Use of hot KCl-NH4-N to estimate fertilizer N requirements

1997 ◽  
Vol 77 (2) ◽  
pp. 161-166 ◽  
Author(s):  
C. A. Campbell ◽  
Y. W. Jamel ◽  
A. Jalil ◽  
J. Schoenau

We need an easy-to-use chemical index for estimating the amount of N that becomes available during the growing season, to improve N use efficiency. This paper discusses how producers may, in future, use crop growth models that incorporate indices of soil N availability, to make more accurate, risk-sensitive estimates of fertilizer N requirements. In a previous study, we developed an equation, using 42 diverse Saskatchewan soils, that related potentially mineralizable N (N0) to NH4N extracted with hot 2 M KCl (X), (i.e., N0 = 37.7 + 7.7X, r2 = 0.78). We also established that the first order rate constant (k) for N mineralization at 35°C is indeed a constant for arable prairie soils (k = 0.067 wk−1). We modified the N submodel of CERES-wheat to include k and N0 (values of N0 were derived from the hot KCl test). With long-term weather data (precipitation and temperature) as input, this model was used to estimate probable N mineralization during a growing season and yield of wheat (grown on fallow or stubble), in response to fertilizer N rates at Swift Current. The model output indicated that the amount of N mineralized in a growing season for wheat on fallow was similar to that for wheat on stubble, as we hypothesized. Further the model indicated that rate of fertilizer N had only minimal effect on N mineralized. We concluded that, despite the importance of knowing the Nmin capability of a soil, it is available water, initial levels of available N and rate of fertilizer N that are the main determinants of yield in this semiarid environment. The theoretical approach we have proposed must be validated under field conditions before it can be adopted for use. Key words: N mineralization, Hot KCl-NH4-N, potentially mineralizable N, CERES-wheat model

2021 ◽  
Vol 13 (10) ◽  
pp. 5649
Author(s):  
Giovani Preza-Fontes ◽  
Junming Wang ◽  
Muhammad Umar ◽  
Meilan Qi ◽  
Kamaljit Banger ◽  
...  

Freshwater nitrogen (N) pollution is a significant sustainability concern in agriculture. In the U.S. Midwest, large precipitation events during winter and spring are a major driver of N losses. Uncertainty about the fate of applied N early in the growing season can prompt farmers to make additional N applications, increasing the risk of environmental N losses. New tools are needed to provide real-time estimates of soil inorganic N status for corn (Zea mays L.) production, especially considering projected increases in precipitation and N losses due to climate change. In this study, we describe the initial stages of developing an online tool for tracking soil N, which included, (i) implementing a network of field trials to monitor changes in soil N concentration during the winter and early growing season, (ii) calibrating and validating a process-based model for soil and crop N cycling, and (iii) developing a user-friendly and publicly available online decision support tool that could potentially assist N fertilizer management. The online tool can estimate real-time soil N availability by simulating corn growth, crop N uptake, soil organic matter mineralization, and N losses from assimilated soil data (from USDA gSSURGO soil database), hourly weather data (from National Weather Service Real-Time Mesoscale Analysis), and user-entered crop management information that is readily available for farmers. The assimilated data have a resolution of 2.5 km. Given limitations in prediction accuracy, however, we acknowledge that further work is needed to improve model performance, which is also critical for enabling adoption by potential users, such as agricultural producers, fertilizer industry, and researchers. We discuss the strengths and limitations of attempting to provide rapid and cost-effective estimates of soil N availability to support in-season N management decisions, specifically related to the need for supplemental N application. If barriers to adoption are overcome to facilitate broader use by farmers, such tools could balance the need for ensuring sufficient soil N supply while decreasing the risk of N losses, and helping increase N use efficiency, reduce pollution, and increase profits.


