Type Of Nitrogen Fertilizer Research Articles

Effect of nitrogen fertilizer type and application rate on cadmium uptake and grain yield of paddy rice

采用盆栽试验, 研究了Cd污染土壤上, 不同氮肥品种和用量对水稻产量和Cd吸收的影响。结果表明, 与磷钾配施的4个氮肥处理中, 施用尿素处理水稻产量最高, 其次为施(NH₄)₂SO₄和NH₄Cl处理, 施NH₄NO₃处理水稻产量最低。与施(NH₄)₂SO₄、NH₄NO₃和尿素处理相比, 施NH₄Cl处理可显著增加水稻对Cd的吸收, 并促进Cd由秸秆向籽粒的转移; 而其他3种氮肥对水稻秸秆和籽粒中Cd含量的影响效应相当。适量尿素[0.2 g(N)·kg^-1]处理能显著降低水稻籽粒Cd含量, 而不施尿素和高量尿素处理都显著提高了水稻籽粒中的Cd含量。研究表明, 在Cd污染的水稻土上, 采用抗Cd污染的水稻品种和优化肥、水管理措施, 可使稻米中Cd含量低于国家无公害大米的限量指标。

Cold Tolerance of Container-grown Green Ash Trees Is Influenced by Nitrogen Fertilizer Type and Rate

A study was conducted to determine whether nitrogen (N) application rate and fertilizer form are related to cold tolerance of buds and stems using container-grown ‘Summit’ green ash (Fraxinus pennsylvanica) trees. Trees were grown with different rates of N from either urea formaldehyde (UF) or a controlled-release fertilizer (CRF) containing ammonium nitrate during the 2006 growing season; and growth, N and carbon (C) composition, and cold tolerance were evaluated in Oct. 2006, Dec. 2006, and Feb. 2007 by assessing the lowest survival temperature (LST) of stem and bud tissues on current season (2006) stems. Both fertilizer type and rate influenced the bud and stem LSTs. The influence of fertilizer rate was most evident on midwinter (December) stem LSTs and the influence of fertilizer type was observed in bud and stem LSTs during the deacclimation period in February. Higher LSTs were associated with higher N concentrations and lower C/N ratios; however, stems and buds of trees fertilized with UF were more cold-tolerant (had lower LSTs) than stems and buds on trees fertilized with CRF. Fertilizer type resulted in several differences in N and C translocation and metabolism during the fall and winter. Our results indicate trees with a similar N status are able to withstand different levels of cold depending on the rate of N and the type or form of fertilizer used during production. This may have to do with differences in how trees metabolize the different fertilizer forms, where and when the N is stored, and how it is remobilized in the spring, especially in relation to C metabolism.

Bud Necrosis of Green Ash Nursery Trees Is Influenced by Nitrogen Availability and Fertilizer Type

A study was conducted to determine whether the nitrogen (N) status of nursery-grown green ash (Fraxinus pennsylvanica ‘Summit’) trees in the autumn is related to bud necrosis during the following spring. In 2005, different rates of N from urea formaldehyde (UF) or a controlled-release fertilizer (CRF) containing ammonium nitrate were applied during the growing season to green ash trees and leaves were sprayed or not with urea in the autumn. Biomass and N content was determined in Autumn 2005 and Spring 2006, and stem biomass and bud necrosis were evaluated for necrosis in Spring 2006. Trees with low N content in Autumn 2005 grew less in Spring 2006 but bud necrosis was more prevalent on trees grown at the highest N rate. Compared with trees grown with a similar amount of N from UF, growing trees with CRF altered N allocation in 2005 and the relationship between carbon (C) and N dynamics (import, export, and metabolism) in stems in 2006. Additionally, trees grown with CRF had less total shoot biomass in Spring 2006 and more bud failure than trees grown with a similar N rate from UF. Significant relationships between bud failure and N status and C/N ratios in different tissues suggest that a combination of tree N status and the balance between N and C in certain tissues plays a role in the occurrence of bud failure of green ash trees in the spring.

