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🌾 Moisture Conservation Techniques

Moisture Conservation Techniques.

Moisture conservation techniques reduce runoff and evaporation losses so that limited rainfall remains available in the root zone for longer crop growth support.

In Situ Moisture Conservation

In situ moisture conservation refers to practices that help retain rainfall in the field where it falls, reducing runoff and increasing infiltration.

Land Configuration Techniques

1. Contour Cultivation

  • All farm operations (ploughing, sowing) done along contours (lines of equal elevation)
  • Ridges and furrows across the slope act as barriers to runoff
  • Reduces runoff by 30–50% compared to up-and-down slope cultivation
  • Effective on slopes up to 6%

2. Contour Bunding

  • Earthen bunds (0.5–1.0 m high) constructed along contours at regular intervals
  • Impounds runoff water behind bunds, increasing infiltration time
  • Spacing depends on slope and soil type (typically 10–30 m apart)
  • Suitable for slopes of 2–6% in low-rainfall areas (<700 mm)

3. Graded Bunding

  • Bunds with a gentle gradient (0.2–0.4%) to safely drain excess water
  • Prevents waterlogging while still reducing runoff velocity
  • Suitable for medium to high rainfall areas and poorly drained soils

4. Broad Bed and Furrow (BBF)

  • Broad raised beds (90–120 cm wide) with shallow furrows (30–60 cm)
  • Dual purpose: Drains excess water in wet periods, conserves moisture in dry spells
  • Developed by ICRISAT for vertisols (black cotton soils)
  • Suitable for soybean, chickpea, wheat on Vertisols

5. Ridge and Furrow

  • Alternating ridges and furrows along or across slope
  • Crops sown on ridges (better drainage) or in furrows (more moisture)
  • Effective for row crops like sorghum, maize, groundnut

Mulching

Types

  • Soil mulch (dust mulch): Breaking the top 5–7 cm of soil after rain to break capillary pores
  • Crop residue mulch: Straw, stubble, dried leaves (3–5 tonnes/ha)
  • Plastic mulch: Polyethylene sheets (used in horticulture)
  • Live mulch: Ground cover crops grown between main crop rows

Benefits

  • Reduces soil evaporation by 30–50%
  • Moderates soil temperature (cooler in summer, warmer in winter)
  • Suppresses weed growth
  • Prevents soil crusting and improves infiltration
  • Adds organic matter (organic mulch)

Tillage for Moisture Conservation

  • Deep ploughing: Once in 2–3 years to break hard pan, increase infiltration depth
  • Summer ploughing: Open furrows before monsoon to capture first rains
  • Minimum tillage: Reduces moisture loss from excessive soil disturbance
  • Subsoiling: Breaking compacted sublayer without inverting soil

Summary Cheat Sheet

Technique Group Core Use
In-situ conservation Retain rainfall where it falls and improve infiltration
Land configuration Guide runoff and store water near crop root zones
Mulching Reduce evaporation, moderate temperature, and suppress weeds
Conservation tillage Minimize moisture loss and improve soil water storage

References

2 sources • [1] [2]

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