2.1. Experimental Site Characteristics Te trial was conducted at the Agriculture Field Laboratory, Noakhali Science and Technology University, Noakhali from February to April 2018. Geographically, the experimental field was located at 24o 75′ latitude and 90o 50′ longitude at a mean altitude of 18 m above the sea level within AEZ (Agro-Ecological Zone) 18, i.e., the Young Meghna Estuarine Floodplain. The soil type is loam with organic matter (0.68%), total nitrogen of 0.04 g kg−1, available P of 27.79 µg g−1, and available K of 0.18 mEq/100 g soil, and pH 7.5. Te soil indexes were determined before fertilization. The experimental area is under the tropical climate and it has considerable rainfall most months with a short dry season. The average annual temperature is 25.6 oC and the average annual rainfall is approximately 3,302 mm. 2.2. Experimental Design and Treatments Te experiment were laid out in a randomized complete block design with three replications. Five levels of phosphorus in the form of triple superphosphate (T1 to T5; 0, 42.5, 85, 127.5, and 170 kg ha−1, respectively) and two varieties of mungbean, BARI Mung-5 (V1) and BARI Mung-6 (V2), were used with a plot size of 3 m × 2 m, having an area of 6 m2. There were 10 treatment combinations. There were three replications for individual treatment combinations because each different fertilizer dose treatment was considered one experiment. Each of the replications represented a block in the experiment. Ten treatment combinations were randomly assigned in each replication. Thus, the total number of unit plots was 30 (2 × 5 × 3) for this experiment. A spacing of 1.0 m and 0.5 m was maintained in between the replications and unit plots, respectively. 2.3. Seed Germination Te collected seeds were soaked in water for 24 hr before planting for sprouting. The seed started sprouting after 35 hr and almost all seeds had sprouted after 40 hr. Te sprouted seeds were ready to sow. This method is effective for seed vigor, helps to break dormancy, and increases germination percentages. 2.4. Fertigation Te entire granular phosphorus fertilizer (according to treatment) was broadcasted at the time of land preparation. 2.5. Sampling and Harvesting The crops were harvested at full maturity. Diferent varieties matured in diferent dates. Generally, mungbean started to ripen after April 17, 2018. The date of harvesting was confirmed when 90% of the pods became black in color and 10 plants were selected randomly from each unit plot and uprooted before harvesting for recording data. Ten, the required data were recorded on April 23, 2018. After that, the total yield of each plot for the two varieties was also recorded. 2.6. Growth and Yield Parameters Experimental plants (n = 10) were randomly selected soon after maturation and marked with bamboo sticks in each plot excluding the border rows for determining growth parameters as well as yield and yield components. Te yield parameters were recorded individually for each plant. After that, the total yield per plot was also recorded and 1,000 seeds were weighed (grams) for the two varieties. The data were collected on April 23, 2018.
2.6.1. Plant Height Te plant height was measured using a measuring tape from the ground level to the top. The heights of 10 plants were measured randomly from each plot. This was done at the ripening stage of the crop. 2.6.2. Number of Pods per Plant At the ripening stage, pods were counted. Pods of 10 randomly selected plants from each plot were counted and averaged. 2.6.3. Pod Length Lengths of pods of 10 plants from each plot were measured randomly. Ten, they were averaged after harvesting. 2.6.4. The number of Seeds per Pod Tis was measured after harvesting. First, the number of seeds per pod was counted. Ten, the number of seeds from 10 random plant pods from each plot were counted and averaged. 2.6.5. Thousand-Seed Weight Thousand seeds of mungbean were counted randomly and then weighed plot-wise. 2.6.6. Seed Yield Seeds obtained from different plots were dried properly. After that, they were weighed carefully and converted into t ha−1.
Statistical Analyses Data recorded for growth parameters, yield, and yield contributing characteristics were compiled and tabulated in a proper form for statistical analysis. Analysis of variance was performed using MSTAT-C. The mean differences among the treatments were determined using Duncan’s new multiple range tests (Gomez & Gomez, 1984; Reddy & Swamy, 2000).