Investigation of Temporal and Spatial Variability for Green Tea Growth Using Precision Agriculture Technology

Spatial and temporal variability of new shoots (number of shoots, dry mass and nitrogen concentration) were investigated under several conditions using precision agriculture technology. The growth and spatial variability of new shoots were both determined using the normalized difference vegetation index (NDVI). At harvest, there were differences in new shoots growth depending on variety, severe shading, and nitrogen fertilizer type. There were differences in new shoot for “Ten-cya” compared to that for “Sen-cya” and temporal variability of growth had a different tendency compared to spatial variability at harvest depending on several conditions. Coefficients of determination (R2) and root mean square error (RMSE) were established by the NDVI model. The accuracy was R2≥0.826 with RMSE≤15.0 g/m2 for “Sen-cya” and R2≥0.877 with RMSE≤13.6 g/m2 (vegetation coverage ratio ≤ 100%) for “Ten-cya”

Mitigation options for N2O emission from a corn field in Kalimantan, Indonesia

Field experiments were designed to quantify N2O emissions from corn fields after the application of different types of nitrogen fertilizers. Plots were established in South Kalimantan, Indonesia, and given either urea (200 kg ha−1), urea (170 kg ha−1) + dicyandiamide ([DCD] 20 kg ha−1) or controlled-release fertilizer LP-30 (214 kg ha−1) prior to the plantation of corn seeds (variety BISI 2). Each fertilizer treatment was equivalent to 90 kg N ha−1. Plots without chemical N fertilizer were also prepared as a control. The field was designed to have three replicates for each treatment with a randomized block design. Nitrous oxide fluxes were measured at 4, 8, 12, 21, 31, 41, 51, 72 and 92 days after fertilizer application (DAFA). Total N2O emission was the highest from the urea plots, followed by the LP-30 plots. The emissions from the urea + DCD plots did not differ from those from the control plots. The N2O emission from the urea + DCD plots was approximately one thirtieth of that from the urea treatment. However, fertilizer type had no effect on grain yield. Thus, the use of urea + DCD is considered to be the best mitigation option among the tested fertilizer applications for N2O emission from corn fields in Kalimantan, Indonesia.

Effects of types and application rates of nitrogen fertilizer on the development and nitrogen utilization of summer maize

To reduce nitrogen fertilizer (NF) loss and improve nitrogen use efficiency (NUE) in summer maize, the effects of the different application rates of three types of NF (urea, coated urea and compound fertilizer) on the growth and development and NUE of summer maize (cultivars: Zhengdan958 and Nongda108) were studied in 2004. The main findings of this study were: (1) The yields of the two cultivars increased significantly with each increment of N application rate from 0–180 kg N·hm−2. The increase in the yield of summer maize treated with compound fertilizer was greater than the yield of those treated with either of the other two fertilizers at the same application rate, while the differences among the three types of NF were not significant. (2) Grain number per ear of the two cultivars rose in relation to the increase in N application rate, while its relationship with the type of NF was very weak. The type of NF had a greater impact on 1000-grain weight, and a difference between cultivars was observed. (3) Leaf area index (LAI), dry matter weight and leaf chlorophyll content grew in relation to the increase in N application rate, and were improved more sharply by compound fertilizer or coated urea than by urea alone. (4) Compared to the results achieved with urea, the NUEs of summer maize treated with coated urea and compound fertilizer were higher but the nitrogen harvest index was not improved. In addition, the NUEs of three types of NF exhibited a genotype difference from summer maize.

