Prilled Urea Research Articles

Response of stevia to foliar application of prilled urea

Urea can be supplied to plants through the foliage, facilitating optimal N management, which minimizes N losses to the environment. The efficiency of N assimilation through foliage depends upon several factors including N levels and varieties or genotypes. No information is available on the effect of the foliar application of urea on stevia (Stevia rebaudiana, Bertoni). The objective of the study was to evaluate the effect of foliar application of prilled urea applied in different concentrations on the growth, yield components, leaf biomass yield, N content and its uptake by stevia. Seven levels of urea viz. 0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3g 2L-1 were sprayed 10 days after planting (DAP) in acid and non-calcareous soils at an interval of one week up to 60 DAP. Foliar urea application significantly increased plant height, branch and leaf number, leaf area, fresh and dry leaf weight, leaf N content and uptake by stevia. Most of the parameters were increased with the advancement of growth period from 30 to 60 DAP. The foliar spray of 2.0g urea solution was found to be most effective for enhancing the growth, leaf yield and yield attributes of stevia. The yield increase was 478% in acid soil and 485% in non-calcareous soil over control. Further increase in the concentrations of urea spray (2.5 and 3.0g) was not found to be useful as it declined the leaf yield by 135% in acid and 175% in non-calcareous soil probably due to its toxicity. N content in stevia leaves was significantly increased with the increased levels of urea up to 3.0g in both soils. Conversely, the trend of N uptake did not follow the trend of N contents of stevia leaves. N uptake as expected increased as foliar application of urea increased up to 2.0g and then decreased with further addition. The results suggest that farmers can be advised to apply prilled urea as foliar spray @ 1g L-1 for higher leaf biomass yield and N uptake by stevia either in acid or non-calcareous soils under the agro-climatic conditions of Bangladesh Agricultural University, Mymensingh.J. Bangladesh Agril. Univ. 13(1): 39-46, June 2015

Sulphur-coated urea as a source of sulphur and an enhanced efficiency of nitrogen fertilizer for spring wheat

Use of high analysis fertilizers such as diammonium phosphate in place of ordinary superphosphate and urea in place of ammonium sulphate over years, sulphur application to crop fields has considerably decreased, which has led to widespread sulphur deficiency in Indian soils. Hence, considering this into account a field study for two years was conducted at the research farm of ICAR-Indian Agricultural Research Institute, New Delhi to evaluate sulphur-coated urea (SCU) as a source of sulphur (S) and an enhanced efficiency of nitrogen fertilizer. Prilled urea (PU) coated with 4 to 5% S significantly increased wheat grain yield to the tune of 9.58 to 11.21% and nitrogen 19.06 to 23.94% and sulphur uptake 21.76 to 29.29% over prilled urea alone by wheat. However, net return and benefit: cost ratio was the highest and significant at 5% S coating onto PU. Five % SCU supplied 50% of the sulphur needs of the wheat crop and enhanced nitrogen recovery efficiency by 60% and is therefore recommended as sulphur as well as enhanced efficiency of nitrogen fertilizer for wheat in Indo-Gangetic plains of India. This is an important finding considering the environmental safety by increased nitrogen recovery and also productivity in present scenario.

Field Performance Evaluation of Push Type Prilled Urea Applicator in Rice Cultivation

CORRECTION: Due to a number of formatting and layout issues, the PDF of this paper was replaced on 10th October 2016. The page numbers of this article have changed from 68-78 to 71-81.BRRI prilled urea applicator was designed and developed to facilitate deep placement of regular urea. Experiments were conducted to evaluate the performance of BRRI prilled urea applicator in the farmers’ fields at Gosaidanga in Shailkupaupazila under Jhenaidah district and at Rashidpur in Mithapukurupazila under Rangpur district during Boro 2015 season. Three treatments: hand broadcasting of urea (recommended dose) (HB), BRRI prilled urea applicator (70% of the recommended dose) (PUA) and BRRI USG applicator (70% of the recommended dose) (USGA) were compared in the experiments. The experiment was laid out in randomized complete block design (RCBD) and replicated in four farmers’ plots in each location using BRRI dhan28 as test crop both the locations. Prior to field experiment, prilled urea applicator was calibrated and urea dispensed was set to 14 gm in one revolution of drive wheel for Boro season. The field capacity of the PUA and USGA was almost similar (0.09-0.10 ha hr-1) in both the locations. Field efficiency of PUA and USGA had 64-65 and 68-69 percent, respectively. PUA and USGA saved 29-32 percent urea fertilizer compared to HB whereas labour requirement of HB (3.74-4.04 man-hr ha-1) in three splits showed similar to single application of urea by PUA (3.68-4.00 man-hr ha-1) and USGA (3.78-3.97 man-hr ha-1). Urea application cost in HB, PUA and USGA was Tk 4,624, 3,216-3,424 and 3,305-3,483 per hectare in both the locations. Prilled urea application method reduced the production cost. Urea application methods showed insignificant effect on grain yield. BRRI prilled urea safely dispensed urea fertilizer in subsurface, increased the efficacy of urea fertilizer and saved urea fertilizer without sacrificing grain yield. BRRI prilled urea applicator could be a viable technology in rice cultivation. Extensive dissemination works should be undertaken in different agro-ecological zones for wide spread adoption of the applicator.Bangladesh Rice j. 2015, 19(2): 71-81

