Placement Of Urea Supergranules Research Articles

Enhancing Yield and Nitrogen Utilization of Boro Rice with Urea Super Granules

A field experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during boro season to assess the comparative performance of prilled urea (PU) and urea super granule (USG) on the growth, yield, and nitrogen uptake of BRRI dhan29. The experiment was laid out in a randomized complete block design with three replications. The treatment combinations were T1: Control, T2: PU at 7 days after transplanting (DAT)+27 DAT+47 DAT, T3: PU at 10 DAT+30 DAT+50 DAT, T4: PU at 15 DAT+35 DAT+55 DAT, T5: USG at transplanting, T6: USG at 7 DAT, T7: USG at 10 DAT and T8: USG at 10 DAT+30 DAT where PU and USG were applied @ 216 kg N ha-1. PU was applied as surface broadcasting whereas USG was placed at 6-8 cm depth by hand between four hills at every alternate row. The results revealed that all the treatments showed better performances than control (T1). Results found that yield components, yield, and nitrogen uptake of BRRI dhan29 responded significantly to deep placement of USG than PU. Treatment T6 (USG at 7 DAT) produced the highest grain and straw yields of 6.56 t ha-1 and 6.95 t ha-1 respectively. Treatment T6 (USG at 7 DAT) also showed the highest grain yield increase (57.16%) and straw yield increase (52.37%) over control. The highest grain, straw, and total N uptake of 87.28, 32.71 and 120 kg ha-1 respectively were obtained in the treatment T6 (USG at 7 DAT). The overall results clearly indicate that deep placement of USG at 7 DAT in rice field increases rice yield and efficient uptake of the applied N. So, treatment T6 (USG at 7 DAT) could be recommended as best treatment for reducing N losses, conserving environment and improving sustainable production of rice.

Effect of variety and nitrogen fertilizer managements on the growth and yield of Transplant aman rice managements

Varietal selection and appropriate placement of nitrogen fertilizer could reduce the magnitude of nitrogen losses to a considerable extent and improve its use efficiency for better grain production. An experiment was carried out during the period from July to December at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the effect of variety and nitrogen fertilizer management on the growth and yield of transplant aman rice. The treatments consisted of three varieties viz. BR11, BRRI dhan49 and Binadhan-7, and five nitrogen fertilizer managements viz. two depth of placement of USG (Urea Super Granule) and three split applications of prilled urea. The experiment was laid out in a randomized complete block design with three replications. The results showed that the effect of variety and nitrogen fertilizer management significantly influenced all the yield contributing characters except weight of 1000- grains, non-effective tillers hill-1 and panicle length. The highest grain yield (3.69 t ha-1) was obtained from Binadhan-7. In the case of nitrogen fertilizer management, the highest grain yield (4.32 t ha-1) was found from the 6 cm depth placement of USG. The highest grain yield (4.82 t ha- 1) was observed from the interaction of Binadhan-7 with the 6 cm depth of placement of USG. It may be concluded that Binadhan-7 with 6 cm depth of placement of USG appeared as the promising practice to maximize the yield of transplant aman rice.
 Res. Agric., Livest. Fish.8(3): 281-289, December 2021

Impacts of different nitrogen forms and doses on agronomic performance of BRRI dhan29

Nitrogen (N) is one of the most important nutrients for rice cultivation and probably the hardest to maintain in soil. This experiment was conducted to investigate the impacts of different N forms and doses as urea on BRRI dhan29 during boro season in Meherpur district, Bangladesh. The two most abundant forms of urea namely granular urea (GU) and urea super granule (USG) were selected with five doses (0, 100, 150, 200, and 250 kg ha-1) for each form. The treatments were replicated thrice in Randomized Complete Block Design (RCBD). GU was broadcasted and USG was applied using deep placement method. Other fertilizers viz. triple super phosphate, muriate of potash, gypsum, and zinc sulfate were applied at 100, 70, 60, and 5 kg ha-1, respectively. Agronomic parameters were measured by randomly selecting five hills from each plot. Application of N through USG significantly improved almost all agronomic characteristics such as plant height, total and effective tiller hill-1, panicle length, total and filled grains panicle-1, straw and biological yields, grain yield, and harvest index. BRRI dhan29 produced the highest grain and straw yields with the highest dose of USG application (250 kg ha-1). The 1000-seed weight was not significantly affected by N doses or by forms that might be due to its genetically controlled trait and environmental influence during the grain filling stage. Deep placement of USG ensured adequate N supply for a longer period that resulted in enhancement of growth and yield components of BRRI dhan29.

