Urea Supergranules Research Articles

Effect of urea super granule application on physiological and yield attributes of rice

Effect of urea super granule application on physiological and yield attributes of rice

COMPARATIVE STUDY OF USG AND NPK BRIQUETTE ON THE PERFORMANCE OF JHUM RICE

Two experiments were conducted at Ramery para, Bandarban sadar, Bandarban, Bangladesh hill district in Chittagong under the AEZ (Agro Ecological Zone) 29 (Northern and Eastern Hills Tract) during March 2017 to November 2017 to study of USG and NPK briquette on the performance of Jhum rice. The experiment was conducted in two field and designed on Randomized Completely Block Design (RCBD). The treatments consisted of 7(seven) levels of USG (Urea Super Granule) and NPK briquette i.e. T1: Control, T2: 100% USG and PK (RFD) (267.5 kg ha-1), T3: 80% USG and PK (RFD) (214.1 kg ha-1), T4: 80% USG and PK (RFD) (320.8 kg ha-1), T5 :100%NPK briquette (267.5 kg ha-1), T6: 80% NPK briquette (214.1 kg ha-1), T7: 120% NPK briquette (320.8 kg ha-1). The growth and yield of Jhum rice were significantly influenced by different levels of USG and NPK briquette. The highest plant height of jhum rice (139.23 cm), effective tillers hill-1 (16.60), panicle length (30.23 cm), highest number of filled grain panicle-1 (245.23), 1000 grain weight (28.0 gm), straw yield (4.15 t/ha) and grain yield (3.56 t/ha) were found from T5 treatment receiving 100%NPK briquette (267.5 kg ha-1) and for all cases lowest results were found in T1 treatment receiving no fertilizer (control).

Effects of nitrogenous fertilizers on rice yield under continuous flooding and alternate wetting and drying conditions

In rice cultivation, water and nitrogen saving strategies are becoming more crucial in order to identify efficient and useful crop production and management approaches. A study was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh to examine the combined effects of irrigation method and nitrogen fertilizer on yield contributing traits and yield of rice cv. BRRI dhan29. The experiment was set up in a split-plot based on a randomized complete block design with 3 replications and 14 treatment combinations. Two irrigation methods such as continuous flooding (CF) and alternate wetting and drying (AWD) were the main factor while nitrogen fertilizers including prilled urea (PU) and urea super granule (USG) were the sub-factor. The treatment T6 (USG at 7 DAT) generated the highest plant height (cm), no. of effective tillers hill-1, panicle length (cm), no. of grains panicle-1, grain yield and biological yield during AWD condition. In terms of grain yield, the treatment combinations AWD + T6 and CF + T7 were statistically equal. In comparison to control, all AWD + USG and CF + PU treatment combinations increased straw yield and harvest index. Under both AWD and CF conditions, USG increased more grain and straw yields compared to PU. So, farmers may be advised to apply USG (216 kg ha-1) at 7 DAT under AWD conditions in order to improve rice yield and ensure food security.

Modelling the diffusion and exchange of ammoniacal nitrogen following deep placement of urea supergranules in wetland rice cultivation

Deep placement of urea in the form of supergranules is often recommended in transplanted rice cultivation as a means of avoiding nitrogen loss in the environment. As ammoniacal nitrogen produced by urea hydrolysis just after deep application is chemically stable in the anaerobic layer of the paddy soil, it is relevant to study the diffusion–exchange phenomenon affecting this ammoniacal-N. More precisely, numerical calculus was called on to solve the nonlinear diffusion–exchange equation, admitting spherical symmetry in this context. The adsorption isotherm for ammoniacal-N intervening in this equation was a Freundlich isotherm. Experiments performed in the laboratory (untransplanted situation) and in the field (transplanted situation) enabled the monitoring of the time course of ammoniacal-N concentration in the central position. The tortuosity factor was evaluated at 0.80 in the paddy soil. In the field, the diffusion–exchange phase was clearly separated from the ammonia assimilation phase. The limit between the two was evaluated in six replicates. The first-order mechanism of ammonia disappearance is interpreted as the indication of a tight physiological regulation at the carbon–nitrogen interface acting within roots pushed to their limit in growth and assimilative capacity. This limit is here reported at 12 mM ammonia, attained 39 d after point application. This delay is enhanced when the tortuosity factor is reduced. Similar modelling in the context of cylindrical symmetry can be an option to study new urea fertilizers in the form of urea rods.

