Converting to zero tillage
Created on February 3, 2014
The most obvious practical obstacle to the uptake of conservation agriculture (CA) in Iraq is that zero-tillage (ZT) seeders are not commercially available. Uncultivated soil is much harder than tilled soil, and the springs and tines on conventional seeders are unable to sow the seed and fertilizer at a consistent depth. What’s more, conventional seeders are prone to the build-up of crop residues and mud on their tines, causing blockages and ineffective seed distribution.
The HSAD initiative is benefiting from expertise developed during an Australian-ICARDA project which works with local workshops to adapt conventional seeders to facilitate the planting of seed directly into untilled soil with crop residues.
The main changes needed to make conventional seeders suitable for ZT are:
• Narrow ‘knife’ points replace the typical ‘duck-foot’ points to reduce soil disturbance and drag by cutting a narrow slot in the undisturbed soil
• Tines with stronger springs and an adequate break-out force are fitted to enable seeding into hard, undisturbed stony and shallow soils without risk of damage to the seeder
• Row spacing is increased to 20-25 cm to allow reasonable flow of residues
• The seeder frame is raised and longer tine shanks are fitted to avoid residue clumping when sowing into thick and standing crop residue
• The distance between each row of times on the seeder is increased from 25 to 50-60 cm to improve residue flow, and tines are placed on 3 or 4 ranks in the 4-meter wide seeder models
• The seed/fertilizer box height is raised to provide good flow of seed and fertilizer down the pipes into the soil, especially for seeders with widely spaced tine ranks. Many seeders are also fitted with two separate boxes, one for seed and the other for fertilizer, to allow greater flexibility in application rates and placement
These changes allow the seeder to work effectively on the harder untilled soil and for the passage of crop residues without clogging up the tines.
The HSAD work plan included the conversion of four conventional seeders belonging to farmers selected from different regions in the Iraqi Kurdistan region. Priority was given to John Shearer, Rama and Nardi seeders because these are the best and most easily converted seeders. The ICARDA CA team directly facilitated the conversion of two seeders and made arrangements for the other two to be converted by farmers.
Immediately after conversion, four farmer field days were organized at Erbil, Bardarash (Duhok), Jam Jamal (Sulaymaniyeh), and Kalar (Garmiyan) at which the converted seeders were demonstrated, the ICARDA CA team and Ministry staff explained the principles and benefits of ZT technology, and farmers were able to ask questions and obtain more information on CA and ZT.
For more information on the benefits of conservation agriculture in the dry areas of the world visit: http://www.icarda.org/conservation-agriculture/teaser
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