Biological Value of Red Beets in Relation to Nitrogen Fertilization

Biological Value of Red Beets in Relation to Nitrogen Fertilization Effects of nitrogen fertilizer and fertilization method on biological value of red beet roots (cv. Boro F1) were studied in pot experiments conducted in 2005 and 2006 years. Pre-sowing nitrogen fertilizers were either UAN (urea-ammonium nitrate solution) or ENTEC 26 (nitrogen fertilizer containing nitrification inhibitor). For both fertilizers the following methods of application were studied: pre-sowing superficially 90 kg N·ha-1 (S-100%), pre-sowing superficially 67.5 kg N·ha-1 with additional foliar nitrogen application during vegetation (S-75%+F), pre-sowing localized 67.5 kg N·ha-1 (L-75%) and pre-sowing localized 67.5 kg N·ha-1 with additional foliar nitrogen application during vegetation (L-75%+F). In harvested roots the contents of dry matter, sugars, phenols, NO3 -, NH4 +, N-protein and P, K, Mg and Ca were determined. Type of nitrogen fertilizer had no effect on dry matter, NH4 +, N-protein, sugars, phenols, Ca and Mg contents in both years and on K in 2005 year. ENTEC 26 reduced nitrates content, particularly in 2005 year. The effect of fertilization method was not univocal, particularly for NO3 - content. In 2005 the lowest NO3 - content was found in treatment S-100% roots, whereas in 2006 in L-75%. In both years the highest sugars content was observed in L-75% roots, and the lowest N-protein in S-100% roots. In both years the method of fertilization had no effect on dry matter, NH4 + and phenols contents. The effect of fertilization method of on mineral composition was apparent only in 2006 year. It can be concluded that by using the fertilizer with inhibitor of nitrification the biological value of red beets assessed by nitrate content can be improved. The effect of method of fertilizer application on the biological value of red beets is not univocal and may depend on the year of cultivation.

Effect of Lupin Extract and Nitrogen Fertilization on Yield Quality of Celeriac

Effect of Lupin Extract and Nitrogen Fertilization on Yield Quality of Celeriac The results of a study on possibilities of utilization of lupin extract are presented. The extract was a waste material from the de-bittering process of bitter lupin seeds and might affect yield and chemical composition of celeriac. Type of nitrogen fertilizer (pure ammonium nitrate or its form supplemented with molybdenum and magnesium) was another factor tested. The study, based on field experiments, was conducted in the years 1999-2001. It was found that fertilization with ammonium nitrate, and especially with its form enriched in magnesium and molybdenum, was a factor significantly affecting yield of celeriac. After use of lupin seed extract slight increase in yield and total nitrogen content as well as evident reduction in nitrates content in celeriac were observed. Average decrease in content of this nitrogen form in roots and leaves was 14.8% and 29.6%, respectively, as compared to control. Tested factors did not influence significantly potassium and sodium contents in leaves and roots of celeriac.

The Effects of Organic and Inorganic Nitrogen Fertilizer on the Morphology and Anatomy of Cannabis sativa “Fédrina” (Industrial Fibre Hemp) Grown in Northern British Columbia, Canada

Abstract The effects of organic and inorganic nitrogen fertilizer on the morphology and anatomy of Cannabis sativa “Fedrina” (industrial fibre hemp) was investigated in both a greenhouse and field setting in Northern British Columbia. Plots (90 stems/m2) treated with 0, 75, 150 or 300 kg N/ha of inorganic nitrogen, or fish meal, blood meal or sea star organic fertilizers were also replicated with 90 kg inorganic P2O5/ha application. The application of 150 and/or 300 kg N/ha of any nitrogen fertilizer type benefited field-grown plant morphology, secondary phloem fibre and xylem development, while greenhouse-grown plant morpology, secondary phloem fibre and xylem were positively influenced by 90 kg P2O5/ha. Primary phloem fibre characteristics of both greenhouse and field-grown plants were benefited by the absence of either nitrogen or phosphorus fertilizer. This study determined that the response of C. sativa “Fedrina” fibre production to organic nitrogen application was comparable to that of inorganic nit...

