ICAR- Central Soil Salinity Research Institute, Karnal, Haryana
Online published on 12 October, 2015.
Irrigated agriculture, contributing about two fifth of global agricultural production from one fifth cropped area is under stress due to associated waterlogging and soil salinity problems. Subsurface drainage, an effective technology practiced extensively for amelioration of waterlogged saline irrigated lands in United States, Pakistan, Egypt, China and Australia, is relatively new in India. Of the 6.74 million hectare salt affected lands in India, severely waterlogged saline soils occur in about 2 million hectare area in arid/semi- arid alluvial north western states and more than 1 million hectare each in coastal and black cotton heavy soil (vertisol) regions. Considering the wide range of climatic, physiographic, soil, geo-hydrological and outlet conditions, drainage problems and solutions are location specific. A number of pilot scale SSD projects, undertaken by CSSRI during 1980’s, have slowly paved the way for mechanically installed large projects in the states of Haryana, Rajasthan, Gujarat, Punjab, Andhra Pradesh, Maharashtra and Karnataka. About 60000 ha waterlogged saline soils have been reclaimed with SSD in India with significant improvement in crop intensity, yields, land value and farmers’ income. The cost of providing subsurface drainage is about Rs. 75000/ha in alluvial soils of northwest India and Rs. 100,000/ha for heavy textured soils of Maharashtra and Karnataka. Both the material and installation costs cover about half of the total cost.
The paper presents an overview of the systematic research conducted in different agro-ecological regions of India on subsurface drainage technology including guidelines on drain spacing, drain depth, envelopes and management options for saline drainage water. Experience on monitoring and evaluation of drainage projects reiterates that high cost, environmental issues relating to disposal of saline drainage effiuent and continuous pumping requirement during post drainage phase are some of the deterrents to long term success of this technology. Involvement of farmers, sharing of construction and operating cost and government subsidy are also vital aspects. The technology is yet to be perfected for salt affected vertisols and sloping areas while regional plans are necessary for sustainable disposal and management of saline drainage water. Sustaining the productivity of irrigated agriculture without environmental degradation is a challenging task and demands a regional perspective for management of waterlogged saline soils.
