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Guo Peiyu
China Agricultural University
Han Lujia
China Agricultural University

Technology flow and equipment

The handling of straw for feed on individual farms in China has mostly been done manually, with the aid of little machinery. However, with increased scales of production and reduced labour force as town enterprises develop and attract away workers, it is inevitable that there will be a gradual move towards mechanization of animal husbandry. Of course, the process will a take long time considering the situation in the country. The purpose of this chapter is to introduce machinery and equipment suitable for different levels of mechanization of straw feeding. It will present types, uses and selection principles of machinery and equipment for upgrading and utilizing straw as feed.

The technical flow from straw collection and processing to feeding could take many routes, from simple to complex, depending on the level of upgrading, the nutritive value of the straw, and commercialization of straw products (Figure 6-1).

Figure 6-1. Technical flow chart of residue processing

Flows 1 and 4 are manual handling systems, some elements of which can be replaced by machines nowadays. Flow 2 is the best processing method to increase intake and utilization of an entire crop without further treatment than the kneading into thread-like pieces. This is appropriate for maize stover of high nutrient value. The final process of flows 3 and 6 is ammonia treatment. The difference between flows 3 and 6 is that 3 is used for whole straw, such as rice and wheat straw, while 6 is suitable for maize stover. The final step of flow 5 is heat extrusion. Its key part is the heat extrusion equipment. Flow 7 shows that, after ammonia and chemical treatment, straw needs to be ground and mixed with nutrients, and finally pelleted or wafered. Straw treated by this method has the advantages of being of high density, easy to store and transport (marketing), reduces waste at feeding and avoids diet selection by the animal.

Both flows 8 and 9 are suitable for ensiling maize or sorghum stover. In flow 8, harvesting, bundling, transporting, chopping and loading into a trench silo are performed separately, and most of them can be done manually, but the chopper or so-called "silage cutter" is absolutely necessary. In flow 9, the residues are harvested, chopped and loaded into the wagon using a combine, then transferred to a silo.

The processes used for upgrading of straw for feeding and the machinery options are listed in Table 6-1.

Table 6-1. Machinery selection for various technical processes in upgrading straw


Machine type

Straw collection

Rectangular baler; round baler; stacker; stationary baler.

Loading and transport

Bale loader mounted on wagon or trailer; round bale wagon; stack-mover; wagon; trailer.

Kneading and cutting

Kneading and cutting machine.


Cylinder chopper; flywheel chopper.

Heat extrusion

Heat-extrusion equipment.

Ammonia treatment

Ammonia treatment equipment at normal temperature; heated ammonia equipment; ammoniation tank; ammoniation oven.


Hammer mill; fixed head mill; claw-type mill; double roller mill.

Pelleting or wafering

Pelleting equipment; wafering equipment.

Silage cutting, chopping and loading

Silage combine and trailer.

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