Temporal and Spatial Variations in N2O Emissions from a Chinese Cabbage Field as a Function of Type of Fertilizer and Application

We conducted a field experiment in an Andosol near Tsukuba (Japan) to study the effects of the type of nitrogen fertilizer on nitrous oxide (N2O) emissions and on nitrogen uptake by Chinese cabbage (Brassica campestris L.). We used four treatments: fertilizer containing no nitrogen (CONT), broadcast application of urea (BR-U), band application of urea (B-U), and band application of controlled-release urea (B-CU). The application rate was 250 kg N ha−1, a conventional rate in the region. We measured N2O flux two or three times a week during the 82-day growth period, then divided the cumulative emissions into three stages: early (28 days), middle (27 days), and late (27 days). The temporal variation in N2O emissions differed among the treatments. Broadcast urea application produced 70% of N2O emissions during the early stage. N2O emissions increased with increasing cabbage growth in the CONT treatment, indicating that plant growth accompanied by increasing root biomass could stimulate N2O emissions from unfertilized soil. There were no differences in the patterns of temporal variation in N2O flux between the two band applications (B-U and B-CU); N2O emissions in the early and middle stages were 46 and 42%, respectively, for B-U, vs. 41 and 40% for B-CU. However, the overall N2O emission was reduced by 40.5% in the B-CU treatment compared with the B-U treatment. N2O emissions from the soils within fertilized bands were dramatically higher than those between the fertilized bands, and this trend continued until harvesting.

Inhibition of seedling establishment by nitrogen application in direct sowing culture of paddy rice in old region

The effects of the nitrogen application rate and type of nitrogen fertilizer on rice seedling establishment for seeds without or with calcium peroxide coating under drained paddy field conditions were investigated. The seedling establishment rate for the seeds without coating decreased with the application of ammonium sulfate (AS) at the rates of 4 and 8 g m−2. The pH in the soil solution was in the appropriate range for rice growth, and the ferrous ion concentration and EC in the soil solution were lower than the threshold for rice growth in all the plots. The ammonium nitrogen concentrations in the soil solution in the AS application plots were exceeded 2 mg kg−1, which is the threshold for seed emergence. Seedling establishment for the seeds with calcium peroxide coating was not inhibited by the AS application even at the rate of 8 g m−2. The application of ammonium phosphate (AP), urea (U), and polyolefin-coated urea (PCU) at the rate of 4 g m−2 did not inhibit the seedling establishment in the case of both calcium peroxide-coated seeds and non-coated seeds. The ammonium nitrogen concentration in the soil solution at the time of sowing was less than 2 mg kg−1 in all the treatments except for the AS treatment. These results showed that nitrogen application, which increases the ammonium nitrogen concentration in the soil solution at sowing, inhibits seedling establishment for non-coated seeds and does not inhibit seedling establishment for coated seeds.

Comparative effects of application of coated and non-coated urea in clayey and sandy paddy soil microcosms examined by the 15N Tracer Technique

