Banani Karmakar
AAUO
Gazipur Sadar, Gazipur
Biswajit Karmakar
PSO
ARD, BRRI Gazipur
Leaf clipping, Forage yield, Grain yield, Harvest index, Vigour index.
Bangladesh Agricultural University, Mymensingh
Crop-Soil-Water Management
The experiment was conducted at the Agronomy Field and Laboratory (24°75/N latitude, 90°50/E longitude and 18 meter above from sea level) of the Bangladesh Agricultural University, Mymensingh, which belongs to the Sonatola soil series under Old Brahmaputra Floodplain (AEZ 9), characterized by medium high silty loam soil with pH 6.5 (BARC, 2012). BRRI dhan41, a high yielding modern rice variety of Aman season (wet season) developed by Bangladesh Rice Research Institute (BRRI) was used in the experiment. Four nitrogen (N) rates, N1 = 46, N2 = 69, N3 = 92, N4 = 115 kg N ha-1 and four times of leaf clipping (cutting) viz C0 = 0 (No leaf clipping), C1 = leaf clipping at 25 DAT (Days after transplanting), C2 = leaf clipping at 40 DAT, and C3 = leaf clipping at 55 DAT. In the clipping treatments, all the leaves (100%) were removed from rice plant and the leaves were cut from 12 hills selected diagonally of each plot. Experiment was laid out in split-plot design with three replications, assigning N Effect of Nitrogen Rates and Leaf Clipping on Forage and Grain Yield 51 rates in the main plots and leaf clipping times in the sub plots. Unit plot size was 3 m × 4 m. Seedbed management was done according to the traditional farm practice (BRRI, 2011). Land preparation was conducted according to the common practice of wetland soil preparation with puddling. Thirty-day-old seedlings were transplanted with 25 × 15 cm spacing using three seedlings hill-1. Fertilizers containing P, K, S and Zn were applied @ 15, 38, 10.6 and 2.7 kg ha-1, respectively using TSP, MOP, gypsum and zinc sulfate. The full amount of TSP, MOP, gypsum and zinc sulfate were applied basally during the final land preparation and incorporated into the soil. Urea fertilizer was top-dressed according to the treatments at three equal splits at 25, 40 and 55 DAT, respectively syncronyzing to immediate after every leaf clipping. Due to frequent rains occurred during cropping period, no irrigation was needed. The crop was protected from pest infestation according to standard management practices. Furadan 10G was applied at panicle initiation stage of the crop to protect from stem borer infestation. Green and dry fodder yield data were collected from 6 m2 area of each plot and converted into t ha-1. From the center of each plot, 6 m2 area was harvested for determination of grain yield when 85% of the grains appeared yellowish (IRRI, 2014). Grain yield was adjusted to 14% moisture content, and expressed in t ha-1. Yield component data were collected following recommended procedures (IRRI, 1994). Harvest index was calculated by using the following formula (Fageria et al., 2011; Karmakar and Sarkar, 2015): Grain yield Straw yield Grain yield Harvest index Germination test was conducted following the rules and procedures of ISTA (ISTA, 1976). Germinated seeds were counted on 7, 10 and 14th days after placement of seed vigour index of seedling was calculated using the following formula of Maguire (1962): Duration of first count , No. of seeds germinated at first count, Vigour Index Duration of last count, No. of seeds germinated at last count...... ? Analysis of variance was conducted using the statistical software MStatC. Mean differences among the treatments were tested using Duncan's Multiple Range Test (Gomez and Gomez, 1984).
Bangladesh Rice J. 23 (2) : 49-57, 2019
50000.00
Journal