Bangladesh Agron. J. 2021, 24(2): 127-136 DEEP PLACEMENT OF NPK BRIQUETTE IN RICE: ENVIRONMENT FRIENDLY TECHNOLOGY FOR SUSTAINABLE RICE PRODUCTION A.B.S. Sarker1, A.J. Mridha2 and M.A. Mazid Miah3 1PSO, Agronomy Division; 2Agronomy Division, 3Ex Head, Soil Science Division Bangladesh Rice Research Institute, Gazipur Corresponding E-mail: sarkerabs@yahoo.com (Received: 05 December 2021, Accepted: 15 December 2021) Keyword: USG, Boro season, T. Aman season, T. Aus season Abstract Nine experiments were conducted at the Bangladesh Rice Research Institute (BRRI) farm, Gazipur, BRRI regional station, Sagardi, Barisal and farmers’ field of Barisal during Boro, T. Aus and T. Aman season, 2012 to evaluate the NPK briquette efficacy in rice production. Experimental results revealed that deep placement of NPK briquette (2 x 2.4 g) increased rice grain yield about 10 % and it saves 51, 9 and 20 kg NPK ha-1 than BRRI fertilizer recommended rate in Boro season. Similarly, NPK briquette (1 x 3.4 g) produced 28 and 18% more rice grain yield than BRRI fertilizer recommended rate with a savings of 29 kg N and 7 kg K ha-1 in T. Aus and T. Aman season, respectively. In general, deep placement method gave higher grain yield compared to conventional urea application. Undiscounted benefit cost ratio (BCR) was 1.44, 2.40 and 3.20 for Boro, T. Aus and T. Aman, respectively when comparing at the same rates of N application. Thus, use of NPK briquette over urea broadcast and incorporation was economically viable and efficient for rice cultivation. This method helps to reduce N loss through soil-water interface which plays a vital role in reducing environmental pollution. Introduction Rice is the most extensively cultivated crop in Bangladesh and staple food of Bangladeshi people also. Bangladesh is an agro-based country and predominantly rice based one which earns about 21.10% of her gross domestic product (GDP) from agriculture (Anonymous, 2008). The area and the production of rice in this country are 11.25 million hectares and 29.75 million tons, respectively (AIS, 2008). The edaphic and climatic factors of Bangladesh are favorable for rice cultivation but the average yield of Boro rice in this country is quite low (2.55 t ha-1) in the fiscal year of 2006-2007 (BBS, 2007). The farmers have to produce maximum rice from minimum land by adopting improved agronomic practices. Deep placement of NPK briquette can play a significant role in increasing yield of Boro rice. Bhuiyan et al. (1988) reported that deep point placement of USG resulted in significantly higher grain yield of rice than split application of prilled urea. Further increases in grain yield, better N use efficiency (kg grain /kg N) and higher apparent N recovery occurred when the hole was closed after USG application. Similarly, Mohanty et al. (1999) reported that USG deep placement resulted additional grain yield of 1080, 510 and 350 kg/ha over prilled urea in alternate wetting and drying, shallow low land and intermediate low land, respectively. Recent increase in the cost of inorganic fertilizer makes it important to examine the relationships between grain yield and N utilization by rice to improve the efficiency of N utilization. Many strategies have been developed to increase the efficiency of urea-N use from fertilizer through proper timing, rate, deep placement, modified forms of fertilizer, and use of nitrification and urease inhibitors. Among them deep placement of urea fertilizer is one of the most effective application method in reducing total mailto:sarkerabs@yahoo.com 128 Sarker