Super Granule Research Articles

Effect of long term conservation agriculture and nitrogen management on soil nitrogen, phosphorus and sulfur fractions under maize–wheat–mungbean cropping system

Conservation agriculture (CA) covers nearly 3.5 mha in Indian. And there is lack of studies on the CA effects soil nutrient dynamics. So, this study examines the effects of nine years of conservation agriculture on soil nitrogen (N), phosphorus (P), and sulfur (S) fractions in an Inceptisol under maize–wheat–mungbean cropping system. Different tillage and nitrogen management practices were evaluated to understand how nutrient management in CA, contrasts with conventional methods. The CA practices and N fertilizer addition significantly enhanced the soil mineral N, alkali-permanganate N, potentially mineralizable N and microbial biomass N. The CA and N fertilization enhanced soluble and loosely bound P by dissolving the iron-bound, aluminum-bound, reductant soluble and calcium-bound P. All the soil S fractions i.e. available S, total water-soluble S, heat soluble S, sodium bicarbonate extractable S, inorganic sulfur, organic sulfur and total sulfur was positively affected by CA and N fertilization practices over conventional tillage and control plots, respectively. It is important to note that the green seeker-based N management options especially with urea super granules showed tendency in enhancing the available nutrient pools of N, P and S compared to recommended dose of N (RDN) applied and control plots indicating that in due course of time it may reduce the amount of RDN without hindering any soil nutrient dynamics. These findings contribute crucial knowledge for sustainable development by offering valuable perspectives on N, P and S management strategies.

IMPACT OF NITROGEN SOURCES ON THE PERFOMANCE OF LOWLAND RAINFED RICE AT EDOZHIGI IN THE SOUTHERN GUINEA SAVANNA OF NIGERIA

Field trials were conducted at Edozhigi, in the southern Guinea savanna of Nigeria during the 2020 and 2021 cropping seasons to determine the response of lowland rainfed rice to two Nitrogen sources (urea super granule (USG) and granular urea (GU)). There treatments consisted of five levels of USG (80, 90, 100, 110, 120 kg N ha-1) and six levels of GU (40, 80, 90, 100, 110, 120 kg N ha-1) and a control (0). The 12 treatments were laid out in a randomised complete block (RCBD) with three replicates. Result of the physical and chemical analysis of soil of the experimental field revealed that, soil had sandy clay loam texture with slightly acidic soil reaction. The soil organic carbon, total N, available P, exchangeable cataionic nutrients were all low in the soil which make the soil to have low fertility. Result of the study indicated that, plant growth and maturity period were not significantly affected by the application of N. The result further shows a significant response to application of USG, but not to GU. The highest paddy yield of 4.53 Mg ha-1 was recorded for USG at 90 kg N ha-1 which was significantly higher than that of the control and the GU treatments, but statistically similar to most of the other USG treatments. The USG is recommended as a source of N for the enhancement of the paddy yield.

Effect of long-term tillage practices on soil nitrogen, phosphorus and sulfur release under different nitrogen management options

The conservation agriculture (CA), presents a promising alternative for restoring soil health and achieving sustainable crop production. In addition, one cannot follow the same nitrogen management of conventional framing in the CA as the crop residue retained leads to N mineralization/immobilization. Hence, the present research was aimed to determine the effect of CA and nitrogen managements on soil nitrogen, phosphorus and sulfur release and the enzymes involved in their mineralization. The results revealed that the CA practice significantly enhanced the mineral N, Olsen P and CaCl2–S release and the soil enzymes involved in this mineralization cycles compared to CT + R plots. Similarly, all the nitrogen fertilizer receiving subplots also recorded significantly higher mineral N, Olsen P and CaCl2–S release and the enzymes involved compared to the control. Furthermore, throughout the incubation period the Urea super granule + Greenseeker treatment significantly outperformed the RDN plot with respect to NO3–N and CaCl2–S release. Whereas, the Urea + Greenseeker treatment registered significantly higher NO3–N and CaCl2–S over RDN plot from 30 and 45 days after incubation, respectively. The NH4–N and Olsen P release had increasing trend up to 45 days after incubation and thereafter it decreased. In nutshell, the research emphasizes the significance of CA alongside optimum nitrogen management approaches in enhancing the soil enzymatic activities and nutrient mineralization. These outcomes hold significance for both farmers and researchers seeking ecologically sound and productive agricultural methods to enhance crop output and maintain soil quality.