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.
 SAARC J. Agri., 17(1): 93-103 (2019)

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.
 Res. Agric., Livest. Fish.6(1): 27-33, April 2019

Response of Some Landrace Rice (<i>Oryza sativa</i> L.) Cultivars to Applied Nitrogen in Lowland Ecosystem

An experiment was conducted to determine the effects of nitrogen (N) fertilization on growth and yield of some landrace rice (Oryza sativa L.) cultivars in lowland ecosystem. Three popular landrace rice cultivars: Rajashail, Kutiagni and Sadamota were treated with five times of N application viz. (i) two split applications of prilled urea (PU) at 10 days after transplanting (DAT) and before panicle initiation (PI) stage, (ii) deep placement of urea super granule (DPUSG) at 10 DAT, (iii) DPUSG before PI stage, (iv) PU application before PI stage and (v) control. The results showed that the landrace rice cultivar Kutiagni had the highest number of tillers under PU, while Rajashail gave the highest number of tillers under DPUSG applied before PI stage. Further, Kutiagni produced higher amount of dry matter under two splits of PU, while Rajashail produced higher amount of dry matter under DPUSG applied before PI stage. However, application of PU before PI stage significantly increased leaf area index in all the three landraces. The varieties responded to applied N and produced the highest yield in Kutiagni. The DPUSG at 10 DAT increased straw yield but failed to increase grain yield even over control. The DPUSG before PI stage significantly increased rice yield and economic return. The yield of rice in DPUSG applied before PI stage was comparable to two splits of PU and top dressing of PU before PI stage. Compared to control (2.93 t ha-1), yield increase was 26% in Kutiagni (3.70 t ha-1) under DPUSG before PI stage. These results suggest that Kutiagni was more responsive to added N and this cultivar could be cultivated with DPUSG at PI stage.The Agriculturists 2018; 16(1) 01-12

Field Evaluation of Brri Usg Applicator in Dry and Wet Season of Rice Cultivation

BRRI (Bangladesh Rice Research Institute) USG (Urea super granule) applicator was developed to apply USG in non-oxidized zone at 6-10 cm depth from surface at desired spacing to maintain the recommended USG fertilizer doses of 118 and 168 kg ha-1 during Aman and Boro season, respectively that could be maintained with the adjustment of the applicator for 20 × 20 cm transplanting spacing. It was designed and fabricated with an adjustable facility for two rows operation in the rice field at spacing of 18 × 20, 20 × 20 and 22 × 20 cm. The modified USG applicator tested in the BRRI regional stations (RS) during Aman 2011 and the farmers’ fields during Boro 2012 season. Walking speed directly influenced the field capacity of the applicator. Walking speed during field operation of the applicator depends on the soil type, USG placement time and puddled condition of the soil and it was varied 2.46-3.72 km hr-1. Field capacity was observed 0.13 and 0.14 ha hr-1 during Boro and Aman season, respectively whereas manual USG application capacity was observed about 0.02 ha hr-1. The depth of USG placement by the applicator (6.01-6.32 cm) was found more compared to manual application (5.61-5.75 cm). The yield performance of USG plots was identical in all locations during both the seasons either applied by hand or by machine. However, in some cases, USG gave significantly higher grain yield compared to prilled urea applied by hand broadcasting method.Modified BRRI USG applicator saved urea fertilizer, ensured proper placement of USG in subsurface zone and reduced drudgery without sacrificing grain yield.Bangladesh Rice j. 2016, 20(2): 49-59

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.

Effects of PU, USG and NPK briquette on nitrogen use efficiency and yield of BR22 rice under reduced water condition