Growth and yield responses of rainfed lowland rice to different nitrogen fertilizer sources, methods and time of applications in Fogera Plain, northwest Ethiopia

Two sets of field experiments under seedling transplanting and drill row seed planting methods were conducted side by side for two years during the main cropping seasons of 2017 and 2018 in Fogera Plain of northwest Ethiopia to study the effect of different sources, application methods and time of nitrogen fertilizer on growth and yield of rain-fed lowland rice. Three N sources of fertilizers (conventional Urea, Urea super-granule, and slow-release Urea) with six, one, and three application methods and times, respectively were laid out in a randomized complete block design (RCBD) in three replicates. These treatments and design were equally applied for two sets of experiments under both planting methods. Results revealed that soil-plant analysis development (SPAD) value, LAI, and biomass and grain yields of rain-fed lowland rice were highest with Urea supergranule N fertilizer sources followed by slow-release Urea and conventional Urea applications in both planting methods. Average grain yields of 3.7 and 3.8 tons ha−1 of rain-fed lowland rice were recorded with the application of Urea supergranule N source fertilizer under seedling transplanting and drill row seed planting methods, respectively. Hence, using Urea supergranule tablet is recommendable for getting better grain yield of rain-fed lowland rice without yield penalty in both planting methods.

Effect of nitrogen management and seedling raising methods on the productivity of Aus rice under tidal ecosystem of Bangladesh

The low productivity of Aus rice in the tidal ecosystem of Bangladesh is mainly due to the difficulties in nitrogen (N) management under high tidal water along with unavailability of irrigation water during the onset of rice cultivation. Our present study demonstrated how the productivity of Aus rice could be improved using appropriate seedling raising methods and N management practices. The study was laid out in split plot design consisting two factors viz., seedling raising methods (wet seed bed and dry seed bed) and N management practices (six N treatments) in three replications. Results indicated that both the seedling raising methods and N management practices had significant effect on all the yield contributing characters of transplanted Aus rice under tidal condition. Specifically, the combination of seedlings raised in wet seed bed and fertilized with urea super granule (USG) at 10 days after transplanting (DAT) i.e., N3W showed the best values for plant height (110.33cm), number of effective tillers hill-1 (14.60), days required 50% flowering (53.00 DAT), days to maturity (84.33 DAT), panicle length (23.37 cm), number of filled grain panicle-1 (88.13), 1000-grain weight (43.17 g), grain yield (4.62 tha-1), straw yield (6.07 tha-1), biological yield (10.67 tha-1), and harvest index (43.17%). However, in considering the productivity/ grain yield, besides N3W, the whole urea application at land preparation along with wet seed bed (N1W) and USG application along with dry seed bed (N3D) also produced statistically similar results (p<0.01) and thus all these three combinations may be practiced for improving productivity and ensuring horizontal expansion of Aus rice in the tidal ecosystem of Bangladesh.

Effect of Different Forms and Levels of Urea Fertilizer on Rice (Oryza sativa L) and Mineral Nitrogen Status in Soil

Field experiment was conducted to determine the effect of prilled urea (PU) and urea super granule (USG) with their different nitrogen levels (N1 : 70, N2 : 100 and N3 : 130% of the recommended dose) on rice and NH4+-N/NO3- -N in post-harvest soil. Experiment was laid out in a randomized completely block design with three replications at Bangladesh Institute of Nuclear Agriculture (BINA) Farm, Mymensingh, Bangladesh during 2015-16. Higher yield attributing characters (plant height, effective tiller panicle-1, panicle length were achieved from USG × N2 treatment. USG, N2 (100% N) and USG × N2 produced the highest grain (3.60, 3.64, 3.78 t ha-1) and straw yield (3.55, 3.45, 3.70 t ha-1) respectively. Though USG × N3 treatment produced the highest effective tiller, panicle length and unfilled grain but USG × N2 treatment produced maximum grain yield of rice due to higher filled grain. In respect of mineral nitrogen, NH4+-N was decreased with the increase in soil depth but opposite result was found in NO3- -N in soil. Deep placement of USG fertilizer released NH4+-N slowly and steadily compared to prilled urea in soil. As a result, one time fertilizer application of USG is better than three times broadcast application of PU in terms of crop yield, nitrogen status in different depth of soil and labour cost. Future research needs to develop the effective USG fertilizer applicator for deep placement in soil during crop production.

