Drought and its mitigation strategies in agriculture SEMINAR on COLLEGE OF AGRICULTURE, DEPARTMENT OF AGRONOMY PRESENTED BY: Soumya Ranjan Bhuyan I.D No.-160111022 MAJOR ADVISOR Dr. Manish Bhan Asst. Professor Agronomy SEMINAR INCHARGE Dr.M.L Kewat Professor,Agronomy
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MAJOR ADVISORDr. Manish BhanAsst. ProfessorAgronomy
SEMINAR INCHARGEDr.M.L KewatProfessor,Agronomy
Sequence of presentation
Introduction
Concept of drought
Mitigation techniques
Mitigation through crop management practices
Soil and water conservation techniques
Conclusion
INTRODUCTION
INTRODUCTION
Source-NICRA,2014
Drought is a situation when the actual seasonal rainfall is deficient
by more than twice the mean deviation (Ramdas,1960)
Drought is defined by deviation from the normal rainfall, it can
happen in all rainfall regions. It also occurs in high rainfall area
but severity or frequency may vary.
Drought is considered to be a strictly meteorological phenomenon.
It is also a complex phenomenon whose severity depends on the
precipitation amount, its time and space distribution, evapo-
transpiration and on hydrological factors.
Definition
Classification of drought
Meteorological drought: It is defined as a situation when there is a25% decrease in average rainfall for a given period oftime(IMD,Pune)
Hydrological drought: Depletion of surface water and consequentlydrying of reservoirs, tanks etc. It results in deficiency of water forall sectors using water.
Agricultural drought: It is the result of soil moisture stress due toimbalance between available soil moisture and evapotranspirationdemand of a crop.
Socio-economic drought: This is associated with the supply &demand of some economic goods. This drought should be linkedhot only to precipitation but also trends of fluctuations in demand.
Classification of drought
Meteorological drought
Hydrological drought
Agricultural drought
o Shortage of water
o Desertification
o Death of livestock
o Lack of water for irrigation
o Reduced crop yield
o Migration of people
o Scarcity of seed
Consequence of drought
Effects of drought on plants
o Loss of turgidity
o Photosynthesis
o Increase in number of stomata
o ABA accumulation
o Rolling and wilting of leaves
o Reduced tillering
o Forced maturity
o Reduction in productivity
Table 1: Economic yield reduction by drought stress in some
representative field crops
Crop Growth stage Yield reduction
Barley Seed filling 49 – 57%
Maize Grain filling 79 – 81%
Maize Reproductive 63 – 87%
Maize Vegetative 25 – 60%
Rice Reproductive (severe stress)53 – 92%
Dryland farming - Crops and Techniques for Arid Regions
-R. Crosswell and F.W. Martin
Drought stress resistance mechanism in plants
Plants optimize the morphology, physiology and metabolism of
their organs and cells.
The reactions of the plants to water stress differs significantly at
various organizational levels depending upon intensity and
duration of stress as well as plant species and its stage of
development
Adaptations
Drought escape Drought resistance
Drought toleranceDrought avoidance
Water conservation More water uptake
Mitigating drought High tolerance to drought
Principles of agronomy Yellamanda Reddy and Shankara Reddy
Stress avoidance : is the ability of plant to maintain high tissue water
potential under drought conditions.
Stress tolerance : is a plant’s stability to maintain its normal
functions even at low tissue water potentials.
Stress resistance
Stress
tolerance
Stress
avoidance
Stress avoidance is usually achieved through morphological
changes in the plant :
Reduced stomatal conductance
Decreased leaf area
Development of extensive root systems
Increased root/shoot ratios
Stress tolerance is achieved by mitigating stress and high
degree of tolerance by plants.
Mitigation strategies
Mitigation of Stress by Crop
Management
Soil and moisture conservation
measures
Mitigation by crop management practices
Selection of crops/varieties
Seed hardening
Sowing of crops
Selection of crops/varieties
Short duration
Early vigour
Deep root system
Dwarf plant with erect leaves and stems
Moderate tillering
Lesser period between flowering and maturity
Moderate dormancy
Wider adoptability
Source-Venketeshwarlu,2009.Indian Journal of Agricultural Science
Relative drought tolerant crops
RABI KHARIF LEGUMES
• Oats• Barley• Triticale
• Sorghum• Pearl millet• Kodo millet• Green gram• Black gram• Niger
•Soybean•Groundnut•Chickpea•Cowpea•Pigeon pea
• Pearl millet: CZIC 923,HHB 67,HHB 68,GHB 183,GHB 1399,etc