Broadcast Urea Research Articles

Nitrogen gas (N2+N2O) flux from urea applied to lowland rice as affected by green manure

A field study was conducted on a clay soil (Andaqueptic Haplaquoll) in the Philippines to directly measure the evolution of (N2+N2O)−15N from 98 atom %15N-labeled urea broadcast at 29 kg N ha−1 into 0.05-m-deep floodwater at 15 days after transplanting (DT) rice. The flux of (N2+N2O)−15N during the 19 days following urea application never exceeded 28 g N ha−1 day−1. The total recovery of (N2+N2O)−15N evolved from the field was only 0.51% of the applied N, whereas total gaseous15N loss estimated from unrecovered15N in the15N balance was 41% of the applied N. Floodwater (nitrate+nitrite)−N in the 5 days following urea application never exceeded 0.14 g N m−3 or 0.3% of the applied N. Prior cropping of cowpea [Vigna unguiculata (L.) Walp.] to flowering with subsequent incorporation of the green manure (dry matter=2.5 Mg ha−1, C/N=15) at 15 days before rice transplanting had no effect on fate of urea applied to rice at 15 DT. The recovery of (N2+N2O)−15N and total15N loss during the 19 days following urea application were 0.46 and 40%, respectively. Direct recovery of evolved (N2+N2O)−15N and total15N loss from 27 kg applied nitrate-N ha−1 were 20% and 53% during the same 19-day period. The failure of directly-recovered (N2+N2O)−15N to match total15N loss from added nitrate-15N might be due to entrapment of denitrification end products in soil or transport of gaseous end products to the atmosphere through rice plants. The rapid conversion of added nitrate-N to (N2+N2O)−N, the apparently sufficient water soluble soil organic C for denitrification (101 μg C g−1 in the top 0.15-m soil layer), and the low floodwater nitrate following urea application suggested that denitrification loss from urea was controlled by supply of nitrate rather than by availability of organic C.

Use of large granular urea (LGU) to improve efficiency of broadcast urea in wetland rice cultivation

Laboratory and greenhouse experiments were conducted to determine whether the efficiency of broadcast urea in wetland rice cultivation can be improved by using large granules which penetrate the puddled soil. In laboratory experiments the penetration increased with increasing granule size. Penetration was improved by having only a waterfilm on the soil and by the granules entering the soil with speed.

Penetration depth of broadcast urea granules in puddled wetland rice soils

The efficiency of urea in wetland rice cultivation is known to be increased by placement below the soil surface. The penetration of broadcast urea into puddled soil might be a way to achieve placement of urea in soil. This paper combines an analysis of the free fall of urea granules in the atmosphere and a layer of water on the soil surface with measurements of granule penetration into puddled soils. The process of free fall can be described in terms of the height of fall in air, the depth of the water layer, and the terminal velocities and characteristic distances for free fall in air and water. The penetration depth of a particular granule with a particular velocity at the water/soil interface depends on the type of soil and its physical condition. Granule mass ranged from 0.1 to 0.5 g, granule velocity from 1 to 10 m s−1, depth of the water layer from 0 to 30 mm and penetration depth from 0 to 35 mm. There is some indication that the penetration depth is proportional to the square root of the kinetic energy at the water/soil interface.

Ammonia volatilisation from urea broadcast in spring on to autumn-sown wheat

Abstract Ammonia volatilisation from nitrogen (N) fertilisers applied at 100 kg/ha N in spring to autumn-sown wheat was measured using a continuous air flow enclosure method. Loss from the bare soil surface was 21 and 29% of urea-N when broadcast in two seasons. Loss from broadcast ammonium sulphate was less than 1% and from urea placed 25 mm in the soil was 1% of applied N. The loss when wheat plants were present averaged two thirds the loss from bare soil. The total loss from the same soil type but with a history of crop or pasture was the same but loss occurred more rapidly from the pasture soil. Ammonia loss was also measured in one season using a micrometeorological technique (integrated horizontal flux). Both the total loss after 9 days and the daily pattern of loss were the same as estimated by the enclosure technique. The hydrolysis of urea and surface soil pH changes in both systems were similar.

