Estimation and evaluation of effective rainfall by water balance method in lowland paddy fields | |
| Author | Rath, Bisweswar |
| Call Number | AIT Thesis no. AE-88-05 |
| Subject(s) | Water balance (Hydrology) Rice--Planting |
| Note | A Thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The water balance model has been modified and used in this study for the estimation of effective rainfall for lowland paddy. The component of interception is included in the water balance and considered as a part of effective rainfall. The relationship of interception to rainfall at three growth stages is e stablished by the help of fie ld experiments and utilized in the simulation. Eight rainfall stations in Thailand were selected for analysis whose rainfall records for the last 30 years are available . Simulation was run with computed crop water requirement and various values of percolation rate, ponding depth and irrigation interval to study their effects on effective rainfall, irrigation requirement and number of irrigation practice . It is found that 15 cm ponding depth and 3/4 days irrigation interval is most suitable for lowland rice from effective rainfall and efficient irrigation point of view . The results of effective rain when plotted against actual rainfall, revealed logarithmic relationship. It is also attempted to study the effect of irrigation management practices on effective rainfall like intermittent irrigation and rotational irrigation . But it is observed that the effect of irrigation management practice on effective rainfall is negligible. Attempt has been made to reflect t h e effects of major variables through a nomogram which can be also used in estimating effective rainfall at certain farming condition. Rainfall analysis is done to study the characteristics of rainfall and to predict effective rainfall at different frequency scales. Polya & Eggenberger distribution is applied for the analysis of continuous dry days. The two programmes developed for simulation and rainfall analysis are in FORTRAN 77 and were run in IBM3083. |
| Year | 1988 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Mizutani, Masakazu |
| Examination Committee(s) | Loof, Rainer ;Nielsen, Steen Asger |
| Scholarship Donor(s) | The Government of Switzerland. |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1988 |