Coating of essential oils onto prilled urea retards its nitrification in soil

ABSTRACTIncreased use of nitrogenous fertilizers in agriculture has led to the increased pollution of ground water and atmosphere. Certain plant products can be used as coating materials onto urea to reduce the N losses. We evaluated the effectiveness of citronella and palmarosa grass oils as nitrification inhibitors in a soil incubation study. The treatments (14) were combinations of 4 N sources (neem, citronella and palmarosa oil coated prilled ureas, and uncoated prilled urea), 2 coating thicknesses of oils (500 and 1000 mg kg−1) and 2 N levels (75 and 150 kg N ha−1), replicated thrice in a randomized block design. N levels at 75 and 150 kg ha−1 were equivalent to 34 and 68 mg N kg−1 soil, respectively. Results showed that N sources citronella (CCPU1000) and neem oil (NCPU1000) coated prilled ureas at 1000 mg kg−1 coating thickness with 75 kg ha−1 released similar amount of ammonical-N to uncoated prilled urea at 150 kg N ha−1, suggesting the beneficial effect of coated ureas. The highest nitrification inhibition (%) was recorded with NCPU1000, the reference nitrification inhibitor, which was significantly greater to all the other N sources at 7 days after incubation (DAI), and at par to CCPU1000 at 14 and 21 DAI.

Field performance of BARI urea super granule applicator

Field performance of BARI Urea Super Granule (USG) applicator was evaluated on BARI research stations (Gazipur, Pabna, and Barisal) and farmer’s field (Pabna, Barisal, Magura,Narshingdi,Jhenadah, Sirajgang, Rajbari and Jhalkathi) during the boro season of 2012-13. The applicator was tested with four treatments- application of USG by hand (165 kg/ha), application of USG by BARI USG applicator (165 kg/ha), application of prilled urea at USG rate (165 kg/ha) and application of prilled urea at farmers practice. In the farmer’s field, USG applicators were evaluated with the traditional broadcasting of granular urea. Similar yield of rice was obtained from machine and hand application of USG in all locations. Higher yield of rice was obtained from USG than granular urea. During field test, average field capacity and efficiency of the applicator were 0.138 ha/h and 81%, respectively. Considering custom hiring, the net income per year was Tk. 71750 and the payback period was 3 days. The price of the applicator is Tk. 3500.Bangladesh J. Agril. Res. 41(1): 103-113, March 2016

A comparative appraisal of urea super granule application in raised bed and prilled urea application in conventional planting for transplanted boro rice (Oryza sativa)

Utilization of urea super granule (USG) with raised bed cultivation system for transplanted boro (winter, irrigated) rice production is a major concern now days. A field experiment was conducted in the chuadanga district of Bangladesh to compare the two cultivation methods: deep placement of USG on raised bed with boro rice, and prilled urea (PU) broadcasting in conventional planting. Results showed that USG in raised bed planting increased grain yields of transplanted boro rice by up to 18.18% over PU in conventional planting. Deep placement of USG in raised bed planting increased the number of panicle m-2, number of grains panicle-1 and 1000-grains weight of boro rice than the PU in conventional planting. Better plant growth was observed by deep placement of USG in raised bed planting compared to PU in conventional planting. Sterility percentage and weed infestation were lower on USG in raised bed planting compared to the PU in conventional planting methods. Forty seven percent irrigation water and application time could be saved by USG in raised bed planting than PU in conventional planting. Deep placement of USG in bed saved N fertilizer consumption over conventional planting. Water use efficiency for grain and biomass production was higher with deep placement of USG in bed planting than the PU broadcasting in conventional planting methods. Similarly, agronomic efficiency of N fertilizer by USG in bed planting was significantly higher than the PU broadcasting in conventional planting. This study concluded that deep placement of USG in raised bed planting for transplanted boro rice is a new approach to achieve fertilizer and water use efficiency as well as higher yield and less water input compared to existing agronomic practices in Bangladesh.