Fate of Subsurface‐Banded and Broadcast Nitrogen Applied to Tall Fescue

AbstractThe purpose of this study was to determine why N uptake and forage production by tall fescue (Festuca arundinacea Schreb.) in southeastern Kansas are greater from subsurface‐banded (knifed) than from broadcast N applications. The fate of urea N fertilizer applied to tall fescue either broadcast or banded in 1982 was determined using a urea ammonium nitrate (UAN) solution containing 15N tagged urea and measuring various components of the N balance. Plant uptake of residual urea N was measured during 1983. In 1982, 62% of the banded urea N was recovered in harvested forage, whereas only 40% was recovered in the broadcast treatment. Tagged N remaining in the soil as residual N at the end of 1982 amounted to 40 and 45% for broadcast and band treatments, respectively. Most of this residual N was not available to plants in 1983 since only 1.4 kg fertilizer N ha−1 (5–6% of the residual N) was recovered in the forage. About 1% of the banded N was unaccounted for, indicating that gaseous losses (denitrification and ammonia volatilization) were about 1% of the applied urea N, whereas 23% of the broadcast urea N was unaccounted for, indicating probable significant gaseous losses. These results suggest that the improved efficiency of knifed N over broadcast N observed in southeastern Kansas may be due to reduced gaseous N losses.

Grass establishment and performance on a high country soil fertilised with nitrogen

Abstract Slow release sulphur-coated urea (SCD) was drilled with seed of ‘Grasslands Nui’ ryegrass (Lolium perenne L.), ‘Grasslands Roa’ tall fescue (Festuca arundinacea Schreb.), ‘Grasslands Wana’ cocksfoot (Dactylis glomerata L.), ‘Grasslands Maru’ phalaris (Phalaris aquatica L.), and ‘Massey Basyn’ Yorkshire fog (Holcus lanatus L.) in glasshouse and field trials to improve establishment on a low fertility high country soil. In the field trial, SCU (50 kg nitrogen(N)/ha) was also broadcast at sowing and uncoated urea (50 kg N/ha) was broadcast after seedling emergence. In the second year, one half of each field plot was given 125 kg N/ha in five applications and in the third year all field plots received 125 kg N/ha in three applications. Grass establishment was greatly enhanced by 25-75 kg N/ ha. SCU, drilled with the seed at rates above 25 kg N/ha,. caused germination injury but surviving seedhngs responded well to any additional N. At the highest N rates (100 kg/ha or more) individual grass plants grew vigorously but their patchy cover allowed the resident hawkweed (Hieracium pilosella L.) to grow vigorously in the intervening spaces. SCU broadcast at sowing or uncoated urea broadcast after emergence were generally less effective than the same rate of drilled SCU. Although Nui and Roa had the most uniform establishment, the second year yields were best overall for Wana and Basyn where N had been applied in both the first and second years. Without N in the second year there was little growth in any plots. Maru seedlings did well initially but appeared to suffer from aluminium toxicity in the second year. Third year yields were highly dependent on the application of N in the second year and to a lesser extent on the first year's application. The cultivarresponse varied, withNui being most affected by lack of N in the second year and Basyn the least. The need to supply N in a manner which minimises germination injury yet maximises uptake by the seedling is discussed. The option of applying N fertiliser is compared with liming, and with using a legume-dommant phase to improve N availability.