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.

Relative Efficiency of Prilled Urea, Urea Super Granules (USG), and Neem-Coated Urea (NCU) for Growth and Yield of Wheat

The experiment took place at the net house of the Agronomy field laboratory, Department of Agronomy and Agricultural Extension, University of Rajshahi, from November 2019 to March 2020, aiming to determine the relative efficiency of prilled urea, urea super granules (USG), and neem-coated urea (NCU) for wheat growth and yield. Five different nitrogenous fertilizers were included: BARC recommended prilled urea at 0.5 g/pot (T1), urea super granules (USG) at 0.25g/pot (T2), neem-coated urea at 0.25g/pot (T3), urea super granules (USG) at 0.5g/pot (T4), and neem-coated urea at 0.5g/pot (T5). The experiment followed a Randomized Block Design (RBD) with three replications. Results indicated significant effects of nitrogenous fertilizer forms on wheat growth and yield characteristics. Across most parameters, the highest values were observed in T5, utilizing 0.5g of neem-coated urea per pot, including plant height (77.34 cm), number of tillers (6.14), effective tillers per pot (23.04), extrusion length (16.57), spike length (17.25), filled grains per pot (1093.43), 1000-grain weight (42.22 g), grain yield (46.39 g/pot), straw yield (77.81g/pot), and biological yield (124.20g/pot). Based on these findings, we can conclude that applying 0.5 g of neem-coated urea per pot (T5) was the most effective treatment for enhancing wheat growth and yield among the tested options.

Modeling maize growth and nitrogen dynamics using CERES-Maize (DSSAT) under diverse nitrogen management options in a conservation agriculture-based maize-wheat system

Agricultural field experiments are costly and time-consuming, and often struggling to capture spatial and temporal variability. Mechanistic crop growth models offer a solution to understand intricate crop-soil-weather system, aiding farm-level management decisions throughout the growing season. The objective of this study was to calibrate and the Crop Environment Resource Synthesis CERES-Maize (DSSAT v 4.8) model to simulate crop growth, yield, and nitrogen dynamics in a long-term conservation agriculture (CA) based maize system. The model was also used to investigate the relationship between, temperature, nitrate and ammoniacal concentration in soil, and nitrogen uptake by the crop. Additionally, the study explored the impact of contrasting tillage practices and fertilizer nitrogen management options on maize yields. Using field data from 2019 and 2020, the DSSAT-CERES-Maize model was calibrated for plant growth stages, leaf area index-LAI, biomass, and yield. Data from 2021 were used to evaluate the model's performance. The treatments consisted of four nitrogen management options, viz., N0 (without nitrogen), N150 (150 kg N/ha through urea), GS (Green seeker-based urea application) and USG (urea super granules @150kg N/ha) in two contrasting tillage systems, i.e., CA-based zero tillage-ZT and conventional tillage-CT. The model accurately simulated maize cultivar’s anthesis and physiological maturity, with observed value falling within 5% of the model’s predictions range. LAI predictions by the model aligned well with measured values (RMSE 0.57 and nRMSE 10.33%), with a 14.6% prediction error at 60 days. The simulated grain yields generally matched with measured values (with prediction error ranging from 0 to 3%), except for plots without nitrogen application, where the model overestimated yields by 9–16%. The study also demonstrated the model's ability to accurately capture soil nitrate–N levels (RMSE 12.63 kg/ha and nRMSE 12.84%). The study concludes that the DSSAT-CERES-Maize model accurately assessed the impacts of tillage and nitrogen management practices on maize crop’s growth, yield, and soil nitrogen dynamics. By providing reliable simulations during the growing season, this modelling approach can facilitate better planning and more efficient resource management. Future research should focus on expanding the model's capabilities and improving its predictions further.

