Floral analysis in fruit crops: A potential tool for nutrient constraints diagnosis

Abstract As we know that inadequate fertilizer particularly chemical fertilizer use usually results in yield losses, lower product quality, weaker resistance to stresses, and adverse environmental impact, scientific recommendation of fertilization is becoming more and more important. Nutrient deficiency symptoms appear only after the nutrient supply is so low that the plant can no longer function properly; visual diagnosis of plant nutrient deficiency is inadequate for making fertilizer recommendation. Base on the curve of plant growth or production yield response to nutrient concentration in tissue (such as leaf), the value of soil and plant analysis in quantifying nutrient requirement depends on careful sampling, analysis, and using tests that are correlated with plant response, with the aim of high yield, high profit and good quality, friendly environment. Procedures for proper sampling, preparation, and analysis of leaves have been standardized; considerable care should be taken from the time leaves are selected for sampling to the time they are received at the laboratory for analysis. It's not easy to establish the diagnosis standard or norm of fruit tree leaf analysis; lots of scientists have done researches and setup diagnosis standards or norms of citrus and the other fruit tree leaf analysis; there are some variations in standards or norms among fruit tree cultivars and planting areas, but it is difficult to distinguish particularly significantly; the average or high frequency value was set up as the recommendation standards or norms. The interpretation is discussed; the leaf nutrients' optimum value for diagnosis can be used not only to identify the nutrient constrains but also to predict the fruit yield or sometimes fruit quality. Soil testing has been practically utilized in agriculture and horticulture for many years successfully and mainly reveals the potential or capacity of tested soil supplying nutrients to plant, but does not characterize efficiently, or sufficiently the nutrient mobility in the soil, leaf, or tissue analysis combined with soil tests can help identify more problems or factors.