Bangladesh Agron. J. 2023, 26(1): 104-111 INFLUENCE OF AGRONOMIC MANAGEMENTS ON GROWTH AND YIELD OF BORO RICE J.C. Roy1*, P.K. Biswas2, M.S. Islam2 and M. H. Mahmud3 1Japan Tobacco International, Kushtia, Bangladesh 2Department of Agronomy, Sher-e-Bangla Agricultural University Dhaka-1207, Bangladesh, 3Project Implementation Unit-BARC, National Agricultural Technology Program-Phase-II Project, Dhaka, Bangladesh. *Corresponding author, Email: jibanroyjc05@gmail.com (Received: 15 April 2023, Accepted: 24 September 2023) Keywords: Agronomic management, boro rice, growth, yield Abstract The study was carried out at Sher-e-Bangla Agricultural University, Dhaka from December 2018 to April 2019, to find out the agronomic practices on the growth and yield of Boro rice. The trial was conducted with two rice varieties namely V1 (BRRI dhan84) and V2 (BRRI hybriddhan5), and 5 different agronomic practices such as M0 (no management), where variety in maim-plot and management practices in sub-plot. The results showed significant variations in weed severity, and l yield of Boro rice. Specific observations included plants reaching heights of 24.81 cm, 51.56 cm, 86.71 cm, and 119.21 cm at 20, 45, 70 days after transplanting (DAT), and at harvest, respectively. V2 exhibited a higher grain yield (5.36 t ha−1) but a reduced straw yield (4.97 t ha−1) compared to V1. Generally, regardless of the agronomic practices, BRRI dhan84 exhibited greater plant height, except under the 'no management' practice. The grain yield (6.70 t ha−1) was obtained with M6, and the maximum straw yield (6.55 t ha−1) to M4. The interaction effects showed that highest grain yield (7.35 t ha−1) from V2M6, while with V1M0.The most significant yield reduction for BRRI dhan84 was 84% with no management and 80% with no fertilizer, while BRRI hybriddhan5 showed a 71% reduction under similar conditions. Introduction Rice is the primary crop in Bangladesh, occupying 75% of the total cropped area, with 92% of farmers cultivating it (Rekabder, 2004). Approximately 75% of all cropped regions and over 80% of irrigated zones are dedicated to rice (BRKB, 2017). While Bangladesh boasts an average rice yield of 3.26 t ha−1 (BBS, 2022), its productivity lags behind countries like China, Japan, and Korea, all of which have average yields of t ha−1 (FAO, 2009). Different fertilization approaches can influence plant growth, maturation, size, phytochemical content, and seed properties (Mevi Schütz et al., 2003). Water management, particularly during the Boro season's flowering stage, affects water use efficiency (Maity and Sarkar, 1990). Water shortages at various growth stages can severely impact grain yield (Patel, 2000). Furthermore, weeds pose the most significant challenge to rice yield, with global yield losses to pests estimated at 40%. Of these losses, weeds are responsible for a staggering 32% (Rao et al., 2007). Effective agronomic strategies profoundly influence rice growth and yield. Yield decreases are often due to suboptimal weed, nutrient, and irrigation management. Consequently, comprehensive management techniques are crucial for optimal rice production in Bangladesh. However, many Bangladeshi farmers spend excessive time and effort on weed control while neglecting proper fertilization and irrigation. Its objectives encompass comparing two Boro rice Agronomic managements on growth and yield of boro rice 105 varieties, evaluating