Soil is the most valuable natural resource for farmers. Due to its long formation period, it is considered a non-renewable resource.
The International Soil Reference and Information Centre (ISRIC) estimates that soil is currently a natural resource seriously threatened by erosion, loss of organic matter and nutrient imbalance.
Current agricultural practices disrupt the soil balance. With each growing season, the agricultural soil where we grow crops degrades and loses nutrients, changes its chemical composition and decreases in quality and fertility.
In order to recover its properties and regenerate all the components of the soil, different techniques are used in agriculture, such as crop rotation or fallow land.
Crop rotation consists of alternating plants from different families and with different nutritional needs in the same region of the land during different cycles. Thanks to this practice, soil depletion is avoided, among other benefits.
What is fallow land?
Fallow is an agricultural technique that consists of not sowing the arable land during one or more growing seasons.
These fallow periods are usually carried out every two or three years and generally account for 40% of the arable area. Therefore, those who apply this method divide the land into: productive or for crop rotation.
This ensures that the orchards are highly productive and that planting is never stopped. One percentage of the land will be temporarily fallow while the other will be producing.
Objectives and benefits of fallowing
The main objectives of this agricultural practice are:
- To achieve the recovery and storage of organic matter in the soil The use of soil conditioners is very important in this case.
- To replenish the nutrients in the soil.
- To recover soil fertility.
- To avoid overexploitation of the land.
- To prepare the soil for the next crops.
- To guarantee the quality of future crops.
In addition, other benefits of fallow are:
- Storing soil moisture.
- Avoiding the spread of pathogens, controlling pests and diseases.
- Combating weeds.
- Reducing pressure on the soil.
Among the disadvantages of fallowing, it is worth mentioning that the land stops producing for at least one year.
Etymology of the term fallow
The term fallow comes from the Latin vervactum, which is composed of the words veris (spring, see spring and summer) and actum (act, participle of the verb agere, see: act), i.e. “made for the spring”.
It is used, as we know, to give a name to areas of land that are maintained but not sown, in order to encourage their regeneration.
Origins of fallow land
Crop rotation emerged at the end of the Middle Ages. In Europe, the demand for food was increasing and there was not enough land to produce such a large quantity of raw materials and, moreover, to produce quality foodstuffs. As a result, these farming techniques emerged, which ensured that the land produced high quality raw materials.
Nowadays, in addition to leaving the land fallow, it is also treated to recover its nutrients by applying fertilisers that accelerate the regeneration process, eliminating weeds and controlling crop pests and diseases.
Types of fallow
There are generally two types of fallow, depending on the fallow period between crops:
- Short fallows: it takes one or two years before the land is cultivated again. The regeneration of the land is not complete. The regeneration of the land is not complete.
- Long fallows: the fallow periods are longer, from three to four years. Land regeneration is complete. The regeneration of the land is complete.
Farmers also use other terms, such as:
- Year and time fallow: the land is fallowed once a year.
- One-third fallow: two years of fallow for each year of cultivation.
However, there is another way of differentiating between types of soil rotation, depending on how it is applied:
- Grass fallow (or stubble fallow): the land is completely abandoned during the fallow period.
- Tilled fallow: the land is maintained during the fallow period.
– Chemical ploughed fallow: weeds are removed with pesticides.
– Mechanical tilled fallow: the soil is treated with tools that accelerate the decomposition processes by burying the weeds, such as disc ploughing.
Finally, another form of classification is adapted to whether or not planting is chosen during the fallow period:
- Seeded fallow: sown during this process for nutritional purposes. Normally leguminous species (chickpeas, lentils, peas, etc.) are sown, as they enrich the soil.
- White fallow: nothing is sown.
What crops is fallow land used for?
It is a common practice in extensive agriculture, belonging to crop rotation systems. Thanks to this technique, soil fertility is maintained and weeds or diseases are controlled, among many other benefits mentioned above.