Influence of nitrogen on the growth and use efficiency of rainfed lowland rice in northwest Ethiopia

Rice productivity in Fogera Plain of Ethiopia is low due to poor soil nitrogen management. A field experiment was conducted for two years during the main cropping seasons of 2017 and 2018 in Fogera Plain to study the effect of N fertilizer rates and application methods on productivity and nitrogen use efficiency of lowland rice. The experiment was conducted using a factorial arrangement of six levels of N rates (46, 92, 138, 184, 230, and 276 kg N ha−1) and two levels of application methods (farmers’ practice and mud-balls form) with the control, laid out in a randomized complete block design (RCBD) in three replicates. Results revealed that N rates had a significant effect on the growth, biomass and grain yields, and N use efficiency of rice. Interaction effects of application methods by N rates had only a significant effect on N use efficiency of rice. Generally, rain-fed lowland rice grain yield (4.2–5.2 tons ha−1) positively responded to fertilizer N rates from 138 to 276 kg ha−1. Nitrogen use efficiency was highest at the low and intermediate levels of N and low on highest levels of N. From this study, mud-balls making Urea is a tedious and labor intensive work. Rather, hence, nitrogen use efficient methods of Urea supergranule tablet should be used based on the recommended 276 kg ha−1 nitrogen rate to exploit more grain yield of rain-fed lowland rice without yield penalty in Fogera Plain.

Application timing of urea supergranules for climate-resilient maize cultivars grown in Northern Ghana

Agronomic effectiveness of urea deep placement (UDP) technology for upland maize production, using urea supergranules (USG) as the supplemental nitrogen (N) source, is affected by USG application time. In field studies conducted in six locations in northern Ghana during 2015–2017 growing seasons, we determined appropriate USG application time(s) for climate-resilient maize (early maturing and medium-maturing drought-tolerant) varieties for increased productivity. USG was applied at a depth of 7-10 cm on either 2, 3, 4, 5, or 6 weeks after planting (WAP). For the medium-maturing maize variety, across all locations and in the three growing seasons, applying USG produced an average grain yield of 4.5 t ha−1, 4.4 t ha−1 and, 4.2 t ha−1 on 2, 3 and 4 WAP, respectively. Applying USG on 5 and 6 WAP produced an average grain yield of 3.4 t ha−1 and 2.8 t ha−1, respectively. For the early-maturing variety, average grain yield when USG was applied on 2 WAP was 4.1 t ha−1, and 4.0 t ha−1 on 3 WAP. Late applications produced an average grain yield of 2.4 t ha−1, and 1.9 and 1.7 t ha−1 on 4, 5, and 6 WAP, respectively. Harvest index, recovery of applied N, and N use efficiency followed similar pattern as grain yields. From the combined results, we conclude that, barring adverse environmental conditions, applying USG as supplemental N within 3 WAP for the early-maturing maize varieties, and 4 WAP for the medium-maturing maize varieties could result in greater agronomic benefits than when applied later.

Agronomic effectiveness of urea deep placement technology for upland maize production