An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during the aman season of 2012 to investigate the effects of prilled urea (PU), urea super granule (USG) and NPK briquette on NH4- N concentration in field water, yield and nitrogen (N) use efficiency (NUE) of BR22 rice under reduced water conditions. The experiment was laid out in a randomized complete block design with three replications. There were altogether eight treatment combinations viz. T1: Control (No N fertilizer), T2: 52 kg N ha-1 from USG, T3: 104 kg N ha-1 from USG, T4: 78 kg N ha-1 from PU, T5: 120 kg N ha-1 from PU, T6: 51 kg N ha-1 from NPK briquette, T7: 78 kg N ha-1 from USG and T8: 78 kg N ha-1 from NPK briquette. Water samples were collected from rice field for seven consecutive days after deep placement of USG and the first split application of PU and the samples were analyzed for NH4-N. The Highest concentration of NH4-N in water was observed at the second day of PU application followed by gradual decrease with time. The yield contributing characters like plant height, panicle length, number of effective tillers hill-1 and grains panicle-1 were significantly influenced by different treatments. The highest grain yield of 3.93 t ha-1 was recorded from 104 kg N ha-1 as USG (T3) and the lowest value of 2.12 t ha-1 was obtained from control. The N use efficiency was increased when the N was applied as USG. The overall results revealed that application of USG and NPK briquette may be practised for obtaining better yields in addition to increasing the efficiency of N fertilizer. DOI: http://dx.doi.org/10.3329/jbau.v11i2.19897 J. Bangladesh Agril. Univ. 11(2): 215-220, 2013

Effect of spacing of transplanting, rate and depth of placement of urea super granules (USG) on the yield of BORO rice

Effect of spacing of transplanting, rate and depth of placement of urea super granules (USG) on the yield of BORO rice

Effect of different times and depths of USG application on the growth and yield of cabbage

An experiment was conducted for two consecutive years in the farmers' field of Palima, Tangail to evaluate the effect of time and depth of placement of urea super granule (USG) on the yield and yield attributes of cabbage during 2003-04 and 2004-05, respectively. USG @ 330 kg per hectare was applied at 0, 10, 15, and 20 days after planting each at 4, 8, and 12 cm depth. The result showed that application of USG at 10 days after transplanting at a depth of 8 cm gave the highest yield of 74.92 and 117.60 t/ha in 2003-04 and 2004-05, respectively. The yield variation was observed due to change of variety (i. e., Atlas 70 in 2003-04 and Autumn Queen in 2004-05). Placement of USG either at 4 cm or 12 cm depth slightly reduced yield than obtained with point placement at 8 cm. USG application later than 10 days of transplanting decreased cabbage yield in both the varieties. Bangladesh J. Agril. Res. 32(2) 2007: 301-306.

Evaluation of placement methods for urea supergranules in wetland rice (Oryza soil sativa) B.K. MISHRA, A.K. DAS, A.K. DASH, D. JENA , S.K. SWAIN^

-- A field experiment was carried out in a lowland soil, having fine loamy mixed hyperthermic Epiaquept, during winter season of 1994-95 and 1995-96 to evaluate the method of urea supergranule (USG) placement in wetland rice (Oryza sativa L.). The experimental plan was randomized block design with 3 replications. The USG was applied @ 76 kg Nlha either as surface broadcast or as deep placement at soil depths of 2.5, 5 or 7.5 cm by manual or mechanical means along with prilled urea (PU) split. Placement of USG significantly increased both the grain and straw yields of rice in comparison to PU or USG broadcast. The response of rice to nitrogen was more under USG placement than split application of PU. Nitrogen-use efficiency of rice was increased from 18 -, kg grainlkg N applied as PU to as high as 26 kg grainlkg N applied as USG. Similarly, the relative efficiency of USG was increased by 40% over PU. The apparent recovery of N in rice was also increased from 21% in case of PU to 40% for USG.

INTEGRATED NITROGEN MANAGEMENT OF LOWLAND TRANSPLANTED RICE OF WEST ZONE OF TAMIL NADU

Field experiments were conducted during 1991-94 at Tamil Nadu Agricultural University, Coimbatore to develop integrated N management practice for lowland transplanted rice. The treatments included placement of urea super granules (USG) at 100 kg N/ha, application of prilled urea (PU) at 100 kg N/ha, application of 75 kg N as PU with azolla or FYM or green manure or azospirillum and application of 50 kg N as PU with the combined use of azospirillum, azolla and green manure. The results of three-years study revealed the superiority of the placement of USG over the other treatments. The next best treatment was the application of PU at 100 kg N/ha. However, application of 75 Kg N as PU combined with either azolla or green manure (Sesbania rostrata) registered comparable yields. Substitution of 25 kg N as chemical fertiliser with either azolla or green manure was clearly seen. Possibility of substitution of chemical N fertilisers even to the extent of 50 per cent by the combined use of 50 kg N as PU with Azospirillum, azolla and Sesbania rostrata green manuring was also observed.

