Crop rotation

Crop rotation is a justified alternation of crops in time and place on a certain arable land.
There are various reasons why growing a crop on the same area reduces the amount of yield from it. They are grouped into four more general groups: biological, chemical, physical, and economic.
The biological causes include the danger of multiplication of the same weeds, diseases, and pests on cultivated plants.
Chemical causes include the risk of unilateral “export” through the production of nutrients in the soil.
The physical reasons include the danger of deterioration of the physical properties of the soil when applying the same type of tillage technology.
The economic reasons include the need to preserve soil fertility by appropriate crop rotation, while obtaining high and stable yields.
The period during which all crops in a certain sequence pass through all fields is called rotation of crop rotation. The cultivation of the crop after a period of 2-3 years is called a short monoculture, and in more years – a long monoculture.

Elements of crop rotations:
Total crop rotation area: This is the area on which the entire crop rotation is located. Its size is equal to the sum of the sown areas of the individual crops included in the crop rotations.
Crop rotation field: Represents a certain arable area on which one crop is grown (or several – in a collective field).

Aggregate fields: are fields in which two or more crops are grown. Their compilation is necessary when the areas provided for a crop do not correspond to the average size of the field. When compiling aggregate fields, certain requirements for the crops that are included in it must be observed:
• the crops have similar requirements for soil fertility and influence it in approximately the same way.
• have similar breeding technology;
• to return at approximately the same time.

When compiling aggregate fields, the crops can be conditionally grouped into the following groups:
Table 1 Grouping of crops

The crop rotation scheme expresses the sequence for growing all crops in all fields of crop rotation.
A distinction is made between general and specific crop rotation schemes. In the general ones the names of the groups of cultures are presented, and in the specific ones the type of culture is indicated. The general scheme is of a recommendatory nature, and when solving the specific tasks, various specific crop rotation schemes can be drawn up.
Example:

Predecessor: The crop grown in a field in the previous year is called the predecessor in terms of the crop grown in the same field in the current year (lentils are the precursor of wheat; wheat is corn, etc.). The role of crops as predecessors and their place in crop rotation is very important and is determined for individual countries and regions experimentally.

Legend: ++ very good predecessor; + good; – bad; + – conditional alternation
Rotation period (crop rotation): Expresses the period (time) for growing all crops in all fields of crop rotation. A rotation table means the presentation of the rotation period in tabular form.
Types of rotations: Rotations of crop rotation with participation of annual crops only:

• With this type of rotation, the rotation period is equal to the number of fields.

Rotations of crop rotation involving annual crops and perennial forage crops:
Option I – when perennial fodder crops occupy as many fields as years are grown in the same place.
Example:

In this case the rotation period is equal to the number of fields, but there is a previous period for mastering the crop rotation (in this case 2 years). In the scheme thus proposed, perennial grass (alfalfa) occupies 60% of the total crop rotation area, and in practice most often occupies 12-14%.
Therefore, with the exception of specialized farm crop rotations, another option is preferred.
II var.- rotation of CO with inclusion of perennial fodder crops in the form of “GRASS WEDGE”.
Example:

Here there is a full rotation = 15 years and a short rotation = 5 years. The rotation period is equal to the number of fields multiplied by the period of growing the perennial crop in one field.
Crop rotation for vegetables, flowers, and medicinal plants
The circle is as follows: complex-flowered-cruciferous-awn-flowered-potato-cereal-legume-honest-snowdrop-pumpkin.

Suitable precursors for vegetable crops
Plants feed on substances left in the soil from previous crops. When planning planting, keep in mind what will be planted in the garden after which.