Effect of Two Urease Inhibitors on Floodwater Ammonia Following Urea Application to Lowland Rice

AbstractOne proposed strategy for overcoming N loss by ammonia volatilization from urea applied to flooded rice (Oryza sativa L.) fields is to amend urea with a urease inhibitor. The inhibitor, in theory, would delay urea hydrolysis and thereby prevent the buildup of ammonia in the floodwater. Field studies were conducted at two locations in the Philippines to determine the effect of two urease inhibitors, phenyl phosphorodiamidate (PPD) and N‐(n‐butyl) thiophosphoric triamide (NBPT), on the vapor pressure of ammonia (pNH3) following application of urea to floodwater. Three rates of urea were applied two‐thirds dosage at 18 d after transplanting (DT) and one‐third dosage at 5 to 10 d after panicle initiation (DAPI). The amendment of urea with either PPD or NBPT retarded the disappearance of urea from floodwater and reduced the buildup of floodwater ammoniacal‐N. NBPT generally matched or exceeded PPD in ability to reduce pNH3 at each N rate and timing for both locations. Whereas PPD only delayed the buildup in pNH3, particularly at higher N rates, NBPT effectively prevented a buildup in pNH3. For the 10 d following the first N application, NBPT reduced the mean pNH3 at 1400 h by 95, 96, and 98% for 23, 47, and 93 kg N ha−1, respectively, at one location. The corresponding reductions with PPD were 82, 54, and 25%, respectively. At the other location, NBPT reduced the mean pNH3 following the first N application by 97, 77, and 79% for 23, 47, and 93 kg N ha−1, respectively. The corresponding reductions with PPD were 79, 77, and 28%, respectively. The results suggested that urease inhibitors can effectively reduce ammonia loss from urea broadcast into the floodwater of rice fields.

Effect of form, method and time of urea nitrogen application on growth, yield and nitrogen uptake of direct sown and transplanted rice under intermediate deep water (15–50 cm) conditions

SummaryUnder intermediate deepwater (15–50 cm) conditions, sulphur-coated urea (SOU) drilled behind the plough at sowing was superior to other coated (neem, lac, coaltar) urea materials and broadcast incorporation of prilled urea in increasing the yield of direct-sown rice. In transplanted rice, the grain yield was highest with urea super granules (USG) placed 30 days after transplanting (DAT) followed by SOU broadcast incorporation at planting. N-use efficiency increased considerably with SCU drilled behind the plough or USG placed 20 days after sowing in shallow standing water in direct-sown rice and SCU broadcast incorporation or USG placed 30 DAT in transplanted rice.

Dynamics of ammonia volatilization losses in wetland soil following the broadcasting application of urea amended with phenyl phosphorodiamedate

Abstract Ammonia volatilization following the application of urea fertilizer to a Bangkok Clay (Typic Tropaquepts) was measured directly in a greenhouse experiment by using the enclosure technique with air turbulence. It was found that the broadcasting application of urea was associated with high concentrations of urea and ammoniacal N in the fioodwater as well as a rise in the fioodwater pH and total alkalinity. Deep placement of urea induced a similar pattern but to a lower extent. Broadcasting of urea amended with 2% phenyl phosphorodiamedate (PPD) on a weight basis delayed urea hydrolysis, decreased the accumulation of ammoniacal N, and delayed the development of high pH and total alkalinity in the fioodwater. Significantly lower NH3 losses were observed in the case of deep placement of urea in the reduced soil layer than with broadcasting on the soil surface. The application of urea with PPD was found to be effective in reducing the NH3 volatilization losses. The results indicated that the maximum loss of ammonia was small (less than 3% of the amount of applied urea) during the 28-day period after the broadcasting of urea which suggests that NH3 volatilization may not be a significant mechanism for the loss in this study.