Effective fertilizer management is critical for sustainable maize production. Field trials were conducted in six locations in northern Ghana during the 2016 and 2017 farming seasons to evaluate the agronomic effectiveness and economic viability of urea deep placement technology (UDP), which involves deep placement of urea supergranules (USG), for maize production. This fertilization strategy was compared with four other maize fertilization strategies: (1) microdosing (MD); (2) farmer practice (FP), which involves surface broadcasting of granular fertilizer; (3) modified farmer practice (MFP), where granular fertilizer was incorporated into the soil; and (4) NPK-only, where no supplemental N was added. Averaged across all six locations and both years, UDP produced 18% more grain yield than MFP, 38% more than MD, 155% more than FP, and 270% more than NPK-only. The greatest apparent N recovery efficiency of 73% occurred in MD, followed by UDP (68%), NPK-only (63%), MFP (61%) and FP (35%), in that order. However, agronomic efficiency followed the order: UDP > MFP = MD > NPK-only = FP. The greatest gross profit margin of 49% was obtained with UDP, followed by MFP (41%) and MD (33%). Farmer practice resulted in a break-even level (3%) whereas NPK-only resulted in a loss (< − 35%). From the combined results, we conclude that, barring other external factors such as drought, flooding, pests, diseases, etc., UDP could be one of the most efficient fertilizer management strategies for sustainable maize production. Further studies should evaluate optimum timing of USG application for increased productivity and profitability.

Performance of Prilled Urea and Urea Super Granule by Applicators on Yield and Nitrogen Use Efficiency in Boro Rice

A field experiment was conducted on validation of prilled urea (PU) and urea super granule (USG) applied by applicators on yield and nitrogen use efficiency during Boro 2014 season at Bangladesh Rice Research Institute (BRRI) farm, Gazipur (AEZ 28). Six treatment combinations of different N doses and methods of N application were tested to compare urea-N application by PU and USG applicator for rice yield, N uptake and N use efficiency over urea broadcasting. Application of N as PU or USG through applicator has same effect on grain yield, N uptake and N use efficiency compared with urea broadcasting. Statistically similar grain yield were observed with N application as PU or USG @ 78 kg N ha-1 by applicator which was comparable with urea broadcasting @ 135 kg N ha-1. The N concentration and uptake in both panicle initiation (PI) and maturity stage were higher in USG deep placement than PU deep placement by applicators but the difference was not significant. Although agronomic use efficiency (AUE) of N was slightly higher in PU than USG applied by applicators but the recovery efficiency (RE) of N was higher in USG than PU.&#x0D; Bangladesh Rice j. 2018, 22(2): 63-69

Theoretical aspects on local alkalinization following hydrolysis of deep-placed urea in paddy soils under transplanting

Urea broadcasting in rice cultivation often leads to ammonia volatilization because the hydrolysis reaction of urea quickly gives ammonium, ammonia and bicarbonate. Particularly ammonia (NH3) is subject to emanation which can be avoided if urea is deep placed. This no loss optimistic scenario is realized by strict positioning of urea supergranules in the anaerobic layer of the paddy soil. In this study, we wanted to verify if the development of alkalinity in the site of placement could be predicted from the chemical equilibria in soil solution, neglecting the effect(s) of the soil matrix. Calculation of pH related to ammoniacal N concentration was performed considering the main acid-basic equilibria taking place within the soil solution. Data were compared to localized pH and ammoniacal N values obtained in two paddy fields following deep placement of urea supergranules. The pH never trespassed 9.25 which is the pKa of ammonia, in theoretical terms as well in the localized point placement sites in the fields. The linear relationship between log of ammoniacal N concentration and pH seems to indicate a strong influence of the cation exchange capacity so far not taken into account by the model. Urea supergranules are compared to mini-bombs of NH3; to prevent any leak to the floodwater (then to the atmosphere) they have to be buried with precision.© 2019 International Formulae Group. All rights reserved.Keywords: Point placement, urea supergranule, generated alkalinity, wetland soil, soil solution, pH

Study of nitrogen use efficiency and yield of rice influenced by deep placement of nitrogen fertilizers

Continuous increase of nitrogen fertilizer use adversely affecting the soil health as well as the environment. It necessitates the systematic study of the impact of nitrogen (N) fertilizer use-reduction on crop yield. In this article, the effects of deep placement of nitrogen fertilizers on nitrogen use efficiency (NUE) and yield of rice variety “BRRI dhan46” were investigated and compared for three N formulations: urea super granule (USG), NPK briquettes and prilled urea (PU). The experiment was conducted in randomized complete block design (RCBD) with eight N treatments replicated three times. The treatments were applied by varying doses (0, 52, 78 and 104 kg ha-1) of nitrogen fertilizers in a known identical soil and weather condition. Applications of PU, USG and NPK briquettes exhibited significant differences on yield attributes of rice. Results revealed maximum grain yield of 6.391 t ha-1 (54% increases over control) for the dose USG 104 kg ha-1 which is statistically similar to the dose USG 78 kg ha-1 and NPK briquettes 104 kg ha-1. The deep placement of USG and NPK briquettes enhanced both the recovery of applied N and N use efficiency compared to broadcast application of prilled urea. However, USG 78 kg ha-1 showed maximum apparent N recovery, N use efficiency, gross margin and marginal benefit-cost ratio. Thus, an application of 78 kg ha-1 USG can be recommended for profitable cultivation of rice variety BRRI dhan46.&#x0D; SAARC J. Agri., 17(1): 93-103 (2019)