individual agronomic techniques on rice growth, and examining the combined impact of variety and agronomic practices on Boro rice performance. Materials and Methods The experiment was carried out at Sher-e-Bangla Agricultural University's field in Sher-e- Bangla Nagar, Dhaka. This site is positioned at a latitude of 23 º74´N and a longitude of 90º35´E, and it stands 8.2 meters above sea level. The soil here originates from "The Modhupur Tract" or AEZ- 28, as categorized by FAO in 1988. This topsoil has an olive-gray, silty clay texture, dotted with distinct dark yellowish-brown spots. It has a pH of 5.6 and contains 0.45% organic carbon.The trial was carried in out in a split-plot design with three replications where variety (BRRI dhan84 and BRRI hybriddhan5) in main-plot and management practices in sub-plot.. on variety, and seven different management i.e., no managements(M0), No weeding, (M1), No fertilizer application, but all other managements (M2), no irrigation in reproductive and ripening stage, but all other managements (M3), No insecticides, but all other managements (M4), no Fungicides/bactericides, but all other managements (M5), complete managements (M6) The var. BRRI dhan84, on average, stands between 90-96 cm tall during its ripening stage, bearing medium fine, white grains. It completes its life cycle in approximately 140-145 days and produces an average grain yield of 6.0-6.5 t ha−1, as reported by BRKB in 2017. The experiment area received fertilization as per recommended methods: 200 kg N, 80 kg P2O5, 125 kg K2O, 20 kg S, and 10 kg Zn. Urea was applied in three portions while other fertilizers were added during the final land preparation. Crop management was based as per need. Various metrics such as plant height, leaf area index (LAI), number effective non-effective tillers hill–1 and panicle length were measured. Leaf area index calculated by foliage from 5 hills canopy, measuring the leaf area per plot and dividing it by the plot land surface area. Grains were categorized as filled or unfilled, counted the data from 10 panicles per plot. The weight of 1000 - grains were measured at 12% moisture content. Both grain and straw yields were calculated from each plot's converted to as t ha−1. Biological yield was calculated with the following formula: Biological yield = Grain yield + Straw yield. Harvest index was calculated as: HI = Economic yield (grain weight) Biological yield (Total dry weight)  100 Finally, the data was analyzed for any significant variations between the treatments. by using Duncan’s Multiple Range Test at a 5% probability level Gomez and Gomez (1984). Results and Discussion Plant height Plant height showed numeric differences at 20, 45, and 70 DAT, and significant differences at harvest for both BRRI dhan84 and BRRI hybriddhan5 (Table 1). The tallest plants at 45, 70 DAT and at harvest were from V1 (BRRI dhan84) with heights of 24.81 cm, 51.56 cm, 86.71 cm, and 119.21 cm respectively. Conversely, the shortest plants were from V1 (BRRI hybriddhan5) with heights of 25.28 cm, 49.53 cm, 79.61 cm, and 104.08 cm. The variations in plant height were attributed to the inherent varietal characteristics. At 20, 45, 70 DAT, and at harvest, the tallest plants were observed under M6 (recommended management) with heights of 25.65 cm, 53.713 cm, 87.26 cm, and 118.15 cm respectively. In contrast, the shortest plants, with heights of 22.73 cm, 39.76 cm, 66.95 cm, and 