Dryland technology

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

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

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 s oil surface , Transpiration - from plant s u r f a c e Evaporation - arrested - not directly related to productivity. Transpiration - reduced to some extent without affecting the productivity. 2

3. TECHNIQUES TO REDUCE EVAPORATION AND TRANSPIRATION LOSS… Mulches Antitranspirants Wind breaks Weed control 3

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. A dditional benefits… S oil conservation, M oderation of temperature, R eduction in soil salinity, W eed control, I mprovement of soil structure. 4

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 . 5

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. 7

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: Stomatal Closing Film forming Reflective Growth retardant 10

11. Stomatal Closing Fungicides - Phenyl M ercuric A cetate ( PMA) H erbicides - atrazine in low conc. R educe the photosynthesis. PMA was found to decrease transpiration to a greater degree than photosynthesis . 11

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. 12

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 D iatomaceous earth product ( celite ) 13

14. Growth Retardant C hemicals reduce shoot growth and increase root growth and thus enable the plants to resist drought. A lso , induce stomatal closure. Cycocel 14

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. 15

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. 16

17. Weed Control Transpiration rate from weeds is more compared to crops. Effective weed control leads to increasing availability of soil moisture to crops. W eed 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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