Using improved variety and management enhances rice productivity in stagnant flood -affected tropical coastal zones uri icon

abstract

  • Rice is the major food crop in most flood-prone areas of South and Southeast Asia. Growing other crops during the wet season (monsoon/kharif, June-December) is difficult due to waterlogging caused by heavy rain. Lowland rice faces stagnant flooding (SF) risk during most of the wet season. Apart from that, farmers in coastal regions often implement suboptimal crop management leading to poor yields. Development of suitable management practices along with improved varieties is therefore, of prime importance for increasing rice productivity in tropical coastal regions. One on-station and five on-farm studies were conducted over two years to assess the effect of variety, seedling density and nutrient management on yield and economic benefits under rainfed lowland conditions. Improved variety (Amal-Mana) combined with improved management practices established in on-station trials were then evaluated in farmers' fields. The best management practices were established as fertilizer rate of 50-20-10 kg N-P2O5-K2O+5 t farm yard manure (FYM) ha(-1) and transplanting of 2 seedlings hill(-1) at spacing of 15 x 15 cm. This package was found to be optimum for increasing productivity and economic returns of transplanted kharif rice in coastal rainfed lowlands. Application of more than 50 kg N ha(-1) through inorganic fertilizers did not increase grain yield, yet increased production cost. The variety Amal-Mana is tolerant of SF and performed better (yield 0.5-1.0 t ha(-1) more) than other local varieties, both in on-station and on-farm studies. Combining improved management and tolerant variety resulted in higher grain yield (4.51 t ha(-1)) compared with farmers' management and varieties (2.55 t ha(-1)) and increased the benefit-cost ratio from 1.32 for farmers' management and varieties to 1.82. These yield advantages were consistent across locations with variable stagnant flooding stress of 38-62 cm during 2013 and 28-47 cm during 2014. Association of grain yield with stagnant flooding water depth was strongest with farmer's management and farmer's variety (R-2 = 0.81**), but weaker for improved management combined with improved variety (R-2 = 0.015), suggesting water depth becomes less significant when a tolerant variety and good management were combined. These technologies will help in sustaining higher productivity and profitability of rice-based cropping systems in the stagnant flood-prone coastal zones. (C) 2015 Elsevier B.V. All rights reserved.

publication date

  • 2016
  • 2016
  • 2016