THE ORGANO-MINERAL FERTILIZATION INFLUENCE AT CORN CROPS ON THE SOIL AGROCHEMICAL INDICATORS AND THE ACCUMULATION OF NUTRIENTS IN THE MAIZE AND IN THE CORN LEAVES FOR IDENTIFYING SOME NUTRITIONAL DISORDERS (POTASSIUM DEFICIENCY) PUBLISHEDC. TOADER, Marilena MĂRGHITAŞ, Andra Ramona PORUŢIU, Lavinia MOLDOVAN, Mihaela MIHAI
The negative vegetation states concerning de absorption, translocation and metabolism of nutrients occur in connection with the manifestation of extreme states of supplying the plants with nutritional elements-deficiency or excess. The causes that determine these states are complex and multiple, in general they depend on the soil attributes (fertility conditions), on biological factors (nutritional attributes of the genotype), on technological factors and last but not least on the climatic conditions. This research conducted an analysis on the agrochemical indicators of chernozem soil (SRTS – 2003) which was organo-mineral differentially fertilized, in different doses and combinations, cultivated with corn and also an analysis on the content in nutritional elements of the plant (for maize and leaves). The soil and the plant analysis was motivated by the necessity for a comparison between the agrochemical attributes of the soil and the accumulations of nutrients in the plant because at a proper soil fertility, the nutritional process of the plant is also proper. However, during the blooming period of the corn, the nitrogen consumption decreases and the potassium consumption increases and on the corn leaves the potassium deficiency is highlighted (marginal necrosis of the leaves), but only for the fertilizations variants with the highest complex mineral fertilizer dose - NP (N 150 P 150 – N 200 P 200 ). The agrochemical analysis of the corn leaves that were affected by the potassium deficiency symptoms emphasized high accumulations of N t (%) and low towards critically low accumulations of potassium (K t %). These results determined us to develop a characterization of the soil agrochemical indicators and a determination of the nutrients content in maize (N, P, K, Ca). Following the analysis conducted on the soil we can conclude that this type of soil holds favorable indices for cultivating corn and the potassium deficiency and the low productions achieved in 2012 can be attributed to the unfavorable climatic conditions. As we mentioned earlier, the negative vegetation states, concerning the absorption, translocation and metabolism of nutrients are determined by various causes, among which, the unfavorable climatic conditions. Concerning the analysis results on the vegetal material in the maize, the nutrient accumulations took values that were specific for the genotype with genetic determination for the species and hybrid cultivated. The vegetation period in 2012 was characterized by climatic conditions that were less favorable for obtaining big, quality crop productions due to a low precipitation rate (much below the normal rate for that specific period) and high temperatures, facts that led to obtaining crop productions that were below the production potential of the hybrid used in the experiments (8-14 t/ha maize). The importance of this research results from the link between the nutrient accumulations in corn plants at different nitrogen doses and the climatic conditions during the vegetation period, even though the soil holds an optimum amount of nutrients from an agrochemical point of view. The detection and diagnosis of these nutritional disorders has a more preventive and corrective nature than the specific treatments for dealing with the intense symptoms.
nutrients, nutritional disorders, K deficiency, agrochemical indices