RECOVERY OF 15N-LABELLED UREA AS INFLUENCED BY STRAW ADDITION AND METHOD OF PLACEMENT

1989 ◽  
Vol 69 (3) ◽  
pp. 543-550 ◽  
Author(s):  
S. S. MALHI ◽  
M. NYBORG ◽  
E. D. SOLBERG

Field experiments were conducted during 1982–1983 at two locations (Rimbey and Ellerslie) in north-central Alberta to determine the influence of date of application (mid-October, late October and spring), method of placement (incorporation, banding and nesting) and straw (0 and 3.4 t ha−1) on the recovery of 15N-labelled urea in plants and soil at harvest. The rate of N was 50 kg N ha−1. The recovery of 15N in mature barley plants at both locations was greater with spring application as compared to fall application, and greater with banding or nesting compared to incorporation. At Rimbey, the average recovery, in plants plus soil, of incorporated urea N was lower with October applications (43% for mid and 55% for late) as compared to spring application (89%). Banding or nesting increased the N recovery of October applications. With spring application, there was more immobilization of applied N when incorporated into soil as compared to band or nest placement. Also there was more immobilization of applied N when straw was added to the soil, but banding or nesting tended to overcome the immobilization effect of straw so that the plant N recovery was greater with banding or nesting as compared to incorporation. At the Ellerslie location, there was heavy rain with consequent saturated topsoil in late June and early July. Recovery of fall-applied N in plants was low, and even with nesting the recovery was only 13%. There was substantial immobilization of applied N at Ellerslie. With spring application, nesting overcame the large immobilization effect and produced normal recovery of applied N in the plants. Addition of straw resulted in more immobilization of applied urea N, particularly when urea was incorporated. The 15N recovery in plants plus soil of spring-applied N indicated N losses during the growing season and the losses were much greater at Ellerslie than at Rimbey. Key words: Band placement, fall application, immobilization of N, incorporation, 15N, N losses, nest placement, spring application

1998 ◽  
Vol 78 (2) ◽  
pp. 377-383 ◽  
Author(s):  
R. Pradhan ◽  
R. C. Izaurralde ◽  
S. S. Malhi ◽  
M. Nyborg

Soil erosion induces variability in soil properties which may influence nutrient use efficiency. A 2-yr field study was conducted with the following objectives: (1) to determine the recovery of 15N-labelled fertilizers applied to barley growing on artificially eroded soil, and (2) to compare N losses from nitrate- and ammonia-based N fertilizers. Field experiments were conducted in north-central Alberta in 1991 and 1992 on an Orthic Gray Luvisol (Site 1) and on an Eluviated Black Chernozem (Site 2) soil. At each site, a factorial experiment of three levels of artificial erosion (0, 10 and 20 cm) and three N sources (KNO3, urea, and control) was laid out as a split-plot design with four replications. The 15N-labelled fertilizers (5.63 atom % abundance) were banded in June 1991 at 150 kg N ha−1 within 46-cm by 46-cm steel frame microplots. The proportion of added N recovered by barley (Hordeum vulgare L.) was not affected by erosion level. Periodical water saturation and NO3− availability suggested denitrification as a major mechanism of N loss. The N losses ranged from 12 to 51 g N ha−1 in 1991 and 20 to 80 kg N ha−1 over the 2-yr period, but the N losses did not relate to erosion level. The N losses after 2 yr were greater from KNO3 than from urea at Site 1. Most of the added 15N was found in the surface 0- to 15-cm layer, but amounts of 15N were detected in the 15- to 30-cm or 30- to 45-cm layers. The results call for continued development of N management techniques geared to optimize crop growth and minimize losses from fields. Key words: Artificial erosion, barley, fate of applied N, 15N-labelled fertilizers, N immobilization, N loss


2018 ◽  
Vol 64 (No. 4) ◽  
pp. 164-172 ◽  
Author(s):  
Ahmed Muneer ◽  
Yu Weijia ◽  
Lei Ming ◽  
Raza Sajjad ◽  
Zhou Jianbin