1992 ◽  
Vol 22 (5) ◽  
pp. 707-712 ◽  
Author(s):  
Xiwei Yin

Published data were analyzed to examine whether nitrogen (N) availability varies along macroclimatic gradients in North America. Extractable N produced during 8-week aerobic laboratory incubation was used as an index of potential net N mineralization. Mean extractable N during the growing season in the forest floor plus top mineral soil was used as an index of the available N pool. Using multiple regression, potential net N mineralization was shown to increase with available N and with litter-fall N (R2 = 0.722). Available N increased with increasing total soil N and with decreasing mean January and July air temperatures (R2 = 0.770). These relationships appeared to hold also for deciduous and coniferous forests separately across regions. Results suggest that net N mineralization output under uniform temperature and moisture conditions can be generally expressed by variations of N input (litter fall) and the available soil N pool, and that the available soil N pool is predictable along a temperature gradient at a regional scale.


1995 ◽  
Vol 42 (1-3) ◽  
pp. 61-75 ◽  
Author(s):  
C. A. Campbell ◽  
Y. W. Jame ◽  
O. O. Akinremi ◽  
M. L. Cabrera

1993 ◽  
Vol 73 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Régis R. Simard ◽  
Adrien N'dayegamiye

An understanding of the mineralization factors in contrasting cultivated soils is necessary for accurate predictions of plant-available N. The objective of this work was to determine the N-mineralization potential and mathematical models that can properly describe the dynamics of the mineralization process in 20 meadow soils from Quebec. The mineralization was monitored over 55.4 wk in a laboratory incubation at 20 °C with intermittent leaching. The cumulative mineralization curves in most soils were characterized by definite lags or a sigmoidal pattern and near-linear release with time after 20 wk. The data were best described by the Gompertz equation; first-order models were inadequate. The total amount of mineralizable N and the potential mineralization rate were very closely correlated with the total amounts of C or N (r > 0.73; P < 0.01). The clay content was also correlated with these mineralization parameters and significantly improved the prediction of the cumulative and potential N-mineralization rate estimated from the total N or C content of soils. The relationships with other soil characteristics such as soil pH and available nutrient contents were weak but significant. The results of this study suggest that textural classes be added in the correction for organic matter content to improve the precision in N-fertilizer recommendation and in soil-quality classifications based on potential mineralization rate. Key words: Soil quality, potentially mineralizable N, Gompertz equation, soil organic matter, soil texture, C, N


HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1712-1718 ◽  
Author(s):  
Laura L. Van Eerd ◽  
Kelsey A. O'Reilly

The increase in fertilizer costs as well as environmental concerns has stimulated growers to re-evaluate their fertilizer applications to optimize nitrogen use efficiency (NUE) while maintaining crop yields and minimizing N losses. With these objectives, field trials were conducted at seven sites with five N rates (0 to 220 kg N/ha) of ammonium-nitrate applied preplant broadcast and incorporated as well as a split application treatment of 65 + 45 kg N/ha. In three contrasting years (i.e., cool/wet versus warm/dry versus average), N treatment had no observable effect on grade size distribution or brine quality. Based on the zero N control treatment, the limited yield response to fertilizer N was the result of sufficient plant-available N over the growing season. In the N budget, there was no difference between N treatments in crop N removal, but there was a positive linear relationship between N applied and the quantity of N in crop residue as well as in the soil after harvest. As expected, apparent fertilizer N recovery and N uptake efficiency were lower at 220 versus 110 kg N/ha applied preplant or split. The preplant and split applications of 110 kg N/ha were not different in yield, overall N budget, or NUE. Considering the short growing season, planting into warm soils, and the generally productive, nonresponsive soils in the region, growers should consider reducing or eliminating fertilizer N applications in machine-harvested cucumber.


HortScience ◽  
2011 ◽  
Vol 46 (9) ◽  
pp. 1294-1297 ◽  
Author(s):  
M. Lenny Wells

