Best Management Practices for Sustainable Crop Nutrition in Bulgaria

In 2008, a 5-year project was established in Bulgaria with the general goal of improving cultivation systems in Bulgaria’s agriculture through efficient and sustainable use of plant nutrients. The project involves five Bulgarian organizations: The University of Forestry, Agricultural University, Nikola Poushkarov” Institute of Soil Science, Executive Soil Resources Agency (Ministry of Agriculture), and the National Plant Protection Service (Ministry of Agriculture). Project activities include: 1) Evaluation of soil nutrient status through summarization of past national soil surveys and more recent localized regional surveys; 2) Systematic summarization of past relevant soil fertility research, existing nutrient uptake and removal information for target crops, and identification of information gaps; 3) Conduct of field nutrient omission plot trials on target crops; 4) Development of tools for site-specific nutrient management that incorporate the national soil survey GIS and other project results into nutrient management software for delivering updated recommendations to farmers and farmer advisers; 5) Outreach activities to assure appropriate use of the developed tools.











Methodology


The idea of the project is to range over the main soil-climatic areas and economically important crops in the country.

For the soil test survey a summary and evaluation of the existing data of last two national soil test surveys plus more localized surveys done more recently are foreseen. The sites and regions where so far no data are available would be completed. On that base a data pool on regional basis about soil fertility and nutrient status will be created.

It is difficult in advance to estimate the volume of the available soil test information for the whole country. In order to have actual information, a quotation for soil nutrient monitoring will be singled out. For that purpose a determination of a transekt, covering the representative for the country soil taxons is foreseen. The selected approach considers the circumstance that in the direction from North to South the most pedo climatic changes in the country are covered. Two of the regions - Veliko Tarnovo and Stara Zagora are settled in direction from North to South and covered the most of the important for the agriculture soil taxon. For that reason and in order to decrease the expenses it is assessed that both regions are very suitable for concentrating the main activity of the project. Likewise those are the regions with the most soil test surveys data and cadastre maps saved. In order to cover the climatic divergences, regions in North-West, South-West and Black Sea parts of the country will be included. Depending on the available information and the budget resources the whole arable area could be covered during the first or second year. On the basis of the past and actualized information the soil nutrient status on different level will be evaluated. Benchmarks and emphasis on specific nutrients for specific areas through consideration of soil classification or parent materials could be outlined. The soil test information will be connected to the soil survey GIS.

The work in the area of soil fertility and response research will start with summarizing past relevant soil fertility research in systematic way and the existing crop nutrient uptake/removal information for major target crops and defining the information gaps. The past achievements will be a base for further development of crop nutrient management system in the agriculture.

Soil fertility research will be focused on the most economically important arable and horticulture crops – wheat, barley, maize, sunflower, oilseed rape, potatoes, tomatoes, pepper, apricots, peaches, chokeberries and vines. The proposal for the field omission plot trials (N, P, K, NP, NK, PK, NPK, NPKMg) carried out under typical soil and climate conditions in traditional for the experimental crops regions is as follow:

Crop	Soils FAO-Unesco, 1997	Regions	No of experiments
Wheat	Verti-luvic Chernozems, fine Calcic or Eutric Vertisols Calcic or Eutric Vertisols	North-West Bulgaria (Vidin) North-East Bulgaria (Dobrich) South – East (Burgas) South - Central Bulgaria (Stara Zagora)	4
Barley	Verti-luvic Chernozems, fine Calcic or Eutric Vertisols Calcic or Eutric Vertisols	North-West Bulgaria (Vidin) North-East Bulgaria (Dobrich) South – East (Burgas) South - Central Bulgaria (Stara Zagora)	4
Maize	Verti-luvic Chernozems, fine Calcic or Eutric Vertisols Calcic or Eutric Vertisols	North-West Bulgaria (Vidin) North-East Bulgaria (Dobrich) South – East (Burgas) South - Central Bulgaria (Stara Zagora)	4
Sunflower	Verti-luvic Chernozems, fine Calcic and Eutric Vertisols Calcic and Eutric Vertisols	North-West Bulgaria (Vidin) North-East Bulgaria (Dobrich) South – East (Burgas) South – Central Bulgaria (Stara Zagora)	2
Oilseed rape	Verti-luvic Chernozems, fine Calcic or Eutric Vertisols Calcic or Eutric Vertisols	North-West Bulgaria (Vidin) North-East Bulgaria (Dobrich) South – East (Burgas) South - Central Bulgaria (Stara Zagora)	2
Potatoes	Åutric Cambisols–coarse Dysric Cambisols–coarse	Samokov (Sofia region) Smolian (Smolyan region)	2
Tomatoes	Dysric or Eutric Regosols–FAO–Unesco, coarse Mollic, Calcaric, Umbric,	Soth-West Bulgaria (Petrich area) South - Central Bulgaria (Plovdiv)	2
Pepper	Eutric Fluvisols (coarse, medium, fine)	North- Central Bulgaria (Veliko Tarnovo)	1
Apricots	Eutric Vertisols, fine	North-East Bulgaria (Silistra area)	1
Peaches	Dysric and Eutric Regosols–coarse	Soth-West Bulgaria (Petrich area) South – East Bulgaria (Sliven)	2
Chokeberries	Haplic or Chromic, Luvisols, coarse or medium	North- Central Bulgaria (V. Tarnovo or Lovech)	1
Vineyards	Dysric Regosols or Eutric Calcic or Rutric Vertisols, fine	Soth-West Bulgaria (Melnik area) South – East Bulgaria (Burgas)	2
No of experiments			27

