The reciprocal impact of stubble cultivation on site conditions and vice versa
Crop cultivation methods incorporate a range of high to low levels of tractive power and deep to ultra-shallow levels of soil cultivation. In fact, the direct seeding method doesn’t require stubble cultivation at all. Ploughing is the most widely used method of preparing the ground for sowing. This method interferes heavily with the soil structure. It does have its advantages, however: it creates a clean sweep, which is great for seed drills and reduces pressure from weeds and pests, especially when the crop rotation is tight. The phytosanitary reasons for ploughing are extremely relevant because self-seeded plants, root-propagated weeds and heavy pest infestations can be a huge problem. In order to combat pest infestations in particular, crop residues need to be chopped, spread and neatly incorporated into the soil. Effective stubble cultivation removes unwanted plants, thus enabling mechanical weed control. If the soil is cultivated at a deeper level, it needs to be reconsolidated in order to safeguard the plants’ water supply.
Nevertheless, there are also disadvantages in terms of soil properties. Conventional cultivation using a plough is the main cause of soil silting, which prevents it from being infiltrated and encourages runoff and erosion. Inadequate aeration causes problems such as a lack of oxygen in the crust, insufficient soil warming, poor root formation in the main crop and poor crop development as a result. Stale surface water leads to water erosion because nutrients and soil particles drift away on top of the soil surface. As a result, so-called “min-till” farming methods (cultivation without using a plough) are gaining in importance.
Long-term trials are already producing valid data in support of these methods. As a general rule, the choice of method depends on the site conditions. That said, just because something is technically possible does not mean it is beneficial from a crop cultivation standpoint. Accordingly, soil that is too wet should not be tilled if it contains high levels of clay. Otherwise, there is a danger of soil compression which can be detrimental to the soil properties. Using higher levels of chemical plant protection to improve weed eradication can cause even greater destruction to soil fauna and have a negative impact on the soil. In a worst-case scenario, poor cultivation can lead to irreversible soil loss and intensified soil damage. Examples of min-till arable farming methods are described in the following section.