title: Optimization of aquatic-terrestrial ecosystem in relation to soil nitrogen status for the cultivation of fish and aquatic food crops of the Indian subtropics.
abstract: A case study was undertaken during wet and postwet seasons to improve the perennial and alternate submerged saucer-shaped ponded lands (tal and semi-tal lands) in the coasts and northeastern plains of the Indian subtropics through pisciculture and cultivation of starch- and protein-rich aquatic food crops like water chestnut (Trapa bispinosa Roxb.) and makhana or fox nut (Euryale ferox Salisb.). The study revealed that the physico-chemical properties of soils (pH, organic C, organic matter, available N, P, and K) as well as quality of water (pH, EC, BOD, COD, CO3 +, HCO3-, NO3-N, SO4-S-, and Cl-), growing fish, makhana, and water chestnut was remarkably influenced by different moisture regimes and exhibited a significant improvement of soil health. The amount of organic C, available N, P, and K content were found significantly highest in the treatment where makhana was grown under alternate flooding and drying situation with a depth >2 m as compared to other treatments. Such enrichment of soil fertility, particularly in available N and P content, might be due to the accumulation of considerable amounts of biomass and fish excreta and their subsequent decomposition in situ in the soils. Therefore, the present study suggests that the N-enriched soil may effectively be utilized further for growing subsequent arable crops surroundings during summer season, which not only saves the amount of applied N fertilizer but also increases the apparent N efficiency with simultaneous increase in yield, and would benefit the farmers in this region.
authors.affiliation: Department of Agronomy, Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal, India. ampuste_bckv@hotmail.com
authors.forename: A M
authors.initials: AM
authors.lastname: Puste
authors.forename: D K
authors.initials: DK
authors.lastname: Das
mesh_terms: D000818:Animals; D006801:Humans; D018533:Biomass; D017753:Ecosystem; D005399:Fishes / Q000254:growth & development; D005618:Fresh Water; D006863:Hydrogen-Ion Concentration; D007194:India; D009584:Nitrogen / Q000378:metabolism; D017672:Nitrogen Compounds / Q000032:analysis; D017553:Phosphorus Compounds / Q000032:analysis; D063245:Plant Development; D017680:Potassium Compounds / Q000032:analysis; D012621:Seasons; D012987:Soil; D014329:Tropical Climate; D014867:Water / Q000032:analysis; D029561:Lythraceae / Q000254:growth & development
chemical_list: D009584:Nitrogen; D017672:Nitrogen Compounds; D017553:Phosphorus Compounds; D017680:Potassium Compounds; D012987:Soil; D014867:Water