Effective land leveling reduces the work in crop establishment and crop management, and increases the yield and quality. Level land improves water coverage that
Improves crop establishment
Reduces weed problems
Improves uniformity of crop maturity
Decreases the time to complete tasks
Reduces the amount of water required for land preparation
Yield
Research has shown a large increase in rice yield due to good field leveling. The following table shows the results of land leveling experiments in Cambodia between 1996 and 1999.
|
Year |
Rice Yield (t/ha) |
|
|
Leveled fields
|
Unleveled fields |
|
|
1996 |
3.40 |
2.67 |
|
1997 |
2.27 |
1.46 |
|
1998 |
2.72 |
2.36 |
|
1999 (CARDI) |
2.34 |
2.00 |
|
Average |
2.72 |
2.19 |
Results of land-leveling experiments conducted by CIAP in Cambodia,
1996-1999
This table of results, for the same rice varieties and the same fertilizer input, shows that the average increase in crop yield was 24% or 530 kilograms per hectare.
In two experiments conducted at different localities, a strong correlation was found between the levelness of the land and crop yield. This correlation is shown in the chart below:
Weed Control
Land leveling increases yield. A large part of this increase is due to improved weed control. Improved water coverage from better land leveling reduces weeds by up to 40%. This reduction in weeds results in less time for crop weeding. A reduction from 21 to 5 labor-days/ha is achieved. This represents a reduction of up to 16 person-days per hectare – a 75% decrease in the labor required for weeding.
Farm Operation
Land leveling makes possible the use of larger fields. Larger fields increase the farming area and improve operational efficiency. Increasing field sizes from 0.1 hectare to 0.5 hectare increases the farming area by between 5% and 7%. This increase in farming area gives the farmer the option to reshape the farming area that can reduce operating times by 10% to 15%.
Seeding Practices
Leveling reduces the time taken for planting, for transplanting and for direct seeding. Land leveling provides greater opportunity to use direct seeding. The possible reduction in labor by changing from transplanting to direct seeding is approximately 30 person-days per hectare.
Efficiency of Water Use
Rice farmers using animal or 2-wheel tractors rely on water to accumulate in the field before starting land preparation. The average difference in height between the highest and lowest portions of rice fields in Asia is 160mm. This means that in an unleveled field an extra 80mm to 100mm of water must be stored in the field to give complete water coverage. This is nearly an extra 10% of the total water requirement to grow the crop. Land leveling effectively terraces fields allowing water in the higher fields to be used in the lower fields for land preparation, plant establishment and irrigation.
