Continual stationary trial on four fields was set up back in 1965/66 on trial fields of the Institute for Agricultural Research in Novi Sad, which is today’s Institute of Field and Vegetable Crops in Rimski Šančevi. It is called a stationary trial, as well as a physiological trial, due to its long duration. It was set up by our recognized plant physiologist Prof. Dr. Miloje Sarić and Dr. Branislav Jocić, who gave enormous contribution to the development and promotion of agricultural science in the former Yugoslavia and Serbia.
The trial was set up in crop rotation with four plant species (4 fields), the most typical for field crop production of Vojvodina: sugar beet, maize, sunflower and wheat. Alfalfa was previously grown for three years on the same plot.
Throughout trial duration (50 years), different cultivars and hybrids of tested plant species were used. They were among the most significant ones in specific periods of production. After 1990, larger number of cultivars/hybrids was gradually included in the trial. In that manner, trial methodology was partially modified, i.e. it was transformed into split-plot trial design, considering that fertilization variants were the same at the main plots (factor A), and larger number of cultivar/hybrids was tested within every variant (factor B).
Therefore, testing reactions of larger number of cultivars and hybrids to mineral nutrition was enabled, as well as the research of an important agro-technical factor – varietal (genetic) specificity of mineral nutrition.
Trial design and applied management practices
Stationary trial is organised in 4 separate fields, with four different crops rotating annually, each of them covering the area of 1.84 ha (68 m x 270 m). Fields are divided lengthwise in 4 replications, with 20 experimental plots of 17 x 13.5 m (229.5 m2) size in every replication (Figure).
Therefore, one field occupies total of 80 plots with randomized layout of fertilization variants, whereby larger number of cultivars/hybrids is present on one plot depending on the year (subplots).
Trial was set up on stationary experimental plots with an aim to test the effect and ratio of nitrogen, phosphorus and potassium on yield and product quality in a long period, as well as on chemical, physical and biological changes that occur in the soil.
Standard management practices typical for agro-ecological conditions of Vojvodina were applied during the whole period. The total quantity of P2O5 and K2O, as well as the half of projected nitrogen fertilizer, are applied immediately before basic tillage. The other half of N fertilizer is used for fertilization of wheat (in early spring, at the beginning of March), and other species (before sowing).
Wheat straw and other crop residues are ploughed under after harvest. Numerous studies were conducted on this stationary field many years ago, and they were initially related to biological potential in agrophytocoenoses of grown crops, depending on mineral nutrition.
Biological potential of grown crops can be realized in crop and environment interaction. Maximum yields are achieved if these conditions are harmonized. However, it is not possible to regulate agro-ecological factors in natural conditions. It is important to understand that functioning optimum of a factor is different during plant growth and development, it is very limited and strictly defined, and very difficult to achieve in natural conditions.
Large number of measured parameters during past few years of research showed significant variations of agricultural and biological yield, depending on grown species, mineral nutrition combinations, duration of fertilizer application, as well as on meteorological conditions. This leads to the conclusion that crop yield, as well as plant growth and development, are conditioned by many physiological and biochemical processes that are dependent on numerous studied factors. Constant changes of agro-ecological conditions are crucial factors in plant productivity. This is the reason for large gap between theory and practice in realisation of biological potential of grown plants. The main task of science and production is to minimize that gap, always considering the principle of cost-effectiveness.
As the result of this trial, many papers in national and international journals have been published, and many reports presented at numerous scientific and professional events. In addition, the obtained results have been used in several master theses and doctoral dissertations.
As the authors said, „even though this issue (mineral nutrition of plants) was studied extensively, it will remain in the focus of researchers and producers for as long as humans grow plants“. The stationary trial is immense wealth and inexhaustible base for wide array of studies from different fields of agricultural practice and theory.