et al. N loss in the floodwater and is likely to minimize losses through volatilization and surface runoff (De Datta & Craswell, 1982). Similarly, Kapoor et al. (2008) reported that broadcast application of N as urea resulted in an average ten times higher amounts of ammonium N in flood water compared to deep placement of urea briquette. They also reported that deep placement of P and K resulted in lower content of P and K in floodwater. In rice cultivation system generally, P and K fertilizer is applied as broadcast but an NPK briquette is applied by deep point placement. For very low level of P and K in soil, particularly under upland condition, initial broadcast application followed by deep point placement to each subsequent planting is generally recommended. The use of urea briquettes gave higher rice yields and resulted in greater removal of NPK than prilled urea (Prasad and Prasad, 1983). Kapoor et al. (2008) reported that deep placed N-P briquettes gave significantly higher rice grain yield, total P and K uptake. They also found that closer spacing (20 cm x 10 cm) led to better utilization of P and K and provided opportunities for deep placement of N-P or N-P-K briquettes in soils with low available P. Bulbule et al. (2008) reported that grain yield of rice significantly increased when the crop was fertilized through briquettes (56-30-30 kg NPK/ha) as compared to the application of conventional fertilizers (100-50-50 kg NPK/ha). The deep placement of NPK briquette combines the concept of balance fertilization and deep placement advantage towards higher nutrient use efficiency in rice. In this context, NPK briquette deep placement technology for higher rice yield as well as better utilization of applied fertilizer by the crop and indirectly to avoid environmental pollution through volatilization and surface runoff to be ascertained. Materials and Methods Nine field experiments were conducted at BRRI farm Gazipur, BRRI Regional Station, Sagordi, Barisal and farmer’s field at Babuganj of Barisal by Agronomy division of BRRI. Eight treatments were tested. The treatments were T1 = BRRI recommended dose of prilled urea at three splits and P K S and Zn fertilizer was applied as basal at final land preparation, T2 = One 2.70 g USG (N78 ) in Boro and one 1.90 g USG (N52) was placed at the centre of each four hills + BRRI recommended rate P K S and Zn fertilizer was applied as basal at final land preparation, T3 = 2.40 g NPK briquette (two in Boro, one in T. Aus and T. Aman) was placed at the centre of each four hills (N:P:K ratio = 7.0:1.6:2.0 and doses of NPK = 87 kg Nha-1, 20 kg Pha-1 and 25 kg Kha-1 in Boro and 43.5 N kg Nha-1, 10 kg Pha-1 and 12.5 kg Kha-1 in T Aus and T. Aman, S and Zn as recommended, T4 = One 3.40 g NPK briquette was placed at the centre of each four hills (N:P:K ratio = 9.1:2.4:3.5 and doses of NPK = 57 kg Nha-1, 15 kg Pha-1 and 22 kg Kha-1 ) and S and Zn as recommended, T5 = NPKS and Zn doses were same as T3 but sources were Urea, TSP, MP, T6 = NPKS and Zn doses were same as T4 but sources were Urea, TSP, MoP, T7 = Absolute Control and T8 = N alone for prilled urea. The nutrients of the treatments for the location and season are given in Table 1. The experiment was laid down in RCB design with three replications. The tested variety was BRRI dhan29 in Boro, BRRI dhan27 in T Aus and BRRI dhan49 in T. Aman season. The unit plot size was 4 x 6 m. Transplanting was done by two seedlings per hill and the seedling age was 40, 30 and 35 days, respectively in Boro, T. Aus and T. Aman season at plant spacing of 20 