IRRIGATION1 Design of Irrigation Systems by Lszl Ormos

IRRIGATION_1 Design of Irrigation Systems by László Ormos

Measurement Apparent specific gravity (bulk density) S where m. M means the weight of given volume of dry soil, air space included, and VM is the volume of soil sample. Real specific gravity S where m. M means the weight of given volume of dry soil, occupied by the solid particles, and VM is the volume of soil sample.

Measurement Porosity P is the ratio of the volume of voids (air and water-filled space) to the total volume of soil plus water and air. Moisturisation FS where m. D means the weight of dry soil sample.

Measurement Field capacity FC Home-made measuring of field capacity is running as follows: 1. Select 1 -2 m 2 surface of field FS 2. Make a heavy irrigation on soil 3. Waiting for draining (sandy soil: 24 hrs, clay: 48 hrs) 4. Take samples from the soil 5. Measure the weight of moisturized sample FC 6. Dry it in an oven at 105°C 7. Measure the weight of dry soil 8. Compute the water content FS 9. Repeat actions 2 -8 till FS is changing 10. When FS is not changing then its value is the field capacity t

Measurement Simple method for measuring FC of sandy soil 1. 2. 3. 4. 5. Fill the sample of sandy soil into a can Drip 5 ml of water on the soil surface After a minute, spill the soil from the can and take the moisturized ball from the soil out Clean the surface of soil ball from dry specks Detremine the water content of soil ball described previously (4. -7. )

Measurement Permanent wilting point PW (by sunflower method) 1. Seem sunflower seeds in a pot 2. Irrigate it to reach field capacity 3. When the plant has three pairs of leaves stop the irrigation 4. When the plant is wilted, the soil moisture content is the wilting point

Evapotranspiration (evaporation + transpiration) – evaporation is running during night and day, – transpiration of most crops is in daytime, only. Integrated effect of radiation, wind, temperature and humidity.

Pan evaporation method 1. Class A evaporation pan 46. 5”(1210 mm) 10”(~255 mm) 2”(~50 mm) 3”(~75 mm) 6”(~150 mm) <2”(~50 mm) Galvanized iron plate thickness 0. 8 mm

Pan evaporation method 2. Class B evaporation pan 18”(~460 mm) 36”(~920 mm) 2”(~50 mm) Galvanized iron plate thickness 0. 8 mm

Pan evaporation method Set of pan Case A wind dry surface 50 m, or more green crop varies pan

Pan evaporation method Set of pan Case B wind green crop 50 m, or more dry surface varies pan

Pan evaporation method Reference crop evapotranspiration where Epan means the evaporation in mm/day and represents the mean daily value of the period considered, Kp is the pan coefficient.

Pan evaporation method Crop coefficient To account for the effect of the crop characteristics on crop water requirements, crop coefficients Kc are presented to relate ET 0 to crop evapotranspiration. Planting date Maturity Harvest Kc t 1 2 3 4 1 initial stage (groundcover<10%) 2 crop development stage (groundcover ~70 -80%) 3 mid-season stage (full groundcover) 4 late season stage

References Azenkot, A. (1998): ”Design Irrigation System”. Ministry of Agriculture Extension Service (Irrigation Field service), MASHAV Israel Dr. Avidan, A. (1995): ”Soil-Water-Plant Relationship”. Ministry of Agriculture Extension Service (Irrigation Field service), CINADCO, Ministry of Foreign Affairs, MASHAV, Israel Sapir, E. -Dr. E. Yagev (1995): ”Drip Irrigation”. Ministry of Agriculture and Rural Development, CINADCO, Ministry of Foreign Affairs, MASHAV, Israel Sapir, E. -Dr. E. Yagev (2001): ”Sprinkler Irrigation”. Ministry of culture and Rural Development, CINADCO, Ministry of Foreign Affairs, MASHAV, Israel Eng. Nathan, R. (2002): ”Fertilization Combined with Irrigation (Fertigation)”. Ministry of Agriculture and Rural Development, CINADCO, Ministry of Foreign Affairs, MASHAV, Israel