RESEARCH REGARDING THE ORGANO-MINERAL FERTILIZATION EFFECT ON THE MAIZE PRODUCTION AND ON THE ACCUMULATION OF NUTRIENTS IN CORN LEAVES FOR IDENTIFYING SOME NUTRITIONAL DISORDERS (POTASSIUM DEFICIENCY) PUBLISHEDConstantin TOADER, Marilena MĂRGHITAŞ, Andra Ramona PORUŢIU, Lavinia MOLDOVAN, Mihaela MIHAI, Adrian Ioan POP
The quantitative and qualitative increase of the agricultural production is an important concern world wide. In the context of the world’s increasing population, of the prognosis according to which the world’s population will double until 2030 and of the diversification of requirements for agricultural raw materials in industry, the agricultural development becomes a primary goal at a global level and also at a local level for each country in particular. In terms of scientific foundation of the complex effects in the food chain, all agricultural systems are perfectible and can’t fully achieve the objectives imposed by the human society, by the consumers and by the increasing requirements for the soil fertility. Through this study we want to clear some aspects concerning the organo-mineral fertilization effect on the maize production, hybrid-Monsanto Dekalb 4626, having a production potential of 8-14 t/ha. The experiments were conducted in 2012 on a chernozem type of soil (SRTS-2003), having a high towards a very high production potential. The vegetation period in 1012 was characterized by less favorable climatic conditions for obtaining a big, quality production due to a low rate of precipitation (much below the regular rate for that specific time of the year) and also due to high temperatures, events that led to productions that were very much below the production potential of the hybrid used in the experiments (2,6 – 4,6 t/ha maize). The differentiated fertilization variants included effects of mineral fertilizers originated from mineral NP fertilizers (in differentiated doses), of organic fertilizers originated from partially fermented stable manure (20t/ha) and partially fermented poultry manure (12t/ha). The production results revealed the beneficial nature of the organic-mineral combinations, where significant production increases were obtained in comparison with the unfertilized witness variant, below the production potential of this hybrid. The unfavorable climatic conditions led to an incomplete binding in the fructification phenophase, in some variants and at the variants that were fertilized with a maximum NP dose during the blooming phenophase, to the specific symptom in potassium deficiency, meaning that the “marginal necrosis” in corn leaves was emphasized. The agrochemical analysis on the corn leaves showed, at the variants that were fertilized with 150-200 kg active substance/ha, nitrogen and phosphorus, an accumulation that was close to the critical threshold regarding the nitrogen level and low towards poor regarding the potassium level. The importance of this study is resulting from the link between the accumulations of nutrients in corn plants at different nitrogen doses and climatic conditions during the corn vegetation period, even though the soil has an optimum level of nutrients from an agrochemical point of view.
productions, nutrients, nutritional disorders, potassium deficiency, maize