Effect of age of seedlings on the performance of drought tolerant Aman rice cultivars

An experiment was conducted at the Field Laboratory of the Department of Agriculture, Noakhali Science and Technology University (NSTU), Sonapur, Noakhali, from July 2017 to December 2017 to study the effect of variety and age of seedling on yield performance of drought tolerant transplant aman rice. The experiment consisted of three varieties viz. BINA dhan7, BRRI dhan56 and BRRI dhan71 and five different ages of seedling viz.15 days old, 20 days old, 25 days old, 30 days old, and 35 days old. The experimental design was randomized complete block design (RCBD) with three replications. Among the three varieties, BRRI dhan71 produced the highest grain yield (5.567 t ha-1) and the lowest grain yield (4.975 t ha-1) was obtained from BRRI dhan56. Among the five ages of seedlings, the highest grain yield (5.502 t ha-1) was obtained from 35 days old seedling and the lowest grain yield (5.092 t ha-1) was obtained from 15 days old seedling. In case of interaction between variety and spacing, the highest grain yield (5.723 t ha-1) was obtained from BRRI dhan71 with 35 days old seedling and the lowest (4.730 t ha-1) was obtained from BRRI dhan56 with 15 days old seedling. The result reveals that relatively older seedlings (35-days old) produce higher grain yield compared to the younger ones

Effect of nitrogen fertilizer and weed management on the yield of transplant aman rice

The research work was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during aman season from July to December 2015 to study the effect of nitrogen fertilizer and weed management on the growth and yield of transplant aman rice cv. BRRI dhan46. The experiment consisted of four fertilizer treatments viz. 0 kg N ha−1 (N0), 40 kg N ha−1(N1), 80 kg N ha−1(N2) and 120 kg N ha−1(N3) and four weeding treatments viz. one hand weeding at 20 DAT (W1), two hand weedings at 20 and 35 DAT (W2), three hand weedings at 20, 35 and 50 DAT (W3), weeding by Japanese rice weeder twice at 20 and 35 DAT (W4) and unweeded control (W5). The experiment was laid out in the randomized complete block design with three replications. The highest plant height (113.00 cm), number of total tillers hill−1 (8.74), number of effective tillers hill−1 (6.18), panicle length (21.98 cm), number of grains panicle−1 (114.20), grain yield (4.00 t ha−1), straw yield (5.25 t ha−1) and biological yield (9.25 t ha−1) were recorded in N2 (80 kg N ha−1) treatment. The lowest plant height (106.00 cm), number of total tillers hill-1 (7.20), number of effective tillers hill−1 (5.00), panicle length (20.70 cm), number of grains panicle−1 (97.60), grain yield (3.52 t ha−1), straw yield (4.46 t ha−1) and biological yield (7.97 t ha−1) were recorded from N0 (No nitrogen fertilizer control) treatment. On the other hand, the highest grain yield 4.23 t ha−1 was observed in three weedings condition because of the highest number of effective tillers hill−1 (6.81), number of grains panicle−1(111.10). The highest straw yield (5.51 t ha−1) was also found in three weeding condition. The lowest grain yield (3.40 t ha−1) was recorded in W5 (unweeded control) treatment. The lowest straw yield (4.31 t ha−1) was also observed in W5 (unweeded control) treatment because of the smallest plant (106.97 cm) and lower number of total tillers hill−1 (7.20). Therefore, 80 kg N ha−1along with three hand weedings at 20, 35 and 50 DAT may be used for obtaining the highest grain and straw yields of BRRI dhan4

Evaluation of the Allelopathic Activity of Albizia procera (Roxb.) Benth. as a Potential Source of Bioherbicide to Control Weeds

Agricultural production depends heavily on the application of synthetic herbicides. Using these herbicides results in the development of herbicide-resistant weeds, poses hazards to human and animal health, and pollutes the environment. To solve these problems, developing and using bioherbicides must be increased. Although different uses of Albizia procera have been well reported, its allelopathic activity against weeds and crop species has not. Hence, we evaluated the allelopathic activity of the A. procera plant and isolated its allelopathic compounds. Extracts of A. procera significantly suppressed the seedling growth of the tested species (cabbage, alfalfa, lettuce, barnyard grass, timothy, and Italian ryegrass). The seedling growth decreased with increasing extract concentrations. The concentrations required for 50% growth inhibition (I50 value) of the tested plants were 0.0225–0.4935 mg/mL. The A. procera extracts were separated using different column chromatography, and two active fractions (AP-5 and AP-7) were isolated. Cress seedling growth was completely restricted by fraction AP-5, and fraction AP-7 restricted the cress shoots to 83.10% and roots to 85.65% of the control treatment. The findings of this study indicate that A. procera extracts have allelopathic activity and these fractions might contribute to the activity

Evaluation of the Allelopathic Activity of <em>Albizia procera</em> (Roxb.) Benth. as a Potential Source of Bioherbicide to Control Weeds

Agricultural production depends heavily on the application of synthetic herbicides. Using these herbicides results in the development of herbicide-resistant weeds, poses hazards to human and animal health, and pollutes the environment. To solve these problems, developing and using bioherbicides must be increased. Although different uses of Albizia procera have been well reported, its allelopathic activity against weeds and crop species has not. Hence, we evaluated the allelopathic activity of the A. procera plant and isolated its allelopathic compounds. Extracts of A. procera significantly suppressed the seedling growth of the tested species (cabbage, alfalfa, lettuce, barnyard grass, timothy, and Italian ryegrass). The seedling growth decreased with increasing extract concentrations. The concentrations required for 50% growth inhibition (I50 value) of the tested plants were 0.0225–0.4935 mg/mL. The A. procera extracts were separated using different column chromatography, and two active fractions (AP-5 and AP-7) were isolated. Cress seedling growth was completely restricted by fraction AP-5, and fraction AP-7 restricted the cress shoots to 83.10% and roots to 85.65% of the control treatment. The findings of this study indicate that A. procera extracts have allelopathic activity and these fractions might contribute to the activity