Fertilizer Deep Placement Increases Rice Production: Evidence from Farmers’ Fields in Southern Bangladesh

Efficient use of fertilizer is needed to meet the increasing food demand, minimize negative environmental impacts, and maximize farmers’ profits. Fertilizer deep placement (FDP) could be one of the best management techniques to achieve these multiple benefits. Experiments were conducted in 115 farmers’ fields spread over 35 upazilas across eight districts over nine contiguous rice (Oryza sativa L.) growing seasons during 2009 to 2012 in southern Bangladesh to compare the effects of deep placement of urea briquettes (UB) and nitrogen–phosphorus–potassium briquettes (NPK), with farmers’ broadcast prilled urea (PU) on rice yield and net economic return. Deep placement of either UB or NPK significantly increased grain yields and net economic return across all the rice‐growing seasons and years compared to PU. Across the years, average yield increase in UB and NPK over PU was higher during the Aus and Aman (wet) seasons (21–31%) than in the Boro (dry) season (11–17%). In addition to increase in grain yield, deep placement of UB and NPK saved urea by 33 and 44%, respectively, during the Aus–Aman seasons, and by 35 and 28% during the Boro season. The deep placement of one 2.4 g NPK (∼44 kg N ha−1) for the Aus–Aman season and two NPK (87 kg N ha−1) for the Boro season would be more profitable for southern Bangladesh. The FDP also provides the greatest benefits under rainfed wet season conditions where farmers have little control of water management and timing of N application.

Effect of integrated nutrient management in boro rice cultivation

An experiment was carried out in the farmer’s field of village Boira under Kotoali Thana, District-Mymensingh in Boro season (Jannuary to May 2013) to find out the effect of integrated nutrient management in Boro rice cv. BRRI dhan29 cultivation. The experiment consisted of the following treatments- control (no manure and no fertilizer) (T1), recommended dose of prilled urea and PKSZn (T2), 50% of the recommended dose of prilled urea and PKSZn + cowdung 5 t ha-1 (T3), 50% of recommended dose of prilled urea and PKSZn + poultry manure 2.5 t ha-1(T4), 50% of recommended dose of prilled urea and PKSZn + cowdung 10 t ha-1 (T5), 50% of recommended dose of prilled urea and PKSZn + poultry manure 5 t ha-1 (T6), cowdung 10 t ha-1 (T7), poultry manure 5 t ha-1 (T8), full dose of USG (2.7g) + recommended dose of PKSZn (T9), full dose of USG (2.7g) + cowdung 10 t ha-1 (T10), full dose of USG (2.7g) + poultry manure 5 t ha-1 (T11), full dose of USG (2.7g) + cowdung 5 t ha-1 (T12), full dose of USG (2.7g) + poultry manure 2.5 t ha-1(T13), USG (1.8g) + poultry manure 5 t ha-1 (T14), USG (1.8g) + poultry manure 2.5 t ha-1 (T15) and farmer’s practice (Urea 250 kg ha-1, TSP 220 kg ha-1, MoP 130 kg ha-1, gypsum 130 kg ha-1) (T16). The experiment was laid out in a randomized complete block design with three replications. Results of the experiment showed that integrated nutrient management had significant effect on yield contributing characters and yield of BRRI dhan29. The tallest plant (93.33 cm) was found in T2 treatment (recommended dose of prilled urea and PKSZn), the highest number of total tillers hill-1(16.85) and effective tillers hill-1 (15.90) were obtained in T11 treatment (USG (2.7g) + poultry manure 5 t ha-1). The highest 1000-grain weight (22.40g), grain yield (7.19 t ha-1) and straw yield (8.08 t ha-1) were recorded in T10 treatment (full dose of USG (2.7g) + cowdung 10 t ha-1) and the lowest grain yield (4.43 t ha-1) and straw yield (5.21 t ha-1) were obtained in T7 treatment (cowdung 10 t ha-1). From the study, it can be concluded that inorganic fertilizer along with manure greatly influence the yield contributing characters and yield of Boro rice and full dose of USG (2.7g) with cowdung (10 t ha-1) appears as the promising combination for Boro rice (cv. BRRI dhan29) cultivation.SAARC J. Agri., 13(2): 131-140 (2015)