Impact of diverse tillage and nitrogen management on growth and yield of conservation agriculture-based wheat (Triticum aestivum)

A study was carried out during the winter (rabi) seasons of 2020–21 and 2021–22 at ICAR-Indian Agricultural Research Institute, New Delhi to assess the effects of diverse tillage and nitrogen management scenarios on growth, development, and yield of a conservation agriculture (CA)-based wheat (Triticum aestivum L.) crop grown in sequence with maize (Zea mays L.). Experiment was conducted in split plot design (SPD) comprised of 3 different tillage practices in main plots [Conventional tillage + residue (CT); Zero tillage + residue (ZT); and Permanent beds + residue (PB)] and 5 nitrogen (N) options in sub plots [Control (zero nitrogen); Recommended dose of N-RDN @150 kg N/ha (50 kg N/ha Basal + 2-equal splits at 37 days after sowing (DAS) and 84 DAS); Green Seeker (GS) based application of N @148 kg N/ha (GS); Urea super granules applied as basal @75 kg N/ha + GS based N application (USG); and Slow release fertilizer as 100% basal application @150 kg N/ha (SRF)] with 3-replications. The findings revealed that in both the seasons, both tillage and nitrogen management approaches significantly affected wheat growth, yield characteristics, and overall yield, whereas the time to anthesis and physiological maturity, and test weight remained unaffected. Within the spectrum of tillage practices, leaf area index (LAI) and yield attributes exhibited the trend PB>ZT>CT. PB recorded the highest grain yield (5159 kg/ha), followed by ZT (4916 kg/ha) and the lowest grain yield was observed with CT (4578 kg/ha). The wheat grain yields were 12.7% and 7.4% higher in PB and ZT, respectively, over to CT. Among nitrogen management options, the grain yield exhibited the pattern USG>N150>SRF>GS>N0. This study emphasizes that adopting conservation agriculture (CA) practices, particularly CA-based permanent beds using urea super granules (USG) for nitrogen management can improve wheat growth and yield.

Modelling and optimization of urea super granule (USG) placement depth in paddy cultivation under check basin irrigation using HYDRUS-2D model

Urea, a nitrogenous fertilizer which plays an important role in enhancing yield, but has a drawback of low nitrogen use efficiency (NUE). Use of urea super granule (USG) and coated urea have advantages over prilled urea in terms of higher NUE and eventually improved yield. Depth of placement (DOP) of USG plays a major role in achieving higher NUE and yield. However, appropriate depth of placement needs detailed knowledge about water and nitrogen (N) movements to provide maximum nutrient to plants. Therefore, an experiment was conducted in the paddy field using USG coated with three different types of coating (USG with nano bentonite and neem oil (T1), USG with heated nano bentonite and neem oil (T2) and USG with sulfer and acacia gum solution (T3)) and placed at the centre of four hills of paddy as basal dose at ICAR-IARI, New Delhi. Spatial and temporal data of soil moisture and Nwere collected for the initial 32 days in paddy field after crops establishment. The HYDRUS-2D model was calibrated and validated using the observed data. Calibrated model was used for simulation of N movement in different soil types and for different depths of USG placement. Results revealed that permissible soil like sandy loam, the optimum DOP irrespective of coating was 5 cm. For sandy clay loam soil, optimum depth of placement was found to be 10 cm, 6 cm and 10 cm for T1, T2 and T3 type of coatings. Similarly, for clay loam soil, depth of USG placement for T1, T2 and T3 type coating was found to be 8 cm, 10 cm and 8 cm, respectively. Using the optimum DOP in sandy clay loam soil, results showed that both i.e., DOP and coating type has significant effect on number of tillers m−2 and yield (t ha−1). In 2020 and 2021, the highest number of tillers per square meter at 30 days after transplanting (DAT) was observed in the T3 treatment at DOP of 10 cm, with counts of 453.66 and 454.88, respectively. Following closely were T2 at DOP of 10 cm (447.33 and 119.55) and T1 at DOP of 6 cm (443.44 and 444.77). Similarly, the best yield in 2020 and 2021 were observed from T3 treatment at DOP of 10 cm (5.41 t/ha and 5.44 t/ha), followed by T2 at DOP of 10 cm (5.33 t/ha and 5.42 t/ha), and T1 at DOP of 6 cm (5.29 t/ha and 5.31 t/ha). This study may assist the farmers, researchers, manufacturers and policy makers to make selection of the optimum depth of placement for higher NUE and yield in different soil types.

