Crop water requirement
Crop water requirement refers to the amount of water needed by a crop to meet its evapotranspiration and maintain optimal growth and yield grow and develop properly. It is influenced by various factors such as crop type, growth stage, climate conditions, soil type, and management practices.
Farmers and irrigation specialists use various methods to determine crop water requirements, including evapotranspiration models, soil moisture monitoring, crop coefficients, and field observations. These methods estimate water loss, soil moisture levels, crop coefficients, and plant characteristics to determine irrigation needs.
Proper estimation and meeting crop water requirements are essential for optimizing irrigation efficiency, preventing water stress, and promoting healthy crop growth. This helps farmers use water resources more efficiently and sustainably, maximizing crop yields.
A crop's water requirement is commonly quantified in terms of evapotranspiration (ET), which comprises both evaporation from the soil surface and transpiration from the plant's leaves. Temperature, humidity, wind speed, sun radiation, and crop characteristics all have an effect on ET.
To determine the crop water requirement, various methods can be used including:
1. Reference Evapotranspiration (ETo): This is the amount of water lost through evaporation and transpiration from a well-watered reference crop (typically grass or alfalfa) under regular climatic conditions. ETo is calculated using weather data and can be estimated using methods such as the Penman-Monteith equation.
2. Crop Coefficient (Kc): The crop coefficient is a measure of how much water is actually used by the crop in relation to a standard amount of evapotranspiration. It considers the crop's particular traits and growing stage. As the crop's water requirements alter over the growing season, the Kc value changes as well.
3. Calculation of Crop Water Requirements: By multiplying ETo by the proper crop coefficient for each stage of the crop's growth, the amount of water that the crop needs may be determined.
The crop's water requirements must be properly met while reducing water waste, which requires proper irrigation management. Under-irrigation can result in lower yields or lower-quality crops, whereas over-irrigation can use too much water, drain nutrients, and raise disease risk. When deciding on irrigation schedules and administering the right amounts of water to satisfy the individual demands of their crops, farmers must consider local climatic conditions, soil moisture levels, rainfall patterns, and other considerations.
The Penman-Monteith method is advised by the FAO for Reference Evapotranspiration (ETo) calculation. It is a straightforward equation that may be used to anticipate irrigation water demand and crop water requirements when combined with ground observation data on the cropping pattern area, crop coefficient approach, and irrigation efficiency.
The data collected for our study included climatological and effective rainfall data from the Egyptian meteorological authority for El-Kharga Oasis, crop data and cropping patterns for three successive years, and a cropping calendar contains the dates of planting (sow/transplanting) and harvesting (end-growth). The length of growth stages and single crop coefficient were r
eviewed using various sources, including Doorenbos (1977) and Allen et al. (1994). The FAO CROPWAT 8.0 was used to process data on water amounts used for agricultural purposes, calculating crop evapotranspiration, crop water needs, and irrigation water requirements based on irrigation efficiency. Reference evapotranspiration (ETo) was estimated from meteorological data and aerodynamic and surface resistance according to FAO Penman Monteith.
The findings showed that there was a significant increase in the need for irrigation water in the crop-growing region. According to our study on the kharga oasis, if irrigation methods were improved as part of efficient water management, like through the creation of new irrigation technology like sprinkler and drip irrigation systems, it would be possible to save 32% more irrigation water than they currently do. we concluded that the Improved irrigation efficiency in 2010, 2011, and 2012 could reduce water requirements by 135.5, 146.6, and 158.5 million m3/total area/year, allowing for increased cultivation areas from 22020, 22013, and 23916 fed to 31929, 31919, and 34677 feds in December 2010, 2011, and 2012. Optimized systems could conserve groundwater, potentially eliminating shortages during high demand months and expanding agricultural land