Nitrogen (N) fertilizer application to plants at rates not adjusted for the N contribution from soil N availability may result in overapplication of fertilizer. Further understanding of proper timing of N applications based on soil N dynamics and plant demand can be valuable information for the efficient use of fertilizer N. The present study measures soil N dynamics in a pecan orchard under various N fertilizer regimes on a southeastern U.S. Coastal Plain soil. The following treatments were evaluated: 1) crimson clover (Trifolium incarnatum L.); 2) poultry litter; 3) crimson clover + poultry litter; 4) ammonium nitrate (NH4NO3); and 5) untreated control. Crimson clover provided from 20 to 75 kg·ha−1 N over the course of the two growing seasons; however, most of the available N from crimson clover became available late in the growing season. As a result, supplemental N may be required in spring where crimson clover is used as an orchard cover crop. Poultry litter, with and without clover, provided available N consistently throughout the growing season with more N becoming available later in the season than earlier. This suggests that poultry litter applications for pecan should be timed before budbreak. Under optimum environmental conditions, N from NH4NO3 is most available within the first 30 days of application. Thus, it appears that synthetic fertilizer applications using NH4NO3 as the N source should be targeted at or 2 to 3 weeks after pecan budbreak.


2002 ◽  
Vol 82 (2) ◽  
pp. 219-225 ◽  
Author(s):  
P. Qian ◽  
J. J. Schoenau

Manures behave differently as sources of available N due to differences in the amounts and forms of N in the manure. The C:N ratio is an important factor affecting the rate of mineralization and release of available N from manures in which the majority of N is contained in organic forms. In order to ascertain the effect of manure C:N ratio on N mineralization in manure-amended soils, 13 solid manures with a large range in C:N ratio were applied to two Saskatchewan soils (Haverhill sandy loam and Blaine Lake clay loam) at 100 mg N kg-1 along with control (no manure) treatments. A growth chamber experiment was conducted to evaluate the relationship between manure C:N ratio and canola yield and N uptake, and a laboratory incubation was conducted to measure how the addition of manures with different C:N ratios affected the pattern of N release in the soils as measured by supply rates to anion exchange membrane (PRSTM) probes placed directly in the soil. Canola (Brassica napus var. Sprint) was grown under the same environmental conditions to maturity, and yield and nutrient contents were determined. A significant increase in canola yield and N uptake was observed over the control in both soils only when amended with poultry manure (C:N 7.6) or a pelletized form of hog manure that was supplemented with fertilizer N (C:N 6.6). A significant negative correlation was found between cattle manure organic C:N ratio and N mineralization. Overall, the manures showed limited release of available N over the short-term (67 d) when the organic C:N ratio was in the range of 13–15 and tended to decrease N availability in the short-term if the organic C:N ratio was over 15. The C:N ratio appears to be a useful parameter to measure when attempting to predict the effects of solid manure amendments on short-term N availability. Key words: Nitrogen availability, mineralization, manure, C:N ratio, anion exchange membrane


2018 ◽  
Vol 98 (3) ◽  
pp. 570-573 ◽  
Author(s):  
J. Dessureault-Rompré ◽  
D.L. Burton ◽  
B.J. Zebarth

We examined soluble organic nitrogen (SON) leached from long-term, sequentially leached, aerobic incubations. Leached SON, present in all depths (0–60 cm), ranged from 35% to 56% of total nitrogen (N). This unaccounted-for SON may have important implications in the estimation of plant available N and the potential for environmental N losses.


BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 8038-8048
Author(s):  
María Rosa Yagüe ◽  
Maria Carmen Lobo

Recycling organic waste for use as fertilizer requires prior knowledge of mineral nitrogen (N) availability for crops. Estimation of soil N release or potentially mineralizable N is an important tool for the design of fertilization strategies that aim to minimize the use of N fertilizer. The aerobic incubation method is considered a standard technique to measure soil potential to mineralize N. In this study, alternative methods of aerobic incubation were evaluated to help overcome its limitations (long time and equipment). In this regard, biological methods (anaerobic incubation at 7 and 14 days) and chemical extraction (hot KCl) procedures were examined. To determine potentially mineralizable N, a silty clay loam soil was fertilized with spent mushroom substrates and anaerobic digestates from different origins (C/N ratio of 4 to 38). Based on the results, chemical extraction emerges as a reliable alternative to the aerobic incubation method, particularly when the C/N ratio of the organic residues ranges from 12 to 15. Moreover, its implementation in routine soil laboratories is straightforward and faster, and it does not require any special equipment.


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