Optimization of Urea Super Granule Boost up for the Efficiency of N and Improved the Potato Quality, Growth and Yield

Potato is the third most important food crop after wheat and rice in Bangladesh. To determine the suitable nitrogen source by observing the growth performance with a view to increasing the yield of potato, a research work was carried out at the Research Farm, Sher-e-Bangla Agricultural University, Dhaka during the period from November 2018 to March, 2019. The experiment consisted of eight treatments. The experiment was laid out with Randomized Complete Block Design with three replications. Experimental results showed that nitrogen sources had significant effect on plant height, number of effective stem hill-1, wt. of tuber (g hill-1), yield of tubers (kg plot-1), yield of tubers (t ha-1), tuber fleshy dry matter content, specific gravity, grading of tubers (% by number). Potato production increased significantly due to the application of Urea Super Granule (USG). The highest production was observed in T3 treatment. The application of T3 treatment showed the highest wt. of tuber hill-1 (57.53g hill-1), highest tuber yield (25.77 kg plot-1), highest tuber yield (29.45 t ha-1) than any other sources of nitrogen treatments. The mean apparent recovery of Nitrogen by tested variety BARI Alu 7 (Diamant) was obtained with the application of USG in other treatment (except control) but the nitrogen use efficiency was highest in T3 treatment. Findings revealed that application of USG showed the superiority over other sources of nitrogen to produce highest tuber yield of potato and for all cases lowest results were found in T1 treatment receiving no fertilizer (control).

Proportional impact prediction model of coating material on nitrate leaching of slow-release Urea Super Granules (USG) using machine learning and RSM technique

An accurate assessment of nitrate leaching is important for efficient fertiliser utilisation and groundwater pollution reduction. However, past studies could not efficiently model nitrate leaching due to utilisation of conventional algorithms. To address the issue, the current research employed advanced machine learning algorithms, viz., Support Vector Machine, Artificial Neural Network, Random Forest, M5 Tree (M5P), Reduced Error Pruning Tree (REPTree) and Response Surface Methodology (RSM) to predict and optimize nitrate leaching. In this study, Urea Super Granules (USG) with three different coatings were used for the experiment in the soil columns, containing 1 kg soil with fertiliser placed in between. Statistical parameters, namely correlation coefficient, Mean Absolute Error, Willmott index, Root Mean Square Error and Nash–Sutcliffe efficiency were used to evaluate the performance of the ML techniques. In addition, a comparison was made in the test set among the machine learning models in which, RSM outperformed the rest of the models irrespective of coating type. Neem oil/ Acacia oil(ml): clay/sulfer (g): age (days) for minimum nitrate leaching was found to be 2.61: 1.67: 2.4 for coating of USG with bentonite clay and neem oil without heating, 2.18: 2: 1 for bentonite clay and neem oil with heating and 1.69: 1.64: 2.18 for coating USG with sulfer and acacia oil. The research would provide guidelines to researchers and policymakers to select the appropriate tool for precise prediction of nitrate leaching, which would optimise the yield and the benefit–cost ratio.