93.88 cm respectively, were recorded under M0 (no management). Considering the interaction between variety and management, the tallest plants at 20, 45, 70 DAT, and at harvest were from V1M6 (BRRI dhan84 + recommended 106 Roy et al. management) with respective heights of 25.89 cm, 55.6 cm, 89.32 cm, and 127.4 cm. The shortest plants, on the other hand, were from V1M0 (BRRI hybriddhan5 + no management) with heights of 22.92 cm, 36.93 cm, 61.28 cm, and 90.6 cm, respectively. Leaf area index The leaf area index (LAI) showed numeric variation at 20 and 45 DAT and significant variation at 70 DAT for both BRRI dhan84 and BRRI hybriddhan5 (Table 1). Table 1. Effect of variety, agronomic managements, and treatment interaction on plant height (cm) and leaf area index (LAI) of Boro rice Treatments Plant height (cm) Leaf Area Index (LAI) 20 DAT 45 DAT 70 DAT At harvest 20 DAT 45 DAT 70 DAT At harvest Variety V1 24.81 51.56 86.71 119.22 0.09 b 3.30 a 6.86 a 7.06 a V2 25.29 49.54 79.61 104.08 0.10 a 2.35 b 6.44 b 5.20 b SE ± 0.45 0.97 1.21 1.69 0.01 0.2 0.18 1.52 CV (%) 17.00 16.29 8.97 8.26 33.41 22.85 8.78 80.43 Agronomic managements M0 22.74b 39.76c 66.95b 93.88c 0.09 a 1.30 b 1.67 c 2.08 d M1 23.22b 41.96c 71.25b 105.17b 0.09 a 1.37 b 3.25 c 3.74 cd M2 26.27a 58.87a 88.44a 116.27a 0.12 a 3.81 a 5.91 b 4.67 bc M3 25.56ab 52.52b 90.18a 115.83a 0.10 a 3.28 a 9.30 a 8.98 a M4 26.02ab 53.98b 86.85a 114.62a 0.09 a 3.27 a 8.70 a 7.68 a M5 25.88ab 53.05b 91.19a 117.63a 0.10 a 3.33 a 8.34 a 6.76 ab M6 25.66 53.71 87.26a 118.15a 0.11 a 3.43 a 9.40 a 9.00 a SE 1.03 1.12 1.40 1.69 0.01 0.26 0.51 0.61 CV (%) 11.48 5.49 6.12 5.46 31.48 33.66 27.48 35.98 Combined influence of variety and agronomic managements V1M0 22.54 b 42.58 de 72.61 d 97.16 de 0.08 abc 1.72 cde 2.13ef 2.95 ef V1M1 22.87 b 38.94 ef 70.94 d 111.20 b 0.07 c 1.11 de 2.51ef 3.17 ef V1M2 26.50 ab 60.04 a 92.60 ab 125.90 a 0.11 abc 4.83 a 6.68bcd 5.54 cde V1M3 27.16 ab 53.92 bc 94.82 a 123.53 a 0.10 abc 3.61 ab 8.6ab 9.12 abc V1M4 24.94 ab 54.79 bc 91.46 ab 124.80 a 0.08 abc 3.71 ab 9.62ab 9.64 ab V1M5 23.75 ab 55.04 bc 95.22 a 124.53 a 0.07 bc 3.95 ab 8.65ab 8.05 abc V1M6 25.89 ab 55.60 abc 89.32 abc 127.40 a 0.12 ab 4.15 ab 9.84a 10.98 a V2M0 22.92 b 36.93 f 61.28 e 90.60 e 0.09 abc 0.87 e 1.22f 1.21 f V2M1 23.56 ab 44.98 d 71.56 d 99.13 cde 0.11 abc 1.62 cde 3.99def 4.31 def V2M2 26.03 ab 57.70 ab 84.28 bc 106.63 bcd 0.12 ab 2.78 bc 5.14cde 3.80 def V2M3 23.95 ab 51.11 c 85.53 bc 108.13 bc 0.10 abc 2.94 bc 10a 8.85 abc V2M4 27.10 ab 53.16 bc 82.23 c 104.43 bcd 0.08 abc 2.82 bc 7.77abc 5.72 cde V2M5 28.01 a 51.04 c 87.16 abc 110.73 b 0.13 a 2.72 bc 8.02abc 5.47 cde V2M6 25.42 ab 51.82 c 85.20 bc 108.90 bc 0.10 abc 2.71 bcd 8.96ab 7.02 bcd SE= 1.13 1.09 1.99 2.39 0.01 0.37 0.72 0.86 CV (%) 11.48 5.49 6.12 5.46 31.48 33.66 27.48 35.98 In a column mean values having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly as per 0.05 level of probability by DMRT Test.V1: BRRI dhan84, V2: BRRI hybriddhan5; M0: No management, M1: No weeding, but all other managements, M2: No fertilizer application, but all other managements, M3: No Irrigation in reproductive and; ripening stage, but all other managements, M4: No Insecticides, but all other managements, M5: No Fungicides/bactericides, but all other managements, M6: Complete Managements. Agronomic managements on growth and yield of boro rice 107 The highest LAI values at 20, 45, and 70 DAT were 0.09, 