Agronomic, economic, and environmental performance of nitrogen rates and source in Bangladesh’s coastal rice agroecosystems

Farmers in low-elevation coastal zones in South Asia face numerous food security and environmental sustainability challenges. This study evaluated the effects of nitrogen (N) rate and source on the agronomic, economic, and environmental performance of transplanted and rainfed ‘aman’ (monsoon-season) rice in Bangladesh’s non-saline coastal areas. Fifty-one farmers participated in trials distributed across two landscape positions described as ‘highlands’ (on which field water inundation depth typically remains <30 cm) and ‘medium-highlands’ (inundation depths 30–90 cm) planted singly with varieties appropriate to each position (BRRI dhan 39 for highlands and the traditional variety Bhushiara for medium-highlands). Researcher designed but farmer-managed dispersed plots were located across three district sub-units (Barisal Sadar, Hizla, Mehendigonj) and compared N source (broadcast prilled urea or deep-placed urea super granules (USG)) at four N rates. Rice grown on medium-highlands did not respond to increasing N rates beyond 28 kg N ha−1, indicating that little fertilization is required to maintain yields and profitability while limiting environmental externalities. In highland locations, clear trade-offs between agronomic and environmental goals were observed. To increase yields and profits for BRRI dhan 39, 50 or 75 kg N ha−1 was often needed, although these rates were associated with declining energy and increasing greenhouse gas (GHG) efficiencies. Compared to prilled urea, USG had no impact on yield, economic, energy and GHG efficiencies in medium-highland locations. USG conversely led to 4.2–5.8% yield improvements at higher N rates on highlands, while also increasing energy efficiency. Given the observed yield, agronomic and economic benefit of USG, our preliminary results that farmers can consider use of USG at 50 kg N ha−1 to produce yields equivalent to 75 kg N ha−1 of prilled urea in highland landscapes, while also reducing environmental externalities. These results suggest that when assessing sustainable intensification (SI) strategies for rice in South Asia’s coastal zones, N requirements should be evaluated within specific production contexts (e.g. cultivar type within landscape position) to identify options for increasing yields without negatively influencing environmental and economic indicators. Similar studies in other parts of coastal South Asia could help policy-makers prioritize investments in agriculture with the aim of improving rice productivity while also considering income generation and environmental outcomes.

Nitrogen management in rice

Nitrogen is the one of most limiting nutrient for rice production, and in India rice cultivation alone accounts approximately 37% of the total fertilizer-N consumption in the year 1917-18. However, 60-70% of applied N is lost from the rice ecosystem system in the form of reactive N species such as ammonia (NH3), nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2) and nitrate (NO3) through various processes. Hence enhancing N use efficiency through improved N management is of greater importance for ensuring food security and environmental sustainability. The decisions on optimum level, time, form and method of N application are crucial to an efficient N management strategy. Earlier studies suggested blanket fertilizer recommendations for different rice ecosystems and soil test based fertilizer applications. Subsequently, innovative methods of N application including deep placement of urea super granule in reduced zone, subsurface incorporation of urea through farmer friendly methods were also recommended Recently several advancements have been made in N management practices for rice crop such as site specific N management, real time N management using leaf colour chart (LCC) and customised LCC, enhanced efficiency N fertilizers (EENF) using N transformation regulators and GIS and remote sensing (RS) - based N application technologies. The objective of this paper is to comprehensively discuss about the established and emerging N management options for improving yield, N use efficiency and environmental sustainability of rice.