Long term conservation agriculture impact on soil nitrogen fractions and wheat (Triticum aestivum) yield in subtropical Inceptisol

The present study was carried out at ICAR-Indian Agricultural Research Institute (IARI), New Delhi over two consecutive years (2020 and 2021) to evaluate the influence of conservation agriculture (CA) and nitrogen management strategies on wheat yield in an intensified maize (Zea mays L.)-wheat (Triticum aestivum L.)-mungbean (Vigna radiata L.) cropping system. Results indicated that grain and straw yields of wheat in CA plots were higher, reaching 4829 and 7231 kg/ha, respectively. However, these yields were statistically comparable to those obtained from conventionally tilled plots (4502 and 6611 kg/ha, respectively). Significantly higher wheat grain and straw yields were observed in plots receiving nitrogen fertilizer. Interestingly, the harvest index remained unaffected by both tillage practices and nitrogen management strategies. After two seasons of wheat cultivation, CA plots had significantly higher soil nitrogen fractions, including mineral, alkali-permanganate, potentially mineralizable, microbial biomass N and total nitrogen, compared to conventionally tilled plots. Moreover, all nitrogen-receiving treatments demonstrated significantly higher nitrogen fractions at both soil depths (0–5 and 5–15 cm) compared to the control. Notably, plots treated with urea super granules exhibited superior results in enhancing plant-available nitrogen. In conclusion, this study underscores the importance of CA and various nitrogen management strategies for increasing wheat crop yield and promoting plant-available nitrogen fractions in the soil. These findings providevaluable insights for farmers and researchers looking for sustainable and efficient agricultural practices to optimize wheat production and soil health.

Influence of nitrogen sources on grain yield of wheat and net global warming potential

ABSTRACT Nitrous oxide (N2O) emission is mainly associated with aerobic crop culture, which is influenced by nitrogen (N) fertilizer sources, rates, placement methods, and water management systems. The influence of N fertilizers on greenhouse gas (GHG) emission patterns are not well documented in Asian region. The present investigation was undertaken to identify GHG emission patterns, net carbon budget, net global warming potential (GWP) and GHG intensity. N fertilizer from prilled urea (PU), urea super granule (USG) and N-phosphorus (P)-potassium (K) briquette (NPKB) were used and compared with control (no fertilizer). Equal nutrient doses were maintained for all the treatments irrespective of fertilizer sources. Static close chamber technique was used for measuring GHG emission. Depending on treatments, total methane (CH4), nitrous oxide and carbon dioxide (CO2) fluxes were 8.16–10.85, 0.57-0.49-0.59 and 1739–2309 kg ha−1 season−1, respectively and net GWPs varied from −1292 to −2438 kg CO2 eq. ha−1 season−1. Wheat grain yields significantly varied from 3.2 to 3.9 t ha−1 because of N sources and rates. Use of USG for wheat cultivation can increase CO2 removal about 22–88% from the atmosphere along with about 2–14% grain yield and 26–48% soil organic carbon (SOC) sequestration improvements compared to other N sources in Bangladesh.

Influence of nitrogen sources and rates on yield and nitrogen use efficiency of tomato

A study was carried out with tomato at the research field of Regional Agricultural Research Station of BARI, Cumilla during two consecutive years 2019-20 and 2020-21. The objective was to evaluate the yield response and nitrogen use efficiency (NUE) of tomato (variety BARI Tomato-15) and to suggest the source and the rate of N fertilizer recommendation for tomato. The experiment was laid out in a RCBD design with three N sources (PU, NCU and DAP) and two N rates (100% and 125% of recommendation as per FRG-2018) replicated three times. In the first year, prilled urea (PU), neem coated urea (NCU) and DAP were used but in the second year DAP was replaced by urea super granule (USG). The recommended dose of N for tomato was 120 kg ha-1. Results revealed that between two rates of N application the yield was the maximum (77.4 t ha-1 and 60.3 t ha-1 in two years, respectively with 125% of RD. The highest agronomic use efficiency of nitrogen (NAUE) was obtained from 100% RD of N as DAP (150.0 kg kg-1) and 125% RD of N as NCU (133.3 kg kg-1). The lowest N use efficiency was observed in 100% PU (84.2 kg kg-1) and 100% NCU (40.8 kg kg-1) treated plots. Due to optimal plant growth, the neem-coated urea treatment yielded little higher than PU treatment. Bangladesh J. Agri. 2023, 48(1): 92-100

