The aim of all the techniques used in conservation agriculture (CA) is to promote the soil’s agronomic potential while maintaining optimum crop yield, long term. As such, soil should be considered as a living environment whose biodiversity, organic matter, and biological processes need protection. For this reason, certain agronomic practices are recommended, while others have been abandoned. Details on the techniques used.
The basis of conservation agriculture: know your soil
To convert to conservation agriculture, you need to know your soil. Soil analyses are essential to determining soil health, fertility and levels of organic matter. To carry out analyses, there are some fairly rapid diagnostic techniques that require little equipment:
- The spade test and visual evaluation of soil structure (VESS) are employed to observe the quality of the soil by looking at its aggregates and porousness. Soil samples are taken and graded using a standard grid to detect structural issues and to define suitable cropping systems or to compare methods.
- The mini 3D soil profile test is deeper (60 cm rather than 30). A telescopic loader and pallet fork are used to access and observe soil structure and clods, which are interpreted with the standard grid. The aim is to resolve problems of compaction and prevent further issues.
- The penetrometer is a quick diagnostic tool to detect soil compaction. The metal rod is used to penetrate the soil to check for resistance, i.e. compacted zones.
The soil profile diagnosis method takes longer and requires more expertise as there are more criteria to take into account.
Seeding without tilling
For minimum disturbance of soil, flora, and fauna, conservation agriculture uses practices with less tillage such as minimum tillage (min-till). The following are recommended:
- Direct drilling, which entails seeding without tilling.
- Direct seeding in established cover crops.
- Strip-till, which requires tilling the seeding line only.
Lengthening crop rotations and diversifying plant families
To control weeds and pests and promote soil fertility, conservation agriculture recommends:
- Diversifying species in the crop rotation.
- Implementing a cropping system with long crop rotations.
- Planting cover crops from different plant families and keeping permanent soil cover between crops. This practice is effective for reducing soil erosion and nitrogen leaching in the autumn.
Using weed control products
In the first few years, weedkillers such as glysophate are often recommended. After a time, fewer weeds will emerge so less herbicides are required. This is the result of greater mastery of the techniques, as well as the combined practices of chemical methods and rotation management (mechanical destruction, long rotations, cover crops, etc.).
Shredding cover crops and using pest control products
Pest control is another problem to manage under CA. In order to destroy pests’ habitats in cover crops, mechanical shredding is recommended. Horizontal shredders, which really rip up the residues, are more effective than vertical shredders. Otherwise, spot rodent control products and slug pellets are effective too.
Source:
Graham Shepherd, 2000, Visual Soil Assessment, Volume 1 - Field guide for cropping and pastoral grazing on flat to rolling country, https://orgprints.org/id/eprint/30582/1/VSA_Volume1_smaller.pdf