Nitrogen deep-placement technologies for productivity, profitability, and environmental quality of rainfed lowland rice systems

The recovery of applied nitrogen by rice is low due to several loss processes operating in the ricefields. Split application of fertilizer suggested for increasing nitrogen-use efficiency is often not practical in rainfed lowland rice due to adverse soil–water situations. Hence, the entire required amount of N has to be applied in one single application when the water regime is favorable. A single broadcast application, however, increases N loss. Deep placement of urea supergranules (USG) has been proven to improve N fertilizer efficiency. The placement technology is best suited to conditions where the predominant N loss mechanism is ammonia volatilization rather than leaching or denitrification. Deep placement of USG thus has greater benefit over surface split application on soils with moderate to heavy texture, low permeability and percolation rate, and high cation exchange capacity and pH. Environments and management factors conducive to high ammonia volatilization potential would benefit most from deep-placement technology. Improved N recovery and efficiency of USG has been well-documented for lowland rice, but its market availability and methods to achieve placement pose problems. The technology has very limited adoption because USG is not commercially available or manufactured in most countries, and labor requirement is high with hand placement. Manual application creates more difficulties in handling the granules, besides taking 36–42 more hours per hectare, than 2 split broadcast applications of prilled urea. Applicators developed so far have not worked satisfactorily under standing water conditions and in direct-seeded rice conditions due to hardness of the soil. Hence, it is necessary to develop a suitable applicator to overcome these difficulties. Alternatively, for direct-seeded rice, N-fertilizers can be subsoil-banded near seedrows. The placement technology, if adopted by the farmers of the potential lowland areas in eastern India, is expected to give an additional production of 5.6 million tons of rice.

Seasonal Influence on Placement of Urea Supergranules in Rice

Seasonal Influence on Placement of Urea Supergranules in Rice

Yield response of wetland rice to band placement of urea solution in various soils in the tropics

Alternative N-fertilizer management practices are needed to increase productivity and the N-use efficiency of flooded rice (Oryza sativa L.). Seven field experiments were conducted at various sites in Bangladesh and Indonesia to evaluate the effect of time and method of fertilizer-N application on grain yield in transplanted rice. Conventional fertilizer application was compared with band placement of liquid urea using a mechanical push-type injector and point placement of urea supergranules. With band placement, grain yields were up to 38 and 55% higher than with researchers' and farmers' practices, respectively, and similar to those with point placement of urea supergranules.

Nitrogen management and fertilizer use efficiency for lowland rice in Pakistan

Abstract With a view to develop simpler techniques for improving the efficiency of nitrogen fertilizer use for lowland rice, field studies were conducted in 1986 and 1987. During 1986, dry soil incorporation of urea was compared with puddled soil application of urea and calcium ammonium nitrate (CAN) and deep placement of urea super granule (USG). In 1987, the application of urea in puddled soil without standing water (soil saturation) was compared with the application in standing water and deep placement of USG. The results revealed that deep placement of USG and dry soil incorporation of urea were comparable in their effect on the increase of the number of productive tillers, straw and paddy yield, and agronomic efficiency. Consequently N utilization and recovery efficiency were higher with these methods of fertilizer application than with the application of urea and CAN in puddled soil. Application of urea fertilizer under soil saturation conditions and deep placement of USG were found to be comparable in the production of tillers, straw and grain yield and both gave similar agronomic and N recovery efficiencies to the application of urea on the Miranpur soil under standing water conditions.

Efficiency of urea-based fertilizers for wetland rice (Oryza sativa)

SUMMARYField experiments were conducted in two wet and two dry seasons in 1984–86 to evaluate efficiencies of different urea-based fertilizers, and methods of application, for irrigated rice. Response to applied N was significant in all seasons. In the wet season, use of dhaincha (Sesbania aculeata) green manure and urea (Dh + U), reduced zone placement of urea supergranules (USG), surface application of laccoated urea (LCU) and prilled urea in three split doses (PU-split) gave similar results, and all were better than basal broadcast application of urea coated with neem (Azadirachta indica) cake (NCU) or prilled urea (PU-basal). In the dry season, USG was significantly superior to PU-basal, NCU and (Dh + U). Nitrogen uptake by rice was greatest 15–30 days after transplanting (DAT), followed by a second peak during the reproductive phase of the crop. Ammonium-N in the soil decreased sharply up to 30 DAT, more slowly up to 60 DAT and then increased slightly. Ammonium-N in the soil was higher with USG, (Dh + U) and PU split than with other treatments, especially in uncropped conditions.