Field experiments were conducted at three sites: Yangling (YL); Zhouzhi-1 (ZH-1) and Zhouzhi-2 (ZH-2) of the Loess Plateau during summer maize crop, to investigate the effectiveness of N-(n-butyl) thiophosphoric triamide (NBPT) and NBPT + dicyandiamide (DCD) with urea on reducing NH<sub>3</sub> volatilization from different soils under different environmental conditions. Four treatments including control (no N), N-220 kg/ha, N-220 + NBPT and N-220 + NBPT + DCD were applied in two splits through the band placement method. Total NH<sub>3</sub>-N loss observed were 65.8, 40.5 and 20.1 NH<sub>3</sub>-N kg/ha (accounting for 29.9, 18.4 and 9.2% of N applied) from urea for YL, ZH-1 and ZH-2, respectively. The application of NBPT and NBPT + DCD significantly reduced NH<sub>3</sub> volatilization by 80–93% and 75–90%, respectively. The meteorologic factors such as precipitation, air temperature and wind speed significantly affected NH<sub>3</sub> volatilization. These results suggested that the amendment of urea with NBPT and NBPT + DCD have potential to mitigate NH<sub>3</sub>-N losses from alkaline soils in the Loess Plateau.


Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.


1988 ◽  
Vol 110 (3) ◽  
pp. 475-479 ◽  
Author(s):  
D. Panda ◽  
R. N. Samantaray ◽  
S. Patnaik

SummaryField experiments were conducted in wet seasons (June-December) for 4 years on a clay loam Haplaquept, to study the effects of different N management practices on yield, urea and ammonium-N in flood water and N nutrition of an clite rice cv. CR 1009, grown in rainfed lowlands. During the first 3 years of the experiment, fertilizer management practices like band placement of neem-cake-coated urea (NCU), broadcast application of sulphur-coated urea (SCU) at sowing, or point placement of urea supergranules (USG) 3 weeks after germination at 40 kg N/ha gave grain yields of 3·1–3·4 t·ha, which were almost equal to that of split application of prilled urea (PU). In the 4th year of the experiment, besides NCU and USG, single dose applications of PU as band placement, incorporation in the soil at sowing or broadcast incorporation of soil-treated urea at early tillering was also found to have similar effect on grain yield and N uptake as split application of PU. The flood water of the treatment receiving broadcast application of PU at tillering contained some urea and ammonium N, which rapidly decreased to negligible amounts in 3·4 days.The results suggest that, depending upon the feasibility, any one of the single dose application methods at sowing time or 3 weeks after germination may be adopted in this system of rice culture, which avoids top-dressing of PU to surface flowing flood water of greater depths at later stages of crop growth.


1989 ◽  
Vol 69 (3) ◽  
pp. 551-565
Author(s):  
F. SELLES ◽  
A. J. LEYSHON ◽  
C. A. CAMPBELL

Prairie farmers are interested in applying nitrogen (N) in the fall or winter to reduce fertilizer costs and allow a better distribution of labor and machinery use. Two studies were conducted in southwestern Saskatchewan to determine the consequences of applying N in late fall. In the laboratory, fertilizer N barely penetrated into the snow at constant subzero temperatures, but under freeze-thaw conditions, urea and ammonium nitrate descended 27 cm in 3 d. In the field, ammonium nitrate and urea were applied to snow-covered and bare microplots of grass sod and cereal stubble (1981–1982) and grass sod only (1985–1986). Nitrogen from ammonium nitrate penetrated deeper into the snow than N from urea. Nitrogen recovery in April 1982 was 55–59% from ammonium nitrate and 39–51% from urea, but was near 100% for both sources on bare soil treatments in April 1986. More N was recovered when fertilizer was applied to bare than to snow-covered soil, especially during 1985–1986 when all the applied fertilizer was blown off the snow-covered plots. Mineral N generally declined from fall to spring in all treatments, probably because of denitrification and immobilization. In 1985–1986, a period of extremely low temperatures in late fall resulted in no movement or transformation of N until after early December. By late January, periods of above-zero soil temperatures resulted in substantial mineralization of soil organic N, in the fertilized plots. This apparent priming effect was attributed to perturbations in the organic matter and microbial biomass due to fertilizer application and freezing and thawing. Following this period there was a general decrease in mineral N towards spring, as observed in 1981–1982. Producers must consider the benefits of using labor and equipment more efficiently and of lower fertilizer cost in the fall against the risk of large potential N losses over winter. Key words: Urea, ammonium nitrate, N recovery, frozen soils, fertilizing in winter


Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 773-779 ◽  
Author(s):  
S. Sanogo ◽  
X. B. Yang ◽  
P. Lundeen

Three-year field experiments were conducted to assess the development of sudden death syndrome (caused by Fusarium solani f. sp. glycines) in three soybean cultivars, tolerant (P9344 and A3071) and nontolerant (BSR101), to glyphosate following foliar application of four herbicides (acifluorfen, glyphosate, imazethapyr, and lactofen) commonly applied to soybeans in the north-central region of the United States. Cultivar A3071 is resistant to sudden death syndrome, whereas cultivars P9344 and BSR101 are susceptible to this disease. There was no statistically significant cultivar-herbicide interaction with respect to the severity of foliar symptoms of the disease and the frequency of isolation of F. solani f. sp. glycines from roots of soybean plants. Across all herbicide treatments, the level of sudden death syndrome was lower in the disease-resistant cultivar than in the susceptible ones. There was an increase in the disease levels under application of acifluorfen, glyphosate, and imazethapyr compared with nontreated or lactofen-treated plants. The results obtained indicate that the response of glyphosate-tolerant soybeans to sudden death syndrome is not different from the response of conventional soybeans to this disease following application of the selected herbicides, and the resistance of soybean to sudden death syndrome was not changed with application of glyphosate.


1985 ◽  
Vol 65 (1) ◽  
pp. 169-177 ◽  
Author(s):  
P. A. O’SULLIVAN ◽  
G. M. WEISS ◽  
D. FRIESEN

Field experiments were conducted in 1982 and 1983 to investigate the tolerance of barley (Hordeum vulgare L. ’Galt’) seeded 5 cm deep in a Ponoka loam soil treated with trifluralin. There were eight rates of application from 0 to 3 kg/ha applied in fall and spring and incorporated by means of a rototiller set to till to a depth of 10 cm. All data were analyzed by regression. Gas chromatographic analysis of extracts of soil samples collected in the spring following fall application of trifluralin (0.0–3.0 kg/ha) indicated that approximately 45% of the herbicide was lost regardless of rate applied. Fall application of trifluralin up to 3 kg/ha and spring application up to 1.1 kg/ha did not adversely affect the numbers of barley seedlings that emerged. Trifluralin treatments within the rate range 0.85–1.4 kg/ha caused severe early injury (delayed growth) to barley, the magnitude of which varied with the season and year of application. Fall application caused less injury than the respective spring application during both years. With fall or spring applications up to 1.3 kg/ha or 1.0 kg/ha, respectively, barley yields were not reduced compared to the untreated control. With fall application at 1.4 kg/ha barley yield was reduced in one of the two years. Rates in excess of 1.8 kg/ha caused significant yield reductions with all treatments. The data indicate that trifluralin could be used as a deep-incorporated fall or spring treatment at rates up to 1.3 or 1.0 kg/ha, respectively for weed control in barley in central Alberta. Fall application would improve the safety to the crop. Barley could also be seeded into soil where trifluralin (1.4 kg/ha) was applied as a fall treatment for weed control in rapeseed (Brassica campestris L. and Brassica napus L.), but some loss of yield could be expected.Key words: Trifluralin rate, soil incorporation, barley, tolerance