Nitrogen Fertilizer and soil types exert an impact on plant and soil microbial biomass (SMB). A 15N tracer experiment was conducted to compare the effects of the application of controlled-release coated urea (CRCU) and urea on SMB in gley (clayey) and sandy paddy soils. The fertilizers were applied at the rate of 8 g N m−2 for CRCU as deep-side placement and 10 g N m−2 for urea mixed into soil or applied into floodwater. The soil type and soil layer (surface: few millimeter depth of surface soil to include benthic algae; subsurface: 1 to 20 em depth), but not the fertilizer type, affected the amount of microbial biomass N (BN). On an area basis, subsurface soil layers contained about 2-3 times the amount of BN in the surface layers. The seasonal average BN amount i.e. at 1 to 20 em depth, in the gley soil was 1.67 g N m−2 , compared to 1.20 g N m−2 for the sandy soil. The proportion of BN in total soil N was significantly influenced by the soil type and soil layer, and was higher for the surface layers of both soils and subsurface layer of the sandy soil than for the subsurface layer of gley soil. Soil type, soil layer, and fertilizer type significantly influenced the amount of microbial biomass 15N (B 15N)Unlike BN, the amount of B 15N was significantly higher in the surface (11,9–177,3 mg N m−2) than in the subsurface soil layers (4.8–83.6 mg N m−2), especially with urea application between 60 and 120 DAT (days after transplant ing). At 30 DAT, the subsurface layer of the sandy soil showed a higher B 15N (218 mg N m−2) amount than the surface layer (133.4 mg N m−2). Sandy soil (4,8-–218 mg N m−2) and urea (6.2–218 mg N m−2) induced a larger increase of the amount of B 15N than the gley soil (6.2–83.6 mg N m−2) and CRCU (4.8–40 mg N m−2). Again, the sandy soil, surface soil layers, and urea induced a higher proportion (% ) of B 15N in BN than the gley soil, subsurface soil layers, and CRCU, respectively. The soil type affected BN more than the fertilizer type, which showed only minimal differences. However, 15N analysis revealed the existence of greater differences in the effects of CRCU and urea on the B 15N amount. Sandy soil and the application of urea led to a higher microbial N immobilization than the gley soil and CRCU application, respectively.

Comparative effects of app1ication of coated and non-coated urea in clayey and sandy paddy soi1 microcosms examined by the 15N tracer technique

Nitrogen fertilizer and soil types exert an impact on plant growth. An experiment was conducted to compare the effects of application of controlled-release coated urea (CRCU) and urea on the growth of rice plants cultivated in gley (clayey) and sandy paddy soils. The 15N labeled fertilizers were applied at the rate of 8 g N m−2 for CRCU and 10 g N m−2 for urea. Both soil and fertilizer types significantly influenced the plant N and 15N uptake at 30 and 60 days after transplanting (DAT), with only the fertilizer type influencing the 15N uptake at 90 DAT. Sandy soil and urea increased the plant N and 15N uptake compared to the gley soil and CRCU at 30 DAT while the opposite was observed at 60 DAT, with CRCU inducing a higher 15N uptake than urea at 90 DA T. Plant 15N uptake at harvest was similar for the two types of fertilizers. Also at harvest, the average fertilizer use efficiency and proportion of unaccounted-for N for CRCU were about 74 and 25%, compared to 39 and 60% for urea, respectively. At harvest time, the total N and 15N contents in the plant parts were similar between gley and sandy soils, and between CRCU and urea, respectively, Except for the harvest index and the percentage of filled grains that were significantly influenced by the soil type, there were no significant differences in the dry weight of straw, panicle, grains, and 1,000-grains between the two soil and fertilizer types at harvest, Statistically non-significant results were obtained for the two soil and fertilizer types despite the fact that the application of CRCU in gley and sandy soils increased the values of the agronomic traits by >40% compared to urea application in the two soil types, The soil type affected the agronomic traits of rice plants much more significantly than the fertilizer type applied. Even though analysis in the absence of 15N tracer showed only minimal variations in the effects of CRCU and urea application on the agronomic traits of rice plants, the 15N analysis revealed a significant influence of the fertilizer type on the plant 15N uptake, Higher fertilizer use efficiency and a lower proportion of unaccounted-for N achieved with CRCU application resulted in a similar or in some aspects superior performance of the rice crop to that obtained with urea application, although the amount of total N applied in the CRCU treatment was 20% less than the total N amount applied in the urea treatment.

