Scheduling Irrigation & Estimating consequent Yield Response
Presentation Presentation by by Anup Anup Kr Kr Srivastava, Srivastava, Director, Director, NWA NWA
Scheduling Irrigation & Estimating consequent Yield Response Structure Structure of of the the Presentation Presentation •• To To showcase showcase aa comparison comparison between between Modified Modified Penman Penman and and Penman Penman Monteith Monteith methods, methods, & & •• To To highlight highlight application application of of CROPWAT CROPWAT & & WEAP WEAP software software in in determination determination of of Water Water Requirement Requirement for for aa crop crop during during its its life life span, span, and and fixing fixing irrigation irrigation scheduling scheduling in in order order to to maximize maximize harvest; harvest; •• Single Single crop crop coefficient coefficient vs. vs. Dual Dual crop crop coefficient coefficient approach approach to to Is Is there there any any soft-tool soft-tool to to finish finish this this task task rapidly rapidly ??
Study Study in in WEAP WEAP software software
Penman-Monteith Penman-Monteith Method Method by by CROPWAT CROPWAT 8.0 8.0 software software
ETo ETo Estimation Estimation by byPenman-Monteith Penman-Monteith Method Method WEAP WEAP software software
Penman-Monteith Penman-Monteith Method Method by by CROPWAT CROPWAT 8.0 8.0 software software
COMPUTATION OF ETc ETc ETc equals equals the the product product of of ETo ETo and and Kc, Kc, the the crop crop coefficient, coefficient, ie, ie, ETc ETc == ETo ETo ** Kc Kc
Outline of Dual Crop Coefficient method
ETc = ETo * Kc • In this approach, Kc is split into two parts: ETc = ETo * (Kcb + Ke) ETc = Ke * ETo
+ Kcb * ETo
= Evaporation + Transpiration
Outline of Dual Crop Coefficient method
Outline of Dual Crop Coefficient method
IRRIGATION SCHEDULING BY CROPWAT 8.0
IRRIGATION SCHEDULING BY CROPWAT 8.0
IRRIGATION SCHEDULING in WEAP
IRRIGATION SCHEDULING in WEAP
IRRIGATION SCHEDULING in WEAP
In Conclusion ••Both Both Modified Modified Penman Penman and and FAO’s FAO’s recommended recommended Penman Penman Monteith Monteith methods methods agree agree closely closely during during rainless rainless period period but but disagree disagree for for rest rest of of the the period. period. More More studies, studies, in in different different part part of of the the countries, countries, are are needed needed to to generalize generalize this this pattern; pattern; ••For For wheat wheat crop, crop, in in his his study, study, single single crop crop coefficient coefficient approach approach recommends recommends five five irrigations, irrigations, while while dual dual crop crop coefficient coefficient concept concept suggests suggests four four irrigations. irrigations. Total Total volume volume of of irrigation; irrigation; ••Volume Volume of of water water required required to to meet meet crop crop water water requirement requirement is is now now assessed assessed at at around around 380mm 380mm as as against against 454mm 454mm obtained obtained with with application application of of single single crop crop coefficient coefficient method. method.
References: • ftp://ftp.fao.org/agl/aglw/docs/ •User, and Reference Manual of CROPWAT 8.0 software • www.weap21.org/ • http://www.fao.org/nr/water/inforesdatabasescropwat.html
THANKS