Adapting the potentially mineralizable N concept for the prediction of fertilizer N requirements

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


1984 ◽  
Vol 64 (3) ◽  
pp. 355-367 ◽  
Author(s):  
V. O. BIEDERBECK ◽  
C. A. CAMPBELL ◽  
R. P. ZENTNER

Effects of rotation length, fallow-substitute crops, and N and P fertilizer on some physical and biological properties of a Brown Chernozemic loam in southwestern Saskatchewan were determined over a period of 16 yr. After 12 yr, the erodible fraction in the top 15 cm of soil (i.e., < 0.84 mm) was inversely related to trash conserved and thus rotation length. Soil organic N (in the top 15 cm) increased from 0.18 to 0.20% in continuous-type rotations receiving an average 32 kg N∙ha−1∙yr−1 and adequate P, but it did not increase in continuous wheat receiving P only, nor in fallow rotations, except the one that included fall rye (Secale cereale L.). This N increase was credited partly to fertilizer and partly to more efficient use and cycling of subsoil NO3-N via plant roots and crop residues. After 10 yr, well-fertilized continuous-type rotations had a 13% greater C content than fallow rotations and continuous wheat receiving only P. In the top 7.5 cm of soil under the four rotations examined in detail, bacterial numbers were lowest in fallow-wheat, intermediate in fallow-wheat-wheat, higher in continuous wheat receiving N and P, and highest in continuous wheat receiving only P. Similarly, microbial biomass C in these four rotations was 180, 226, 217 and 357 kg∙ha−1; biomass N was 52, 65, 54 and 72 kg∙ha−1; and biomass C/N ratios were 3.4, 3.5, 4.1 and 5.1, respectively. Differences in biomass C/N, respiration rates and numbers of bacteria, actinomycetes and yeasts indicated both quantitative and qualitative microbial changes and reflected increasing rotation length and differences in fertility. Potentially mineralizable N (No) was 192 kg∙ha−1 for adequately fertilized continuous wheat, and exceeded No in fallow-wheat by 45%, in fallow-wheat-wheat by 17% and in continuous wheat receiving only P by 25%. The latter rotation contained a large but fairly inactive microbial population. We concluded that land degradation caused by frequent summerfallowing can be arrested and the decline in amount and quality of organic matter reversed by use of available agronomic technology. Key words: Microbial biomass, microbial activity, potentially mineralizable N, respiration, soil erodibility


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.


1982 ◽  
Vol 62 (4) ◽  
pp. 651-656 ◽  
Author(s):  
C. A. CAMPBELL ◽  
W. SOUSTER

Although it is known that considerable loss in total organic matter has occurred due to cultivation of prairie soils, there is little information on changes in the fertility-related fraction of the organic matter. Twelve prairie surface soils representing paired virgin and cultivated coarse-, medium-, and fine-textured soils from the Brown, Dark Brown, and thin Black Chernozem and Gray Luvisol soil zones were analyzed and used to assess changes in total C, N and potentially mineralizable N. Cropping caused large losses of organic C (41–53%) and N (31–56%), but losses of potentially mineralizable N (N0) were even greater for the Chernozems (55–67%) though not for the Gray Luvisols. N0 in virgin soils ranged between 133 and 401 μg N/g soil and increased from Gray Luvisol to Brown to Dark Brown to thin Black Chernozem. In cultivated soils, N0 was generally similar among soil zones and values ranged between 66 and 141 μg N/g soil. Medium-textured soils generally had the greatest organic matter content and N0. The active N fraction (N0/N) ranged between 4 and 20.5% and was greatest in Brown soils and in the coarser-textured soils. Losses of organic matter, N0, and N0/N were greatest from the coarser-textured soils. The findings of this study help to explain why a significant portion of prairie soils now require N fertilizer even after being summer-fallowed.