Nitrogen management in rice

Nitrogen is the one of most limiting nutrient for rice production, and in India rice cultivation alone accounts approximately 37% of the total fertilizer-N consumption in the year 1917-18. However, 60-70% of applied N is lost from the rice ecosystem system in the form of reactive N species such as ammonia (NH3), nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2) and nitrate (NO3) through various processes. Hence enhancing N use efficiency through improved N management is of greater importance for ensuring food security and environmental sustainability. The decisions on optimum level, time, form and method of N application are crucial to an efficient N management strategy. Earlier studies suggested blanket fertilizer recommendations for different rice ecosystems and soil test based fertilizer applications. Subsequently, innovative methods of N application including deep placement of urea super granule in reduced zone, subsurface incorporation of urea through farmer friendly methods were also recommended Recently several advancements have been made in N management practices for rice crop such as site specific N management, real time N management using leaf colour chart (LCC) and customised LCC, enhanced efficiency N fertilizers (EENF) using N transformation regulators and GIS and remote sensing (RS) - based N application technologies. The objective of this paper is to comprehensively discuss about the established and emerging N management options for improving yield, N use efficiency and environmental sustainability of rice.

Nitrogen use efficiency and yield of BRRI dhan49 as influenced by different forms of N fertilizers under AWD condition

An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during Aman season of 2016 to evaluate the effects of deep placement of N fertilizers in the form of urea super granule (USG) and NPK briquettes in comparison with prilled urea (PU) on nitrogen use efficiency and yield of BRRI dhan49. The soil was silt loam in texture having pH 6.27, organic matter content 1.95% and total N 0.136%. The experiment was laid out in a Randomized Complete Block Design (RCBD) with eight treatments and three replications. The treatments include T1 (Control), T2 (PU, 104 kg N ha-1), T3 (USG, 104 kg N ha- 1), T4 (USG 78 kg N ha-1), T5 (USG, 52 kg N ha-1), T6 (NPK briquettes, 104 kg N ha-1), T7 (NPK briquettes, 78 kg N ha-1) and T8 (NPK briquettes, 52 kg N ha-1). All the treatments except T6, T7 and T8 received 16 kg P and 42 kg K ha-1 from TSP and MoP, respectively. In T6, T7 and T8 treatments, P and K were supplied from NPK briquettes. The PU was applied in three equal splits. The USG and NPK briquettes were deep placed 10 DAT and the briquettes were placed at 8-10 cm depth between four hills at alternate rows. Application of PU, USG and NPK briquette under alternate wetting and drying (AWD) condition exerted significant influence on yield attributes as well as grain and straw yields of BRRI dhan49. The maximum grain yield of 6311 kg ha-1 (100% increases over control) and straw yield of 6956 kg ha-1 was recorded in T3 (USG, 104 kg N ha-1). The second highest grain yield of 5865 kg ha-1 produced by T2 (PU, 104 kg N ha-1) was statistically similar with T4 (USG 78 kg N ha-1) and T6 (NPK briquettes, 104 kg N ha-1). The lowest grain yield (3155 kg ha-1) and straw yield (3908 kg ha-1) were recorded in T1 (Control). The deep placement of USG and NPK briquettes enhanced both the recovery of applied N and N use efficiency in comparison with broadcast application of prilled urea. The T5 (USG, 52 kg N ha-1) showed maximum apparent N recovery, and N use efficiency. Next to T5, the T4 depicted the position in respect of N recovery and N use efficiency. So the application of 78 kg N ha-1 in the form of USG can be recommended for the production of BRRI dhan49.&#x0D; Res. Agric., Livest. Fish.6(1): 27-33, April 2019

Reducing Ammonia Volatilization and Improving Nitrogen use Efficiency of Rice at Different Depths of Urea Supergranule Application

