DETERMINATION OF ECONOMIC EFFICIENCY OF DEEP PLACEMENT AND FOLIAR APPLICATION OF UREA FERTILIZER THROUGH THE PERFORMANCE OF BORO RICE cv . BRRI dhan 29

Rice crop Rice is the most extensively cultivated cereal crops in Bangladesh and nitrogenous fertilizer, especially urea is the most pressing fertilizer to supply nutrient in the paddy field. With this view, an experiment was conducted to evaluate the effect of deep placement and foliar application of urea fertilizer on BRRI dhan29 rice cultivar in boro season at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during December 2015 to May 2016. The experiment was laid out in a randomized complete block design considering twelve treatments with three replications. The treatments wereT0 ( No N application), T1 [140 kg N/ha (as prilled urea)], T2 (1.8 g 1-USG + 5 foliar spray @ 1% N solution), T3 (1.8 g 1-USG + 5foliar spray @ 1.5% N solution), T4 (1.8 g 1-USG + 5 foliar spray @ 2% N solution), T5 (1.8 g 2-USG), T6 (2.7 g 1-USG), T7 (2.7 g 1-USG + 3 foliar spray @ 1% N solution), T8 (2.7 g 1-USG + 3 foliar spray @ 1.5% N solution), T9 (2.7 g 1-USG + 3 foliar spray @ 2% N solution), T10 (1.8 g 2-USG + 3 t/ha cowdung), T11 (2.7 g 1-USG + 3 t/ha cowdung). Results showed that the grain and straw yield of the rice variety responded significantly to the application of prilled urea (PU), deep placement of USG and foliar application of N. The highest grain yield (4.8 t/ha) was recorded in T8 which was identical to the yield (4.7 t/ha) obtained in T3. The highest straw yield (6.0 t/ha) was found in T5. The lowest grain yield (3.7 t/ha) and straw yield (4.5 t/ha) were found in T0. Considering the economic efficiency, the treatment T8 showed the maximum gross margin and marginal gross margin with lowest cost per unit of product. Therefore, to get highest grain yield (4.8 t/ha), 82 kg N/ha as USG and 3 foliar spray of N @1.5% concentration i.e. total 219 Kg urea/ha can be applied to the rice field of BRRI dhan29. This will save an amount of 81 Kg urea per rice growing season per hectare.


INTRODUCTION
Bangladesh is an agro based country where agriculture is the single largest sector and the main stay of the country's economy (Sabnam, 2013).Rice (Oryza sativa L.) is the most extensively cultivated cereal crop in Bangladesh.Rice (Oryza sativa L.) is also the staple food for more than two billion people in Asia and four hundred millions of people in Africa and Latin America (Aktar, 2017).In 2016-2017, 475.64 million metric tons of rice were consumed worldwide (Statista, 2018).Nitrogen is one of the major plant nutrients required for plant growth.Farmers of Bangladesh use mainly urea in rice field to meet the demand of nitrogen.For maximizing yield of rice, nitrogenous fertilizer is the kingpin in rice farming.Therefore, excessive use of nitrogen fertilizer is one of the major concerns in sustainable agriculture for its decreased N-utilization efficiency by crops and increased N released to the environment, resulting atmosphere and water systems pollution (Zhu et al., 1997).In Bangladesh, N fertilizer input is as high as 265 kg Nha -1 yr -1 in rice-rice cropping pattern (BBS, 2011).
Fertilizer is a critical input in Bangladesh for rice production and most farmers broadcast prilled urea to fertilize their rice fields.This method for supplying nitrogen to rice plants leads to losses in effective nitrogen uptake in the rice plants.On the other hand, the urea deep placement (UDP) technology represents a possible alternative to increase rice yields and to reduce the nitrogen loss associated with broadcasted urea (Bautista et al., 2000).However, foliar spray of fertilizer did not only increase the crop yields but also reduce the quantities of fertilizer applied through soil (Rahman et al., 2017).Foliar application can also reduce the lag time between application and uptake by the plant (Stefan et al., 1990).The use of foliar application in agriculture has been a popular practice within farmers since the 1950s, when it shows that foliar-applied fertilizers passed through the leaf cuticle and into the cells.Various studies have shown that a small amount of nutrients (nitrogen or phosphate) applied by foliar spraying increases significantly the yield of crops (Vaiyapuri et al., 2003;Alam, 2009).In this connection, Bangladesh has a good stock of data for the fertilizer management of high yielding rice.However, minimal efforts have been made to study in particular the nitrogen use efficiency of rice varieties with nitrogen efficient fertilizer management practice.Therefore, the present investigation is undertaken to develop a combined approach of using N fertilization via deep placement and foliar application for maximizing rice yield as well as minimizing N loss to the environment.Therefore the present study aimed to find out the economic efficiency of different urea application method through the performance of boro rice cv.BRRI dhan29.

