations.

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Section: Corn Stalk Nitrate Testmentioning

confidence: 99%

Strengths and Limitations of Nitrogen Rate Recommendations for Corn and Opportunities for Improvement

et al. 2018

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“…Binford et al (1990Binford et al ( , 1992b specified that CSNT samples were to be collected 1 to 2 wk after physiological maturity (black layer formation) for grain corn. Hooker and Morris (1999) suggested that the test could be used for corn silage as well but that the optimal range should be adjusted to 500 to 1000 mg NO 3 -N kg -1 . Fox et al (2001) also stated that the CSNT can be used for silage corn but did not suggest a change in critical values for corn harvested for silage from what was put forth by Binford et al (1990).…”

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confidence: 99%

“…For example, Wilhelm et al (2005) passed the sample through a 2.0-mm screen whereas Isla and Blackmer (2007) and Hooker and Morris (1999) used a 1.0-mm screen, and Sims et al (1995) ground samples to pass a 0.85-mm screen. In the Binford et al (1990) study, samples were ground using a Wiley mill with a 1.0-mm screen and then with a cyclone mill with a 0.5-mm screen.…”

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confidence: 99%

“…The permanganate-reduced Fe method to include nitrate was used to determine Kjeldahl N. Binford et al (1992a) used the same methods, with a Lachat flow-injection procedure, as did Brouder et al (2000) and Fox et al (2001). In the study of Hooker and Morris (1999), samples were extracted by shaking with 0.05 M Al 2 (SO 4 ) 3 for 20 min. To minimize differences in ionic strength, 1.0-mL of 2.0 M (NH 4 ) 2 SO 4 was added to each extraction followed by determination of NO 3 -N using a nitrate specific ion electrode (SIE).…”

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Improving Sample Collection, Sample Processing, and Laboratory Analyses for Corn Stalk Nitrate Test

et al. 2017

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A gronomy J our n al • Volume 10 9, I ssue 5 • 2 017 T he end-of-season CSNT was developed in Iowa by Binford et al. (1990) as a tissue test for grain corn, with samples taken at physiological maturity for distinguishing between fertilizer N applications that resulted in a crop yield increase and those that exceeded crop needs. Binford et al. (1990) showed that CSNT-N increased linearly with N fertilizer rate when N was applied beyond what was needed for maximum yield. A critical CSNT-N of 250 mg NO 3 -N kg -1 was established, based on a linear-to-plateau crop yield response model with relative corn yield as the dependent variable.Two years after the introduction of the CSNT, the optimum CSNT range was adjusted (700 to 2000 mg NO 3 -N kg -1) ) to identify deficiencies or excesses of N (Binford et al., 1992b). Similarly, Blackmer and Mallarino (1996) introduced four sufficiency categories including 250 and 700 mg NO 3 -N kg -1 defined as marginal and 700 to 2000 mg NO 3 -N kg -1 as optimal. The marginal category was described as the range in which N availability was very close to the minimal amounts needed, close enough to not be a concern, but too close to be a target for optimal N management (Blackmer and Mallarino, 1996).The initial studies in Iowa were followed by studies in other regions. Sims et al. (1995) and Varvel et al. (1997), working in Delaware and Nebraska, respectively, also concluded the CSNT was successful in separating essential vs. excessive fertilizer N applications. Studies by Fox et al. (2001) confirmed the usefulness of the CSNT in Pennsylvania and suggested that the original critical value of 250 mg NO 3 -N kg -1 resulted in a lower error rate (incorrect classification) than the value of 700 mg NO 3 -N kg -1 suggested in 1992.With the expansion of use of the CSNT, changes in methodologies were introduced. In the original work in Iowa, the NO 3 -N content was determined in 20-cm long corn stalk sections, with dry leaves removed, cut at 15 and 35 cm aboveground (Binford et al., 1990). This field sampling method has served as the convention for sampling for the majority of subsequent studies and is what is recommended currently to farmers by many Land Grant universities. Searching for a method to reduce the amount of plant material to be collected, dried, and ground, Isla and Blackmer (2007) ABSTRACTThe corn (Zea mays L.) stalk nitrate test (CSNT) is a site-specific, after-the-fact, diagnostic tool for N management of corn. Although considered effective, widespread adoption of CSNT is limited due to somewhat impractical sample collection, handling, and laboratory sample processing protocols. Five studies were conducted to evaluate the impact of alternative sampling, sample handling, and laboratory processing protocols on CSNT outcomes. Study 1 evaluated the effect of stalk length and position on CSNT values. In Study 2 timing of sampling or growth stage was evaluated. In Study 3 several sampling patterns within a field (samples taken within a corn row vs. perpendicular or under an angle to r...

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“…A relatively new tissue test for measuring the sufficiency of N for corn is based on NO 3 –N concentrations in the lower portions of cornstalks at the end of the season (Binford et al, 1990, 1992b; Hooker and Morris, 1999; Brouder et al, 2000; Fox et al, 2001). Studies across a wide range of conditions show that cornstalk NO 3 –N concentrations greater than 0.75 g N kg −1 indicate that N supplies were sufficient for plant growth.…”

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Testing Soils and Cornstalks to Evaluate Nitrogen Management on the Watershed Scale

et al. 2003

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High nitrate (NO3-N) concentrations in Iowa rivers have been linked to areas of intensive row crop production, but they have not been experimentally linked to specific management practices used during row crop production. This study demonstrates how the late-spring test for soil NO3-N and the end-of-season test for cornstalk NO3-N can be used to measure N sufficiency levels across many fields and how the results can be used to evaluate management practices within a watershed. More than 3200 soil and cornstalk samples were collected over a 12-yr period from fields planted to corn (Zea mays L.) and already fertilized by farmers using their normal practices. Results showed that early-season rainfall and associated N losses were major factors affecting N concentrations in soils and cornstalks. Evidence for NO3-N movement from fields to rivers was provided by an inverse relationship between annual means for NO3-N concentrations in soils and rivers. Because these losses can be avoided by delaying N applications, the practice of applying N several weeks or months before plants grow was linked to inefficient use of fertilizer and manure N by crops. Results of the study demonstrate how aggregate analyses of soil and cornstalk samples collected across many farms and years make it possible to identify the major factors affecting N management outcomes and, therefore, N management practices that are likely to produce the best outcomes within a watershed or region. This approach seems to have unique potential to interrelate the management practices of farmers, the efficiency of N fertilization, and NO3-N concentrations in rivers.

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End-of-Season Corn Stalk Test for Excess Nitrogen in Silage Corn

Cited by 26 publications

References 17 publications

Strengths and Limitations of Nitrogen Rate Recommendations for Corn and Opportunities for Improvement

Strengths and Limitations of Nitrogen Rate Recommendations for Corn and Opportunities for Improvement

Improving Sample Collection, Sample Processing, and Laboratory Analyses for Corn Stalk Nitrate Test

Testing Soils and Cornstalks to Evaluate Nitrogen Management on the Watershed Scale

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