EFFECT OF SOIL TYPE ^JDEPTH ON WATER HOLDING CAPACITY OF SOIL.pptx

effect of soil type depth on water holding capacity

1. ODISHA UNIVERSITY OF AGRICULTURE AND TECHNOLOGY COLLEGE OF AGRICULTURE,CHIPLIMA AG(E)-221 WATER MANAGEMENT AND MICRO-IRRIGATION TOPIC-EFFECT OF SOIL TYPE,DEPTH ON WATER HOLDING CAPACITY OF SOIL SUBMITTED BY:- FIROJ SAHOO ADMISSION NUMBER:-231310014 GROUP:-A SUBMITTED TO:- Dr. Bhabani Shankar Bishoyi Associate Professor Agronomy

2. INTRODUCTION Water Holding Capacity (WHC):The ability of soil to retain water available for plant use after gravitational water drains. Importance: 1. Determines irrigation frequency. 2. Influences drought tolerance. 3. Critical for crop yield.

3. S0IL MOISTURE FRACTIONS Gravitational water: drains quickly, not available to plants. Capillary water: available for plant roots (most important). Hygroscopic water: tightly bound to soil particles, unavailable. Field capacity: water retained after drainage. Permanent wilting point: moisture level where plants cannot recover.

4. FACTORS AFFECTING WHC Soil type (texture & structure) Soil depth Organic matter content Bulk density & porosity Root distribution Topography & slope

5. S0IL TYPE (TEXTURE) & WHC Sandy soil: Large pores → low WHC, quick drainage. WHC ~ 0.5–1.0 cm water/30 cm depth. Silty soil: Medium pores → moderate WHC. Clay soil: Very fine pores → high WHC, poor aeration.WHC ~ 4.0–4.5 cm water/30 cm depth. Loam soil (ideal): balanced texture, good WHC + aeration.

6. ROLE OF SOIL STRUCTURE Granular structure → increases porosity & WHC. Compact/cloddy soil → reduces WHC. Soil management (tillage, adding FYM/organic matter) improves WHC.

7. SOIL DEPTH AND WHC Shallow soil (<30 cm): very low water storage. Medium depth (30–60 cm): moderate storage. Deep soil (>60 cm): high storage capacity. Example:Shallow soil may hold only 5–7 cm water. Deep loam may hold 15–20 cm water. Deeper soil → deeper root penetration → more moisture available.

8. ROOTING CHARACTERISTICS Shallow-rooted crops: onion, garlic, most vegetables (10–30 cm). Medium-rooted crops: rice, wheat, maize (30–60 cm). Deep-rooted crops: sugarcane, cotton, fruit trees (>60 cm). Roots absorb 70–80% water from top 30 cm, even in deep soils.

9. MOISTURE EXTRACTION PATTERNS Water extraction decreases with depth 0–30 cm → 40–60% extraction 30–60 cm → 20–30% 60–90 cm → 10–20% Shallow soils limit rooting → quick moisture stress. Deep soils support crops during dry periods.

10. CONCLUSION WHC increases with clay content & depth. Soil depth determines rooting zone & water storage. Crop water management must be based on soil type & rooting depth. Improving organic matter & structure enhances WHC.