Effect of Teesta barrage project on Aman rice production

Abstract

Although the Teesta Barrage Project (TBP) went into operation in 1993, the full scale supplementary irrigation was provided from 2000. This study was initiated to assess the impact of supplementary irrigation on the expansion of HYV Aman area and yield. The study was based on secondary data on irrigation coverage, HYV Aman area and yield (for both ‘within and outside the TBP command area’ as well as ‘before and after project period’), collected from BWDB and DAE. In order to assess the farmers’ perception about supplementary irrigation, FGDs were carried out in 5 out of 12 Upazilas of the TBP. Although the irrigated area of the TBP has been increasing steadily since 2000 and the maximum irrigated area of 76,000 ha was achieved in 2005, variability in the command area occurs from year to year mainly because of variability of monthly rainfall. The average ‘before’ project yield has increased marginally from 3.64 t/ha to 3.88 t/ha in the ‘after’ project condition. The average ‘with’ and ‘without’ project’ yields are 3.89 t/ha and 3.66 t/ha, respectively. The small increase in yield in TBP implies that the project did not have a significant impact in increasing Aman production as irrigation is one of the many inputs in rice production. Analyses of variability of yields of Aman show that the ‘with project’ variability is much less (standard deviations of 0.14 t/ha at Jaldhaka) compared to the ‘without project’ areas (0.28 and 0.27 t/ha in Diaper and Panchagarh, respectively). This signifies the TBP’s impact in stabilizing the yield within the project area. Similarly, comparison of ‘with’ and ‘without’ project standard deviation of Aman area shows that the variability is much less in ‘with project’ areas compared to ‘without project’. This implies that the TBP had contributed towards stabilizing the rain-fed Aman area with assured supplementary irrigation. There is no change in the trend of the total seasonal rainfall. Nevertheless, there is variability in monthly rainfalls that indicate the importance of supplementary irrigation from the TBP in order to stabilize the Aman yield. Supplementary irrigation had a positive impact in increasing the recharge during the Aman season, although further analysis in more areas of the project is necessary in order to reach a conclusion. In the project area, the farmers have switched from local to high yielding varieties of Aman rice. They reported yield increase and realized irrigation requirement during transplantation and reproductive stages. Nevertheless, they are reluctant to pay irrigation service charge (ISC) during the Aman season. In order to ascertain the study findings, an extensive study is necessary in each of the 12 Upazilas and Upazilas beyond the project area.