Предвиђање производно економских параметара у повртарству у Србији / Forecast of Production - Economic Parameters for Vegetable Farming in Serbia

The topic of this research is the analysis of the trends and future tendencies of the production and economic parameters of some of the more important vegetable crops, i.e. the cropland, yield, total output, prices and parity prices in Serbia and Vojvodina. The main aim of the research is to formulate quantitative models for the forecast of the cropland, yield, total output, prices and parity prices of the significant vegetable crops in Serbia and Vojvodina, based on the analysis of the appropriate time series. The prediction covers the following: potato, peas, beans, tomato, pepper, cucumber, carrot, onion, garlic, cabbage and kale. The forecast period is 2011-2015. The statistical methods used in this case study are the methods of descriptive analysis and the analytical and statistical methods. The methods of descriptive statistics are employed in the analysis of the obtained characteristics of the vegetable farming from 1991-2010. The primary statistical indicators are: the average value of the phenomenon, the extreme values (minimum and maximum), the coefficient of variation and the rate of change. With the goal of forecasting the observed phenomena, we have used the method of time series analysis, i.e. ARIMA models based on the time series analysis have been applied. The time series analysis has encompassed the obtained production and economic characteristics of the vegetable farming during the twenty-year period, and the prediction refers to the future five-year period, 2011-2015. The expectation of the growth in the cropland, yield and total output of the vegetable crops, which would contribute to the faster overall development of the national agriculture, is partly acknowledged in this paper. The predictions indicate that the land under vegetables in Serbia and Vojvodina will shrink in the forecast period, in both absolute and relative values, i.e. its part in the arable land will decrease. At the end of the forecast period, the land under vegetables in Serbia will cover 258.000 hectares, which represents significantly less than the average in the analyzed period (1991- 2010), 302.700 ha. The land under vegetables, as part of the arable land, will also decrease to 7.56%, while it formed 8.68% in the analyzed period. In Vojvodina, the areas under vegetables will drop to 60.000 hectares (the average was 79.000 ha), i.e. their part in the arable land with the average 5% in the analyzed period will decrease to 3.82% in the last year of the forecast. Unlike the cropland, the forecast about the increase in the yield and output is mainly X proven. In Serbia, the yield of five (out of ten) vegetable species will go up (potato, pepper, carrot, onion and garlic), the yield of one species will stagnate (peas), and of four will decrease (beans, tomato, cucumber and cabbage). In Vojvodina, the yield of six vegetable crops will increase (peas, cucumber, carrot, onion, garlic and cabbage), the potato yield will be at a standstill, while the yield of three vegetable crops will decrease (beans, tomato and pepper). In Serbia, there will be a production growth with five vegetable crops (potato, peas, pepper, carrot and garlic), and the remaining five crops show a downward trend in the production(beans, tomato, cucumber, onion and cabbage). In Vojvodina, a rise in the production of five species is predicted as well (peas, pepper, cucumber, carrot and cabbage), stagnation in the production of onion and garlic, and a fall in the production of three vegetable crops (potato, beans and tomato) is forecast. The assumption that the forecast of the production-economic characteristics in vegetable farming contributes to the high-grade macro and micro-economic planning in the development of vegetable farming is acknowledged by the fact that it has been quantitatively proven that different vegetable species have different future tendencies, concerning both production and economic parameters. Furthermore, these variations relate to the territory for which the predictions are made, Serbia, i.e. Vojvodina. Different predictions lead to different planning, i.e. different mechanisms for their regulation. The idea that the use of quantitative methods and models ensures a noteworthy analysis of the condition of the observed phenomena and provides basis for the realistic forecast in the future period, is proven by the fact that in this research we have successfully used 82 forecast models, namely: 2 models for the prediction of the arable land in Serbia and Vojvodina, 4 for the prediction of the absolute area under vegetables and its part in the arable land, 30 for production parameters of the important vegetable species in Serbia, and the same number of models is used in Vojvodina, and 12 for the forecast of absolute and relative prices of the six significant vegetable crops. The success of the models manifests itself in the statistically significant effect of the phenomena from the previous period with the great majority of models. The number of models which are significantly affected by incidental processes only or whose value from the previous period is not statistically relevant is very low. The belief that the methods of descriptive and analytic statistics are adequate for the examining and the real forecast of the observed phenomena in vegetable farming is in accordance with the previous hypothesis. It is reflected in the similarities between the tendencies from the previous period, which are analyzed by the methods of descriptive statistics, and the results of the prediction which used ARIMA models in the following period. No prediction model has illogical results. When proving the assumptions that the real forecast facilitates making rational decisions connected to the vegetable farming development in Serbia and Vojvodina, the outcome of the forecast of the economic (price) production parameters of certain vegetable crops performs a major role. The real, discounted vegetable prices compared to the year 1994, using the consumer price index, will have different trends. Potato, beans, onion and cabbage will have relatively stable prices. Tomato will show an upward trend, whereas pepper will indicate a downward one. Therefore, the absolute price conditions will be stable with four vegetable species, in one case there will be improvement, while in another a downturn in the price conditions will be noticed. XI The relative prices, i.e. the parity prices of vegetables with wheat, as an indicator of the relative economic position of vegetables towards other, competitive arable crops, had tendencies similar to absolute, discounted prices. Onion and cabbage will show the stagnation of parity and prices. Potato and beans will have a slight increase in parity, with significant oscillations, whereas the parity of tomato and pepper will act the same as discounted prices – it will increase with tomato and decrease with pepper. The implementation of the adequate methods and models for analysis and prediction creates an opportunity to predict the volume and structure of vegetable production in Serbia and Vojvodina. The sowing structure of the vegetable production will change, the total land under vegetables will decrease, but the production intensity of the majority of the analyzed crops will grow, which will have a positive effect on the increase in the yield and the annual output.