A Review on Interpretation Methods of the Results of Plant Analysis and Introduction of Spectroscopy Method

Increasing the yield and improving the quality of agricultural crops play an important role in the country's food security. Assessment of soil fertility and optimal fertilizer recommendation requires the diagnosis of the nutritional status of plants. Meanwhile, leaf analysis and interpretation of its results is a suitable method to determine the nutritional balance of orchards and agricultural fields. There are different methods for the interpretation of leaf analysis results that this article investigated some of these methods, including the critical level (CL), diagnosis and recommendation integrated system (DRIS), deviation from optimum percentage (DOP), compositional nutrient diagnosis (CND), and introducing the imaging and spectroscopy method. The study results showed that each of these methods has advantages and disadvantages. Although the DRIS resolves the defects of the CL method, DOP is a simpler and easier method compared to the DRIS comprehensive method in interpreting the results of leaf analysis. The CND method is also more comprehensive than other methods due to considering the mutual effects of all nutrients. Due to the advancement of technology, imaging and spectroscopic methods in the visible and near-infrared regions (Vis-NIR) are used for determination of the plants nutritional status and prevent reduction of product yield. This method is inexpensive, fast, and non-destructive due to no need for chemical analysis and is applicable to large areas and large-scale management. Generally, choosing a suitable method to determine the nutritional status of crops and orchards can contribute to food security, in addition to increasing the efficiency of the fertilizers used and improving the yield of agricultural products.