Sansoulet Julie, Cabidoche Yves-Marie, Cattan Philippe, Clermont Dauphin Claridge, Desfontaines Lucienne, Malaval Cécile.
2004. Solute transfert in an andisol of the french west indies after application of KNO3 : from the agreggate to the field experiment.
In : Volcanic soil resources in Europe. COST Action 622 final meeting. Abstracts. (Eds) Hlynur Oskarsson, Olafur Arnalds
Résumé : Since 30 years, fertilizer supply on banana cropped on andosol in the French West Indies, takes into account a high leaching of potassium and nitrates, that had been measured on oxisol and some andosol by Godefroy et al (1975) and Godefroy and Dormoy (1988). The nitrogen and potassium supply can reach respectively more than 400 kg N ha-1 year-1 and 800 kg K ha-1 year-1. Both fertilizers are supplied around the bottom of the banana pseudo-stems. On one hand, the banana canopy by-passes the incident rainwater into a main streamflow around the pseudo-stem (stemflow) and a lower dripping flow under leave borders. On the other hand, andosol allophanes exhibit pH dependent electric charges. The diversity of cropping systems, including liming, induces a diversity of physico-chemical status. Ranges of observed pH are frequently under the Zero Point of Charge (ZPC) and these andosol could then develop Anion Exchange Capacity (AEC) in deep layers which are likely to retain anions as NO3 -. With such characteristics, understanding distributed water flows and consecutive solute leachings under banana cropping on andosol can help to improve fertilizer supply by minimising solute losses. We performed 3 types of experimentations : (i) The AEC and the capacity of the andisol to retain NO3 - and K+ have been measured using the batch method of Wada and Okamura (1980) under different pH conditions. (ii) Undisturbed soil columns of 1.5 dm3 allowed to study the anion and cation elutions. An initial amount of solid KNO3 or LiBr has been spread on the top face of the columns, which has been immediately dissolved during the first V/V0 elution. Discrete elutions were applied every two days, until 8 V/V0. (iii) Wick lysimeters, set up at 0.75 m depth, allowed to estimate in situ drainage distribution and the associated solute leachings, through both high infiltrability layers A (Ksat > 150 mm h-1) and B (Ksat = 30 +/- 7 mm h-1). The type and length of the wicks have been chosen in order to collect the same average flow in lysimeters than the flow in undisturbed wet soil ; the HYDRUS 2D model allowed to verify that lysimeters minimized bias. Five replicates of four positions in respect to the stem positions were set up. The banana cropping received homegeneous KNO3 supplies - 70 kgN(NO3) ha-1, 200 kgK ha-1 - each 3 months. The breakthrough curves of the B layer for pointed out that 2 phases occured during elutions: the first one resulted from quick solute elution and the second one from the slow lixiviation of a sorbed fraction of the NO3 - input. K+ showed a similar behaviour. For Li+, only the first phase occured, without evidence for sorption (fig.1.). The A layer showed usual behaviour of K+ and Li+ which was characterized by immediate sorption. Nevertheless NO3- exhibited the same two phase behaviour than in the B layer. In both layers, the final sorbed Br-/Li+ ratio strongly increased while pH decreasing, according to AEC increasing. The batch experiment confirmed those trends. The lysimeter outflow clearly showed the impact of the stemflow on over-supplied drainage bellow the pseudo-stems (a) and on their downstream neighbourings (b), and the umbrella effect of leave covers (c). Under a banana cover which LAI was 4, the resulting apparent drainage / incident rainfall volume ratio were respectively 1.2, 1.6, and 0.3, while the bare soil (d) exhibited a ratio of 0.5. The associated solute leachings were consistent with a high sorptivity of NO3- and a low sorptivity of K+ (fig. 2) : for NO3-, immediate moderate leaching during the three first rainfall events after supply was followed by a low leaching ; finally, the total leaching reached 30 % of the input. For K+, a strong leaching occured until 200 mm of drainage, followed by a desorption phase whose slope was moderate. The total leaching of K+ reached 80% of the input. Finaly, localised over-supplied drainage downstream to the banana stemflow result in high losses of K+, whose supply have to b
Mots-clés Agrovoc : Musa, fertilisation, engrais, Andosol, azote, potassium, système de culture, type de sol chimique, pH, nitrate de potassium, expérimentation au champ
Mots-clés géographiques Agrovoc : Antilles françaises, France
Classification Agris : P33 - Chimie et physique du sol
F04 - Fertilisation
Auteurs et affiliations
- Sansoulet Julie, INRA (GLP)
- Cabidoche Yves-Marie, INRA (GLP)
- Cattan Philippe, CIRAD-FLHOR-BPA (GLP)
- Clermont Dauphin Claridge, INRA (FRA)
- Desfontaines Lucienne, INRA (FRA)
- Malaval Cécile, CNEARC (FRA)
Autres liens de la publication
Source : Cirad - Agritrop (https://agritrop.cirad.fr/521329/)
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