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Title of Thesis  
DEVELOPMENT OF IRRIGATION SCHEDULING FOR WHEAT AND COTTON CROPS  
Author(s)  
MD. SALIM ULLAH KHAN EUSUFZAI  
Institute/University/Department Details  
Sindh Agriculture University, Tandojam / Irrigation And Drainage  
Status (Published/ Not Published/ In Press etc)  
Published  
Date of Publishing  
November 27, 1999  
Subject  
IRRIGATION  
Number of Pages  
296  
   
Keywords (Extracted from title, table of contents and abstract of thesis)  

Irrigation scheduling Wheat Cotton crops Water Water resource Crop growth Water stress Numerical model Calcarious clay NIAB 78 TJ 83 Grain maturity Optimum water Deficit irrigation Over irrigation IC42 IC63 IC105 Treatment IC0 IC55c IC28f WUE Evapotranspiration Stress day index SWAP93 Depth of irrigation Soil moisture regime Soil profile Water flow models Irrigation scheduling models

 

 

 
Abstract  

Water a finite and vulnerable resource of Pakistan is an essential component of ainable agriculture. Its judicial use and scheduling are the important elements for best zation of the limited water resource for successful irrigated agriculture. To achieve high use efficiency of the available water resource and to assess the sensitivity of crop growth to water stress various irrigation schedule of wheat and cotton crops were tested by ucting field experiments supported by one dimensional transient numerical model study numerical model study greatly reduced the field trials which otherwise were impractical tested in the field due to large requirements of space labor and expenses. Field experiments were conducted on calcarious clay soil located at Agriculture earch Institute. Tandojam Sindh during Rabi 1995 96 1996 97 and 1997 98 and Kharif 7 to quantify the effects of different irrigation treatments on wheat ( variety TJ 83 ) and on ( variety NIAB – 78 ) for the development of irrigation schedules for wheat and cotton crops. The results of wheat revealed that the early growth periods ( crown root initiation and ring stages ) were the most sensitive to dry stress followed by milky and booting statges ting significantly ( 14 to 17 % ) lower yield than that of full six irrigation. The dry stress osed at grain maturity stage resulted similar grain yield response as that of fuul irrigation cating that for normal wheat growth five irrigations were sufficient for maximum crop uction and optimum water use efficiency than recommended six irrigations. Both the cit irrigation and over irrigations reduced grain yield by almost 8 % of the full irrigation were not significantly different. Irrigaion applied at 38 % of the available water capac did not respond well and produced significantly 15 % lower yield than full irrigation. gation frequency of 14 days showed 8 % lower yield than full irrigation frequency of 21 days they were not significantly different. The maximum WUE was under IW126 (grain matu stage ) and the minimum WUE was achieved under over irrigation treatment ( WI01). The results of cotton experiment showed that water stress at all the three crop growth es of cotton ( IC42 IC63 and IC105 ) were detrimental to seed cotton yield resulted significantly 14 to 21 % lower yield than full six irrigations ( treatment IC10). Irrigation based on soil moisture depletion (IC55c ) produced maximum seed cotton yield and was significantly lower seed cotton yield than IC10 treatment . Over irrigation treatment IC10 performed ally well as IC0 treatment. The WUE was the maximum under deficit irrigation ment followed full irrigation treatment. A maximum WUE was achieved under 55 % moisture depletion treatment. Based on the results of water stress treatment and stress day concept a direct tionship between relative evapotranspiration and relative yields and an inverse tionships between stress day index and relative yields of wheat and cotton were eloped using simple regression analysis. The results of all irrigation treatments yielded bolic relationship of leaching fraction and relative yield. Suitable irrigation schedules wheat and cotton were developed based on stress day index concept which allowed 6.6 8.7 10.1 and 6.9 cm irrigation depths during the respective growth period of wheat and 6.25 6.25 7.04 8.04 and 11.27 cm irrigation depths during the respective growth ods of cotton. The SWAP 93 model was calibrated against the response of full irrigation treatments in eat and cotton during the periods of Rabi 1996 97 and Kharif 1997. It was then validated mst the response of other treatments during Rabi 1995 96 1996 97 and 1997 98 and Kharif 7. The SWAP 93 model performed reasonably well in describing the behaviour of the erent irrigation regimes imposed to wheat and cotton crops. The simulations of irrigation agement alternatives for wheat and cotton indicated that the number of irrigation lications time of application irrigation frequency and depth of irrigation greatly influenced soil moisture regime of the soil profile and subsequent changes in relative potranspiration and yield. Two irrigations applied at tillering and booting stages produced maximum relative garin yield of 59 % compared to the reference treatment. Three irrigations lied at tillering booting and heading stages achieved 79% grain yield of the reference. Four ations applied at crown root initiation tillering and booting stages produced maximum relative grain yield of 59 % compared to the reference treatment. Three irrigations lied at tillering booting and heading stages achieved 79% grain yield of the reference. Four gations applied at crown root initiation tillering booting and heading stages produced 92% n yield of the reference. Five irrigations applied at crown root initiation booting ding and milky stages produced relatively same yield as refernce. The minimum seed cotton yield reduction of 33 % occurred when four irrigations were lied at 42 63 84 and 105 days after sowing. On the other h and five irrigations applied at 42 63 84 and 105 days after sowing reduced the minimum seed cotton yield of 14 % of the rence. The increase in irrigation frequency increased the relative evapotranspiration for both at and cotton crops. The relative evapotranspiration for cotton was considerably lower than wheat and experienced lower deep percolation. The irrigation frequency of seven days ieved the maximum relative yield of both wheat and cotton crops. Under high irrigation frequency of 14 days over irrigation by 25% showed better performance for both wheat and on than under irrigation by 25% . Under irrigation and over irrigation showed more onunced difference in relative yield of cotton than wheat crop.  

 
   
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Sr.No Chapter TABLE OF CONTENTS i 180.kbs
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1 1

INTRODUCTION

2
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2 2 REVIEW OF LITERATURE 09
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3 3 MATERIALS AND METHODS 57
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4 4 RESULTS AND DISCUSSION 88
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5 5 SUMMARY AND CONCLUSION 204
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6 6 REFERENCES 215
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7 7 APPENDIX "A" 230
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8 8 APPENDIX "B" 233
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9 9 APPENDIX "C" 241
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