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Drip-irrigation can improve uniformity in water distribution, water use efficiency, and crop productivity in the saline and nonsaline regions of South Asia and in Bangladesh where the availability and quality of water resources are scare for sustainable crop production. However, the currently available drip-irrigation systems (DIS) have limitations especially in the design and field performance of emitters. A new type of emitter with low pressure (gravity) was developed, installed and evaluated using the locally produced materials in two locations (nonsaline and saline zones) of Bangladesh. The emitter discharge rate was measured for the variable operating heads of 1.5, 2, and 2.5 meter (m) with 0%, 1%, and 1.5% slopes with eggplant (Solanum melongena L.), a commonly grown vegetable in the region. The tested parameters of the emitter were manufacturer coefficient of variation (CVm), emission uniformity (EU), coefficient of uniformity (CU), and the statistical uniformity (Us) of water application. Our results reveal that the discharge rates of the emitter varied from 3 to 5 L h−1 under the operating head of 1.5 to 2.5 m with the slope of 0–1.5%, with better performance of the DIS at 2 m operating pressure head and for slopes of 0% and 1%. The CU of all the test parameters was more than 80%, implying that the DIS was designed and installed with appropriate dimensions for the efficient application and distribution of water to the individual plants, with the emitter performance classified as fair to excellent considering water application and distribution, as well as crop yield. The new emitter used for DIS in field conditions showed that the eggplant yield, water use, and water productivity were greater by 4.6%, 38%, and 70%, respectively, compared to farmers’ irrigation practice. We conclude that the DIS has a great prospect to save water, and could be a convenient irrigation water application method for sustainable crop production in saline and nonsaline regions of Bangladesh and similar soil and climatic conditions in South Asia.

Response of wheat (Triticum aestivum L., cv. Shatabdi) to irrigation water of five salinity levels was investigated at the Bangladesh Agricultural University (BAU) farm with a view to search for a possible advantageous salinity level for the crop. The experiment comprised five treatments − I 1 : irrigation by fresh water of background salinity 0.385 dS m −1 (control) and I 2 − I 5 : irrigation by synthetic saline water (prepared by mixing sodium chloride salt with fresh water) of electrical conductivity (EC) 4, 7, 10 and 13 dS m −1 (at 25 o C), respectively. Wheat was grown under three irrigations applied at maximum tillering, booting and milking/grain filling stages, and with recommended fertilizer dose. Irrigation water of EC ≥10 dS m −1 significantly (p = 0.05) suppressed most growth and yield attributes, and yield of wheat compared to irrigation by fresh water (I 1 ). An attention-grabbing observation was that irrigation by saline water of 4 dS m −1 (I 2 ) contributed positively to the crop attributes. Leaf area index (LAI), spike length, spikelets and grains per spike, 1000-grain weight and above ground dry matter (ADM) of wheat increased by 1.9−3.4, 0.9, 2.6, 7.4, 2.1 and 2.8−6.0%, respectively in I 2 compared to the control. The improvement in the LAI and ADM in I 2 was significant over I 1 . Because of the largest spike density, the utmost grain (3.85 t ha −1 ), straw (5.09 t ha −1 ) and biomass (8.93 t ha −1 ) yields of wheat were however obtained under I 1 . The proposition of the advantageous irrigation water salinity level of 4 dS m −1 thus warrants further investigation.