Source: [15] https://agronovinite.com/kakvo-e-seitbooborot-i-kak-se-pravi-rotatsiya-na-kulturite/

2.1.1. Blagoevgrad region
Climate
The climate has a strong Mediterranean influence along the Struma, Strumeshnitsa and Mesta rivers. This determines suitable conditions for growing a large number of heat-loving Mediterranean plant species, unlike other regions of the country. The conditions for irrigation and reclamation in the river valleys are good. The soil conditions are good for growing tobacco, vineyards, orchards, heat-loving crops, herbs, mushrooms and more. Particularly typical for the region are the long summer droughts in the lowlands, and the precipitation is below the national average and is unevenly distributed by seasons and months.
Plant growing

The specialization of the region in the plant production of the country is determined by the production of tobacco, potatoes, tomatoes, peaches, grapes.
The arable land amounts to 155,091 decares or 27% of the UAA. The largest share of arable land is occupied by cereals 38%, and technical crops are 24%. The largest relative share of cereals is wheat, which occupies 57%. From all technical crops, the share of tobacco is the largest – 92% or 33,712.5 decares, which is 14% of the area with tobacco in the country. Potatoes occupy 3% of the UAA or 14% of the potato area in the country. They are concentrated in the municipalities of Yakoruda, Satovcha, Petrich and Gotse Delchev. Fresh vegetables occupy 6% of the area with vegetables in the country, and the areas with vegetables grown under tall greenhouses are 22% of all greenhouses. The permanent crops in the region occupy 51,634 decares. (8.8% of the UAA), with the largest areas of vineyards – 34,994 decares. (68% of perennials in the region). Peaches and nectarines are 5,279 decares, apples – 5,187 decares, cherries – 1,952 decares, plums – 1,474 decares. The positive trend of development of organic farming continues.
On the territory of Blagoevgrad region localities of herbs of commercial importance are not known, except for St. John’s wort, oregano, thyme, yarrow and others. Attempts are also being made to grow herbs for commercial purposes by private farmers who grow lavender, white oregano, echinacea and others.

Source: [1] PROJECT REPORT on STUDY AND ASSESSMENT OF THE STATE OF THE MAIN SOCIAL, ECONOMIC AND ENVIRONMENTAL PROBLEMS OF THE AGRICULTURAL SECTOR IN THE CROSS-BORDER BORGER OF GREECE AND BULGARIA AND THE ROLE OF THE YOUNG PEOPLE IN SOLVING THESE PROBLEMS; Sofia, September 2020
2.1.2. Smolyan region
Climate
The territory of Smolyan region covers a belt with a predominantly mountainous climate, which in the southeastern parts of the region is transitional Mediterranean. It is characterized by mild and snowy winters and cool summers. The region is characterized by mild snowy winters, cool springs, summers without extreme heat and relatively warm and long autumns, formed by the altitude and the direct impact of the nearby Aegean coastal lowlands. Precipitation is relatively irregular, there is a pronounced winter and spring-summer precipitation maximum.
Plant growing
The existing specific soil and climatic conditions are suitable for growing mainly potatoes, oriental tobacco, fodder crops, as well as strawberries, raspberries, essential oils and medicinal plants in some settlements. All other crops in the municipalities are grown for personal consumption and have no economic significance.
Potato production in the area is the most common plant production and has very favorable conditions for development, given the soil and climatic conditions and the experience of the population for growing, harvesting and storing potatoes, not least also due to the inertia of thinking. Potato production is an opportunity for the survival of individual households and is a significant source of cash within municipal economies. The analysis shows that if there are initiatives to find and offer domestic market for the produced potatoes, especially given their high quality, the problem of their growing is solved. An increase in potato production has been achieved, but there are negative factors, such as non-sanctioned imports from abroad, as well as the lack of good organization for their market realization, both within the country and abroad. In recent years, there has been a tendency to reduce the area planted with potatoes and significantly reduce the average yields. The reasons for this are complex, but must be sought primarily in the high cost and increasingly difficult market realization of production, deteriorating quality of planting material and varietal composition, extensive agriculture with a predominance of manual labor.
Tobacco is the second most important agricultural crop grown in the Smolyan region. For the municipalities located in the eastern half of the region it is the main livelihood of the population and has economic significance. At the same time, it is extremely dependent on nature and climatic conditions and especially on the economic conjuncture.
There are about 3,500 tobacco growers in the region, who produce nearly 1,500 tons of tobacco.
In Smolyan distrcit there are favorable natural conditions for the growing of berry crops. In recent years, there has been a tendency to increase the area for growing, especially of strawberries. In addition, the local population has gained significant production experience in growing these crops. Proof of this are the significant areas (200 ha) of berry crops grown 15-20 years ago. This production is in great demand, the crops are more suitable for organic and ecological farming than potatoes. They are sold at a good price, but due to the perishability of the fruits, the lack of refrigeration facilities and good organization for their fast purchase, the areas are still limited. In addition, most berry crops are perennials with a strong root system and protect the soil from erosion on sloping terrain or they have anti-erosion and soil-strengthening role, which is of great importance for the area.
Another possibility in the development of plant growing is the cultivation of essential oil and herbal plants. Mursal tea, lavender, sage, white oregano are grown on small areas in the area. In recent years, more and more farmers in the municipality of Banite grow lavender seedlings in small areas and in their backyards, which are sold in other parts of the country.
Orchards are capital-intensive, but create conditions for long-term, efficient agriculture. The region grows mainly apples. Favorable conditions such as alternative crops are available for apples, plums, walnuts, hazelnuts, cherries. Frozen fruits – cherries, sour cherries, blackcurrants, raspberries, strawberries and some wild fruits – blackberries, blueberries have good opportunities for realization on the western markets. Dried apples and plums are best accepted from all dried fruits.
Forage production occupies approximately 58% of the arable land in the region. Its development is of great importance as it provides roughage for livestock. In recent years, the average yields of natural meadows have been significantly reduced in terms of their potential. This is mainly due to one-sided fertilization, and often lack thereof.
Source: [1] PROJECT REPORT on STUDY AND ASSESSMENT OF THE STATE OF THE MAIN SOCIAL, ECONOMIC AND ENVIRONMENTAL PROBLEMS OF THE AGRICULTURAL SECTOR IN THE CROSS-BORDER BORGER OF GREECE AND BULGARIA AND THE ROLE OF THE YOUNG PEOPLE IN SOLVING THESE PROBLEMS; Sofia, September 2020