Mung bean (Vigna radiata L.) growth response to prilled and super granule urea application

Indiscriminate use of nitrogenous fertilizers not only causes soil degradation but also significantly increases production costs, thus sought the urgent call for judicial application of this fertilizer to sustain soil fertility, particularly in producing pulse crops as they also trap atmospheric nitrogen. This study was conducted at the farm of Sher-e-Bangla Agricultural University, to explore the best nitrogenous fertiliser (prilled and super granule urea) application rate fostering better growth and yield of mung bean. A randomized complete block design (RCBD) was adopted with 16 treatments having three replications. Data on different growth contributing characteristics of mung bean were recorded, and statistical analysis was conducted to present the results. Findings of this study revealed significant variations in majority of the yield and yield contributing parameters of the mung bean influenced by the rate and methods of nitrogenous fertilizer application. The results demonstrated that application of prilled urea in furrows fostered the growth-related parameters of the mung bean crop such as the highest plant height (50.57 cm), the maximum number of leaves plant-1 (22.57), the maximum number of branches plant-1 (6.00) and the highest above ground dry matter plant-1 (12.08 g) which could enhance better yield as compared to any other treatments studied. However, application of urea super granule (USG) placement at 10 cm depth with a 40 cm distance exhibited the worst growth responses in regard to yield contributing parameters of mung bean.

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

Effects of Rice Husk Biochar Coated Urea and Anaerobically Digested Rice Straw Compost on the Soil Fertility, and Cyclic Effect of Phosphorus

Fertilizer application in rice farming is an essential requirement. Most of the high-yielding varieties which are extensively grown throughout the country require recommended levels of fertilizers to obtain their potential yields. However, effective, and efficient ways of fertilizer application are of utmost importance. Coated fertilizers are used to reduce leaching nutrients and improve the efficiency of fertilizer. However, conventional coated fertilizers such as Sulphur coated urea and urea super granules are not popular among rice farmers in Sri Lanka owing to the high cost. Mixing urea-coated rice husk biochar causes a slow release of nitrogen fertilizer. This coated fertilizer and rice straw compost reduction the cost of importations of nitrogen-based fertilizers per unit area of cultivation. The study aimed to evaluate the effects of rice husk biochar coated urea and anaerobically digested rice straw compost on the soil fertility, and the cyclic effect of phosphorus. Concerning the pot experiment, rice grain yield was significantly higher in Rice husk biochar coated urea, triple super phosphate (TSP), and muriate of potash (MOP) with anaerobically digested rice straw compost. The lowest yield was observed in the control. The release of phosphate shows a cycle effect which is an important finding. Rice husk biochar coated urea can potentially be used as a slow-releasing nitrogen fertilizer. In addition, the urea coated with biochar is less costly and contributes to mitigating pollution of water bodies by inorganic fertilizers (NPK).

Performance of Transplant Aus Rice Varieties under Different Nitrogen Management Practices

