Optimal Levels for Nutrient Diagnosis of Crops and On-Site Application: Dry- or Water Soluble-Based Leaf Analysis

Abstract

It is one of most important works to recognize the nutritional status of crops for promoting best nutrient management. Furthermore, a rapid and accurate diagnosis of mineral nutrients is strongly required at agricultural on-site. Here, we described the optimal range for favorable crop growth and development based on the results of previous researches performed since 1990 in NAS, RDA, and focused on explaining analytical method and optimal range of water soluble-based N, P and K for greenhouse crops. Water soluble mineral N, P and K differently responded with leaf position and crop; overall, soluble N was higher in fully expanded leaves, soluble P was relatively higher young leaves and soluble K constantly remained in all leaves. Given the results, water soluble mineral nutrients of greenhouse crops showed relatively higher in Solanaceae (e.g. paprika and eggplant) than in Cucurbitaceae (e.g. cucumber and watermelon). In this respect, the nutrient management in terms of fertilization and crop uptake is necessary to make crop-specific strategy. Although the criteria for nutrient diagnosis based on water soluble extracts was described in this paper, we carefully suggest that better criteria for nutrient diagnosis should be advanced with consideration for diurnal pattern of water soluble minerals, difference in sample destruction degree, duration of storage of samples taken, and etc.