Utilization of Urea Super Granule in Raised Bed Versus Prilled Urea in Conventional Flat Method for Transplanted Aman Rice (Oryza Sativa)

Bed planting with urea super granule (USG) application of rice production systems is very new and research on it is still at an introductory phase. Impact of granular urea application on growth and yield of transplanted aman rice as well as evaluation of water and fertilizer use efficiency of rice-fallow-rice cropping system was investigated under raised bed cultivation method. Result showed that the USG in bed planting method increased grain yield of transplanted aman rice up to 12.32% over prilled urea (PU) broadcasting in conventional method. The USG application in bed planting method increased the number of panicle m-2, number of grains panicle-1 and 1000-grains weight of rice than the PU in conventional method. Sterility percentage and weed infestation were lower at USG application in bed planting method than the PU in conventional method. Forty percent irrigation water and time for application could be saved through the USG in bed planting than the PU broadcasting in conventional method. Water use efficiency for grain and biomass production was higher by the USG application in bed planting than the PU broadcasting in conventional method. Likewise, agronomic efficiency of the USG in bed planting was higher than the PU broadcasting in conventional method. This study concluded that the USG in bed planting method is a new approach to get better fertilizer and water use efficiency as well as higher yield compared to the existing agronomic practice in the world.

Floodwater ammonium, nitrogen use efficiency and rice yields with fertilizer deep placement and alternate wetting and drying under triple rice cropping systems

Fertilizer management should consider optimum time, rates and methods of application to increase use efficiency and crop yield. We conducted field experiments at Bangladesh Agricultural University, Bangladesh, to investigate the effects of deep placement of urea briquettes (UB) and NPK briquettes (NPK) compared to broadcast prilled urea (PU) at different N rates on dynamics of floodwater NH4 +-N, ammonia (NH3) volatilization, rice yield and nitrogen use efficiency (NUE) during four consecutive rice-growing seasons in 2012–2013. The floodwater NH4 +-N and NH3 volatilization in broadcast PU increased with N rates, while in deep-placed treatments irrespective of N rates it was similar to the control. Across seasons and water regime, UB or NPK significantly (P < 0.05) increased grain yield and nitrogen recovery compared to broadcast PU. During the Boro season (across water regime), UB78 and NPK78 increased grain yield by 40 and 29 %, respectively, compared to broadcast PU78, while N recovery increased from 35 % of PU to 63–67 % in deep placement. Deep placement of UB52 or NPK52 during Aus–Aman and UB78 or NPK78 during Boro can be one of the best N management options for increasing NUE and crop yield. Alternate wetting and drying irrigation, though, had no significant effect on grain yield or on NUE. Its adoption could save irrigation water without any yield reduction during the Boro season. However, more studies across different soils, climate and management practices are needed for further understanding the interactive effects of fertilizer and water management on yield, NUE and soil fertility.

Effect of nitrogen levels and coated urea on growth, yields and nitrogen use efficiency in aromatic rice

ABSTRACTResults from a field experiment conducted at the Indian Agricultural Research Institute, New Delhi, India showed that coating urea with elemental sulfur or gypsum or phosphogypsum gave higher yields (12.08, 6.78 and 6.14% higher grain yield compared to prilled urea) of high yielding an aromatic rice cultivar ‘Pusa Sugandh 5’ (Pusa 2511) and increased the efficiency of prilled urea. As regards nitrogen use efficiency sulfur coated urea was nearly twice as effective as gypsum or phosphogypsum coated urea; the latter two were equally effective compared to prilled urea alone.

