A recent JRC-led article estimates the possible total soil loss due to harvesting crops in the European Union for two major crops to be in the region of 14.7 million tonnes per year.
When root or tuber vegetables (such as potatoes, sugar beet, carrots, onions and chicory roots) are harvested, some soil clings to them and is thereby removed from the field.
It turns out that quite a lot of soil is lost in this way – about 14.7 million tonnes per year in this study of sugar beet and potato crops in the EU-28. Most (65%) of this loss is due to sugar beet harvesting, 35% to potatoes.
While this Soil Loss by Crop Harvesting (SLCH) is much less than soil loss due to water erosion (about 950 million tonnes per year), it can be quite significant in regions of Belgium, the Netherlands, Ireland and North-East France, where root and tuber crops are important for the local economy.
Based on 1975-2016 data, the study finds that SLCH has fallen by 37% in recent years due to the reduced cultivation area of root and tuber crops, the EU sugar reform of 2006, the decline in sugar consumption, and the increased production of root and tuber crops in Asia and Latin America.
These soil loss figures are set to fall further as a result of technological developments in machine harvesting, increased awareness among farmers, and sustainability concerns within the sugar beet industry.
However, global SLCH may increase as a result of increased demand to sugar beet, due to the exponential use of biofuels in the transport sector, increased demand for root and tuber energy crops (bioethanol) and increased global sugar consumption.
The amount and rates of SLCH depend on several factors, including soil properties, crop type, agronomic practices and harvest techniques, and can differ by country and crop type. For example, soil loss due to sugar beet harvesting ranges from 4 tonnes per hectare per harvest in the Mediterranean countries (dry climate) to 10 tonnes per hectare per harvest in north-west Europe (wet climate). The SCLH rates for potatoes are around 3 tonnes per hectare per harvest.
As soil loss/erosion is recognised as one of the main causes of land degradation and a major threat to agricultural soil productivity, the authors recommend that Soil Loss by Crop Harvesting be included among the soil erosional processes (alongside soil losses due to water and wind erosion) considered by policymakers.
- Soil loss due to crop harvesting in the European Union: A first estimation of an underrated geomorphic process
- 1 mars 2019