Peer review

Tillage is one of the primary activities for crop production. It is a major cost for crop production and has a strong influence on yield through its interaction with timely planting and good plant stand. In the South Asian rice-wheat systems of the Indo-Gangetic Plains the tillage for rice is unique in that wet plowing (locally called puddling) is most commonly used to prepare the field for eventual transplanting of rice seedlings. The field is usually plowed dry, flooded, and then puddled (plowed when flooded) to create a soil with poor soil physical properties and low water infiltration. Most farmers puddle their fields for rice. Wheat and other non-rice crops grown in this system after rice in the same year receive normal dry plowing before the seeds are planted, usually by broadcasting the seed and incorporating by plowing. Traditional methods of land preparation are either done by animal or by tractor power although there are pockets of land where manual labor provides the power for this work. Animal power is more common in the eastern belt of the Indo-Gangetic Plains in Eastern India, Bangladesh and Nepal. Tractor power has almost replaced animal power in NW India and Pakistan and is gradually replacing animal power in the rest of the region. Land preparation for rice and wheat usually requires multiple passes of the plow and a practice called planking (a wooden plank is drawn over the field) to level the fields and help break the clods. When animal power is used this can take many days and lead to delayed planting of the crop. Even with tractor power, land preparation can take several weeks. If the land is too wet or dry this can be even longer. Poor availability of tractor power can also delay planting. Late planting is a major cause of low wheat yields. If wheat is planted after the end of November, yields can be reduced by one percent or more for every day's delay in planting. In addition, the systems of broadcasting seed to establish wheat can result in poor plant stands and even lower yields than anticipated. In order to overcome the problems of late planting, poor plant stands and to reduce the costs of production research has been evaluating the use of zero- and reduced-tillage systems for wheat in the rice-wheat system. In rice, research has started on systems that do away with puddling the soil since it is hypothesized that by not puddling the soil, the next upland crop will have better soil physical conditions for growth. This paper first describes the present practices for tillage and crop establishment for rice and wheat and then goes on to describe some of the new tillage and crop establishment options being researched in the region. For wheat, the following systems are described and research results presented: 1. Surface seeding. In this system no land preparation is used and seed are merely broadcast onto saturated soils. 2. Zero-tillage. In this system wheat is planted directly into the rice stubble without land preparation. Different soil coulters are needed depending on the rice residues present at planting. 3. Reduced-tillage systems. Usually a rotavator is used to prepare the soil ahead of a seed drill and compaction mechanism. This allows wheat to be planted at the same time as land is tilled. 4. Bed planting systems. These ridge and furrow systems have been introduced to improve water and fertilizer efficiency, allow mechanical weeding and reduced herbicide use and increase yield potential because of less lodging. Beds can be made for every crop or left permanent for succeeding crops. For rice, the major research presented is in the area of dry seeded rice where puddling is not done. Weeds become a major problem in this system and various options for this problem are discussed. Some time is also devoted to the use of mechanical transplanters and use of direct seeding on puddled soils. This article discusses several new tillage options for rice and wheat that have great potential in the rice-wheat systems of South Asia. They offer reduced costs of production, the ability to plant on time, give better plant stands and higher crop yields. They also reduce the use of natural resources such as fuel and tractor parts, save water and fertilizer resources and increase the efficiency of agriculture. Also because they can reduce fuel emissions and reduce residue burning they contribute to less global warming.

Text in English

0111|R01JOURN|AL-Wheat Program|3