2.1.3. Kardzhali region
Climate
The formation of the transitional continental and transitional Mediterranean climate is determined by the nature of the atmospheric transport and the transformation of the air masses on the surface of the relief. The average annual temperature is around 12-13 0С, and the annual precipitation is within 700‐800 mm. The region is in the South Bulgarian climatic region and more precisely in the Eastern Rhodope climatic region with a warm Mediterranean influence. Winters are relatively mild. Minimum temperatures during the winter months are relatively high – the average is about 0 degrees. The days with snow retention are 39. The summer is long and hot, with maximum temperatures reaching 39-40 0С and average at about 24 degrees.
During the autumn-winter period, under the influence of Mediterranean cyclones, some of the heaviest precipitation falls. There are two maxima: winter – November, December, January; spring – May, June, July, and a minimum – August, September. Due to the southern position of the area, most of the winter precipitation falls in the form of rain or rain and snow.
Plant growing
The agricultural sector is declining. Much of the agricultural land is given for rent or lease /90% of their UAA/. The activity is aimed at growing basic agricultural crops and large livestock farms. The plant growing in the area is dominated by oriental tobacco and has an almost monocultural character. Other more common crops are cereals (mainly wheat and rye), as well as vegetables (mostly potatoes and peppers). Perennials such as vineyards, fruit trees and oilseeds have a small share, but with the potential for expansion.
The land in the small farms is own and serves mainly for the production of fodder for the raised animals and the cultivation of tobacco and potatoes, and there is no frequent change of ownership. The agricultural production is aimed mainly at satisfying own needs. The potential for agricultural development is limited physically and geographically by the available resources, including the development of the hydromeliorative network. Again, due to the geographical features of the region, the share of arable land is much lower than in other parts of the country.
The region of the Eastern Rhodopes is suitable for growing stone and walnut fruit species. Fruit growing has a tradition in the Eastern Rhodopes, but have not been developed due to decades of monoculture tobacco cultivation and lack of need for development of alternative agriculture. There is a renewal and establishment of new orchards. The financing under the measures of the Rural Development Program gives a serious impetus to the increase of the areas occupied with fruit crops. Despite the availability of financial resources, the cultivation of fruit crops requires specific knowledge and skills that most farmers lack.
The soil and climatic conditions of the region are a prerequisite for growing technical crops /flax, cotton, peanuts, etc./ and essential oil and herbs for the pharmacy needs /lavender, mint, oil-bearing rose, etc./, as well as some less demanding cereals, like rye.
Source: [1] PROJECT REPORT on STUDY AND ASSESSMENT OF THE STATE OF THE MAIN SOCIAL, ECONOMIC AND ENVIRONMENTAL PROBLEMS OF THE AGRICULTURAL SECTOR IN THE CROSS-BORDER BORGER OF GREECE AND BULGARIA AND THE ROLE OF THE YOUNG PEOPLE IN SOLVING THESE PROBLEMS; Sofia, September 2020