Description of experimental site
The study was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from December 2015 to May 2016.The experimental site is located at 240 75´ N latitude and 900 50´ E longitude in the south-west part of Brahmaputra at an elevation of 18 m above the sea level.This site belongs to non-calcareous dark grey floodplain soil under the agro-ecological zone Old Brahmaputra Floodplain "AEZ-9" (UNDP and FAO, 1988).

Characteristics of test variety
BRRI dhan29, a high yielding variety of rice was used as the test crop in this experiment.This variety was released for boro season by the Bangladesh Rice Research Institute (BRRI); Joydebpur, Gazipur in 1992 after regional and zonal trial and evaluation.It is a transplant boro rice cultivar and matures after 103 days after transplanting with average yield of 5.0-7.5 t ha -1 .Life cycle of this variety ranges from 155 to 160 days, which however may vary due to changes in climatic condition.The plant height is 90-95 cm and the cultivar is of nonlodging type.It is somewhat resistant to pests and diseases and especially blast diseases.

Preparation of the experimental land and raising of crop
The land was first opened with a tractor drawn disc plough on 14 December, 2015.After two days, the land was irrigated slightly and subsequent ploughings and cross ploughings were given and leveled by laddering.The field layout was made on 28 January, 2016 according to experimental specification immediately after final land preparation.Weeds and stubbles were cleared off from individual plots and finally plots were leveled properly by wooden ladder so that no water pocket could remain in the field.Forty-five days old seedlings were carefully uprooted from nursery bed and transplanted in the plots on 1 February, 2016 maintaining a spacing of 25 cm × 15cm.Three healthy seedlings were transplanted in each hill.Various intercultural operations viz.irrigation, weeding, disease and pest management etc. were done as and when necessary to ensure and maintain the favorable condition for normal plant growth and development of crop.

Layout of the experiment
The experiment was laid out in a randomized complete block design (RCBD), where the experimental site was divided into 3 blocks representing the replications to reduce the heterogenic effects of soil.There were altogether 12 different treatment combinations.A total of 36 plots were prepared for the experiment and the treatments were distributed to the unit plots in each block.The size of each plot was 4m × 2.5m and plots were separated from each other by ails.There was 1m drain between the blocks that separated the blocks from each other.

Treatments and fertilizer application
The treatments used for the experiment were as follows: TSP, MOP, gypsum and Zinc sulphate were applied to all the experiment plots as basal during final land preparation to supply 100 kg/ha, 160 kg/ha, 110 kg/ha and 10 kg/ha, respectively (BRRI, 2016).In T1 urea @ 300 kg/ha was applied.All prilled urea are applied in 3 equal split at 15, 35 and 55 days after transplanting (DAT).Five foliar sprays were applied in T2, T3 and T4 at 20, 30, 40, 50 and 60 DAT, respectively.Three foliar sprays were applied in T7, T8 and T9 at 30, 40 and 50 DAT, respectively.The USG were placed at 8-10 cm depth between four hills at alternative rows.

Sampling, harvesting and data collection
The crop was harvested at full maturity.The date of harvesting was confirmed when 90% of the grains became golden yellow in color.Harvesting of BRRI dhan29 was done on 10 May 2016.Five hills (excluding border hills) were selected randomly from each individual plot and uprooted before harvesting for recording data.After sampling the whole plot was harvested.The harvested crop of each plot was separately bundled, properly tagged and then brought to the threshing floor.The harvested crops were threshed manually.The grains were cleaned and dried to a moisture content of 14%.Straws were sun dried.

Statistical analysis of data
Data were compiled and tabulated in proper form for statistical analysis.The recorded data were statistically analyzed to find out the significance of variation resulting from the experimental treatments.All the collected data were analyzed and adjudged by Duncan's Multiple Range Test (Gomez and Gomez, 1984).

Crop characteristics and yield attributes
Application of PU, deep placement of USG and foliar application of N significantly increased the plant height of BRRI dhan29 (Table 1).The plant height of rice varied from 93.87 cm to 104.1 cm.The tallest plant of 104.1 cm was observed from T4 treatment (1.8g 1-USG + 5 foliar spray @ 2.0% N solution).Second plant height 103.8 cm was recorded from T9 treatment which was statistically similar to T1, T2 and T8 treatments.The treatment T0, T7, T5, T10, T11 and T6 gave the medium plant height with the values of 99.40, 98.80, 98.33, 98.20, 97.53 and 96.80 cm, respectively among the fertilizer treatments.The treatment T3 had the smallest plant height (93.87 cm).This might be due to the application of urea by spraying five times and plant could effectively use the N from that spray.
According to the Table 1, the use of PU, deep placement of USG and foliar application of N showed significant influence on effective tillers hill -1 of BRRI dhan29.The maximum number of tillers hill -1 of 11.07 was found from T4 (1.8 1-USG + 5 foliar spray @ 2.0% N solution) which were statistically similar to T5 and T2.The treatment T11, T7, T1, T8 and T0 gave the medium number of tillers hill -1 with the values of 10.00, 9.73, 9.27, 9.00 and 8.93 respectively among the fertilizer treatments.The minimum value of 7.200 was observed from T6.
The effect of PU, deep placement of USG and foliar application of N on grains panicle -1 varied from 134.6 to 141.4.The highest grains panicle -1 (141.4) was measured from T0 (No N application) which was statistically similar to T8.The treatment T9, T6, T3, T7 and T10 gave the medium grains panicle -1 with the values of 139.2, 138.2, 137.5, 137.4 and 136.5 respectively among the fertilizer treatments.The lowest value (134.6) was recorded from T2 and T5 treatment.