ABSTRACTAn experiment was conducted to determine the depth of urea supergranule (USG) application that reduces ammonia (NH3) volatilization and improves nitrogen use efficiency of rice. Canne, Voudou, Akuse, and Bumbi series were used. Treatments involved surface application of prilled urea (PU), USG applied at 0, 4, 8, 12 and 16 cm depths and a control. Rice variety IR-841 was grown up to maturity. Closed chamber device was used to trap NH3. Results indicated that the highest mean NH3 loss occurred in Bumbi series (13.67%) while the lowest was Canne series (8.16%). USG applied at 0 cm resulted in the highest NH3 loss (37.2%). NH3 volatilization decreased with increasing depth of USG application. The highest grain yields were obtained when USG was applied at 4 and 8 cm. In Canne series, the highest agronomic use efficiency (AE) of N (57 g g−1) was obtained with USG applied either at 8 or 12 cm while the highest recovery efficiency (RE) (84%) occurred at 8 cm. In Akuse series, the highest AE (55 g g−1) and RE (78%) were obtained when USG was placed at 8 cm. In Voudou and Bumbi series, the highest AE (45 and 48 g g−1 respectively) and RE (64%) were obtained with USG deep placed at 4 cm. The results therefore suggested different specific depths of USG application to reduce ammonia loss and improve nitrogen use efficiency.

Economics of Boro Rice Production in Rangpur District of Bangladesh: Comparative Assessment of Urea Super Granule and Traditional Urea Application

The study was examined the profitability of Boro rice production using Urea Super Granule (USG) and traditional urea in Rangpur district of Bangladesh. 60 farmers were selected randomly for the present study. The cultivation of Boro rice was profitable from the viewpoint of the farmers. Per hectare net return for USG user and traditional urea user was Tk. 40264.4 and Tk. 26740.2, respectively. Benefit cost ratio for USG user and traditional urea user was estimated at 1.5 and 1.3, respectively. BCR was higher for USG user because they were efficient producer. Power tiller cost, seed/seedling cost, TSP cost, MoP cost, cowdung cost and irrigation cost; and human labor cost, seed/seedling cost, urea cost, MoP cost, cowdung cost and irrigation cost had significant impact on gross return from Boro rice production for USG and traditional urea user, respectively. Age of farmer, price of USG, soil nutrient availability and extension contact had significant impact on farmers’ preference for using USG in Boro rice production. The price of fertilizer should be regulated strictly by the government and extension programs should be arranged in order to motivate farmers for adopting USG use in Boro rice production.

Response of broccoli to USG and prilled urea in shallow red-brown terrace soil under Madhupur tract

A field experiment was conducted at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during the period from 2012-13 to verify the effectiveness of urea super granule (USG) and prilled urea (PU) on the yield and quality of broccoli, to assess the comparative performance of USG and PU on nutrient uptake and nitrogen use efficiency and to evaluate the effect of USG and PU on post-harvest nutrient status in Shallow Red-Brown Terrace Soil of Madhupur Tract (AEZ-28). The experiment was designed in a randomized complete block with three replications having 5 treatments as T1: Control, T2: USG-N140, T3: USG-N160, T4: USG-N180 and T5: PU-N180. Result showed that USG performed better than PU. The comparative performance of USG in relation to yield, head quality (ascorbic acid, β-carotene and chlorophyll content), SPAD value, nutrient (NPKS) uptake and N use efficiency was found higher as compared to PU. USG treated broccoli plants gave significantly higher yield where the highest yield (13.49 ton ha-1) was recorded with USG-N160 kg ha-1. Moreover, USG showed higher β-carotene and chlorophyll content over PU and those were increased with increasing levels of N. However, ascorbic acid content was slightly decreased with increasing rate of N fertilizer. Nitrogen, phosphorus and potassium uptake increased with increasing N rate upto USGN180 but sulphur uptake was increased upto USG-N160. Nitrogen use efficiency was higher in USG treated plots than that of PU having the highest value of 111.71% with USG-N160 kg ha-1. Post-harvest soil nutrient status was not significantly influenced by the treatments although it was slightly higher in USG as compared to PU. Considering all, USG @ 160 kg N ha-1 (USG-N160) with other recommended fertilizers (@ 53 kg P, 83 kg K, 20 kg S, 2.0 kg Zn, 1 kg B and 0.8 kg Mo ha-1) could be the best USG based fertilizer dose for quality broccoli production in Shallow Red-Brown Terrace Soil of Madhupur Tract.Bangladesh J. Agril. Res. 43(4): 557-574, December 2018