Titre :
|
Ammonium losses through subsurface drainage effluent from rice fields of coastal saline sodic clay soils
|
Auteurs :
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M. Singh ;
A. Bhattacharya ;
T. Nair ;
AL Et
|
Type de document :
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article/chapitre/communication
|
Année de publication :
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2001
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Format :
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p. 1-14
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Langues:
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= Anglais
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Catégories :
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EAU
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Mots-clés:
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DRAINAGE SOUTERRAIN
;
LESSIVAGE DU SOL
;
ECARTEMENT DES DRAINS
;
SALINITE DU SOL
;
AMELIORATION DU SOL
|
Résumé :
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Subsurface tile drainage systems with drain spacings of 15 m in 0.4 ha and 25 m in 3.2 ha were installed at the farmers' field in 1986 and 1987, respectively, to study their effect on the reclamation of the coastal saline sodic clay soils. The system's performance in terms of the changing physical and chemical properties of the soil and rice yield was continuously monitored for a decade. Field data suggested the possibility of adopting wider drain spacings and thus, drainage system with 35 and 55 m spacings was laid in 1997 in a 4 ha area. On these installations the losses of NH4+-N through sub-surface drainage effluent were estimated. The area under 25 m drain spacing was the control with no crops, fertilization and irrigation. Analysis of water samples collected daily for 10 days starting from 40 DAT from the drain laterals revealed that there were no trace of NH4+-N in the effluent from 15 and 25 m drain spacings. However, the effluent from 35 and 55 m spacings contained an average of 6.704 mg L-1 and 4.205 mg L-1 of NH4+-N, respectively, before irrigation and 2.438 and 1.650 mg L-1 after irrigation. The magnitudes of the losses of NH4+-N during the crop season were 6.43 kg ha(-1) in 35 m spacing with a drainage rate of 5.6 mm d(-1) and 2.14 kg ha(-1) in 55 m spacing with a drainage rate of 3.5 mm d(-1).
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Source :
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Water Air and Soil Pollution, vol.127, vol.1-4
|