Evaluation of N Efficiency Using Prilled Urea and Urea Super Granules in T. Aman Rice

An experiment was conducted at the Experimental field of Department of Agronomy, Bangladesh Agricultural University, Mymensingh, during June to December 2007 to evaluate the nitrogen use efficiency of transplant aman rice using prilled urea (PU) and urea super granule (USG). Three rice varieties (BR11, BRRI dhan30 and BRRI dhan39) were compared at three doses of nitrogen, i.e., PU@125 kg N ha-1, USG @170 kg N ha-1 and USG @ 70 kg N ha-1 in a Randomized Complete Block (RCB) design with three replications. USG each weighing 1 g and 2.6 g were placed manually at the depth of 8-10 cm in the middle of four hills in alternate rows at 12 days after transplanting and PU applied in split applications. The rice var. BR11 at USG @70 kg N ha-1 has produced the maximum grain yield (4.75 t ha-1) which was statistically identical to BRRI dhan30 at USG @ 70 kg N ha-1 (1 g pellet-1). The highest nitrogen use efficiency, partial factor productivity and marginal rate of return (1966%) were recorded from the treatment of BR11 at USG @ 70 kg N ha-1.Bangladesh Agron. J. 2015, 18(1): 59-63

Performance of Prilled Urea and Urea Super Granules on the Growth and Yield of Wheat

An experiment was conducted at the Agronomy Field of Sher-e-Bangla Agricultural University, Dhaka-1207 during the period from November 2011 to March 2012 to evaluate the performance of prilled urea and urea super granules (USG) on the growth and yield of wheat varieties. The experiment comprised of four wheat varieties viz., BARI Gom 21, BARI Gom 24, BARI Gom 25 and BARI Gom 26, and five nitrogen (N) levels viz., control (no Nitrogen), 84 kg ha-1 N from USG, and 30, 50 and 70 kg N ha-1 from prilled urea i.e., 67, 112 and 155 kg urea ha-1. The experiment was laid out in a split-plot design with three replications where wheat varieties were placed in the main plot and nitrogenous fertilizers in sub-plots. Experimental results indicated that different varieties had the significant effect on plant height, number of tillers and dry weight plant-1, and number of grains spike-1, grain and straw yield, and harvest index. The variety BARI Gom 24 produced the highest grain yield (2.49 t ha-1) that mainly attributed by the maximum number of spikes plant-1, number of grains spike-1 and 1000-grain weight. Among the different nitrogenous fertilizers 84 kg N ha-1 from USG (1.8 g) gave the highest grain yield (2.69 t ha-1) due to the maximum number of spikes plant-1, maximum number of grains spike-1 and 1000-grain weight. The variety BARI Gom 24 produced the highest grain yield (2.80 t ha-1) with 80 kg N ha-1 from USG application.Bangladesh Agron. J. 2015, 18(1): 37-48

Effect of coated urea on cadmium accumulation in Oryza sativa L. grown in contaminated soil.

Experiments were conducted to determine the effects of three types of coated urea on the accumulation of cadmium (Cd) in rice (Oryza sativa L.) grown in contaminated soil. Pot-culture experiments were conducted in a greenhouse from July to November 2012 on the rice cultivar "Hua Hang Si Miao" in Guangzhou (China). The experimental design was completely randomized with four treatments and three replications. The treatments were control (CK) (N 0 mg/kg), prilled urea (PU) (N 200 mg/kg), polymer-coated urea (PCU) (N 200 mg/kg), and sulfur-coated urea (SCU) (N 200 mg/kg). Our results indicated that applications of PCU and SCU slightly increased the dry weight of rice grains. The application of SCU significantly decreased the CaCl2 and toxicity characteristic leaching procedure (TCLP)-extractable Cd concentrations by 15.4 and 56.1%, respectively. Sequential extractions showed that PCU and SCU applications led to a significant decrease in Cd in the exchangeable fraction and an increase in the bound iron (Fe) and manganese (Mn) oxides fractions. Cd concentrations in grains treated with PCU were reduced by 11.7%, whereas SCU significantly reduced Cd concentrations by 29.1%. SCU reduced Cd transfer from the straws to the grain. Our results demonstrated that PCU and SCU may be effective in mitigating Cd accumulation in rice grown in acidic Cd-contaminated soil, especially in plants receiving SCU.

