LIST OF ABBRIVIATIONS
3.1 Location of experimental sites and weather parameters
Location of experimental sites and weather parameters are presented in appendix I.
3.1.1 Location of experimental sites
The location is presented in appendix 1 a. The present investigation was conducted both at SAU, Dhaka and on farm at Shahpur, Charghat, Rajshahi during rabi season 2016-17 for experiment 4 and 5 and 1, 2 & 3 experiment started from 2013-14, 2014-15 and 2015- 16.
SAU is located on 23074/N latitude and 90035/E longitude with an elevation of 8.2 meter from sea level while that of the Rajshahi 240 3' N latitude and 380 2' E longitude with a height of 18 m above the sea level (Appendix I a). Geographical location has been shown in appendix 1 b.
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3.1.2 Weather data
The weather parameters are presented in appendix II. Bangladesh has a subtropical monsoon climate characterized by wide seasonal variations in rainfall, high temperatures and humidity. There are three distinct seasons in Bangladesh: a hot, humid summer from March to June; a cool, rainy monsoon season from June to October; and a cool, dry winter from October to March. In general, maximum summer temperatures range between 30°C and 40°C. April is the warmest month in most parts of the country. January is the coldest month, when the average temperature for most of the country is about 10°C.
Temperature
Average temperature in Bangladesh was showed in appendix 1. (b). Temperature in Bangladesh decreased to 18.440C in December from 23.080C in November of 2015.
Temperature increased in every year in Bangladesh due to its climate changes and averaged temperature 24.820C and reaching an all time high of 32.790C in May and a record low of 14.790C in January (Appendix II).
Maximum and minimum temperature
Growing period maximum and minimum temperature was showed in appendix I b. for Rajshahi. It was estimated that the lowest average minimum temperature happens in January (3.4°C) which continue to increase from this month of March reaching the highest (42.8°C) in May and starts decreasing from June. Maximum average temperature was also found in higher in the month of May (42.5°C) which continue to decrease up to the month of October and the lowest average maximum temperature (12.3°C) was also found in January and again increase from the month of March and up to the month of May. But the growing season of wheat from November to March in our country that time the average maximum temperature were 5.3-35.7°C in Rajshahi.
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Growing period maximum and minimum temperature was showed in appendix table II in SAU, Dhaka. It was estimated that the lowest average minimum temperature happens in January (13.4°C) which continue to increase from this month of March reaching the highest (32.4°C) in May and starts decreasing from June. Maximum average temperature was also found in higher in the month of May (38.5°C) which continue to decrease up to the month of October and the lowest average maximum temperature (18.3°C) was also found in January and again increase from the month of March and up to the month of May. But the growing season of wheat from November to March in SAU that time the average maximum temperature were 15.3-32.7°C in SAU, Dhaka which hampers on wheat growing season.
Rainfall
Heavy rainfall is characteristic of Bangladesh (appendix I c). With the exception of the relatively dry western region of Rajshahi, where the annual rainfall is about 1600 mm, most parts of the country receive at least 2000 mm of rainfall per year. Because of its location just south of the foothills of the Himalayas, where monsoon winds turn west and northwest, the regions in northeastern Bangladesh receives the greatest average precipitation, sometimes over 4000 mm per year. About 80 percent of Bangladesh's rain falls during the monsoon season.
Growing period average rainfall showed in appendix 1(c) and 1 (j) which was under the subtropical climate and its climatic conditions is characterized by three distinct seasons, namely winter season from the month of November to February and the pre-monsoon period or hot season from the month of March to April and monsoon period from the month of May to October. The average annual rainfall was about 800-950 mm in Rajshahi where as average annual rainfall was 1200-1800 mm in SAU, Dhaka which was received during the monsoon period from July to September in both the location and it was uneven distribution in all the years. However a few showers were received during winter season also.
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Monthly sunshine hours
The average maximum and minimum monthly bright sunshine hours showed in appendix 1 d). The sunshine hour‘s duration were recorded 5.8 to 9.4 hrs; respectively during the period of investigation in both the location but maximum sun shine hours occurs in Rajshahi over Dhaka to its longitudinal effect and it increase wheat yield in Rajshahi than Dhaka
Relative humidity
The weekly maximum relative humidity showed in appendix 1 (e) which ranges from 55 to 94% and weekly minimum relative humidity varied from 52 to 86% during the period of experimentation in both the location but it was higher in Dhaka than Rajshahi. As a results, yield was increased in Rajshahi over in Dhaka.
Solar radiation
The average solar radiation showed in appendix 1 (f) which was mostly occurs in December to February was maximum in Rajshahi and January to February was maximum in Dhaka but solar radiation was higher in Rajshahi than Dhaka. As a results, maximum yield was also higher in Rajshahi over Dhaka.
3.1.3 Soil characteristics
Soil characteristics of the Rajshahi and SAU site have been presented in appendix IV, V and VI. The soil belongs to ―The Modhupur Tract‖, AEZ-28 (FAO, 1988). Top soil was silty clay in texture, olive-gray with common fine to medium distinct dark yellowish brown mottles. Soil pH was 6.2 and had organic carbon 0.45%. The experimental area
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was flat having available irrigation and drainage system and above flood level. The selected plot was medium high land.
The farm belongs to the General soil type, Shallow Red Brown Terrace Soils under Tejgaon Series. Top soils were clay loam in texture, olive-gray with common fine to medium distinct dark yellowish brown mottles. The experimental area was flat having available irrigation and drainage system. The land was above flood level and sufficient sunshine was available during the experimental period. Soil samples from 0-15 cm depths were collected from experimental field. The analyses were done by Soil Resources and Development Institute (SRDI), Dhaka. The physicochemical properties of the soil are presented in AppendixV.