2.1.4. Haskovo region

Climate
The climate in the region is extremely favorable, as it is influenced by the Mediterranean. It is especially pronounced in the southern part of the region and along the Arda River in Ivaylovgrad, Lyubimets, Madzharovo and others. It is characterized by mild winters and volatile snow cover, hot summers – often temperatures reach up to 40˚ C. Spring comes early – in early April, and autumn is longer and warmer. Droughts are often observed in summer.

Plant growing
The Agriculture is one of the leading industries for Haskovo region, which boosts the employment for a large part of the population in the region. There are extremely favorable soil and climatic conditions for the development of crop production in the region. The temperate-Mediterranean climate, combined with the abundant water resources in the region, are important prerequisites for the cultivation of a wide variety of crops. The tobacco is a widespread technical crop in the area. It is grown mainly in the lower parts of the Eastern Rhodopes and the Sakar Mountain. Haskovo region is famous for the production of watermelons, melons, excellent grapes, tomatoes, cucumbers and many other fruits and vegetables. Priority in the development of crop production is the planting and replanting with young vineyards, increasing the area, perennials and the establishment of seed plots for certified species.
Crop production, as a branch, produces a larger share of the total agricultural production in the region with production of cereals, technical and fodder crops predominantly. Vegetables, perennials – vines, fruit species, etc. are also grown.
Summarized for the municipalities in the region, it can be concluded that there is a certain territorial distribution of the different groups of agricultural crops. This is due to the climatic and soil features, as well as to the possibility of consolidation of agricultural land. Predominant crops in the plains and mountains of the region are quiet different. In general, cereals are predominantly cultivated in the municipalities of Dimitrovgrad, Haskovo, Harmanli, Simeonovgrad. Leading in vegetable production and cultivation of perennials are the municipalities of Lyubimets, Svilengrad, Harmanli, Dimitrovgrad. The cultivation of oriental tobacco has traditions in the area, as it is mainly presented in the semi-mountainous parts of the municipalities – Stambolovo, Mineralni Bani, Ivaylovgrad, Topolovgrad, Svilengrad and Haskovo.
In general, based on the total arable agricultural area, Lyubimets municipality is a leader in the cultivation of the entire spectrum of agricultural crops. Dimitrovgrad Municipality is characterized by the most consolidated areas and the highest average yields per decare. The area is known for high yields of cherries, apples, plums, peaches, watermelons and melons – above the national average.
The positive fact is that the holdings with UAA over 150 decares is 4%. This is an indicator for consolidated intensive agriculture.
Haskovo Region has and is at a leading region in the country in terms of the area of agricultural land occupied by perennial crops and mostly vineyards. The cultivation of wine grape varieties is determined by the extremely favorable soil and climatic conditions – as evidenced by the high quality wine grapes harvested, serving as raw material in the wine industry. Wine production is really placed on an industrial basis, as the main part of the processing facilities are new, realized through projects under the Rural Development Program 2007-2013. Big share of labor is employed by the newly enlarged farms with processing facilities. To a large extent they are structurally determining for the economy of the municipalities of Lyubimets, Ivaylovgrad, Svilengrad, Harmanli, Stambolovo.
, Ивайловград, Свиленград, Харманли, Стамболово.