3.3, and 6.9 respectively, was recorded from V1 (BRRI dhan84). On the other hand, the lowest values were 0.1, 2.35, and 6.44 respectively from V2 (BRRI hybriddhan5). Different agronomic managements showed significant impacts on the LAI at 20, 45, and 70 DAT. Specifically, the highest LAI values were observed under M6 (recommended management) with values of 0.11, 3.43, 9.40, and 9.00 respectively. Conversely, the lowest LAI values 0.09, 1.30, 1.67, and 2.08 respectively, were recorded under M0 (no management). The interaction between variety and management revealed the highest LAI values at 20, 45, 70 DAT, and harvest from V1M6 (BRRI dhan84 + recommended management) with 0.12, 4.15, 9.84, and 10.98 respectively. The lowest values were from V2M0 (BRRI hybriddhan5 + no management) with values of 0.09, 0.87, 1.22, and 1.21, respectively. Effective tillers hill−1 For BRRI dhan84 and BRRI hybriddhan5, the number of effective tillers per hill at harvest showed notable variation (Table 2). Table 2. Effect of variety, agronomic managements, and interaction on number of effective tillers, non-effective tillers hill−1, panicle length, number of filled grains panicle–1 and number of unfilled grains panicle–1 of Boro rice Treatments Number of effective tillers hill−1 Number of non- effective tillers hill−1 Panicle length (cm) Number of filled grains panicle−1 Number of unfilled grains panicle−1 Variety V1 10.83 a 0.26 b 25.91a 123.81 26.00 V2 7.33 b 0.54 a 24.36a 161.24 16.29 SE ± 0.44 0.02 1.59 51.86 14.64 CV (%) 3.87 4.63 20.49 12.05 3.40 Agronomic managements M0 5.60 d 0.17 a 22.43b 101.17c 8.50d M1 8.20 bc 0.50 a 24.68b 146.50ab 15.17cd M2 7.27 cd 0.50 a 24.04b 125.50bc 20.50bc M3 10.90 a 0.37 a 24.77b 143.17ab 26.17ab M4 10.90 a 0.53 a 25.94ab 165.17a 22.67ab M5 9.90 b 0.40 a 28.65a 155.50a 28.17a M6 10.80 a 0.33 a 25.44ab 160.67a 26.83ab SE ± 0.59 0.09 0.87 101.17c 8.50d CV (%) 4.21 14.58 12.45 146.50ab 15.17cd Combined influence of variety and agronomic managements V1M0 7.53 de 0.02 cde 22.86 b 93.00f 7.67f V1M1 8.93 cd 0.60 bc 24.98 b 134.67cde 15.67def V1M2 8.80 cd 0.40 b-e 23.76 b 98.00f 20.00cd V1M3 12.33 ab 0.20 de 25.02 b 123.67def 36.33ab V1M4 14.00 a 0.07 e 26.37 b 143.00bcde 27.33bc V1M5 11.20 bc 0.13 e 32.52 a 135.00cde 39.33a V1M6 13.00 ab 0.13 e 25.86 b 139.33cde 35.67ab V2M0 3.67 f 0.07 e 21.99 b 109.33ef 9.33ef V2M1 7.47 de 0.40 b-e 24.39 b 158.33abcd 14.67def V2M2 5.73 ef 0.6 bc 24.31 b 153.00abcd 21.00cd V2M3 9.47 cd 0.53 bcd 24.52 b 162.67abc 16.00def V2M4 7.80 de 1.00 a 25.50 b 187.33a 18.00cde V2M5 8.60 d 0.67 ab 24.79 b 176.00ab 17.00def V2M6 8.60 d 0.53 bcd 25.02 b 182.00a 18.00cde SE ± 0.95 0.09 0.87 8.12 2.22 CV (%) 4.21 14.58 12.45 14.55 26.83 In a column mean values having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly as per 0.05 level of probability. Additional details are as Table 1. 108 Roy et al. BRRI dhan84 (V1) had a higher with averaging 10.83, while BRRI hybriddhan5 (V2) averaged at 7.33. Various agronomic practices and their interaction with different varieties caused significant differences. The highest average (10.90) from M4 (all managements except insecticides), with the least (5.60) under M0 (no management). The combined practice of BRRI dhan84 and M4 showed the highest of 14.00, but when BRRI hybriddhan5 was combined with M0, (3.65). Non-effective tillers hill–1 The number of non-effective tillers per hill at harvest also varied between