1982 ◽  
Vol 62 (1) ◽  
pp. 187-196 ◽  
Author(s):  
M. S. AULAKH ◽  
D. A. RENNIE ◽  
E. A. PAUL

A study designed to assess gaseous losses of N as N2O and N2 from soils of conventional till fields seeded to wheat in the Chernozemic soil region of Saskatchewan, together with limited supporting laboratory investigations, has confirmed that for the May-November period losses were in the vicinity of 3 kg N∙ha−1 or less. In contrast, total losses from a summer-fallowed field were approximately 300% higher. Comparisons at one site were made of N losses from a conventionally tilled and zero-tilled Dark Brown Chernozemic soil seeded to wheat; the total losses of N were twice as high for the zero till as the conventional till treatments. The N2O fluxes were shown to be the result of both reductive (denitrification) and oxidative (nitrification) processes and generally, under the conditions of these field experiments, both occurred simultaneously. This experiment also confirmed that C2H2 inhibited nitrification in a manner very similar to N-serve, a well-known nitrification inhibitor.


2021 ◽  
Vol 19 (1) ◽  
pp. 31-47
Author(s):  
Y. Garba ◽  
Z. Yakubu ◽  
A.I. Yakubu ◽  
J. Alhassan ◽  
M. Gana ◽  
...  

Two field experiments were conducted at the Research Farm of the Ibrahim Badamasi Babangida University, Lapai, Niger State during the 2018 and 2019 rainy seasons to determine the effect of neem fertilizer rates and weed control methods on the growth and yields of soybeans. The experimental treatments were made up of four neem fertilizer rates (0, 50, 100 and 150 kg ha-1) and six weed control methods (pendimethalin at 1.5 kg a.i ha-1 followed by one hoe weeding, pendimethalin at 2.0 kg a.i. ha-1 followed by diuron at 1.5 kg a.i ha-1, weeding once at 3 WAS, weeding twice at 3 and 6 WAS, weed free and weedy check. The experiment was a 3 × 3 factorial experiment laid out in a Randomize complete block design replicated three times. TGX 1448 – 2E variety of soybean was used for the study. Result showed that weed control efficiency was better with the use of 150 kg ha-1 of neem fertilizer, while decrease in weed dry matter was obtained at 50 kg ha-1. Increase in number of leaves and leaf area were encouraged with 150 kg ha-1 of neem fertilizer. Weed free treatments recorded the highest grain yield and 100 seed weight of soybean. Pendimethalin at 1.5 or 2.0 kg a.i ha-1 supplemented with one hoe weeding or diuron at 1.5 kg a.i ha-1 respectively can be an alternative for better control of weeds to obtain greater yield of soybean in the study area.


Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3881 ◽  
Author(s):  
Jose Luis Gabriel ◽  
Miguel Quemada ◽  
María Alonso-Ayuso ◽  
Jon I. Lizaso ◽  
Diana Martín-Lammerding

Nitrogen (N) losses from agricultural systems increase air and water pollution, and these losses are highly correlated with the excessive fertilization. An adjusted N fertilization is then a key factor in increasing the N fertilizer efficiency, and leaf clip sensors can help to improve it. This study (combining five different field experiments in Central Spain) tried to identify the ability of the clip sensors in maize N status identification and yield prediction, comparing two different devices (SPAD-502® and Dualex®) and identifying the best protocol for maize leaf sampling. As a result, the study demonstrated that different leaf clip chlorophyll sensors presented similar results, although some differences appeared at larger N concentrations. Complementary polyphenol information (as flavonol) can improve the maize N deficiency prediction. Moreover, valuable information for a proper sampling protocol was obtained with this study. It proved that the sampling position (in the leaf and in the plant) and sampling time were crucial for a better estimation of the maize N status. Proper fertilization recommendations could be achieved based on clip chlorophyll sensor measurements.


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