Crop residues are natural resources with tremendous value to farmers. These residues are used as animal feed, composting, thatching for rural homes and fuel for domestic and industrial use. About 25% of nitrogen, 25% phosphorus, 50% of sulphur and 75% of potassium uptake by cereal crops are retained in residues, making them valuable sources of nutrients. However, a large portion of the residues, about 140 Mt, is burned in field primarily to clear the field from straw and stubble after the harvest of the crop. Each tonne of straw (rice or wheat) on burning releases 3 kg particulate matter, 60 kg CO, 1,460 kg CO2, 199 kg ash and 2 kg SO2. About 32-76% of the straw weight and 27-73% nitrogen are lost due to burning. The problem is serious in irrigated agriculture, particularly in the mechanized rice-wheat system. The main reasons for burning crop residues in field include lack of labour, high cost in removing the residues and use of combines in rice-wheat cropping system especially in the Indo-Gangetic plains (IGP). Currently residue from nine crops, rice, wheat, maize, millet, sugarcane, cotton, rapeseed, mustard and groundnut are subjected to burning. Crop residue management may include developing systems to plant into residue, baling and removal for use as animal feed or for industry.

Machinery for Crop Residue Management

Straw reaper combine

Straw reaper combine is tractor mounted and tractor power take off shaft operated. It consists of cutter bar reel, feeding auger and bruising cylinder like a traditional thresher. Straw and stubble left by the combine harvester is collected by straw combine and delivered to the cylinder concave section, where it is cut into small pieces and passed through the concave. The reciprocating cutter bar is utilized for reaping the standing stubbles and the portion of the straw left uncut by the combine harvester. The remained straw passed through the concave is aspirated by anin-built blower and fed into a trolley on back side covered by a wire net. Recovering of the left grains from the straw, a sieve system is provided beneath the concave.Straw combines are used to recover the wheat straw after combine operation with tractor having 35 hp or above. It capacity is 600 kg/h.

Straw combine harvester

It is tractor drawn pto operated straw reaper with trailer. Crop stubble cut height is 70-80 mm .The crop residue after cutting reaches to thresher, where it is threshed. A trailer is filled with straw at half an hour. The straw loaded trolley is unloaded with the help of tractor hydraulic in the field or straw can be unloaded to another trolley and transported to the farm shed.  70-80% crop residues are cut and threshed by this machine. The capacity of machine is 730 kg/h with tractor having 35 hp or above. 

Tractor mounted flail type chopper cum spreader

The tractor operated straw copping machine harvest the straw left in the field after the combining and chops in to pieces for spreading in the field in a single operation. The machine consists of rotary shaft mounted with blades /flails to harvest the straw and knives for chopping. The capacity of machine is 4 ha/day and can be operated by a 30 kW tractor.  The average height of stubbles was after cut was 30 mm. Traditional seed drill was found satisfactory after incorporating the chopped straw by disking and planking twice. The straw after cutting by the flails, pass on to the chopping mechanism. The chopping mechanism chops the cut straw to 50 mm size and spreads it in the field uniformly. The cutting unit has 38 flails mounted in three rows. The chopping mechanism has 300 mm diameter cylinder with six rows of serrated knives and four counter rows each having 22 knives fixed at the bottom. This machine is used for chopping of paddy straw with tractor having 35 hp or above, which helps in easy incorporation of straw in the soil in fewer operations by using traditional equipment. Since the incorporation of rice straw checks environmental pollution problem providing rich organic manure, there is great acceptability of the machine in rice –wheat cultivation system.

Stubble shaver

The machine consists of a rotary blade assembly, mainframe, fenders, platform, gearbox and three point linkages. Rotary blade assembly consists of three blades, which cut the stubbles and spreads the cut stubbles on ground uniformly because of higher blade speed. The blades are swinging type and this recoil on striking stone or a hard object.  35 hp or above size tractor operated stubble shaver is a versatile machine for cutting any crop residues such as wheat, paddy and grasses from the ground level. The operation of this machine for cutting paddy stubble replaces two disking operations, which saves time, energy and money.

Shrub master

It is a tractor pto operated equipment. It consists of cutting blades (swinging flails) joined to the bar, gear box for transmission of power at right angle, universal joints with telescopic shaft to connect the tractor pto and gearbox, adjustable side skids for controlling cutting height of shrubs or grass, safety guard and hitching frame. The bar having cutting blades at the ends is mounted on the gearbox shaft. The cutting process takes placed purely through impact and flails need not be sharp-edged. The blades are made of medium carbon steel or alloy steel and hardened. It is used for the clearance of shrubs, monsoon growth in forests, fields, fairways, verges, helipads and general clearance of grasses in fields with tractor having 25 hp or above.

Mowers and shredders

Mowers and shredders are available in two basic types: rotary or flail. Power requirements for both are relatively high, but they produce a more uniform residue cover. A balance is needed between standing stubble and chopped residue on the surface. Too much chopping to create short or no stubble leaves a matt of residue which may not flow around the ground opener. Besides mowers, shredders are another type of machines used for mulch management. They consist of knifes, rotating vertically at high speed around a horizontal axle. Usually they reduce the biomass to small pieces. The advantages include a fairly even spreading of the mulch, the control of pests and diseases and the shredded pieces do not interfere with the planting operation. However, the biggest disadvantage of shredders is that the chopped residues decompose much more quickly which means they would not last as long on the soil surface as non-chopped residues. Another serious disadvantage is the high energy consumption. For this reason shredders should only be considered in special cases for residue and cover crop management. Rotary slashers suffer from the same disadvantage.


It is tool for minimum or reduced tillage. It has rigid curved or straight shank with relatively narrow shovel points. The standards are arranged on heavy frames in two or three staggered rows to permit trash to pass between them without choking.  The depth of ploughing may be shallow as desired or as deep 450 mm or more. As the soil is broken by stirring, it is not inverted and pulverized to the extent that MB or disc ploughs crush the soil. Hence the chisel plough is used for stubble mulch or sub-surface tillage practice. It can used to loosen hard, dry soils before the regular plough is used. It is also used to broking up hard layers of soil just below regular ploughing depth. Equipment need proper soil moisture for working otherwise result clogging with residue, poor weed control and lifting of stones/clods on top surface.


Subsoiler ploughs are heavier than chisel plough,since they are used to penetrate the soil depths of from 500 900 mm. Tractors of 60-85 hp are required to pull single standard subsoiler through a hard soil at a depth of 900 mm. One standard is generally used for the deeper depth, but two or more can be used for sallower operations. Subsoilers are commercially available in both trailing and mounted units. For conservation agriculture subsoilers should work under crop residues (have cutting disks), not lift clods to the soil surface requiring subsequent tillage (shanks bent to the side), be only considered as exceptional repair tool. It can be used in dry soil only and water infiltration will not improve a lot when used improperly


Rotavator is suitable for preparing seedbed in a single pass both in dry and wetland conditions. It is also suitable for incorporating straw and green manure in the field. It consists of a steel frame, a rotary shaft on which, blades are mounted, power transmission system, and gearbox. Rotary motion of the PTO is transmitted to the shaft carrying the blades through gearbox and transmission system. A good seedbed and pulverization of the soil is achieved in a single pass of the rotovator. The size of rotavators vary from 1.2 to 2.2 m. The field capacity of equipment is 0.36 – 0.44 ha/h. Residue left after operation of plough and chisel is minimum 10% and it is maximum 50-70 with one cultivator operation.