Abstract
The underground water and water storage reservoirs are rapidly depleting due to nominal recharging by the rainfalls making water a scarce resource for irrigation resulting in poor crop growth and production. Irrigation water application should focus on the proficient use of each drop of water. Water productivity (WP) in agriculture can be improved through crop diversification, proper land and water management techniques. Considering this, a field investigation was carried out during 2013–2014 and 2014–2015 to study the crop response of rice (Oryza sativa L.) + okra (Abelmoschus esculentus L.) system to land configurations and irrigation regimes. Three raised-sunken beds (RSB) having width (m) ratios of 1:3, 2:3, 3:3 and two irrigation schedules viz. continuous standing water (CSW) of 5 ± 2 cm depth and alternate wetting and drying (AWD) at 3 ± 1 days interval for rice in sunken bed were tested. Rice yield was more (4.36 and 4.89 Mg ha−1) under CSW irrigation than AWD irrespective of raised bed width. The highest okra yield was noted by 14.09 and 15.43 Mg ha−1 with AWD in 1:3 RSB systems, whereas the lowest yield was recorded in CSW 1:3 RSB systems. Rice equivalent yield (REY) was found as the maximum in AWD than CSW irrespective of raised and sunken bed configurations. The AWD in 3:3 RSB systems exhibited the highest WP of 1.02 and 1.01 kg m−3 during the first and second year of study, respectively. Wider RSB system of land configuration ratio of 3:3 saved about 40–45% of irrigation water. Such information will help in the planning of an innovative intercropping system of summer rice + okra in the field by changing the land configuration to the raised bed and sunken bed with the AWD irrigation system.
Highlights
Production growth of rice was marvelous over 3 decades with the introduction of high yielding varieties, irrigation water, and chemical fertilizers
The irrigation water supply in sunken bed rice crop varied depending upon the irrigation scheduling ranging from continuous standing water (CSW) to alternate wetting drying (AWD) and the land configuration of raisedsunken bed ranging from 1:3 to 3:3 (Table 2)
It may be concluded that water productivity of okra and summer rice grown in raised and sunken bed (RSB) system has been increased by two times and saved precious underground irrigation water by 40–45% as compared to traditional rice cultivation
Summary
Rice (Oryza sativa L.) is one of the most important grain crops for more than 50% of the world’s population, accounting for approximately 20% of total energy intake and an annual increase of 8–10 million tons is estimated necessary to meet future needs [1,2]. Being the staple food for more than 70% of the Indians, our national food security hinges on the growth and stability of rice production It is a drought-susceptible crop exhibiting serious deleterious effects when exposed to water stress at critical growth stages especially at the reproductive stage [3]. Rice growers have limited options to increase rice productivity when land and water resource are dwindling and the cost of cultivation is soaring
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