Fate and efficiency of urea fertilizer in wetland rice soil

Abstract Pot experiments conducted with a non-acid marine soil (Typic Tropaquepts) from the Central Region of Thailand showed that in general, urea, DAP, MAP, and urea supergranule were equally effective for increasing rice yield. Evidence indicated that soil incorporation of N fertilizers was superior to the broadcasting method. The grain and straw yields as well as N uptake by rice increased significantly with increasing rates of urea application. Incorporation resulted in a significant increase in grain and straw yields and N uptake compared with the broadcasting method. In a series of experiments in which labelled 15N was used to study the fate of urea applied to flooded soil, the recoveries of fertilizer N measured directly with 16N gave lower values than those estimated by the difference method. The 16N balance showed that on the average, 29–47% of the fertilizer applied was recovered in the grain, 12–20% was recovered in the straw while 27–33% of the fertilizer N remained in the soil and roots after harvest. The total recovery of fertilizer in the rice-soil system differed significantly depending upon the method of N application. The recovery of urea applied by broadcasting (74%) was considerably lower than that of incorporated urea (94%) and that in the case of split application (94%). It was found that 26% of fertilizer N in broadcast urea could not be accounted for and was presumably lost as gaseous nitrogen through the nitrification-denitrification process and NH3 volatilization. Incorporation of fertilizer N played an important role in the increase of crop yield and also in the improvement of the nitrogen fertilizer efficiency.

Spatial and temporal distribution of nitrogen in a puddled rice soil following application of urea-based fertilizers by different methods

Field experiments were conducted on transplanted rice (Oryza sativa L., var. Ratna) in a submerged soil, in order to study the distribution of N applied at 100 kg/ha. N was introduced as prilled urea or neem cake coated urea broadcast on the soil, and as urea supergranules, 1 or 2.5 g in size, point-placed at 5 cm depth. The surface-broadcast N was found mostly in the top 0–5 cm layer of soil and there was only a small vertical movement of applied N to 5–10 cm depth. With point placement of 1-g urea granules, the fertilizer N was found mostly at 5–10 cm depth and within 2.5 cm horizontal distance from the point of placement, compared with 5–10 cm depth and within 5 cm horizontal distance from the point of placement for the 2.5-g granules. With the two broadcast applications, the NH4+-N content reached peaks of 40–68 mg/kg soil in the top 0–5 cm of soil within the first 3–6 days, decreased at a faster rate from the 6th to 12th day and then at a slower rate up to the 32nd day. In contrast, the NH4+-N content around the points of placement of the urea supergranules reached peaks of 570–900 mg/kg soil during the first 3–12 days after placement, then decreased rapidly during the next 6–9 days, after which the values remained more or less unchanged but were still higher than the untreated control value.

Fate of broadcast urea in a flooded soil when treated with N-(n-butyl) thiophosphoric triamide, a urease inhibitor

The compound N-(n-butyl) thiophosphoric triamide (NBPT) was found to be a more effective ureas inhibitor than phenyl phosphorodiamidate (PPDA) in flooded soils when compared at concentrations of from 0.5 to 5% of the weight of urea. It allowed essentially no ammoniacal-N to acumulate in the floodwater when added at 0.5% of the weight of urea. The fate of urea was also determined in a flooded, unplanted soil with NBPT used as an inhibitor at a rate of 2% by weight of urea. At 41 days, fertilizer-N loss without the inhibitor was 73.4%, whereas with NBPT, 34.7% of the fertilizer was lost, presumably all by denitrification. With NBPT, urea hydrolysis was not inhibited below a 1 cm depth in the soil and most of the N (35.0%) accumulated as exchangeable NH4+-N. Except for 15.0% of the fertilized accumulated as organic-N on the soil surface layer, immobilized N accounted for only an additional 7.0% in the soil at 22 days. Although the N saved from NH3 volatilization loss obviously is eligible for denitrification losses, denitrification apparently was not enhanced to an appreciable extent by use of the inhibitor in that total losses were 15.7% at 22 days.