The Effect of Nitrogen Fertilization on Fusarium Head Blight Development and Deoxynivalenol Contamination in Wheat

AbstractThe impact of nitrogen (N) fertilization on the development of Fusarium head blight (FHB) in wheat and the resulting deoxynivalenol (DON) contamination in the kernels was studied. In a first experiment, the disease was assessed on two locations under natural infection pressure. Five different types of nitrogen fertilizer (both organic and mineral) were investigated, each applied at five input rates from 0 to 160 kg N/ha. With all fertilizers, a significant increase of disease intensity was observed with increasing N input, while the type of N fertilizer had poor or no effects on FHB. Depending on the fertilizer used, the percentage of diseased spikelets increased from 2.2% at zero N rate up to 6.6% at 160 kg N input per hectare. In a second series of trials, three spring wheat varieties including one Durum wheat line were artificially inoculated with a Fusarium graminearum and a F. culmorum strain, known producers of DON. A mineral N fertilizer was applied at five input levels from 0 to 160 kg N/ha. A significant increase in FHB intensity and DON contamination in the grain was observed with increasing N from 0 to 80 kg/ha. At higher input rates, relevant in contemporary crop husbandry, disease intensity and toxin contamination remained at constant levels. It is concluded that adaptation of N fertilization represents no relevant tool in managing FHB in practical wheat cultivation.

Methane emission from fields with differences in nitrogen fertilizers and rice varieties in Taiwan paddy soils.

Flooded rice fields are one of the major biogenic methane sources. In this study, methane emission rates were measured after transplanting in paddy fields with application of two kinds of nitrogen fertilizers (ammonium sulfate, NH4+-N and potassium nitrate, NO3(-)-N) and with two kinds of rice varieties (Japonica and Indica). The experiment was conducted in fields located at Tainan District Agricultural Improvement Station in Chia-Yi county (23 degrees 25'08"N, 120 degrees 16'26"E) of southern Taiwan throughout the first and the second crop seasons in 1999. The seasonal methane flux in the first crop season with NH4+-N and NO3(-)-N ranged from 2.48 to 2.78 and from 8.65 to 9.22 g CH4 m(-2); and the values ranged 24.6-34.2 and 36.4-52.6 g CH4 m(-2) in the second crop season, respectively. In the first crop season, there were significantly increased 3.1-3.7-fold in methane emission fluxes due to plantation of Indica rice. In comparison of two rice varieties, the Indica rice variety showed a tendency for larger methane emission than the Japonica rice variety in the second crop season. Moreover, ammonium sulfate treatment significantly reduced CH4 emissions by 37-85% emissions compared to potassium nitrate plots. It was concluded that the CH4 emission was markedly dependent on the type of nitrogen fertilizer and rice variety in Taiwan paddy soils.

Agronomic considerations for reducing deoxynivalenol in wheat grain

Wheat fields under an array of agronomic practices were studied during harvest across southern and eastern Ontario. Mature wheat grain samples were harvested by hand and analyzed for deoxynivalenol (DON). DON levels from wheat grain samples harvested by hand were likely more representative of levels in the field than samples that are typically harvested by machine. The amount of variation in DON levels associated with year and agronomic effects were calculated from simple linear models. As expected, the largest factor associated with variation in DON levels was the year. Year effects accounted for 48% of the variation in DON levels across all fields during 4 years of the survey, followed by cultivar (27%), and the crop 1 year previous to wheat (14–28% depending on the year). No effect on DON could be detected from other agronomic factors including tillage system, crops planted 3 years before wheat, or type of nitrogen fertilizer applied in the spring.

Effects of Tillage and Nitrogen Fertilizer Type on Emergence of Dent Corn in Cultivation with Single Basal Co-situs Fertilization

Effects of Tillage and Nitrogen Fertilizer Type on Emergence of Dent Corn in Cultivation with Single Basal Co-situs Fertilization

Agronomical and physiological aspects of ammonium and nitrate nutrition of plants

AbstractField studies comparing yield responses of crops treated with different nitrogen fertilizer types have led to very contradictory results. This can be explained by the fact that the application of different forms of nitrogen may affect plant growth via numerous processes in the soil and within the plant. In this review the significance of these processes for nutrient availability in soil are briefly outlined. Then, data from literature and own results are used to show that an enhanced ammonium supply may promote certain yield components such as the number of ears per plant in wheat or the number of kernels per plant in maize whereas other yield components such as the number of grains per ear in cereals or the number of tillers in linseed may be adversely affected by ammonium supply. These different effects of ammonium and nitrate supply on yield structure of plants are related to physiological changes in the plant using a model.