For every one experiment a detailed program will be worked out. The fertilization rates will be defined more accurately on the basis of the nutrient status of the selected plots. During the crop vegetation the experiments will be observed carefully for the development stages, pest attacks and other factors. The detailed weather data for Veliko Tarnovo area could be obtained using Campbell weather station CR-10 installed in the MTO plot of the airport of Gorna Oryahovitsa. For the weather data in the other areas the possibilities have to be checked. At harvest soil and plant samples from the main and secondary production of the experimental crops will be collected for analyzes. Chemical composition, nutrient uptake, quality parameters will be determined.

The experiments will be demonstrated to the farmers at appropriate stage. Later the experimental results will be discussed with producers and researchers.

During the second phase of the project all the research results and soil test information will be connected to the soil survey GIS and will be used for development of nutrient management software. The outputs of the project will serve for delivering the updated recommendations to farmers and farmer advisers and for educational and demonstration programs working out.




Objectives

The target of the project is to improve cultivation systems in Bulgarian’s agriculture through efficient and sustainable use of plant nutrients. The specific objectives are:

• To summarize and update the information about the nutrients response depending on the crop and site specificity in the country.
• To evaluate to the possible extent the soil nutrient status on national and regional level.
• To develop a nutrient management software for farmers advising.
• To train and teach farmers and students in good fertilization practices.
• To contribute for improving the fertilization practice in the country.

Justification

Bulgarian agriculture is clearly in transition from at least three perspectives: 1) from the centrally controlled systems of socialistic times to free-enterprise; 2) from the very small, non-sustainable farms resulting from privatization of farmland to manageable business units; and 3) from a non-EU to an EU member country. It also seems clear that Bulgarian agriculture could be more productive than it is today and that improved fertilizer use could be a significant factor in increasing that productivity.

Therefore, this is an excellent time to launch an agricultural development program with a focus on sustainable nutrient management.

Generally, the fertilization practice in Bulgarian agriculture is strongly deteriorated. The farmers use single nitrogen in most of the cases. Lately, only 10% of the nitrogen fertilized area received phosphorus and 4% potassium. The summarized crop fertilization practices for wheat, sunflower, maize, and barley showed that current N use for these crops is 53, 41, 29, and 60 % of recommended rates respectively for these four crops which represent in total 83% of the cultivated area of Bulgaria. Phosphorus and potassium use ranged from 0 to a high of only 5 kg/ha for these crops. It is supposed that soil test levels have very likely declined below those assumed when defining the “recommended” rates so use as a percent of recommended is likely less than these estimates suggest.

During the cooperative farming soil sampling and analyses were organized for the utilized agriculture area every 4-5 years. Based on the soil nutrient status fertilizer recommendations were prepared for the majority of the cooperatives. During the last 20 years (after the transition to market economy) the soil nutrient monitoring system does not exist anymore.

Free soil analyses offered farmers by the National Agricultural Advisory Service (NAAS) in the past resulted in a considerable amount soil analysis results. However, lately NAAS closed its laboratory and do not offer that service to the farmers any more. Some other university and private labs do soil analyzes but in a limited number and not in a systematic way.

To generalize, there is some past experience in nutrient management but there is almost no soil testing of production fields and site-specific fertilizer recommendations currently taking place in the country. As it was mentioned the prevailing fertilization practices are not good. At the same time the development of competitive agriculture in the country requires competent nutrient management. The EU direct payments will afford an opportunity for increasing the fertilizers use. All this determines the great need to improve the fertilization practices in Bulgaria based on science.