CLIMATE UNCERTAINTY EFFECTS ON CROP WATERREQUIREMENTS OF MICRO-IRRIGATION

Climate uncertainty, particularly in climate change context, nowadays is acknowledged as an essential issueto be taken into account in agricultural water management. The concept originates from spatial and temporalvariability and measurement errors of climatic factors, among which the rainfall variability is one of the mostimportant ones both at growing-season and multi-year temporal levels. This research employs anecohydrological stochastic-analysis-based model, building upon the stochastic differential equation of soilmoisture dynamics, as a basis for deriving analytical expressions for statistics (probability density function)of micro-irrigation’s water requirement considering temporal stochasticity of rainfall. The methodology dealswith estimation of statistical properties of the total water requirement in a growing season that could be usedin shorter time-horizon applications under special circumstances. Also a wide range of irrigation managementpolicies from stress-avoidance to rainfed, including deficit irrigation, could be addressed. The sensitivityanalysis on the most prominent parameters of the model has been performed. Results show that whileincrease in rainfall parameters (leading to increase of total seasonal rainfall) reduces irrigation waterrequirement, they have contrasting effects on uncertainty of irrigation requirement. Also the effects of soiland crop features and also irrigation policies on p.d.f. of irrigation requirement could be observed.