Skip to content

Compartmental bunding (rainfed red soils) Photo: brazil topno · Pexels License · source ↗

Compartmental bunding (rainfed red soils)

Compartmental bunding is an in-situ moisture conservation practice in which a rainfed field is divided into small, level sub-compartments by low intersecting earth bunds so that rainwater is held in place long enough to infiltrate. It is one of the most cost-effective treatments for shallow-to-medium red soils on gentle slopes in the Deccan plateau, recommended by ICAR-CRIDA and ICAR-IISWC for groundnut, redgram, sunflower, castor and Korralu.

Principle

Red soils (Alfisols) in Anantapur, Kurnool and adjoining Karnataka tracts have low water-holding capacity (60-90 mm in the upper metre) and high runoff coefficients. Monsoon rains of even 20-30 mm produce surface runoff within minutes on 1-3 percent slopes, leaving the crop water-stressed within a week. Compartmental bunds break the slope into 10-20 m level micro-catchments. Each compartment behaves like a shallow pond that drains slowly into the profile rather than off the field.

Procedure

  • Survey the field with an A-frame or hand level on a 5 m grid to mark the contour layout.
  • Lay primary bunds along the contour at a vertical interval of 0.3-0.6 m depending on slope.
  • Add cross-bunds at 10-20 m spacing perpendicular to the contour, creating rectangular compartments.
  • Bund dimensions: 30 cm height, 60-90 cm base width, formed by a tractor-drawn bund-former or animal-drawn plank.
  • Provide a controlled overflow notch every fourth compartment so that excess water moves down-slope without breaching the bund.
  • Stabilise bund tops with stylo, agave, vetiver or sunn hemp to prevent rilling.

When and where it applies

The practice suits rainfed red and shallow black soils on slopes of 0.5-3 percent. It is most effective when laid out before the onset of the south-west monsoon. ICAR-CRIDA on-farm trials in Anantapur have shown 15-25 percent yield gains in groundnut and 20-35 percent in redgram against unbunded controls in below-normal rainfall years. The treatment is routinely funded under the Watershed Development Component of PMKSY (Watershed Development Component Pmksy Wdc) and the legacy Neeru Meeru programme (Neeru Meeru Watershed Ap).

Limitations

In years of exceptionally heavy rainfall the bunds can breach if the overflow notches are undersized, scouring the compartment below. Bunds must be reformed every 2-3 seasons as rodent burrows and ploughing reduce height. Very heavy black cotton soils on flat terrain do not benefit because runoff is already low; in those soils, raised beds (Raised Bed Groundnut) and farm ponds (Farm Pond) work better.

See also: Farm pond, Raised-bed groundnut, Rainwater recharge pits, Neeru Meeru watershed.

Sources

  1. Compartmental bunding for in-situ moisture conservation. ICAR-Central Research Institute for Dryland Agriculture, Hyderabad.
  2. Rainwater management for rainfed agriculture. ICAR-Indian Institute of Soil and Water Conservation.