18th Congress of the European Society for Agronomy

A comparison of plant sap and plant dry tissue analysis in winter wheat using three interpretation approaches and their correlation with yield

Not scheduled

15m

Les Dortoirs (1st floor) (The Couvent des Jacobins)

Poster Synergies between disciplines Poster session #2

Speaker

Wiebke Reymann (FiBL)

Description

Balanced nutrient management is critical for both long-term sustainability and productivity of farming systems.
Plant analyses such as dry matter (DM) and sap analysis are tools to identify nutrient imbalances at plant level. They can indicate nutritional challenges within the season, while fertilizer application is still effective. DM analysis reflects the total concentration of nutrients in the plants, while sap analysis reflects the nutrients which are readily available for plant development (Esteves et al., 2021).
The commonly used interpretation method is the univariate Critical Value (CV) approach. It is based on sufficiency ranges established through fertilizer experiments and is simple to use, but does not account for nutrient interactions or climatic variabilities (Sumner, 1990). The bivariate Diagnosis and Recommendation Integrated System (DRIS) (Beaufils, 1973) evaluates the nutritional status based on dual ratios rather than absolute values. Its main advantage is the insensitivity to crop age, variety and nutrient accumulation or dilution effects. The multivariate Compositional Nutrient Diagnosis (CND) (Parent and Dafir, 1992) originates in the compositional data analysis. As it accounts for all possible nutrient interactions, it has been suggested to be superior to the DRIS.
Fertilizer guidelines commonly use CV based on DM samples, but the usage of sap analysis is increasing. However, no standardized sampling and interpretation protocols exist. The DRIS and CND might be especially suited for interpretation due to their insensitivity to absolute values. Here, we wanted to test whether DRIS and CND can be used to estimate the nutritional status in arable crops, and to assess which sampling (DM or sap) or interpretation (CV, DRIS or CND) method is more suitable as fertilizer recommendations.

In June 2023, before flowering, we took DM and sap samples of winter wheat grown on loamy soils in Western Switzerland. 15 fields of exemplary farms and 12 reference fields of a research station were sampled. The references represented N limited, PK limited and sufficient fertilization (Blanchet et al., 2016). The youngest, fully developed and the oldest, still functioning leaf (whole leaf, without petiole) were sampled per plant. DM and sap samples were analyzed for N, P, K, Ca, Mg, S, Cu, Zn, Fe, Mo and Mn, using ICP-OES and CNS analyzer for DM samples, and a commercial lab for the sap analysis. The results were interpreted using CV ranges (Richner et al., 2017 for DM; ranges suggested by the sap analysis lab), as well as interpreted through the calculation of DRIS and CND indices.

Nutrients in DM and sap were significantly correlated (except Fe). However, preliminary results suggest that the nutritional status indicated by the three different interpretations does not align. Only Nitrogen was clearly identified as limited by all methods. Overall, DRIS indices (DM and sap) suggested stronger nutrient imbalances than CND indices. The indices of sap and DM correlated for CND, but not for DRIS. Opposingly, yield was correlated to the DRIS indices for DM and sap, but not to CND indices.
The in-depth analysis of soil and plant nutrients will continue and the methods will be further assessed in a field trial in 2024/2025.

References

• Beaufils, E. (1973). Diagnosis and recommendation integrated system (DRIS). Soil Science Bulletin No.1.
• Blanchet, G., Gavazov, K., Bragazza, L., and Sinaj, S. (2016). Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system. Agriculture, Ecosystems & Environment, 230:116–126
• Esteves, E., Locatelli, G., Bou, N. A., and Ferrarezi, R. S. (2021). Sap Analysis: A Powerful Tool for Monitoring Plant Nutrition. Horticulturae 2021, Vol. 7, Page 426, 7(11):426.
• Parent, L. and Dafir, M. (2019). A Theoretical Concept of Compositional Nutrient Diagnosis. Journal of the American Society for Horticultural Science, 117(2):239–242.
• Richner, W., Sinaj, C. C., Flisch, R., Gilli, C., Huguenin-Elie, O., Kuster, T., Latsch, A., Mayer, J., Neuweiler, R., Richner, W., Sinaj, S., and Spring, J.-L. (2017). Grundlagen für die Düngung landwirtschaftlicher Kulturen in der Schweiz Spezialpublikation Agrarforschung Schweiz.
• Sumner, M. E. (1990). Advances in the use and application of plant analysis. Communications in Soil Science and Plant Analysis, 21(13-16):1409–1430