BRRI dhan84 and BRRI hybriddhan5, influenced by agronomic practices and rice varieties (Table 2). BRRI hybriddhan5 (V2) recorded a higher of 0.54, in contrast to BRRI dhan84's (V1) 0.26. M4 practice led to the highest average of 0.53, while M0 resulted in the least at 0.17. The combination of BRRI dhan84 with M4 resulted in the peak count of 1.00. Conversely, BRRI hybriddhan5 combined with M0 marked the lowest at 0.07 in BRRI dhan84 combinations. Length of panicle The length of the panicle varied between BRRI dhan84 and BRRI hybriddhan5 where BRRI dhan84 (V1) had a longer panicle length of 25.91 cm, while BRRI hybriddhan5 (V2) had a shorter length of 24.36 cm (Table 2). Uzzaman et al., (2015) was also found significant differences in panicle length of 16 rice varieties under SRI. Different agronomic practices also influenced panicle length, with the longest (28.65 cm) observed under M5 and the shortest (24.03 cm) in M2 (Table 2). The longest panicle in the interaction effect of variety and agronomic management was 32.52 cm from V1M5 and the shortest (21.99 cm) from V2M0 (Table 2). Number of filled grains per panicle There was a numerical variation in the number of filled grains per panicle where BRRI hybriddhan5 (V2) had a higher (161.24), whereas BRRI dhan84 (V1) had 123.81 (Table 2). Ahmed et al., (1997) and Uzzaman et al., (2015) reported varying percentages of filled grains among different rice varieties. Agronomic practices also led to significant differences, with the highest no. (165.17) was observed under M4 and the lowest (101.17) IN M0 (Table 2). For the interaction of variety and agronomic practices, the highest and lowest counts were observed from V2M4 (174.67) and V1M0 (93.00) respectively (Table 2). Number of unfilled grains per panicle The number of unfilled grains per panicle also varied between the two varieties. BRRI dhan84 (V1) had a higher (26.00), while BRRI hybriddhan5 (V2) recorded 16.29 (Table 2). Uzzaman et al., (2015) was found significant differences in panicle length 16 rice varieties under SRI. Agronomic practices influenced this count, with the highest (28.17) observed under M5 and the lowest (8.50) in M0 (Table 2). For the interaction between variety and agronomic practices, counts ranged from a high of 39.33 (V1M5) to a low of 7.65 (V1M0) (Table 2). The highest number of unfilled grains per panicle (39.33) was noted in V1M5 (BRRI dhan84 without fungicides/bactericides) followed by V1M6 (35.67). Conversely, V1M0 (BRRI dhan84 with no management) registered the lowest (t 7.65) followed by V1M1, V2M1, V2M3, and V2M5 (Table 2). Weight of 1000- grains The weight of 1000- grains didn't show much variation between BRRI dhan84 and BRRI hybriddhan5, but there were significant differences among the various agronomic managements and their interactions (Table 3). The higher t weight for 1000 grains (26.70 g) from M6 Agronomic managements on growth and yield of boro rice 109 (recommended management), closely followed by M5, M4, and M3. The V2M6 combination (BRRI hybriddhan5 + recommended management) had the maximum 1000 -grains (31.97 g) close to V2M4(31.88 g) whereas V1M0 recorded the lightest at 20.17 g. Table 3. Effect of variety, agronomic managements, and interaction on Weight of 1000 grains (g), Grain yield (t ha–1), Straw yield (t ha–1), Biological yield (t ha–1) and Harvest index of Boro rice Treatments Weight of 1000- grains (g) Grain yield (t ha−1) Straw yield (t ha−1) Biological yield (t ha−1) Harvest index (%) Variety V1 21.71b 4.31 5.22 9.85 45.41 V2 31.10a 5.36 4.97 10.01 48.62 SE ± 1.41 0.37 0.22 0.63 5.08 CV (%) 0.33 24.69 9.31 20.64 34.99 Agronomic managements M0 25.68b 1.68b 2.22 c 3.90 c 43.02 b M1 25.70b 1.85b 4.02 bc 8.57 b 52.15 ab M2 25.88b 1.98b 4.31 bc 6.29 bc 29.52 c M3 26.01ab 6.28a 6.50 a 12.78 a 49.20 ab M4 26.14ab 6.02a 6.55 a 12.57 a 49.78 ab M5 26.57ab 6.69a 5.47 ab 12.16 a 55.16 a M6 26.70a 6.70a 6.53 a 13.23 a 50.26 ab SE ± 0.37 0.28 0.50 0.64 2.77 CV (%) 3.61 20.73 31.94 20.92 19.09 Combined influence of variety and agronomic managements V1M0 20.17d 1.00f 2.36 ef 4.35 ef 44.34 ab V1M1 23.55c 3.71cd 3.62 def 7.92 cd 53.84 a V1M2 21.60d 1.85ef 4.77 bcd 5.81 def 17.99 c V1M3 21.65d 5.53b 6.36 abc 12.52 a 49.13 ab V1M4 23.62c 5.67ab 7.37 a 13.24 a 47.41 ab V1M5 23.66c 6.05ab 5.21 bcd 11.62 ab 55.62 a V1M6 23.75c 6.34ab 6.87 ab 13.50 a 49.50 ab V2M0 30.18b 1.51ef 2.07 f 3.44 f 41.69 b V2M1 30.60ab 3.39cd 4.43 cd 9.22 bc 50.46 ab V2M2 30.16b 2.97de 3.85 def 6.78 cde 41.04 b V2M3 31.45ab 7.04ab 6.64 ab 13.04 a 49.26 ab V2M4 31.88a 6.36ab 5.74 bcd 11.90 ab 52.15 ab V2M5 31.47ab 7.33a 5.73 bcd 12.70 a 54.69 a V2M6 31.97a 7.35a 6.34 abc 12.96 a 51.02 ab SE ± 0.37 0.39 0.50 0.64 2.77 CV (%) 3.61 20.73 31.94 20.92 19.09 In a column mean values having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly as per 0.05 level of probability. Additional details are as Table 1. Grain yield The grain yield didn't show any significant differences between BRRI dhan84 and BRRI hybriddhan5 but varied significantly among the different agronomic managements and their interactions (Table 3). M6 (recommended management) yielded the highest grain yield, 6.70 t ha−1, 110 Roy et al. comparable to M5, M4, and M3 while M0 had the least yield. The combination V2M6 resulted in the highest grain yield, while V1M0 recorded the lowest. Straw yield Straw yield showed variations between BRRI dhan84 and BRRI hybriddhan5, with significant differences appearing in different agronomic managements and their interactions (Table 3). V1 (BRRI dhan84) produced a higher straw yield of 5.22 t ha−1 compared to V2 (4.97 t ha−1). The highest straw yield was recorded from M4, a management strategy without insecticides but including all other management practices. The V1M4 combination recorded the highest straw yield, while V2M0 noted the lowest. Biological yield Biological yield per hectare varied slightly between BRRI dhan84 and BRRI hybriddhan5 but showed significant changes depending on agronomic managements and interaction effects (Table 3). V2 recorded the highest biological yield of 10.01 t ha−1, followed by V1 (9.85 t ha−1). The combination V1M4 yielded the highest biological yield, whereas V2M0 had the least. Harvest index The harvest index showed significant differences based on variety, agronomic managements, and their interaction (Table 3). V2 (BRRI hybriddhan5) had the maximum harvest index (48.62%), followed by V1(45.91%). Among management strategies, M5 recorded the highest harvest index, while M2 had the lowest. When considering combinations, V1M5 produced the maximum harvest index, with V1M2 registering the minimum. Conclusion Based on the results presented, it's evident that agronomic management, the absence of fertilization, and lack of weeding have a substantial negative impact on grain yield. 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