Dasar-dasar Ilmu Tanah. BAB Konservasi Tanah dan Air. part 2

Summary

This video explains the causes and types of soil erosion and methods for soil and water conservation. It covers the two main factors of erosion: erosivity (external factors like climate) and erodibility (soil-related factors). The six main types of erosion are discussed, including splash, sheet, rill, gully, streambank erosion, and landslides. The script also introduces the USLE formula for calculating soil loss and outlines conservation methods like vegetative, mechanical, and chemical approaches. The video emphasizes the importance of choosing the right conservation techniques based on the level of erosion in a given area.

Takeaways

• 😀 Erosion can be caused by two main factors: erosivity (external to the soil) and erodibility (directly related to the soil itself).
• 🌧️ Erosivity factors are mainly related to climate, especially rainfall and humidity, which influence the intensity of erosion.
• 🌱 Erodibility factors depend on soil physical properties like texture, structure, and consistency, as well as land management practices such as tillage and vegetation.
• 💧 A rough soil texture, loose soil structure, and low soil consistency increase erosion risk, as they allow easier displacement of soil particles.
• 🌍 Land with steep topography and little vegetation is more prone to erosion, as the lack of vegetation fails to slow water runoff and reduce soil displacement.
• 👩‍🌾 Human activities significantly impact erosion, both in exacerbating it and in mitigating it through proper soil and water conservation techniques.
• 🌾 Vegetation plays a crucial role in reducing erosion by slowing water flow and protecting soil from direct rainfall impact.
• 🛠️ Soil erosion can be categorized into six main types: splash erosion, sheet erosion, rill erosion, gully erosion, riverbank erosion, and landslides.
• 🏞️ Splash erosion occurs when rainwater detaches soil particles, with the extent of the erosion influenced by slope, wind speed, and surface roughness.
• 🌊 Gully erosion and riverbank erosion are characterized by more severe soil removal, with water flow carving out deeper channels or undermining riverbanks.
• 🔬 The USLE (Universal Soil Loss Equation) method is commonly used to estimate soil erosion, taking into account factors like rainfall, soil type, slope, and vegetation management practices.
• 🌱 Soil and water conservation methods include vegetative techniques (like agroforestry and mulching), mechanical methods (such as terraces and dams), and chemical methods (using additives to stabilize the soil).

Q & A

What are the two main factors that cause erosion?

The two main factors causing erosion are erosivity and erodibility. Erosivity refers to factors external to the soil, such as climate, while erodibility is related to the soil's properties and its management.

What is the role of climate in erosivity?

Climate, specifically rainfall and humidity, plays a significant role in erosivity. High rainfall can lead to increased water runoff, contributing to higher erosion rates.

How does soil texture affect erodibility?

Soil texture affects erodibility in that coarser soils tend to experience more erosion. Soils with larger particles are less able to retain water, leading to higher erosion potential.

What are the physical soil properties that influence erosion?

The physical properties of soil that influence erosion include texture, structure, and consistency. Soils with loose structure or low consistency are more prone to erosion.

What is the impact of vegetation on soil erosion?

Vegetation helps reduce soil erosion by stabilizing the soil. It reduces the speed of water runoff, decreases the force of raindrops, and provides a protective cover that prevents soil particles from being displaced.

What are the different types of erosion mentioned in the script?

The types of erosion discussed include splash erosion, sheet erosion, rill erosion, gully erosion, riverbank erosion, landslides, and internal erosion.

How does rill erosion differ from gully erosion?

Rill erosion refers to the formation of small, shallow channels on the surface of the soil, while gully erosion involves the formation of deeper, larger channels or ditches in the land.

What causes landslides according to the script?

Landslides occur due to the movement of a large mass of soil, usually triggered by saturated soils. A smooth, impermeable layer beneath the soil, such as a clay horizon, often causes landslides as it prevents water drainage.

What formula is used to calculate soil erosion in a given area?

The Universal Soil Loss Equation (USLE) is used to calculate soil erosion. The formula is A = R * K * L * S * C * P, where each variable represents a factor like rainfall, soil type, slope, vegetation, and management practices.

When should soil conservation techniques be applied based on the erosion calculations?

Soil conservation techniques should be applied if the erosion rate exceeds 40 tons per hectare per year. For erosion rates below 15 tons per hectare per year, no conservation measures are necessary.