Effect of Prilled Urea, Urea and NPK Briquettes on the Yield of Bitter Gourd in Two Upazillas of Jessore District

An experiment was conducted to evaluate the performance of deep placement of urea and NPK briquettes compared to broadcast application of prilled urea for bitter gourd production during the Kharif-1 season of 2013. The experiments were conducted in two locations in Jessore district, Chowgacha and Jessore sadar. Seven treatments were designed to evaluate crops response: T1: Control, T2: Farmer’s practice, T3: Recommended doses of all fertilizers except N, T4: Recommended doses of all fertilizers, T5: Urea briquette + other fertilizers, T6: NPK briquette + other fertilizers and T7: NPK briquette + other fertilizers except cowdung. The rate of urea and NPK briquette was 10 percent less than the rate of recommended prilled urea. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. The sizes of NPK and urea briquette were 3.4 g and 2.7 g, respectively. The recommended fertilizer doses were used to supply N, P, K, S, Zn and B from Urea, TSP, MoP, gypsum, zinc sulphate (hepta) and boric acid, respectively. The results showed that deep placement of NPK briquette gave significantly the highest yield of bitter gourd (32.16 tha-1) followed by urea briquette (30.45 tha-1) which were 12.34 and 7.41 percent higher over recommended doses of all fertilizers. The highest N recovery (77.4 %) was found when 72 kg N ha-1 was applied as NPK briquette.J. Environ. Sci. &amp; Natural Resources, 8(1): 157-160 2015

Floodwater Nitrogen, Rice Yield and N Use Efficiency as Influenced by Deep Placement of Nitrogenous Fertilizers

An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during the Aus season of 2012 to investigate the effects of deep placement of nitrogen (N) fertilizers on floodwater NH4-N concentration, rice yield and N use efficiency under alternate wetting and drying (AWD) condition. The experiment was laid out in a randomized complete block design with three replications. There were eight treatment combinations viz. T 1 (Control), T 2 [52 kg N from Urea super granule (USG)], T 3 (104 kg N from USG), T 4 [78 kg N from prilled urea (PU)], T 5 (120 kg N from PU), T 6 (51 kg N from NPK briquette), T 7 (78 kg N from USG) and T 8 (78 kg N from NPK briquette). The results regarding the floodwater NH 4 -N concentration revealed that, the highest value of (NH 4M -N) was observed at the second day of PU application followed by gradual decrease with time. USG and NPK briquette treated plots showed negligible amounts of NH 4 -N in flood water during the sampling periods. The highest grain yield (5265 kg ha -1 ) and straw yield (6434 kg ha -1 ) was recorded from 104 kg N from USG (treatment T 3 ) and the lowest values were obtained from control. Apparent nitrogen recovery by rice plants was much higher when 78 kg N was applied as USG. Nitrogen use efficiency decreased with the increase in N rate either as PU, USG and NPK briquette and treatment T 7 (78 kg N as USG) showed the highest value. These results clearly indicate that the deep placement of N in the form of USG and NPK briquette minimizes the loss of N that results in higher N use efficiency and increased grain yield of rice as compared to broadcast application of N in the form of PU. DOI: http://dx.doi.org/10.3329/jesnr.v7i1.22173 J. Environ. Sci. & Natual Resources, 7(1): 207-213 2014

Urea Deep Placement in Rice as an Option for Increasing Nitrogen Use Efficiency

Prilled urea applicator is a nitrogen saving technology. Aiming to find out the efficiency of BRRI prilled urea applicator, a field experiment was conducted during boro season of 2013-2014 at the Bangladesh Rice Research Institute (BRRI) experimental farm, Gazipur and at farmer’s field of Dhirasshram village under Gazipur Sadar Upazilla, Gazipur, Bangladesh. Four treatments viz. 1) hand broadcasting of prilled urea as per BRRI recommendation (T1), 2) prilled urea application by applicator (70% of the BRRI recommended dose) (T2), 3) hand broadcasting of prilled urea (70% of the BRRI recommended dose) (T3) and 4) N-control (T4) were evaluated in the study. The T2 treatment gave the highest grain yield of 6.96 t·ha-1 and 7.20 t·ha-1 at BRRI farm and Dhirasshram village, respectively, followed by those of T1 treatment. The highest agronomic use efficiency was obtained from T2 treatment in both the locations. Similar scenario for apparent recovery efficiency, utilization efficiency and partial factor productivity was also observed in T2 treatment. Moreover, about thirty percent prilled urea was saved due to deep placement of urea by applicator in boro season.