Differences in rainfall and temperature define the use of different types of nitrogen fertilizer on managed grassland in UK, NL [Netherlands] and Eire

There are distinct differences between the Netherlands (NL) and the United Kingdom (UK) in the use of urea and calcium ammonium nitrate (Ca-AmmN) fertilizers on grassland. It has been known for some time that rainfall and temperature affect NH3 volatilization from urea and its agronomic efficiency. This study aimed (i) to examine rainfall and temperature pattern in NL and UK in relation to the observed urea efficiency, and (ii) to provide a simple decision support model for farmers to enable them to choose the most appropriate N fertilizer. A statistical analysis (residual maximum likelihood) of existing data from numerous field trials was undertaken. The agronomic efficiency of urea compared to Ca-AmmN in field trials was expressed as (i) urea relative N yield (Urel-N-y), and (ii) apparent-urea relative (N) yield (Uarel-(N)-y). In NL, (Urel-N-y) did not significantly differ from 100% on peat grassland. Mean (Urel-N-y) on sand and clay was 95%, in both cases. Mean seasonal Uarel-y and Uarel-N-y for the summed data of sand and clay soils was 92.3 and 86.4%, respectively, without significant differences between first and later cuts. There was no significant improvement of UNapp-relY in the last decades. In the first cut, mean Uarel-y was lower than in UK (100.9%) and Eire (100.2%). Differences in efficiency between countries could be described by short-term rainfall and temperature. By aggregating NL, UK and Eire data a simple regression equation was derived: Uarel-y= 89.48(+or-0.78) +[2.188(+or-0.15)xR3] -[1.091(+or-0.07)xT3], where R3 and T3 are rainfall amount and average temperature within three days after fertilizer application, respectively. The decision support model based on this equation showed that under prevailing NL weather conditions it will be profitable for the farmer to apply urea instead of calcium ammonium nitrate, for the first and second cut, only once every 5 and 7 years, respectively, because R3's exceeding 6 and 9.5 mm are required.

Effects of type and amount of applied nitrogen fertilizer on nitrous oxide fluxes from intensively managed grassland

Five field experiments and one greenhouse experiment were carried out to assess the effects of nitrogen (N) fertilizer type and the amount of applied N fertilizer on nitrous oxide (N2O) emission from grassland. During cold and dry conditions in early spring, emission of N2O from both ammonium (NH4+) and nitrate (NO3−) containing fertilizers applied to a clay soil were relatively small, i.e. less than 0.1% of the N applied. Emission of N2O and total denitrification losses from NO3− containing fertilizers were large after application to a poorly drained sand soil during a wet spring. A total of 5–12% and 8–14% of the applied N was lost as N2O and via denitrification, respectively. Emissions of N2O and total denitrification losses from NH4+ fertilizers and cattle slurry were less than 2% of the N applied. Addition of the nitrification inhibitor dicyandiamide (DCD) reduced N2O fluxes from ammonium sulphate (AS). However, the effect of DCD to reduce total N2O emission from AS was much smaller than the effect of using NH4+ fertilizer instead of NO3− fertilizer, during wet conditions. The greenhouse study showed that a high groundwater level favors production of N2O from NO3− fertilizers but not from NH4+ fertilizers. Inereasing calcium ammonium nitrate (CAN) application increased the emitted N2O on grassland from 0.6% of the fertilizer application rate for a dressing of 50 kg N ha−1 to 3.1% for a dressing of 300 kg N ha−1. In another experiment, N2O emission increased proportionally with increasing N rate. The results indicate that there is scope for reducing N2O emission from grasslands by choosing the N fertilizer type depending on the soil moisture status. Avoiding excessive N application rates may also minimize N2O emission from intensively managed grasslands.