The experiment was conducted at the Crop Physiology and Ecology Field Laboratory, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh during the period from November, 2015 to April, 2016. The experimental field was a medium high land sandy loam textured soil belonging to agro-ecological zone-1 (AEZ-1). The pH of the soil was 6.1. The experimental site was located at 25038/ N and 88041/ E longitude and at the elevation of 34.5 m above the sea level. The experiment was laid out in a split-split plot design with 3 replications. The irrigations were assigned in the main plots, date of sowing was in the sub plot and the barley variety was assigned in the sub–sub plots. The unit plot size was 2.5 m X 2 m having a plot to plot distance of o.5 m. The treatments included three sets of factors. Factor A. Irrigations: i) No irrigation (control) - I 0 ii) One irrigation (30 mm) (25 DAS i.e., at the tillering stage) - I 1 iii) Two irrigations (30+30 =60 mm) (25 and 45 DAS i.e., one at the tillering stage and another at the booting stage) - I2 iv) Three irrigations (30+30+30 =90 mm) (25, 45 and 65 DAS i.e., one at the tillering stage, one at the booting stage and one at the grain filling stage)- I3. Factor B. Date of sowing: i) 1 November(S1) ii) 16 November(S2) iii) 1 December(S3) iv) 16 December(S4) and factor C. Barley variety: i) BARI Barley 5 (Hulled) ii) BARI Barley 6 (Hull-less). The land was fertilized with 180 kg urea,125 kg TSP, 100 kg MP and 100 kg Gypsum per hectare and cowdung at the rate of 5t/ha (BARC 1997).
Determination of soil moisture: Soil samples were collected from each plot with an auger up to 1 meter depth of soil for determining soil moisture content before sowing and after harvest of the crop. Soil moisture was determined gravimetrically up to l m depth of soil profile from 5 soil layers (0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm and 80-100 cm) before sowing of seeds and at the final harvest with the help of an auger.
To study the growth pattern, total dry matter production (TDM), crop growth rate(CGR),leaf area index(LAI) and net assimilation rate(NAR) were determined during different growth period by using standard methods (Radford,1965).
YIELD AND YIELD COMPONENTS At the time of harvesting, 5 random plants were used for recording data on yield attributes. The experimental plots were harvested separately at full maturity. The central 5 rows of crops were harvested for collecting data on yield. Harvest index(HI) and water use efficiency were calculated as follows. Harvest index was calculated by dividing economic yield by biological yield of the plant in each plot and by multiplying with 100 and expressed in percentage.
Harvest index (%) = Economic yield / Biological yield x 100
Water use efficiency (WUE): Water use efficiency was calculated as follows-
WUE = Grain yield (kg/ha) / Cosumptive use of water (mm) x 100
Statistical analysis: All the necessary parameters recorded were analyzed statistically. A program called Microsoft Excel 2000 was used for the spreadsheet analysis and numerical calculations. All the recorded data were statistically analyzed following the ANOVA technique and the significance of mean differences were adjusted by Duncan's New Multiple Range Test, DMRT (Gomez and Gomez 1984) with the help of computer package M-STAT.