A comparison under grazing of pasture production, pasture N content and soil mineral N levels between granular urea and ONEsystem® on two contrasting dairy farms in New Zealand

Field trials under grazing on two contrasting dairy farms in mid-Canterbury (Site C) on a stony silt loam under irrigation, and in rain-fed central Waikato (Site W) on a volcanic ash-derived soil, compared standard granular urea (4-5 mm diameter granules) with ONEsystem®. This uses prilled urea (0.8-2.8 mm diameter prills), passed through a fine water spray (50 litres/ha) that contains the urease inhibitor nbpt (2 gm nbpt/kg N) during application. A nil N control and three rates of each fertiliser were applied to 12 × 25 m plots on four occasions after rotational grazing during spring/early summer 2014. ONEsystem® resulted in extra dry matter (EDM) to N applied compared with granular urea at Site C. At Site W, the initial advantage to ONEsystem® in Period 1 (early spring) was not maintained. To produce EDM of 1250 (±750) kg/ha required 120 and 126 kg N/ha as granular urea at Sites C and W, respectively (giving EDM factors of 10.4 and 9.9 (± 2) kgDM/ kgN applied respectively). This compares with 50 and 74 kg N/ha required with ONEsystem® for higher EDM factors of 24 and 17 (± 5) kg DM/ kg N. Pasture N concentrations were higher at Site C following ONEsystem® application, and total N uptake was increased 3-fold compared to granular urea. At Site W, increases in EDM with ONEsystem® only occurred in the first period. The results of this study have implications for both the economic and environmental efficiency of fertiliser urea use on grazed pastures. Keywords: ONEsystem®, prilled urea, nbpt, granular urea, N efficiency, pasture, N uptake

Nitrogen use efficiency and rice yield as influenced by the application of prilled urea and urea super granule with or without organic manure

An experiment was conducted to examine the effect of prilled urea (PU), and urea super granule (USG) alone or in combination with poultry manure or cowdung on NH4-N content of rice field with nitrogen use efficiency (NUE) and the yield of rice (cv. BRRI dhan50). The experiment was carried out at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during Boro season of 2012 and laid out in a randomized complete block design with three replications. There were six treatments viz. T1 (Control), T2 (78 kg N ha-1 from USG), T3 (136 kg N ha-1 from PU), T4 (58 kg N ha-1 from USG), T5 (58 kg N ha-1M from USG + 3 t ha-1 poultry manure) and T6 (58 kg N ha-1 from USG + 5 t ha-1 cowdung). All plots received recommended doses of P, K, S and Zn fertilizers. The NH4-N in rice field water increased rapidly when N was applied as PU. In contrast, NH4-N release was very slow when applied as USG over the crop growth period. Application of PU, USG alone or in combination with poultry manure or cowdung significantly influenced grain and straw yield, all the yield components except 1000-grain weight of BRRI dhan50. Urea super granule with poultry manure (treatment T5) produced the highest grain and straw yield and the lowest values were recorded from control. Nitrogen content and uptake, apparent N recovery and NUE were also influenced significantly by the application of PU, and USG alone or in combination with organic manure. Among the treatments, T5 demonstrated the highest N recovery and NUE. The overall results suggest that application of USG in combination with poultry manure could be considered more effective for increasing the yield and NUE of BRRI dhan50. DOI: http://dx.doi.org/10.3329/jbau.v12i1.21237 J. Bangladesh Agril. Univ. 12(1): 37-43, June 2014

Effect of variety and method of USG placement on the yield performance of transplanted aman rice

A field experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from July to December 2011 to evaluate the effect of variety and placement method of urea super granule (USG) on the yield performance of T. aman rice varieties. The experiment consisted of three aman rice varieties viz., Pajam, BR11, BRRI dhan40 and four placement methods viz., broadcasting method of prilled urea (PU), USG placement by hand, by BAU USG applicator and by BARI USG applicator. The experiment was laid out in a randomized complete block design with four replications. The highest value of grain yield (5.13 t/ha), straw yield (5.90 t/ha) and biological yield (11.04 t/ha) were found in BR11. On the other hand, the lowest grain yield (3.54 t/ha) was produced in variety Pajam. The highest grain and straw yields (5.13 and 5.21 t/ha, respectively) were obtained from the hand placement method of USG. Regarding the interaction of variety and USG placement method, BR11with hand placement method appeared as the best method among others. DOI: http://dx.doi.org/10.3329/jbau.v12i1.21183 J. Bangladesh Agril. Univ. 12(1): 7-12, June 2014