Nitrogen fertilizer application practices for barley production under Southwestern Canadian prairie conditions

Abstract A field study was conducted in southern Alberta to compare the effectiveness of three forms of nitrogen fertilizer, two application times, and two methods of application in increasing barley (Hordeum vulaare cv. Galt) yields and N uptake. Urea, ammonium nitrate, and anhydrous ammonia were added in spring and late fall (soil temperature < 5°C) at rates of 30, 60, 90, and 120 kg N/ha. Banded and broadcast methods of applying urea and ammonium nitrate were compared. All plots received supplemental water when necessary. There was no difference in yield among the fertilizer practices used, except for broadcast urea where yields were lower by 101. Differences in yield produced by the three fertilizers were eliminated when they were banded. Time of application had no significant effect on the banded fertilizers and broadcast ammonium nitrate, but fall‐applied broadcast urea was more effective than spring‐applied broadcast urea. Nitrogen uptake differences reflected variations in yields.

Tests of nitrification and of urease inhibitors, when applied with either solid or aqueous urea, on grass grown on a light sandy soil

SummaryIn 1984 and 1985 a field experiment on a grass ley on a light sandy soil at Woburn Experimental Farm, Bedfordshire, tested injected aqueous urea and broadcast prilled urea, applied alone or with a nitrification or urease inhibitor. Aqueous urea, prilled urea and ‘Nitro-Chalk’ were applied as a single 375 kg N/ha dressing, and prilled urea and ‘Nitro-Chalk’ also as three 125 kg N/ha dressings. The nitrification inhibitor nitrapyrin or a mixture of sodium trithiocarbonate (STC) plus potassium ethyl xanthate (KEtX) was injected with aqueous urea. The nitrification inhibitor dicyandiamide (DCD) or the urease inhibitor phenyl-phosphorodiamidate (PPDA) was broadcast with prilled urea.The nitrification inhibitors significantly retarded nitrification of both aqueous and prilled urea. PPDA reduced ammonia volatilization from 375 kg N/ha broadcast as urea, and hence losses to the atmosphere, which otherwise ranged from 13 to 33 kg N/ha.Nitrapyrin or STC and KEtX increased yield and nitrogen uptake in both years when urea was injected in January. Nitrapyrin also increased yield and nitrogen uptake in 1985, but not in 1984, when urea was injected in March, whereas the STC and KEtX mixture was then either detrimental or ineffective. DCD increased yield and nitrogen uptake from a single dressing of broadoast urea only in 1985. PPDA increased yield and nitrogen uptake from a single broadcast dressing of urea in both years, but had little effect when applied with divided dressings.In 1984 a divided broadcast dressing of ‘Nitro-Chalk’ gave the largest yield and nitrogen uptake, but in 1985 aqueous urea injected with nitrapyrin in January or without or with a nitrification inhibitor in Maroh and prilled urea broadcast as a divided dressing all gave a larger yield. Similarly, a single application was generally more effective as ‘Nitro-Chalk’ in 1984, but as urea in 1985.

Effect of soil bulk density on hydrolysis of surface-applied urea in unsaturated soils

In situ hydrolysis of broadcast urea occurs in unsaturated soils with different bulk densities. The effect of increasing soil bulk densities on the hydrolysis of urea was studied in open and in covered unsaturated soil columns incubated at 30°C. An increase in bulk density from 0.8 to 1.4 Mg/m3 markedly increased the hydrolysis of surface-applied urea in soils containing water > 6% up to near field capacity. Increased diffusion of urea to sorbed soil urease with an increase in bulk density may have enhanced formation of urease-urea complexes and therefore increased the hydrolysis. As urea diffused farther in more dense soils, the retarding effects of high urea concentration gradients on the hydrolysis probably decreased. In light-textured soils, increases in the bulk density had no apparent effect on the hydrolysis of surface-applied urea when evaporation occurred.

