DRAINAGE REQUIREMENT IN BANANA NextEnd

INTRODUCTION  Poor drainage is a major cause of reduced yield and quality of bananas.  In many cases, the effects of poor drainage are not recognized;  Hence, it is not given Proper attention.  Banana farms must have good surface and internal drainage to attain good yield. PreviousNextEnd

EFFECTS OF POOR DRAINAGE A poorly drained site does not allow for the rapid disposal of surface water, resulting in ponding. The water table often rises into the banana root zone, particularly during the wet season. Thus, the soil in such a site becomes waterlogged. Water logging is also caused by flood waters and sustained heavy rain. Air (specifically oxygen) in the soil is essential for healthy root growth of plants PreviousNextEnd

Poor drainage decreases production because plant roots become stunted or killed and these can no longer supply the plant with the necessary water, nutrients, and anchorage. Poor drainage is indicated by: Shallow root systems Small plants and bunches Choking Pseudostem breakage Yellowing, reddening or scorching of leaves Reduced finger length PreviousNextEnd

Damage to roots owing to burrowing nematodes is also believed to be worse in poorly drained soils. Certainly, the impact of nematodes would be worse in a poorly drained situation because of the poorer root growth due to water logging. Sub-soil coloring can indicate past water logging if a water table is not present when inspecting a site. An orange and black mottling of the soil is caused by ferric and manganese ions and indicates periodic water saturation. Blue or grey colored soil indicates prolonged water saturation. PreviousNextEnd

Drainage strategies The drainage system required depends on the soil type and situation. Alluvial soils need to be drained well but even soils in sloping situations can suffer from water logging where there are changes in soil type, impermeable layers, and springs. PreviousNextEnd  Before planting, implement a drainage plan on your farm to ensure that runoff water is efficiently controlled and disposed of. This may first involve a grid survey to determine the best planting direction. Surface drainage

Where possible, land should be shaped to allow the ready movement of water off the block and into a system of grassed waterways (shallow drains) or into natural drainage lines. This may involve land- planning to ensure a continuous steady fall. Rows should be aligned so that water can move along the interrow passageways. Rows of bananas should be mounded up either before or after planting. It is particularly preferable to do so in double rows before planting so that water does not pond between the two rows of the double row causing water logging. PreviousNextEnd

The mound should peak between the 2 rows of the double row. Mounds may be formed with plows or special delving plows. Mounding of banana rows is an important strategy to reduce the effects of water logging. PreviousNextEnd  Deep ripping of land before planting greatly improves plant growth and the movement of water through the soil profile so improving the internal drainage of the soil.  Deep drains are necessary to take excess surface water away from the plantation to water courses.  They can also assist in lowering the water table of the soil so that more of the soil profile is aerated allowing for root growth. Subsurface drainage

Fluctuating water tables are particularly damaging to banana root systems. If the water table rises to the root zone for 24 hours or longer many roots are killed. Water tables should be maintained below 1 meter. The level of the water table can be assessed by digging observation holes. Deep drains can also act as part of the drainage network for taking excess surface water away. In Mindanao where bananas are produced for export, very elaborate drainage systems are used in the plantations PreviousNextEnd

 The frequency of drains depends upon a number of factors including the duration and intensity of rainfall and the rate of water movement in the soil.  The effectiveness of a drainage system can be assessed during periods of heavy rainfall.  Standing surface water should not be present for more than two hours after the heavy rain has stopped.  Water should be moving freely towards the main drains PreviousNextEnd

OTHER CONSIDERATIONS Plantation access can be badly impeded by poor drainage or too many drains. This makes it difficult to get the fruit to the packing shed. The latter can lead to additional mechanical damage of fruit due to the uneven road surface. Water logging problems can also be induced by over irrigating. Generally, bananas require from mm of water per week. PreviousNextEnd

Applying more than this amount of water will cause the soil in the root zone to be saturated longer than is necessary. Special attention should be paid with drip irrigation to ensure the correct spacing of drip emitters (approx 80 cm will be good in most situations) to limit the extent of the saturated zone, which occurs for extended periods directly below the emitter. PreviousNextEnd