Grain yield and straw yield
Significant response of the grain yield of BRRI dhan29 was found due to the application of PU, deep placement of USG and foliar application of N. The grain yield ranged from 3.74 t/ha to 4.75 t/ha where the highest grain yield was (4.75 t/ha) recorded from T8 (2.7 g 1-USG + 3 foliar spray @ 1.0% N solution) and the lowest value was observed from T0 (no N application].Second highest grain yield (4.70 t/ha) was recorded from T3 [1.8 g 1-USG + 5 foliar spray @ 1.5 % N solution).The treatment T7 (2.7 g 1-USG + 3 foliar spray @ 1.0% N solution), T9 (2.7 g 1-USG + 3 foliar spray @ 2.0% N solution), T10 (1.8 g 2-USG + 3 t/ha cowdung), T11 (2.7 g 1-USG + 3 t/ha cowdung) gave the medium yield with the values of 4.66, 4.69, 4.30 and 4.36 t/ha, respectively among the fertilizer treatments.The treatment T1 (140 kg N/ha (prilled urea)), T5 (1.8 g 1-USG), T6 (2.7 g 1-USG) gave lowered yield with the values of 4.10, 3.97 and 3.90 t/ha, respectively (Figure 1).Treatment T8 gave the highest yield that might be due to the combined application of urea as super granule and foliar application for three times.Due to the combined application of urea with two different methods, the loss of urea was less and uptake and assimilation was greater and probably this phenomenon leads to the highest grain yield with the treatment T8.Straw yield of BRRI dhan29 responded significantly to different treatments under study.The highest straw yield (6.083 t/ha) was found from T5 [1.8 g 2-USG (240 kg N/ha)] and the lowest value (4.520 t/ha) was observed from T0 (No N application).The straw yields obtained due to different treatment ranked in order of T5>T9>T8>T2>T3>T11>T4>T10>T6>T7>T1>T0.

Economic performance
The economic performance of different treatments was evaluated through economic analysis (Table 2).The analysis showed that the highest total cost of production (Tk.69,370) was obtained from T1 and the lowest one (Tk.64,570) was obtained from T0 treatment.The analysis also showed that the highest gross income was recorded in T8 (Tk.95,000) and lowest one was recorded from the treatment T0 (Tk.74,800).Net income also varied due to different treatments.The highest BCR (Beneficial cost ratio) was obtained (1.39) from T3 treatment which is similar to T8 treatment and the lowest one (1.15) was obtained from T6 treatment.From the economic analysis the highest CPUP (cost per unit of product) was obtained (9.6) from T1 treatment which is similar to T5 treatment and the lowest one was obtained (8.0) from T3 treatment which is similar to T8 treatment.

CONCLUSION
The overall results indicated that the highest grain yield of BRRI dhan29 was found in treatment [2.7 g 1-USG (82 kg N/ha) + 3 foliar spray @ 1.5% N solution (13.5g urea/spray)].This reveals that the deep placement of USG fertilizer with foliar application enhanced the N use efficiency.As a consequence, the grain yield of BRRI dhan29 was increased to significant extent.The treatment also demonstrated the highest gross income followed by with the value of 95,000 (Tk/ha) and lowest value was obtained in with the value of 74,800 (Tk/ha).Therefore, the treatment [2.7 g 1-USG (82 kg N/ha) + 3 foliar spray @ 1.5% N solution/ha (13.5g urea/spray)] i. e. total 219 kg urea/ha can be recommended for successful cultivation of boro rice, BRRI dhan29.This will save an amount of 81 kg urea per rice growing season per hectare.

Figure 1 .
Figure 1.Effect of deep placement of USG and foliar application of N on the grain yield of BRRI dhan29 USG means one piece of urea super granule and 2-USG means two pieces of urea super granule.Each urea super granule was applied for every four hills of rice plant

Table 1 .
Effect of PU, deep placement of USG and foliar application of N on yield and yield contributing characters of BRRI dhan29

Table 2 .
Economic analysis of BRRI dhan29 as influenced by the application of PU, USG and foliar application of N