Response of No‐Tillage Corn Grown in Corn and Soybean Residues to Several Nitrogen Fertilizer Sources1

AbstractProper management of different N fertilizer sources to reduce effects of ammonia volatilization, denitrification and N immobilization potentials is necessary for successful no‐tillage corn (Zea maysL.) production. A 2‐yr study was conducted on a Canfield silt loam (fine‐loamy, mixed, mesic Aquic Fragiudalf) to evaluate corn response to several N sources‐anhydrous ammonia, broadcast urea, and broadcast urea‐ammonium nitrate solution, when the crop was grown in two crop residues (corn or soybean [Glycine maxL. (Merr.)]. Nitrogen was applied at 112 and 168 kg N ha−1at planting. In both years, urea produced lower yields than ammonia in corn residue but yields equivalent to ammonia in soybean residue. Urea‐ammonium nitrate solution produced (i) lower yields than ammonia in both years in corn residue; (ii) equal yields to ammonia in soybean residue in 1982, but (iii) lower yields than ammonia at the low N rate in soybean residue in 1983. It appears that N source selection for no‐tillage corn can be affected by residue conditions, with less potential for decreased yields when urea‐based N materials are used in soybean residue conditions.

Effect of Azolla on Irrigated Rice in Brazil

AbstractA 1‐year study was conducted in 1983/84 at 2 experimental sites in Brazil to determine the effect of Azolla green‐manure (AO), A. intercrop (OA) and their combination (AA) on rice yield in comparison to mineral fertilization with urea. Nitrogen sources were combined with 4 rice sowing/planting systems.On terraced terra‐roxa soil (Paleudalf) in subtropical northern Paraná State, transplanted rice (T) yielded 8.66 t · ha−1 compared to pregerminated (P), direct‐sown (D) and conventionally sown (C) rice with 7.92; 7.73 and 7.48 t · ha−1, respectively. N‐source treatments yielded 9.33; 8.54 and 7.34 t · ha−1 for AA, OA and AO compared to 8.46; 7.98 and 6.05 for 100, 50 and 0 kg N · ha−1, respectively. Fertilizer‐nitrogen equivalence (FNE) of Azolla treatments compared to urea broadcast in 3 applications ranged between 0 and more than 100 kg N · ha−1.On hydromorphic latosol (Ustic Dystropept) in tropical Goiás State, rice yields were 4.07; 2.52; 1.46 and. 1.33 t · ha−1 for systems T, P, C and D, respectively. N‐source treatments yielded 2.79; 1.98 and 1.78 t · ha−1 for AA, AO and OA compared to 3.43; 2.63 and 1.46 t · ha−1 for 60; 30 and 0 kg N · ha−1 as urea broadcast in 2 applications, respectively. FNE of Azolla was between 0 and 56 kg N · ha−1.

Comparison of the effects of aqueous and of prilled urea, used alone or with urease or nitrification inhibitors, with those of ‘Nitro-Chalk’ on ryegrass leys

SummaryField experiments on ryegrass leys at Rothamsted in 1981, 1982 and 1983 examined the eifects of injected aqueous urea and of broadcast prilled urea applied alone or with one of several nitrification or urease inhibitors, on yields and N, K, Ca and Mg uptakes. Aqueous urea, prilled urea or ‘Nitro-Chalk’ were applied as single 375 kg N/ha dressings, and prilled urea or ‘Nitro-Chalk’ as three 125 kg N/ha dressings. The nitrification inhibitors etridiazole or nitrapyrin were injected with aqueous urea, but dicyandiamide (DCD) was broadcast with prilled urea. Neither the urease inhibitor hydroquinone nor the nitrification inhibitors slowed the rate of urea hydrolysis. Neither hydroquinone nor DCD diminished volatilization losses of ammonia from broadcast urea which ranged from 8 to 25 kg N/ha; they were less than 4 kg N/ha from injected urea or broadcast ‘Nitro-Chalk’. Nitrapyrin, etridiazole and DCD effectively inhibited nitrification. DCD, and to a lesser extent hydroquinone, increased yields and nitrogen uptakes from a single broadcast application of prilled urea given either in winter or in spring. However, these yields were still smaller than those given by injected urea or by divided dressings of urea, whether or not an inhibitor was used. The inhibitors did not increase yields with divided broadcast dressings of urea, which were slightly smaller than those with equivalent dressings of ‘Nitro-Chalk’. Inhibitors did not consistently increase yield when injected with aqueous urea. Inhibitors applied with injected or broadcast urea slightly increased K uptakes, and slightly decreased Ca and Mg uptakes.

