About the various techniques that are followed in dryland to enhance the production.

1. DRYLAND
TECHNOLOGY
FOR CROP
PRODUCTION
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AGR 302 – RAINFED
AGRICULTURE AND
WATERSHED
MANAGEMENT (1+1)
Presented By…
Guhan.C, B.Sc.(Hons).Agri,
Id no : 2018033029
JKKMCAS, Erode, TN

2. DRYLAND
 Dryland farming - crop production in areas with
< 750 mm of annual precipitation
 Dryland farming -
Annual potential water evaporation > annual precipitation.
 Soil moisture is the most limiting factor in dryland agriculture.
 Evaporation - from soil surface, Transpiration - from plant
surface
 Evaporation - arrested - not directly related to productivity.
 Transpiration - reduced to some extent without affecting the
productivity.
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3. TECHNIQUES TO REDUCE EVAPORATION
AND TRANSPIRATION LOSS…
1) Mulches
2) Antitranspirants
3) Wind breaks
4) Weed control
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4. Mulches
 Mulch is any material applied on the soil surface to
check evaporation and improve soil water.
 60 – 75% of rainfall is lost through evaporation.
Additional benefits…
 Soil conservation,
 Moderation of temperature,
 Reduction in soil salinity,
 Weed control,
 Improvement of soil structure.
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5. Types of Mulches…
Soil mulch or dust mulch:
 If the surface of the soil is loosened, it acts as a mulch for
reducing evaporation.
 This loose surface soil is called soil mulch or dust mulch.
 Intercultivation creates soil mulch in a growing crop.
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6. Stubble mulch
 Crop residues like wheat straw or cotton stalks etc., are
left on the soil surface as a stubble mulch.
 Advantages - Protection of soil from erosion and
reduction of evaporation losses.

7. Straw mulch
 If straw is used as mulch, it is called as straw mulch.
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8. Plastic mulch
 Plastic materials like polyethylene, polyvinyl
chloride(PVC) are also used as mulching materials.

9. Vertical mulching
 To improve infiltration and storage of rainwater.
 It consists of digging narrow trenches across the slope at
intervals and placing the straw or crop residues in these
trenches.

10. ANTI-TRANSPIRANTS
 99% of the water absorbed is lost by transpiration.
 Antitranspirant is any material applied to transpiring
plant surfaces for reducing water loss from the plant.
These are of four types:
1. Stomatal Closing
2. Film forming
3. Reflective
4. Growth retardant
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11. Stomatal Closing
1. Fungicides - Phenyl Mercuric Acetate (PMA)
2. Herbicides - atrazine in low conc.
 Reduce the photosynthesis.
 PMA was found to decrease transpiration to a greater
degree than photosynthesis.
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12. Film Forming Type
 Plastic and waxy materials - thin film - on leaf surface -
retard water escape – forms physical barrier.
 Mobileaf,
 Hexadeconol,
 Silicone
 The success of these chemicals is limited since they also
reduce photosynthesis.
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13. Reflectant Type
 The white materials forms a coating on the leaves and
increase the leaf reflectance.
 By reflecting the radiation - reduce leaf temperatures and
vapour pressure gradient from leaf to atmosphere -
reduce transpiration.
 5% kaolin spray
 Diatomaceous earth product (celite)
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14. Growth Retardant
 Chemicals reduce shoot growth and increase root
growth and thus enable the plants to resist drought.
 Also, induce stomatal closure.
 Cycocel
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15. Wind Breaks
 Wind breaks are any structures that obstruct wind flow
and reduce wind speed.
 The direction from which wind is blowing is called
windward side.
 Direction to which wind is blowing is called leeward
side.
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16. Shelterbelts
 Shelterbelts are planted across the direction of wind.
 Due to reduction in wind speed, evaporation losses are
reduced and more water is available for plants.
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17. Weed Control
 Transpiration rate from weeds is more compared to crops.
 Effective weed control leads to increasing availability of soil
moisture to crops.
 Weed control eliminates the competition of weeds with crops
for limited soil moisture
 Urea or DAP spray @2% for quicker regeneration of crops -
legumes and castor after rain.

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