الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
Abstract
According to the constant and limited water resources in Egypt, besides, the expected climate changes and the continuous increasing population, therefore, water should be utilized as a rare commodity. This can be achieved through a lot of procedures that can all lead to lessen water consumption by plant and maximize irrigation water use efficiency. In other words; to obtain the best productivity from a water unit.
Adjusting water quantities given to plant via probes or tensiometers measure the soil moisture content and connected to control valves is one of the modern irrigation management methods. Using meteorological data accessed to special software programs, i.e., CROPWAT or AQUA CROP, to calculate ETC, allow passing the net irrigation needs to the crop at certain soil moisture depletion point, is more developed irrigation management practice.
The study was carried out in the Experimental Farm of Agricultural Production and Research Station of National Research Centre (APRS, NRC), El Nubaria Province for two seasons of 2012-2013 and 2013-2014. The soil is sandy, irrigated by drip system. Pea (master B) was taken as an indicator for crop.
The experiment included:-
A. Three methods to estimate the irrigation requirements for peas included:
1. CROPWAT Program using to calculating of water requirements for pea from climatic data by using the records of the Central Laboratory of Agricultural Climate (CLAC).
2. CROPWAT Program using to calculating water requirements for the same crop by using the daily registered data taken from automatic meteorological station, installed in the experimental site. Water was compensated according to the daily evapotranspiration water losses.
3. Using tensiometers connected to electrical valves programmed to give water to plant at certain percentage of water levels (125% - 110% - 90%).
B. Three potassium doses applied through the drip irrigation system (50 - 75- 100 Kg/fed) under each irrigation treatment to investigate the effect of controlling both water and K fertilizer on productivity, fruits quality, and economical aspects.
C. Validation of Aquacrop program of soil moisture for different AWC % under irrometer.
D. Measurement of soil moisture and distribution pattern in the soil profile under different treatments.
E. Effect of treatments on plants
The following parameters were studied:
1. Vegetative growth parameters:-
- Plant height (cm)
- Number of pods / plant
- Total plant dry matter
2. Total yield per area.
- Pod length
- Pod thickness
- Pod weight
- Number of seeds / pod
3. Water use efficiency (kg / m3)
4. Fertilizer use efficiency (kg / kg potassium)
5. Total economic aspects for automatic irrigation system.
The main results in this study could be summarized in the following:
1) Automatic scheduling of drip irrigation led to saving 16% to 35% of supplied irrigation water compared to uncontrolled drip irrigation method, with an increase in the yield of the crop estimated by 20%.
2) Possibility of benefiting from meteorological station and stored data for multiple purposes .i.e, adjusting the irrigation water needs of the plant according to the growth stage.
3) Scheduling irrigation using data of the meteorological station gave the best results concerning water fertilizer management.
4) The increase in the rate of K-fertilization in general from 50% to 100% officially recommended rates led to a significant increase in the yield of green pods.
5) The tendency of water distribution and its average content in the soil profile increase relevant to the irrigation under the CROPWAT 8 CLIMWAT 2 when comparing the average contents of water in the profile for all the cases of irrigation treatment.
6) The results of the interaction between the factors showed that the best results of pea production and water and K - fertilizer use efficiency were obtained from the addition of 100 % of recommended K fertilizer under irrigation scheduling system using data from the meteorological station installed in the farm.
7) Increase water use efficiency under scheduling system using meteorological station set up in the farm compared to the scheduling by other ways. While the highest values of the fertilizer use efficiency e of manure treatment when 75% of the recommended rate of fertilizer.
8) The possibility of developing the system to work automatically without human intervention in irrigation operations.
9) The possibility of using these methods in irrigation scheduling easily, and without the need of high skills in operation and maintenance and follow-up.