Irrigation Modeling for Crops Drip Irrigation & Row Plantings Mohunnad Massimi Irrigation Modeling Scholar at Florida (A&M) Univ Agronomist and Extension Officer at NCARE Master of Field Crops from JUST

Lecture Sep, 9 2017 Agricultural Eng Ass Zarqa Number of Targets: 10 Engineers

Irrigation Modeling is a Term

Irrigation Modeling Modeling is Scheduling. Scheduling is two terms !! Irrigation Time. Irrigation Amount.

Irrigation Simply ! Timing Amount

Why Modeling is important ? Crop Water Requirements. Drought Sensitive Stages of Crops. Drought and Salinity. Treated Waste Water.

Sensitive Stages Forage and green plants = after cut. Silage Corn. Forage Sorghum. Sudan grass.

Sensitive Stages Cereal grains and field crops = at time of flowering and tillering. Barley. Wheat. Triticale. Oat. Grain Sorghum and Corn.

Vegetables Summer Crops: Tomato (2) Eggplant (2) Pepper (2) Squash (2) Bean (2) Okra (2) Melon & Water Melon (2) Winter Crops: Cauliflower (1) Cabbage (2) Potato (1) Onion & Garlic (1 or 2) Faba bean & Peas (2) Carrot (1) Lettuce (1) Radish (1) Turnip (1) Spinach (1)

Leaf Vegetables & Potato Sensitive (1) = Head Formation or at Enlargement

Legumes, Cabbage, Pepper, Tomato, Melons = Flowering, Fruit Filling Sensitive (2)

Agronomy Science of Crops Production and Soil Management. Themes: Seeds, Irrigation, Fertilization, Rotations, Machinery, and Protection. Olericulture: Growing horticultural vegetable crops.

Seeds Irrigation Fertilization Rotation Machinery Protection Agronomy

Drought and Salinity = Fx (CC) !!

Irrigation Terms Mathematical Modeling. Soil Texture. Field Capacity %. Permanent Wilting Point %. Managed Allowable Depletion. Root Depth (cm) Drip Irrigation. Surface / Flood Irrigation. Sprinkler Irrigation. Irrigation Efficiency.

Mathematical Modeling Clay Silt and Loam Sand Texture Field Capacity (v%) Permanent Wilting Point (v%) Sand 10 5 Loamy Sand 12 Sandy Loam 18 8 Sandy Clay Loam 27 17 Loam 28 14 Sandy Clay 36 25 Silt Loam 31 11 Silt 30 6 Clay Loam 22 Silty Clay Loam 38 Silty Clay 41 Clay 42

Managed Allowable Depletion % = Percent of water available that taken by the plant. Usually MAD % around 30 – 50 %. It is an indicator to irrigate again.

General Modeling Equations Net Irrigation Requirements = Managed Allowable Depletion % (Field Capacity % - Permanent Wilting Point %) * Root Depth NIR = MAD % (FC %-PWP%)*D. Gross Irrigation Requirement = Net Irrigation Requirement / Irrigation Efficiency % GIR = NIR / E%.

Special Modeling Equation Case of Drip Irrigation: [1] Application Rate (mm/hr) = Emitter Flow Rate / Emitter Spacing * Row Spacing. [2] Running Time (hr) = Gross Water Depth / Application Rate

Example (1) Silage Corn hybrid (P1197YHR) grown in Florida . Calculate both net and gross irrigation requirements if you know that Managed allowable depletion was 30 %, soil is clay, and root depth is 91 cm. drip Irrigation Efficiency is 90 %.

Example (2) Sorghum Sudan grass hybrid (Graze II) grown in Florida. Calculate both application rate (mm/hr) and running time (hr) if you know that emitter flow rate is 17 ml/minute, emitter space is 0.30 m, row spacing is 1.83 m, drip Irrigation Efficiency is 90 %, and Gross water depth is 36.4 mm/m2

Amount mm per meter Square is irrigation depth. In Jordan it measured in m3 / du. At time of rain, there is another calculations. Example (3) On May 6 2017 a rain amount of 28.51 mm dropped. Reschedule your irrigation using inputs of previous examples?

Timing is Interval Interval is number of days. Water Depth Stored in Soil = Gross Irrigation Requirement * Irrigation Efficiency %. WDS = GIR * E % WDS = NIR. Interval (days) = Water Depth Stored in Soil / Daily Requirements. Int = WDS / DR.

Timing Calculate daily irrigation intervals for forage sorghum hybrid (ss2010) if you know that gross irrigation requirement is 36.4 mm/m2 using drip irrigation, and maximum daily requirement is 8 mm.

Timing and Amount They are just averages of water irrigation modeling. Modified according: Climate. Growth Stage.