cm x 20 cm. All fertilizer was applied as per treatment before and after transplanting. The USG and NPK briquettes were deep placed between four hills as per treatment after 7 days of transplanting. Table 1. Summary of treatments applied at different locations and across seasons Treatments Description Location Season N Rate (kg/ha) P Rate (kg/ha) K Rate (kg/ha) T1= Rec. fertilizer rate BRRI Recommend On-Station (Gazipur)) Boro 138a 26b 75b Aus 77a 15b 37b Aman 93a 16b 42b On-Station (Barisal) Boro 138 30 30 Aus 77 11 17 Aman 93 15 17 On-Farm Boro 138 30 30 Deep Placement of NPK Briquette in Rice: Environment Friendly Technology 129 (Babuganj) Aus 77 11 18 Aman 93 15 18 T2 = USG N78 kg ha-1 + Rec. PKSZn USG (one-2.7 g briq) All All 78c PK rate similar as T1 in respective season T2 = USG N52 kg ha-1 + Rec. PKSZn USG (one-1.8 g briq) All T. Aus and T. Aman 52 T3 = (2x2.40) NPK briquette N87 NPK (two-2.4 g briq) All Boro 87c 20c 25c T3 = (1x2.40) NPK briequette N44 NPK (one-2.4 g briq) All T. Aus and T. Aman 43.5c 10c 12.5c T4 = 3.40 g NPK briequette N57 NPK (one-3.4 g briq) All All 57c 15c 22c T5 = NPK same at T3 from urea, TSP and MoP NPK (urea,TSP, MoP) All Boro 87a 20b 25b NPK (urea, TSP, MoP) All T. Aus and T. Aman 43.5a 10b 12.5b T6 = NPK same at T4 from urea, TSP and MoP NPK (urea, TSP, MoP) All All 57a 15b 22b T7 = Abs. control Absolute Control All All 0 0 0 T8 = Only N N alone All All 102 25d 64d Placement of USG and NPK briquette was done 10 days after transplanting. Flood water NH4-N was determined through Spectrophotometer by using Nessler Reagent (Radov et al., 1985) and continued for seven days. Grain yield (t/ha) was determined from 5m2 from each treatment and straw yield per square meter was calculated from 16 hills. The data were statistically analyzed. Table 2. Treatment description for Boro rice Treatments Description N Rate (kg/ha) P Rate (kg/ha) K Rate (kg/ha) Basal /deep placed N (kg/ha) 1st Top- Dress N (kg/ha) 2nd Top- Dress N (kg/ha) T1 Check 0 25a 64b 0 0 0 T2 USG (one-2.7 g briq) 78 25a 64b 78 0 0 T3 USG (two-1.8 g briq) 104 25a 64b 104 0 0 T4 Urea 78 25a 64b 26 26 26 T5 Urea 104 25a 64b 34 35 35 T6 NPK (two-2.4 g briq) 78 16c 42c 78 0 0 T7 Urea 156 25a 64b 52 52 52 T8 NPK (two-3.4 g briq) 102 25d 64d 102 0 0 a Applied as TSP, b Applied as MoP (KCl), c P and K is applied as NPK briquette (Treat. 6; made with 45 kg Urea + 27 kg DAP + 28 kg MoP), d P and K is applied as NPK briquette (Treatment 8; made with 40 kg Urea + 30 kg DAP + 30 kg MoP) Table 3. Treatment description for T. Aus and T. Aman rice Treatments Description N Rate (kg/ha) P Rate (kg/ha) K Rate (kg/ha) Basal /deep placed N (kg/ha) 1st Top- Dress N (kg/ha) 2nd Top- Dress N (kg/ha) T1 Check 0 16a 42b 0 0 0 T2 USG (one-1.8 g briq) 52 16a 42b 52 0 0 T3 USG (one-2.7 g briq) 78 16a 42b 78 0 0 T4 Urea 78 16a 42b 26 26 26 T5 UDP (two-1.8 g briq) 104 16a 42b 104 0 0 T6 NPK (one-3.4 g briq) 51 13c 32c 51 0 0 130 Sarker et al. T7 Urea 120 16a 42b 40 40 40 T8 NPK (two-2.4 g briq) 78 16d 42d 78 0 0 a Applied as TSP, b Applied as MoP (KCl), c P and K is applied as NPK briquette (Treat. 