Speaker
Description
Introduction
In conventional intensive banana monoculture systems, fertilization, mainly mineral-based, is managed to keep high levels of mineral elements in soil, in order to ensure maximal crop nutrition and compensate for leaching losses. It actually results in excessive applications of fertilizers, far surpassing plant’s uptake and soil absorption capacity (Godefroy & Dormoy, 1983).
With the development of agroecological banana cropping systems in French West Indies (FWI), adjusting fertilization to plant’s requirements in order to reduce nutriment losses by leaching became a priority. But these new banana cropping systems, based on increasing use of organic fertilizers and cover crops in association with bananas could show nutritional stresses for crop. To prevent them, the nutritional status of crop is typically assessed through chemical leaf analysis, it allows a prompt correction of deficiencies. However, this method is not easy to use because it doesn’t take into account N dilution with biomass growth (Lemaire et al., 1984). Furthermore, long-term management by soil nutrition is crucial to ensure fertility, although soil diversity in the French West Indies with different exchanges capacity complicates even more this management.
The management of fertilization in the new banana cropping systems, more complex, requires the design of new decision support tools in order to adjust the inputs of fertilizers dynamically based on plant nutritional status and soil resources availability. Here, we present a conceptual framework of a Decision Support Tool designed to assist agricultural advisory in fertilization management of banana cropping systems in the French West Indies.
Materials and Methods
The conceptual framework of the decision support tool has been realized in three steps:
1. A literature review of plant and soil nutritional status diagnostic methods.
2. A detailed analysis of recommendations for fertilization of banana cropping systems through interviews between farmers and private agricultural advisor during three days. This step enabled the identification of limits on actual method and expectations for the new tool.
3. Designing conceptual framework of the decision support tool for fertilization management and identification of needs of data for parameterization.
Results
Three methods are used for analyze nutrient soil availability: Sufficiency Level of Available Nutrients (SLAN), also called “Critical Tresholds Method”, Basic Cation Saturation Ratio (BCSR) or “ideal soil” suggested a balanced soil cation ratios for optimal plant growth and Nitrogen Balance method.
Concerning foliar diagnostic, three methods are used: Critical Values Approach (CVA) that compared nutrient levels to individual thresholds, Diagnostic and Recommendation Integrated System (DRIS norm) that used ratios of two nutrients and Compositional Nutrient Diagnosis (CND) that allows to compare ratios of one nutrient to the levels of all other nutrients.
Current fertilization strategy was reviewed, and leaf and soil analysis were analyzed using CVA method for foliar diagnostic and SLAN method for nutrient soil availability. References of norms used and threshold associated are sometimes unknown or seems very old (1990’s). The introduction of cover crop in system was never considered.
Figure 1 illustrates that fertilization management for agroecological banana cropping systems should carried out on two distinct compartments (soil and plant) for taken into account the both tactical - short term and strategic - long term management.
Figure 1 : Conceptual framework of a Decision Support Tool for fertilization management in banana cropping system.
Discussion
The conceptual framework realized in this study presents an innovative Decision Support Tool, able to assist farmers for fertilization management by combining tactical and strategical management. This dual approach, taking into account both long-term requirements linked to soil fertility and immediate adjustments to correct deficiencies will allow dynamic and sustainable management of soil fertility of agroecological banana cropping systems in FWI.
References
Godefroy, J., & Dormoy, M. (1983). Dynamique des éléments fertilisants dans les sols des bananeraies martiniquaises. Fruits, 38, 451‑459.
Lemaire, G., Salette, J., Sigogne, M., & Terrasson, J.-P. (1984). Relation entre dynamique de croissance et dynamique de prélèvement d’azote pour un peuplement de graminées fourragères. I. —Etude de l’effet du milieu. Agronomie, 4(5), 423‑430.
| Keywords | Musa sp. ; French West Indies ; Plant nutrition ; Fertilization issues ; Soil fertility |
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