Field water use and productive efficiency of selected crops grown in the dry zone of Sri Lanka during the dry season | |
| Author | Goonasekere, Kapila Gamini Abhayawardene |
| Call Number | AIT Thesis no. 1148 |
| Subject(s) | Water conservation--Sri Lanka--Research Agricultural research--Sri Lanka |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand |
| Publisher | Asian Institute of Technology |
| Abstract | The study was conducted in the dry zone of Sri Lanka during the 1977 dry season. Chillies, soybeans and upland rice were grown on two terrace types (bench and graded terraces) and three soil drainage classes (well, imperfectly, and poorly drained) under experimental conditions. Lowland rice was studied under farmers' lowland field conditions. The objectives were to find the effect of terrace type and drainage class on yield and water use; to find the productive efficiencies (yield per mm) of water use for different terrace types and drainage classes; to determine the productive efficiencies of water used for rice under upland and lowland field conditions; to make economic evaluations of productive efficiencies under upland and lowland conditions, and to evaluate irrigation management under highland experimental and lowland field conditions. Results of the study revealed that terrace type has no effect on yield and field water use. Bench terraces had, due to levelling, soil problems which need further investigation, but they appear to be more suitable than graded terraces with respect to irrigation management during the dry season for a rice based cropping system. Drainage class has no significant effect on yield when the water table is at sufficient depth, which was the case during the 1977 dry season. There was significant difference in field water use between well drained and poorly drained soils due to reduced seepage and percolation in poorly drained soils. Productive efficiency was highest for soybeans followed by chillies and rice. But chillies had the highest net returns per unit of water used, followed by soybeans. Upland rice had negative returns per unit of water due to high labour required for irrigation and other management practices. Lowland rice field sites showed similar yields, field water use, and productive efficiencies to those of upland rice, but they had very low net returns per unit of total water supplied due to large surface wastage of water. Market prices of the crops dictated the relative profitability of crops in terms of water. The high labour requirement for irrigation management for upland crops is a critical factor to be considered in introducing upland crops in place of lowland rice during the dry season, since lowland rice requires very little labour for water management. The labory requirement for irrigation management can be reduced by increasing the irrigation interval, but further studies are necessary to find the savings in labour and water and the resultant effects on yields, benefits, productive efficiencies, and profitability. Soybeans appears to be a promising crop in place of rice during the dry season, both in terms of productive efficiency and profitability. Other upland crops should also be identified which have favorable yields, field water use, productive efficiencies and profitability. |
| Year | 1978 |
| Type | Thesis |
| School | Student Research Before 1979 |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Thesis (Year <=1979) |
| Chairperson(s) | Nielsen, Jens Moller ; |
| Examination Committee(s) | Singh, Gajendra ;Apichart Anukularmpha ; |
| Scholarship Donor(s) | Carl, Duisberg Gesellschaft (Germany) ; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1978 |