6; made with 45 kg Urea + 27 kg DAP + 28 kg MoP), d P and K is applied as NPK briquette (Treatment 8; made with 40 kg Urea + 30 kg DAP + 30 kg MoP) Results and Discussion Grain yield of nine locations with all treatments of Boro, T. Aus and T. Aman are presented in Table 4- 6 and grain yield advantage (%) over recommended fertilizer rate is shown in Table 7. BRRI recommended fertilizer rate (NPKSZn) produced higher grain yield than without fertilizer and N alone treatment irrespective of locations and seasons. The only exception was observed for the first cropping (Boro) at Babuganj where N alone treatment with available soil P and K gave similar yield as the BRRI recommended treatment. Overall, the highest grain yields were obtained with the deep placement of NPK briquette at all locations. During the Boro season T3 (two-2.4 g NPK briquette) which was three locations average 10.06% higher. During the T. Aus and T. Aman season T4 (one-3.4 g NPK briquette) gave the highest grain yield and it was three locations average 17.69% higher in T Aus and 27.99% in T Aman season (Table 7). Table 4. Effect of different treatments on the grain yield of BRRI dhan29 during Boro season 2012 at different locations Treatments Boro On-Station (Gazipur) On-Station (Barisal) On-Farm (Barisal) T1 = Rec. fertilizer rate 7.00 b 6.99 ab 6.67 bc T2 = USG N52 kg ha-1 + Rec. PKSZn 7.13 ab 7.15 a 7.03 b T3 = (2 x 2.40) NPK briqutte N87 7.47 a 7.29 a 7.94 a T4 = 3.40 g NPK briqutte N57 5.92 c 6.43 b 6.13 c T5 = NPK same at T3 from urea, TSP and MoP 6.96 b 6.89 ab 7.16 b T6 = NPK same at T4 from urea, TSP and MoP 6.12 c 6.26 b 6.22 c T7 = Absolute control 3.89 d 3.20 c 4.14 d T8 = Only N 5.88 c 6.19 b 6.88 bc Figures in a column means followed by different letters differ significantly, whereas figure with common letter(s) are not significantly different at the 5% level by DMRT Table 5. Effect of different treatments on the grain yield of BRRI dhan49 during T Aman season 2012 at different locations Treatments T. Aman On-Station (Gazipur) On-Station (Barisal) On-Farm (Barisal) T1 = Rec. fertilizer rate 4.20 bc 4.77 bc 4.40 b T2 = USG N52 kg ha-1 + Rec. PKSZn 4.44 b 5.26 ab 4.94 ab T3 = (1x2.40) NPK briqutte N44 3.89 c 5.54 ab 4.22 b T4 = 3.40 g NPK briqutte N57 4.85 a 5.70 a 5.19 a T5 = NPK same at T3 from urea, TSP and MoP 3.27 d 4.68 bc 4.01 bc T6 = NPK same at T4 from urea, TSP and MoP 4.03 d 4.70 bc 4.37 b T7 = Absolute control 2.96 e 3.60 d 3.16 d T8 = Only N 3.30 d 4,29 cd 3.55 cd Deep Placement of NPK Briquette in Rice: Environment Friendly Technology 131 Figures in a column means followed by different letters differ significantly, whereas figure with common letter(s) are not significantly different at the 5% level by DMRT Table 6. Effect of different treatments on the grain yield of BRRI dhan27 during T.Aus season 2012 at different locations Treatments T. Aus On –Station (Gazipur) On- Station (Barisal) On-Farm (Barisal) T1 = Rec. fertilizer rate 3.24 c 2.84 d 2.73 b T2 = USG N52 kg ha-1 + Rec. PKSZn 3.57 b 3.34 b 2.90 b T3 = (1x2.40) NPK briquette N44 3.20 c 3.10 c 2.96 b T4 = 3.40 g NPK briquette N57 3.93 a 3.58 a 3.72 a T5 = NPK same at T3 from urea, TSP and MoP 2.96 d 2.80 d 2.72 b T6 = NPK same at T4 from urea, TSP and MoP 3.18 c 3.04 c 2.87 b T7 = Absolute control 2.13 e 2.02 e 2.38 d T8 = Only N 2.51 d 2.47 d 2.51 cd Figures in a column means followed by different letters differ significantly, whereas figure with common letter(s) are not significantly different at the 5% level by DMRT Table 7. Effect of different treatments on the grain yield advantage over recommended fertilizer rate average of three locations during Boro, T Aman and T. Aus season Treatments Average yield increase in Boro over recommend rate (%) Average yield increase In T. Aman over recommend rate (%) Average yield increase over recommend rate (%) T1 = Rec. fertilizer rate 0.0 0.00 0.00 T2 = USG N52 kg ha-1 + Rec. PKSZn 3.25 11.43 9.41 T3 = NPK briquette N87 (Boro) and N44 (T. Aus and T. Aman) 10.06 5.47 - 1.85 T4 = 3.40 g NPK briquette N57 -10.51 