Impact of polder on agricultural water management and livelihood in the south-west region

Abstract

A comparative study was carried out to assess the agriculture along with the water management practices for crops and to understand, evaluate and compare agriculture-based livelihood in a polder and a non-polder area. The study was conducted in Batiaghata Union (in Polder 30) and Jalma Union (an adjacent non-polder area) located in Batiaghata Upazila of Khulna District. Farmers’ field study and survey were conducted for field measurements of on-farm irrigation water use for three common Rabi crops (i.e. Boro rice, sesame and mungbean) and profitability analysis for selected Rabi crops as well as Aman rice. In order to establish linkages between crop production and livelihood, Farmers’ Livelihood Security Index (FLSI) was used. Assessment of different indicators for FLSI was achieved through Focus Group Discussion (FGD) in both polder and non-polder areas. From the comparative water management analysis of the farmers, the average crop water uses for Boro rice were found to be 800 mm and 1191 mm in polder and non-polder area, respectively. The average water use in non-polder area exceeded the potential water requirement of 836 mm. The number of irrigation varied from 14 to 15 in polder and 16 to 17 in the non-polder area. The average yields were 3.92 t/ha in polder and 4.51 t/ha in non-polder area. This lower yield in polder area might be attributed to less availability of irrigation water and more salinity found in the canal water used for irrigation in the fields. The field water uses of sesame were found to be 95 mm and 69 mm in polder and non-polder area, respectively, which were less than the potential requirement of 265 mm. None of the farmers applied irrigation. The average yields of sesame were more or less the same (0.68 t/ha and 0.74 t/ha in polder and non-polder area, respectively), but about half of the average yield obtained by BARI (1.38 t/ha). This lower seed yields might be because of encountering moderate rainfall in late season which resulted in seed damage. The field water uses of mungbean were found to be 56 mm (with 2 irrigations) in polder and 42 mm (with 1 irrigation) in the non-polder area, which were less than the estimated water requirement of 162 mm. The yields were found to be 0.96 t/ha and 0.57 t/ha in polder and the non-polder area, respectively, compared to average yield obtained by BARI (1.8 t/ha). In the non-polder area, the lower yield than in the polder area might be due to the lower application of irrigation water as well as the higher salinity in irrigation water. From profitability analysis, the Benefit-Cost Ratio (BCR) of Boro rice in non-polder area (2.58) was higher than that in polder area (1.92). The BCR of sesame in polder and non-polder area were almost the same (1.54 to 1.55). The BCR of mungbean in polder area (1.2) was slightly higher than that in non-polder area (1.05). The average yields of Aman rice in polder (2.25 t/ha) was much higher than that in non-polder area (1.74 t/ha). The BCR of Aman rice was also much higher in polder area (3.2) than that in non-polder area (1.64). This higher yield and BCR of Aman rice in polder area might be attributed to seasonal flood protection and better water control by the polder. From the livelihood analysis, the highest livelihood security level was found for mungbean producing farmers in both polder (64%) and non-polder area (55%), whereas the lowest security level was measured for Boro rice (24%) in polder area due to less availability of fresh water for irrigation and sesame (41%) in non-polder area due to seed damage during rainfall in late season. For Aman rice, the livelihood security of the farmers in polder area (61%) was found to be much higher than that in the non-polder area (47%) due to flood protection and water control provided by the polder. It was evident from the FGDs that most of the farmers in the non-polder area were interested in being inside the polder for better protection of crops due to polder water management.