Moisture/ Water stress

• Too much water (water logging condition) or too less water (draught condition) can cause problem for horticultural crop production

a. Drought condition

• It is one of the major factors limiting crop production in Nepal for horticultural crops
• It is a condition that means a lack of precipitation over a prolonged period of time
• Plant response to drought accompanies change in both physical and physiological components in plants

Physical changes due to draught condition in plants

• Reduction of water potential or activity of cellular water
• Turgor pressure is decreased and plasmolysis takes place

• Salt concentration increases
• Leaves become senescent faster
• Nutrient uptake from soil is decreased

Physiological changes due to draught condition

• Cell growth and cell division decreases
• Chlorophyll formation is decreased due to decrease in enzymatic activity
• ABA(abscissic acid) and ethylene are increased while cytokinin is decreased
• Respiration rate is reduced due to stomatal closure

Draught Overcome

• Regular irrigation
• Planting draught resistant crops
• Use of mulches
• Increase field capacity by adding organic matter

b. Water logging condition

• It is a condition of water in field, excess than required
• Excessive rainfall, excessive water retention by soil, too much field irrigation, poor drainage, high water table etc. causes water logging condition Effects of excess water in plants
• Decrease respiration in plant root
• Water uptake is greatly reduced
• Leaching of nutrient take place
• Some disease problem are also seen Example: damping off

Water logging overcome

• Maintain proper drainage system
• Planting resistance variety and appropriate crops like paddy crops select