27.99 17.69 T5 = NPK same at T3 from urea, TSP and MoP 1.82 -4.45 -10.97 T6 = NPK same at T4 from urea, TSP and MoP -9.89 3.49 -2.02 T7 = Abs. control -45.51 -25.21 - 27.45 T8 = Only N -8.04 14.50 16.83 NPK briquette deep placement increased rice grain yield when compared with urea broadcast and incorporation during Boro season at three locations with equivalent N87 rate (Fig. 1) with same PK level. Similar yield increase was also observed in all locations in both T. Aus and T. Aman season (Fig. 2-5). In Figures 3 and 5-6, a single 3.4 g NPK briquette deep placement (N57 rate) is compared with same rate of N, P, and K applied as urea, TSP and MoP for T. Aus, Aman and Boro season respectively. The NPK rates were low for the Boro rice; hence there was no difference between deep placement of NPK and the conventional application (Fig. 6). However, for both the T. Aus and T. Aman crop NPK briquette deep placement produced higher yield than conventional application of NPK (Fig. 3 and 5). The results indicate that the deep placement of NPK briquette has some yield advantage over urea, TSP, and MoP application at equivalent rate in wetland rice culture system. In Boro season deep placement of NPK briquette with 87 kg N/ha produced higher yield than the higher level of BRRI recommended N138 rate (Fig. 7). It means deep placement method saved on an overage 51-9-20 kg NPK/ha across location with increase of 10% rice yield in Boro season. Similarly, T. Aus and T. Aman season also showed 28 and 18% yield increase with less fertilizer as NPK briquette deep placement as compared to higher level of BRRI recommended N rate (Figure 8-9). 132 Sarker et al. Fig. 1. Influence of NPK briquette and urea-N at equivalent rate (N87) on the yield of BRRI dhan29 in Boro season at different locations. Fig. 2. Yield comparison between NPK briquette and urea-N at equivalent rate (N44) at different locations in T. Aus season. Again, deep placement method saved N fertilizer 20 kg/ha in T. Aus and 36 kg/ha in T. Aman season. Based on these results it may be concluded that NPK briquette deep placement in wet land rice culture enhanced rice yield with less amount of fertilizer than using the conventional method of urea, TSP and MoP application. Deep Placement of NPK Briquette in Rice: Environment Friendly Technology 133 Fig. 3. Influence of NPK briquette and urea-N at equivalent rate (N57) on the yield of BRRI dhan27 in T. Aus season at different locations. Fig. 4. Yield comparison between NPK briquette and urea-N at equivalent rate (N44) at different locations in T Aman season. Fig. 5. Yield comparison between NPK briquette and urea-N at equivalent rate (N57) on the yield of BRRI dhan49 at different locations in T Aman season. 0 1 2 3 4 5 6 7 HQ,Gazipur RS, Barisal FF,Barisal Location Y ie ld (t /h a) NPK briq-N57 Urea-N57 Fig. 6. Yield comparison between NPK briquette and urea-N at equivalent rate (N57) with same level of PK on the yield of BRRI dhan29 in Boro season. 134 Sarker et al. Fig. 7. Comparison of grain yield between recommended fertilizer rate (N138) and NPK briquette (N87) deep placement in Boro season at different locations. Fig. 8. Comparison of grain yield between recommended fertilizer rate (N77) and NPK briquette (N57) deep placement during T Aus season at different locations. Fig. 9. Grain yield comparison between recommended fertilizer rate (N93) and NPK briquette (N57) deep placement during T Aman season at different locations. Deep Placement of NPK Briquette in Rice: Environment Friendly Technology 135 A partial budget analysis was done to