DEGREE AND FREQUENCY OF NITROGEN AMENDMENTS INFLUENCING THE OFF-SEASON OKRA PRODUCTION IN THE SEMI-ARID NORTH-WESTERN BANGLADESH

Abstract

Vegetables scarcity due to soil nutrient declination as one of the major concerns has been the persistent scenario in the late and post-monsoon period in Bangladesh. Hence, an experiment was executed at the research field of University of Rajshahi, Bangladesh to investigate the crop yield potentiality of okra upon application of varied nitrogen doses in different frequencies in off-season (July-November, 2019). Upon application five levels of nitrogen amendments viz., 70 kg N/ha and 110 kg N/ha applied in 3 splits and 4 splits and control or farmers’ practices [70 kg N/ha once at final land preparation (FLP)] to three okra varieties (Local, BARI Dherosh-2 and Hybrid); the Local cultivar exhibited superiority in most of the vegetative characters except the number of branches and leaves per plant being maximum in Hybrid and root: shoot ratio higher in BARI Dherosh-2. The hybrid variety didn’t show much growth after 60 DAS but it performed superior in early flowering (39.27 days) and harvesting (43.67 days) along with the highest yield (374.03 g/plant and 12.47 t/ha) and BARI Dherosh-2 had its excellence in exhibiting extended duration harvesting (57.00 days) and pod dry matter content (30.96 %) in off-season. Again, plants treated with 110 kg N/ha applied in 4 splits exhibited maximum growth at least from 60 DAS to the end of harvest and produced the highest yield (440.24 g/plant and 14.68 t/ha) that yield was almost double to that of control (228.06 g/plant and 7.60 t/ha). Consequently, BARI Dherosh-2 combined with 110 kg N/ha applied in 4 splits gave the utmost yield (469.50 g/plant and 15.65 t/ha) along with maximum pod dry matter (32.03 %) compared to control yield (195.97 g/plant and 6.53 t/ha). Besides, N-amendment extended the harvesting period of okra by at least 8 days (from 43.78 days to 51.22 days) compared to control and BARI Dherosh-2 was harvested for significantly longer duration (61.67 days after the first picking) when 110 kg N/ha applied in 4 splits compared to only 37.67 days of picking period in local cultivar under farmers’ practice. Therefore, it is evident that extended but judicial and intermittent N-amendments helped in increased okra production with long duration harvest in the lean season.