|Author:||Belder, P. ; Spiertz, J. H. J. ; Bouman, B. A. M. ; Lu,G. ; Tuong, T. P.|
|Book Group Author:||NA|
Water saving in irrigated lowland rice production is increasingly needed to cope with a decreasing availability of fresh water. We investigated the effect of irrigation regimes on grain yield and nitrogen (N) uptake and recovery, and the effect of N management on water productivity (grain yield/evapotranspiration (ET)). Four field experiments were carried out - three summer seasons at Tuanlin (2000-2002), China, and one dry season at Muñoz (2001), Philippines - using a hybrid for Tuanlin and an inbred cultivar for Muñoz. Several water-saving regimes were compared with continuous submergence. N fertilizer was applied at 180 kg ha-1 at Tuanlin and at 90 and 180 kg ha-1 at Muñoz and compared with a 0-N application. Grain yield ranged from 4.1 t ha-1 at Muñoz in 0-N plots to 9.5 t ha-1 at Tuanlin in 2001 with 180 kg N ha-1. Alternately submerged-non-submerged regimes showed a 4-6% higher yield than continuous submergence. Other water-saving regimes led to yield reduction. In all seasons, N application significantly increased grain yield largely through an increased biomass and grain number. Water productivity was significantly increased by N application in three out of four seasons and under limited water stress ranged from 0.70 to 1.17 in 0-N plots and from 1.27 to 1.66 kg m3 at 180 kg N ha-1. Water-saving regimes also increased water productivity under non-water-stressed conditions compared with continuous submergence. A synthesis of the data of three seasons at Tuanlin showed that biomass and apparent N recovery declined linearly with the duration of the crop growth without submergence. We concluded that the absence of an effect of water-saving regimes was caused by shallow groundwater tables of <40-cm depth in 2000-2001 at Tuanlin and at Muñoz, whereas at Tuanlin in 2002 there was water deficit in all treatments caused by a deeper drainage. In irrigation systems with a relatively shallow water table, optimal N management is as important as water-saving irrigation to enhance water productivity.
|Pages:||169 - 185|
|Journal:||Field Crops Research|
application rates, biomass production, crop yield,irrigation, mineral uptake, nitrogen, nitrogen fertilizers, nutrientuptake, plant nutrition, plant water relations, rice, water stress,water use efficiency, China, Philippines, Oryza, Oryza sativa, Poaceae,Cyperales, monocotyledons, angiosperms, Spermatophyta, plants,eukaryotes, Oryza, East Asia, Asia, Developing Countries, South EastAsia, ASEAN Countries, paddy, watering, Field Crops (FF005) (New March2000), Plant Nutrition (FF061), Plant Water Relations (FF062), PlantProduction (FF100), Environmental Tolerance of Plants (FF900),Fertilizers and other Amendments (JJ700), Soil Water Management(Irrigation and Drainage) (JJ800) (Revised June 2002) [formerly SoilWater Management]