Drainage requirement in rice

EndNext

Rice is the most important food crop of the world.

Rice is a semi-aquatic plant and hence survives better under

water logged condition compared to other crops.

Drainage is the artificial removal of water in excess of the

quantity required for the crop.

Drainage includes removal of excess water of both surface and

subsurface in the root zone of crops.

Water logging occurs due to excess rainfall, floods, tidal waves

etc. and water loss happens due to runoff, deep percolation,

evapo-transpiration etc.

Previous EndNext

INTRODUCTION

When the former one exceeds the later, drainage requirement is realized.

There are many causes are realized due to water logging in rice fields.

Removal of excess water through drainage improves the soil condition and in turn growth and yield of rice.

Previous EndNext

Water logging occurs due to excessive rainfall, floods, rise of

ground water level, tidal water and even excessive irrigation.

Though rice is grown under submerged conditions, it responds well

to adequate drainage.

Due to continuous growing of rice under submerged condition, the

soils develop ill or poor drained conditions.

WATER LOGGING

The natural processes like surface runoff, deep percolation and

evapo-transpiration are not adequate enough to drain such

waterlogged areas within reasonable period without affecting the

crop yields.

Previous EndNext

Causes of water logging:

At a number of places, the problem of excess water is also

associated with the salinity and alkalinity problems, which further

aggravate the situation.

Continued stagnation of water often leads to accumulation of toxic

bio-chemical substances and silt deposition.

Rice grown in ill-drained soil is subject to toxic effect of reduced

products as sulphides and methane.

Further, the problem is more acute when organic matter content

of the soil is high.

The benefit of drainage is attributed to better aeration and / or

removal of toxic substances such as high concentration of ferric

ions and hydrogen sulphide.

Previous EndNext

Drainage is necessary in heavy clay soils. Drainage in sandy soils

leads to leaching of nutrients.

Drainage can be through vertical drainage or surface drainage.

There is no difference in beneficial effect between them since they

serve the same purpose.

Drainage exerts beneficial effects on soils with abundant production

of toxic substances and also in fields where large quantity of green

manure have been applied.

The extent of drainage and type of drainage system to be adopted

will depend on several factors relating to soil, crop, weather and the

hydrological characteristics of an area.

Previous EndNext

DRAINAGE

Moreover, certain stages of

growth like early flowering have

been reported to be more

susceptible to water logged

conditions than other stages of

crop growth (CRRI, 1980).

Excess water draining form rice fields

Previous EndNext

The drainage should be synchronized with the period just following

tillering and flowering.

Even 4 days complete submergence at flowering was more

detrimental than 8 days of submergence at seedling establishment

and 12 days of submergence during the late vegetative phase.

The drainage period could last from 3-7 days depending upon the type

of soil.

In case of sandy soils, drainage is about 3 days while in the case of

clayey soils it is about 5 to 7 days.

Previous EndNext

A study on depth and frequency of drainage conducted at Cuttack

(CRRI, 1968) revealed that lowering the water table up to 30-45 cm

below the surface gave the highest yield.

The design of drainage system will also vary with the situation

(Sarkar, 1980).

However, surface drainage system would be adequate for rice fields

as the water table is not required to be lowered too deep.

Previous EndNext

Rice is a semi-aquatic plant and hence survives better under

water logged condition than other crops.

Though rice is grown under submerged conditions, it responds

well to adequate drainage.

Continued stagnation of water often leads to accumulation of

toxic bio-chemical substances and silt deposition.

Rice grown in ill-drained soil is subject to toxic effect of reduced

products as sulphides and methane

Previous

EndNext

Summary

Drainage is necessary in heavy clayey soils. Drainage in sandy

soils leads to leaching of nutrients.

The extent of drainage and type of drainage system to be

adopted will depend on several factors.

The drainage should be synchronized with tillering and flowering

periods of rice.

Surface drainage system would be adequate for rice fields as the

deep water table is not required to rice.

Previous EndNext

1.Rice is a semi-aquatic plant and survives well under water logged

condition (True/False).

2.Rice will not respond to adequate drainage (True/False).

3.Rice grown in poor drained soil produces toxic substances like

sulphides and methane (True/False).

4.Drainage is more necessary in heavy clayey soils than sandy soils

for rice (True/False).

5.The drainage is much needed during tillering and flowering stages of

rice (True/False).

6.Rice field needs sub surface rather surface drainage system

(True/False).

Previous EndNext

ASSESSMENT

:CRRI, 1968. Annual Report. Central Rice Research Institute, Cuttack, India.

CRRI, 1980. Rice Research in India – An overview. Central Rice Research

Institute, Cuttack, India.

Rajendra Prasad, 1999. A Text book of Rcice Agronomy. Jain Brothers, New

Delhi.

Sankara Reddi, G.H. and T. Yellamanda Reddy, 2009. Efficient Use of

Irrigation Water. Kalyani Publishers, Ludhiana.

Sarkar, T.K. 1980. Drainage System Designs. In: Design Manual. Water

Technology Centre. Indian Agricultural Research Institute, New Delhi.

   

Previous End

REFERENCES