Management of applied nitrogen in rice field is one tool that could lead to increase in rice yield, but often ignored by most farmers. The experiment was carried out from April to July 2015 at the Agronomy Field Laboratory of Patuakhali Science and Technology University, Dumki, Patuakhali to find out the influence of different nitrogen management and variety on the yield performance of transplant Ausrice. The study consisted of four levels of nitrogen viz. Control (without N), 30 kg N ha-1, 60 kg N ha-1 and urea super granule @ 52 kg N ha-1 and four Transplanted aus rice varieties viz. KaliHitta, ChaitaBoro, Abdul Hai and Gota IRRI, and was laid out in a split-plot design with three replications. The levels of nitrogen were assigned in the main plot and varieties were allocated in the sub-plots. Nitrogen management, variety and their interactions exerted significant (P ≤ 0.05) influence on plant characters, yield contributing characters and yield of transplanted Aus rice. In the case of nitrogen management, the tallest plant was 161.60 cm, maximum leaf area index(2.97, the highest number of effective tillers hill-115, longest panicle 24.30 cm with the maximum number of filled grains as94.73, 1000-grain weight gave 29.97 g. Grain yield of 2.48 t ha-1 were obtained from USG @ 52 kg N ha-1 and the shortest plant height of 136.90 cm with lowest leaf area index of 1.78, lowest number of effective tillers hill-1 (8.43), shortest panicle (18.84 cm) with the lowest numbers of filled grains panicle-1 (53.18), 1000-grain weight (24.33 g) and grain yield (1.40 t ha-1) were obtained in control (N1=O, kg N ha-1). Among the varieties, ChaitaBoro gave the tallest plant height (151.60 cm) and maximum leaf area index (2.54). While the highest number of effective tillers hill-1 (12.20), longest panicle (22.42 cm) with the maximum number of filled grains panicle-1 (73.50), highest 1000-grain weight (27.41 g) and highest grain yield (2.39 t ha-1) were recorded from Gota IRRI than other varieties. In case of interaction, Gota IRRI Fertilized with USG at 52 kg N ha-1 produced the highest number of effective tillers hill-1 (16.87), panicle length (25.13 cm), number of grains panicle-1 (105.70) and grain yield (3.13 t ha-1). The lowest number of effective tillers hill-1 (8.13), lowest panicle length (17.47 cm) with minimum numbers of filled grains 47.67) and grain yield (1.12 t ha-1) were produced by the interaction of control (N1=O, kg N ha-1) and Kali Hitta. So, cultivation of transplant Aus rice (Gota IRRI) appeared to be the best performance with USG @ 52 kg N ha-1 and recommended to the end users.

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.

Conservation agricultural practices for minimizing ammonia volatilization and maximizing wheat productivity.

A large amount of ammonia volatilization from the agricultural system causes environmental problems and increases production costs. Conservation agriculture has emerged as an alternate and sustainable crop production system. Therefore, in the present study, ammonia losses from different agricultural practices were evaluated for the wheat crop under different tillage practices. The results of the present study showed that the cumulative emission of ammonia flux from the wheat field varied from 6.23 to 24.00 kg ha-1 (P ≤ 0.05) in conservation tillage (CA) and 7.03 to 26.58 kg ha-1 (P ≤ 0.05) in conventional tillage (CT) among different treatments. Application of basal 80% nitrogen resulted in the highest ammonia flux in conventional and conservation tillage practices. The ammonia volatilization followed the following trend: urea super granules with band placement > neem-coated urea with band placement > neem-coated urea with broadcast before irrigation > neem-coated urea with broadcast after irrigation > slow-release N fertilizer (urea stabilized with DCD and N(n-butyl)thiophosphoric triamide) with band placement. The conservation agricultural practices involving conservation tillage appear to be a sustainable approach for minimizing ammonia volatilization and improving wheat productivity.

English

Optimum nitrogen fertilization from the right source is the most important production factors for higher grain yield of wheat. Study to investigate the effect of type and rate of Nitrogen fertilizer on yield of bread Wheat was conducted in Ofla and Endamehoni districts of northern Ethiopia in 2017 and 2018 main cropping season. The treatments consists four levels of different sources of nitrogen fertilizer (Prilled urea, granular urea, urea super granule and UREAstabil) each with three application rates (46, 69 and 92 kg N ha−1) and one control (without any N fertilizer application) laid down in a randomized complete block design replicated three times.  Grain yield of was affected significantly to the application rates and source of nitrogen fertilizer at Adigolo and Mekan districts of Ofla and Endamehoni respectively.  The highest grain yield of 5.11 and 4.08 tha-1 was obtained from application 92 and 69 kg N ha-1 of UREAstabil at Adigolo and Mekan districts respectively.  In both Adigolo and Mekan districts, grain yield of wheat showed that a linear increase with increasing rate of N fertilize while,  application of 46 kg N ha-1 from UREAstabil reaches optimum agronomicaly and economically for the study areas. Key words: Prilled urea, super granular urea, granular urea, UREAstabil.