The agricultural model in the second half of the XX century usually favoured high biological and landscape diversity. The factors which affected that situation are:
- A big dispersal of land creating a mosaic of landscape,
- Existence of many refugia of natural ecosystems (little ponds, peat-bogs, sand meadows),
- Extensive management of significant part of cultivation, in the same time using few fertilizers,
- A low degree of soil degradation because of technology of cultivation,
- Cultivation of traditional plants varieties and raising traditional animals breeds in some regions.
Thanks to these factors, agricultural land in many Polish regions is still marked by bigger diversity than in other European countries.
On the other hand, in those times there were numerous factors degrading agricultural land:
- Dehydration in huge areas, drainage of peat-bogs, swamps and meadows, regulation of river beds,
- Decreasing water retention of valleys by deepening their beds and cutting down riverside trees,
- Introduction of monoculture cultivation in huge areas,
- Using many chemicals in agriculture, especially in 1970-1990,
- Introduction of alien, often genetically modified plant and animal varieties, mainly in the last decade of the XX century.
Another very dangerous factor joined the others mentioned before. It is the expansion of small buildings, roads providing access to them, and fences. This takes place mainly in previously open areas, especially around big cities, and in attractive places.
At the turn of the XXI century, we can observe a clear downward tendency in the share of arable land in the country. In the other agricultural land, we can clearly see a decreased percentage of cultivated land in favour of fallow land.
Because of the significant impoverishment of rural society at the turn of the XXI century, the processes of exploitation of natural resources have intensified. People poach and gain wood and fruits of the undergrowth illegally. A great group of farmers gave up cultivation because of its unprofitableness. That is why, the area of fallow land is significantly rising. Such land is often overgrown with forest, which, maybe strange, is not always conducive to biological diversity. It was extensive exploitation of agricultural utilisation that promoted high diversity of agricultural landscapes.
A part of uncultivated land is afforested by State Forests, particularly in huge areas. It is made according to modern principles of silviculture. Species composition usually considers biological diversity. However, there is a problem with individual farmers' areas, which often simply overgrow with light seeded species.
The changes in agriculture decreased the demand for meadows and pastures and their vast areas were left to natural succession. The lack of mowing or grazing by animals reduces biological diversity in these areas.
Wandering stray dogs and cats are also a problem as they reduce the populations of birds and little animals.
Insects form a group, which decreases its number in the fastest rate. They are killed in great numbers as a result of communication development, chemicals used in agriculture, vanishing wooden buildings, and liquidation of particular habitats. The reduction of insects fauna causes the decrease in number of insectivorous species: amphibians, birds and small mammals, as well as limits pollination of many plant species.
The main threats to the diversity of agricultural land after Polish accession to the European Union are:
- The enlargement of agricultural land, which is connected with the increase of fields area and agricultural monocultures,
- The increase of water consumption in agriculture,
- The increase of chemicals use in agriculture,
- The use of heavier farming equipment which degrades soil,
- The pressure of foreign concerns on building huge animal farms which degrade the environment,
- Replacement of pastoral farming with closed farms, which results in the disappearance of last meadows,
- Introduction of genetically modified varieties and breeds of species.
In order to counteract these changes it is necessary to:
- Preserve diversity of habitats,
- Maintain extensive management of pastures and meadows,
- Renaturalise wet areas,
- Enlarge forest areas taking landscape mosaic needs into consideration,
- Introduce many afforestations,
- Increase water retention,
- Protect river beds against erosion,
- Preserve local traditional plant varieties and animal breeds,
- Develop ecological agriculture.
The instruments helpful in achieving these aims may be agri-environmental programmes, afforestation of agriculture land programme, and the programme specifying actions in less favourable conditions of farming. These programmes were defined in 2003 in the Plan of Agricultural Land Development (PROW) for 2004-2006. Another important task is a complex spatial planning, which respects the nature and its interaction with any other activities in agricultural land.