determine the economic benefit of NPK briquette over urea broadcast and incorporation. Table 4 revealed that additional yields obtained from NPK briquette deep placement were 577, 713 and 880 kg/ha in Boro, T. Aus and T. Aman season, respectively and thus additional returns (Tk./ha) were Tk. 8655, Tk. 10695 and Tk. 13200, respectively. On the other hand, by using NPK briquette for rice production additional cost were incurred Tk. 3540, Tk. 3144 and Tk. 3144 in Boro, T. Aus and T. Aman production, respectively. Therefore, in all seasons, positive net returns were obtained from NPK briquette placement for rice cultivation. Table 7 also showed that undiscounted BCR (3.20) were highest in T. Aman production followed by T. Aus production (2.40). Finally, it may conclude that use of NPK briquette over urea broadcast and incorporation was economically viable and efficient for rice production. Table 7. Partial Budget Analysis of NPK Briquette for rice production in different seasons over urea broadcast and incorporation Season NPK Briquette Additional Yield (t/ha) Additional Return (Tk./ha) Additional Cost (Tk./ha) Total Cost (Tk./ha) Net Return (Tk./ha) Undiscounted BCR Cost for Briquette Manuf. Labor Requirement Boro 2.4g: 87- 20-25 577 8655 1140 2400 3540 5115 1.44 T. Aus 3.4g: 57- 15-22 713 10695 744 2400 3144 7551 2.40 T. Aman 3.4g: 57- 15-22 880 13200 744 2400 3144 10056 3.20 Note: Estimated price of paddy was Tk. 15/kg, Manufacturing cost of NPK briquette was Tk. 6/kg, Labor required for NPK briquette placement was 8 man-day /ha and wage rate of labor was Tk. 300/day Experimental result revealed that deep placement method of NPK briquette in rice production saved 51 kg N/ha in Boro and around 29 kg N/ha in T. Aus and T. Aman season. Deep placement method favors to obtain higher yield compared to urea application to some extend. Undiscounted benefit cost ratio (BCR) was 1.44, 2.40 and 3.20 for Boro, T. Aus and T. Aman rice, respectively. Conclusion Deep placement of NPK briquettes (2 x 2.4g) increased about 10% higher rice grain yield and saved 51, 9 and 20 kg NPK/ha than BRRI fertilizer recommended rate in Boro season. Similarly, 23% more rice yield obtained from NPK briquette (1 x 3.4 g) use than BRRI recommended fertilizer rate with a savings of 28 kg N and 7 kg K /ha irrespective of T. Aus and T. Aman season. NPK briquette use also promotes balance fertilization in rice production. Deep placement of NPK briquette leads to the accumulation of nutrients in the reduced zone of soil and subsequently these nutrients are utilized efficiently by rice plants for better growth and increased yield. 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Denitrification in paddy soils. (In Japanese.) Kagaku (Science in Japan) 16: 104-116. 1PSO, Agronomy Division; 2Agronomy Division, 3Ex Head, Soil Science Division Bangladesh Rice Research Institute, Gazipur Corresponding E-mail: sarkerabs@yahoo.com Keyword: USG, Boro season, T. Aman season, T. Aus season Abstract Nine experiments were conducted at the Bangladesh Rice Research Institute (BRRI) farm, Gazipur, BRRI regional station, Sagardi, Barisal and farmers’ field of Barisal during Boro, T. Aus and T. Aman season, 2012 to evaluate the NPK briquette efficacy i... Introduction Materials and Methods Results and Discussion Experimental result revealed that deep placement method of NPK briquette in rice production saved 51 kg N/ha in Boro and around 29 kg N/ha in T. Aus and T. Aman season. Deep placement method favors to obtain higher yield compared to urea application t... Conclusion References