Response of Transplant Aman Rice Varieties to Planting Spacing

The experiment was conducted at the Field Laboratory of the Department of Agriculture, Noakhali Science and Technology University (NSTU), Sonapur, Noakhali, during July 2017 to December 2017 to study the effect of variety and spacing on yield performance of transplant aman rice. The experiment consisted of three varieties viz. BINA dhan7, BRRI dhan56 and BRRI dhan71 and four spacings viz. 25 cm × 15 cm, 25 cm × 10 cm, 20 cm × 15 cm and 20 cm × 10 cm. The experiment was laid out in a randomized complete block design (RCBD) with three replications. In case of variety, the highest grain yield (4.502 t ha-1) was obtained from BRRI dhan71 and the lowest grain yield (4.313 t ha-1) was obtained from BINA dhan7. In case of spacing, the highest grain yield (4.701 t ha-1) was obtained from 20 cm × 10 cm spacing and the lowest grain yield (4.146 t ha-1) was obtained from 25 cm × 10 cm spacing. In case of interaction between variety and spacing, the highest grain yield (4.850 t ha-1) was obtained from the interaction of BRRI dhan71 at 20 cm × 10 cm spacing and the lowest grain yield (3.963 t ha-1) was from BINA dhan7 at 20 cm × 15 cm spacing. The study also found that among all three varieties and four spacings used in this experiment, grain yield were not significantly influenced by the interaction of variety and spacing. [Fundam Appl Agric 2018; 3(3.000): 531-536

Exploring the possibility of using Agroplus Biodecomposer for boosting up rice productivity under Bangladesh condition

Over dependence on chemical fertilizers is a threat to the sustainability of rice ecosystem. Application of organic and biofertilizers might reduce reliance on chemical fertilizers and thus can play a vital role to boost up rice productivity in an eco-friendly way. An experiment was conducted at Mymensingh (24&#xb0;10'0'' N latitude and 90&#xb0;25'0" E longitude at 15 m above the sea level), Bangladesh during November 2015 to April 2016 to evaluate the effect of different dosages of Agroplus Biodecomposer, an organic biofertilizer containing Streptomycetes bacteria, on the growth and yield performance of some rice. The experiment included four winter rice varieties viz. (i) Hybrid rice Hira and (ii) Hybrid rice Tej (iii) BRRI dhan28 and (iv) BRRI dhan29; and four concentrations of Agroplus Biodecomposer viz. (i) no Agroplus Biodecomposer (Control), (ii) 2% Agroplus Biodecomposer (iii) 3% Agroplus Biodecomposer and (iv) 4% Agroplus Biodecomposer. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Agroplus Biodecomposer positively influenced growth and productivity of winter rice. It was evident that both plant height and tillering ability of winter rice were increased gradually with increased concentration of Agroplus Biodecomposer at all the growth stages of rice. All the yield contributing characters of rice were enhanced due to Agroplus Biodecomposer application which resulted in increased grain yield. Compared to control, rice grain yield was increased by 14, 20 and 28%, respectively due to application of Agroplus Biodecomposer at 2, 3 and 4% concentration. Rice variety also differed significantly in terms of growth and yield performance among themselves. Hybrid varieties performed better than inbred ones. Hybrid variety Hira appeared as the best performer followed by another hybrid Tej. Hybrid variety Hira interacted favorably with 4% Agroplus Biodecomposer to produce the highest grain yield of rice (7 t ha-1). Therefore, biofertilizer Agroplus Biodecomposer can be introduced to Bangladesh and foliar spray with 4% Agroplus Biodecomposer at 30, 45 and 60 DAT can be recommended for boosting up winter rice yield in a sustainable way. [Fundam Appl Agric 2018; 3(1.000): 372-381

Phytotoxic Activity and Identification of Phytotoxic Substances from Schumannianthus dichotomus

The phytotoxic potential of plants and their constituents against other plants is being increasingly investigated as a possible alternative to synthetic herbicides to control weeds in crop fields. In this study, we explored the phytotoxicity and phytotoxic substances of Schumannianthus dichotomus, a perennial wetland shrub native to Bangladesh, India, and Myanmar. Leaf extracts of S. dichotomus exerted strong phytotoxicity against two dicot species, alfalfa and cress, and two monocot species, barnyard grass and Italian ryegrass. A bioassay-driven purification process yielded two phenolic derivatives, syringic acid and methyl syringate. Both constituents significantly inhibited the growth of cress and Italian ryegrass in a concentration-dependent manner. The concentrations required for 50% growth inhibition (I50 value) of the shoot and root growth of cress were 75.8 and 61.3 &mu;M, respectively, for syringic acid, compared with 43.2 and 31.5 &mu;M, respectively, for methyl syringate. Similarly, to suppress the shoot and root growth of Italian rye grass, a greater amount of syringic acid (I50 = 213.7 and 175.9 &mu;M) was needed than methyl syringate (I50 = 140.4 to 130.8 &mu;M). Methyl syringate showed higher phytotoxic potential than syringic acid, and cress showed higher sensitivity to both substances. This study is the first to report on the phytotoxic potential of S. dichotomus and to identify phytotoxic substances from this plant material