Preliminary the Diagnosis and Recommendation Integrated System (DRIS) Norms for Evaluating the Nutrient Status of Apple

Abstract

The Diagnosis and Recommendation Integrated System (DRIS) is an important tool for increasing fruit yield and fruit quality. There are still no studies on the use of DRIS for nutritional diagnosis of the apple tree for China conditions. The objectives of this study were to establish norms for apple, to compare mean yield, leaf nutrient contents and variance of nutrient ratios of low- and high-yielding subpopulations. The study covered the apple producing areas of the Wei-bei Loess Plateau in the northwest of China, in 164 orchards selected for their high productivity and employment of excellent management techniques. The concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese and zinc were determined in leaf samples. The data were divided into high-yielding (>45 t/ha) and low-yielding (<45 t/ha) subpopulations and norms were computed using standard DRIS procedures and a preliminary DRIS norms for apple growing in the Wei-bei Loess Plateau are selected. These norms were developed with data from only one region, so data from future surveys and field trials may subsequently be used to enlarge the database allowing the refinement of model parameters. The results elucidate that the DRIS model for apple, developed in this study, is a diagnostic tool that may be used to predict if insufficiencies or imbalances in N, P, K Ca, Mg, Fe, Mn and Zn supplies are occurring in apple production area in the Wei-bei Loess Plateau, China and indeed elsewhere in the other apple production areas with similar c1imatic and soil conditions.