1992 ◽  
Vol 72 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Suzanne Beauchemin ◽  
Marc R. Laverdière ◽  
Adrien N’dayegamiye

A field trial with potato (Solanum tuberosum L.) was conducted on a sandy soil to estimate N immobilization after applying tree clippings to the soil. N availability was evaluated by mineralizable N, N recovery coefficients and N derived from fertilizer. Fresh and composted tree clippings (50 t ha−1) were compared with an unamended control. In each principal treatment, nitrogen fertilizer was added at the rates of 0, 150, 200 and 250 kg N ha−1. Mineralizable N was lowest (P ≤ 0.001) in plots amended with wood residues by comparison to the unamended control. N recovery was 0.49 and 0.54 for fresh and composted residues, respectively, which indicates a higher N immobilization for fresh wood residues. N immobilization was estimated at 46 kg N ha−1 and increased in treatments receiving fresh tree clippings and also with increasing N rates. Moreover, a significant linear increase of N derived from fertilizer (P = 0.03) was observed with fertilizer N rates especially in amended treatments. Thus, the incorporation of ligneous material to the soil may have reduced the availability of soil mineralized N and potato growth depended mainly on N fertilizer addition. This study indicates that during the first growing season following the application of ligneous materials, N immobilization remained the main restricting factor on potato production. Key words: N availability, N derived from fertilizer, N immobilization, N recovery coefficient, potato, tree clippings, wood residues


2010 ◽  
Vol 56 (No. 9) ◽  
pp. 429-433
Author(s):  
B. Jalili ◽  
F. Nourbakhsh ◽  
M. Ghiasi

It has been demonstrated that azo dyes, the xenobiotics widely use in industries, can pose threats to public health. 3,3'-diaminobenzidine (DAB), as a benzidine analogue, is generated from reduction of azo dyes by intestinal or environmental microorganisms. The compound was applied at doses of 0 and 100 mg N/kg into two soils of contrasting textural properties belonging among Haplic Calsisols (Juzdan soil) and Calcaric Cambisols (Shervedan soil) and the effects on N mineralization kinetics were evaluated. Kinetic behavior of N mineralization in either the control or the DAB-treated soils consistently followed first-order models. In the early 7&ndash;10 days of the incubation period, net N mineralization was adversely influenced by DAB. After the early 7&ndash;10 days of incubation, the accumulation of inorganic N was greater in DAB-treated soils than those of control soils. This finding indicated that the degradation of DAB was started. Potentially mineralizable N in Haplic Calsisols and Calcaric Cambisols were 1.1 and 1.4 times greater than those of controls, respectively. Similarly, initial potential rates of N mineralization in the DAB-treated soils were 1.3 and 1.1 times greater than those of controls, respectively. The potentially mineralizable N and initial potential rates of N mineralization in both soils were significantly (LSD, P &lt; 0.05) increased when soils were treated with DAB. About 95 and 82% of the initial DAB-N were mineralized to inorganic N after 60 days of aerobic incubation, respectively. Overall, DAB can be a potentially toxic xenobiotic for soil N mineralization shortly after application and the rate of its inhibition or stimulation is time-dependent.


1968 ◽  
Vol 70 (3) ◽  
pp. 323-329 ◽  
Author(s):  
J. K. R. Gasser

SUMMARYSoil samples taken in the autumn after ploughing ryegrass, clover, and ryegrass/clover leys were used to measure the mineral-N (ammonium-N + nitrate-N) in the fresh soil (mineral-Nfresh), the increase in mineral-N on incubating the fresh soils (Δmineral-Nfresh), and the increase in mineral-N on incubating the re-wetted air-dry soils (Δmineral -Nair-dry). Mineral-Nfresh and Δ mineral-Nair-dry were measured on further soil samples taken the following spring. Values of Δmineral-Nair-dry, not only correlated best with grain yields and N uptakes by wheat without fertilizer-N, but also with yield responses and fertilizer-N recovered from fertilizer-N applied to the winter wheat.Treatment of the ley altered measurements on samples taken in the autumn but not those taken the following spring.Soil samples taken in the autumn 1960 from under three-year grass leys were used to measure mineral-Nfresh, Δ mineral-Nfresh and Δ mineral-Nair-dry Spring wheat was grown in 1961 followed by spring barley in 1962. Further soil samples were taken in spring 1962 after cultivations were complete and before the barley was sown or fertilizers applied.A mineral-Nair-dry was the best measurement to use on soils from under grass leys. Values depended on grass species, and were increased by N applied to the ley. Differences had largely disappeared 18 months later. A mineral-Nalr.dry was positively correlated with grain yields of spring wheat grown both with and without fertilizer-N, and with the yield response or the nitrogen recovered from, a dressing of 56 lb N/acre.With fertilizer-N yields of winter wheat after the mixed leys tended to the same maximum value independently ofmineralizable-N in the soil. After grass leys maximum yields of spring wheat given fertilizer-N increased with increasing mineralizable-N in the soil.


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