Labeled nitrogen fertilizer research with urea in the semi-arid tropics

As part of a research program to determine the fate of N fertilizers applied to dryland sorghum in the semi-arid tropics,15N balance studies were conducted with various N sources in the greenhouse. Two American soils, Houston Black clay (Udic Pellustert) and Windthorst sandy loam (Udic Paleustalf), similar in properties to the Vertisol and Alfisol in the semi-arid tropics of India, were employed. Experiments were conducted with large pots containing 20 or 60 kg of soil which was subjected to several watering regimes. The15N not accounted for in the plant and soil was presumably lost. Losses of N on calcareous Houston Black clay were greatest for broadcast urea, 16%–28%. Amendment of broadcast urea with 2% phenyl phosphorodiamidate, a urease inhibitor, reduced N losses only slightly to 15%–20%. Point placement of urea at a 6 cm soil depth reduced losses to 1%–11%. Granule size had no effect on N loss from point-placed urea. Ammonia volatilization was apparently the main N loss mechanism, since N losses from sodium nitrate were less than 7%, except when the soil surface was waterlogged. N losses on the Windthorst soil averaged 30% from urea and 11% from ammonium nitrate. Amendment of urea with urea phosphate to form a 27% N and 13% P product reduced fertilizer N losses but did not increase grain yield on Windthorst soil. N losses were also less from ammonium nitrophosphate than from urea. Band and point placement of urea 6 cm below the soil surface were equally effective in reducing N loss on Houston Black clay. The findings give credence to the recommendation of deep band placement for urea in the semi-arid tropics.

Nitrogen Fertilizer Efficiency in Bermudagrass Production

AbstractEfficient N applications are necessary to maximize bermudagrass (Cynodon dactylon L.) dry matter yield and N uptake in forage. Significant losses of NH3 from surface applications of urea and NH4‐N fertilizers by volatilization have been reported. Field experiments were conducted over a three‐year period under a wide range of climatic and soil conditions in Oklahoma to determine the efficiency of N applications for dry matter production and N uptake in bermudagrass forage. Four locations were selected in 1978 and one each in 1979 and 1980, representing four typical soil types for bermudagrass production with a pH range of 4.7 to 6.9. Anhydrous ammonia (AA) and ammonia passed through a Cold‐Flo adapter (ACF) were injected into bermudagrass sod and urea‐ammonium‐nitrate (UAN), urea, and (NH4)2SO4 (AS) were broadcast. Rates of N were 0, 112, 224, and 448 kg·ha−1 initially as well as 224, 336, and 448 kg·ha−1 in split applications. An additional experiment was established in 1980 to evaluate the effect of S on yield and N uptake. Rates of S were 0 and 64 kg · ha−1 and sources were elemental S, CaSO4 · 2H20, MgSO4, and AS. There were two harvests at each location in 1978, three in 1979, and two in 1980.Yield and N uptake from AA and ACF applications were not significantly different, but generally were lower than with broadcast UAN, urea, and AS. Yield and N uptake generally were lower from urea than UAN and AS. Relative efficiency of N sources obtained from averaging across N response experiments were in the order of AS &gt; UAN &gt; urea &gt; AA &gt; ACF. Split application of N in 1978 and 1980 did not increase yield, but in 1979 an increase in yield was obtained with more even rainfall distribution during the growing season. Sulfur fertilization decreased N:S ratios in forage, but did not increase yield or N uptake or improve N efficiency. Potential losses of NH3 by volatilization from broadcast urea, UAN, and AS in these experiments were considered minimal.