Soil and Water Conservation Practices

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Muhajir Utomo, University of Lampung

2013

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Soil and Water Conservation: Why we need this?

Soil erosion exceeds tolerance level due to unsustainable management

Forest

Cropping Wood andgrazing

Construction

Urban

Mean sedim

ent concentration

Year, land use change

Sediment and Land Use Change

Strategy for Soil and Water Conservation Practices

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Aim of Strategy: To reduce erosion to a level at which the maximum sustainable of production can be obtained Tolerance level: rate of soil forming (world basis) 0.01-7.7 (average 0.1) mm/yr Tolerance level (equal to rate of soil forming): 0.3-2 ton/ha/yr with average 1 ton/ha/yr or 0.1 mm/yr

Strategy for Soil and Water Conservation Practices

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Principles of Soil Conservation:

Covering the soil to protect it from raindrop impact Increasing the infiltration capacity to reduce runoff improving the aggregate stability of the soil and increasing surface roughness to reduce the velocity of runoff

Soil and water conservation practices: 1. Cultivated land2. Grazing land3. Forest land (land clearance, mining land, urban land)

Approaches to Soil Conservation

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Cultivated Land:

o A risk of erosion exists due to trees, bushes and grasses are removedo Erosion is exacerbated by mismanagement practiced such as tillage, cultivating up-and –down, etc.o Conservation strategy: establishing and maintaining good ground cover and reducing tillage frequency.

Approaches to Soil Conservation

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Grazing Land:

o Erosion problems arise when vegetative cover is removed through overgrazingo Erosion problems also arise by soil compaction due to traffic of cattleo Conservation strategy: establishing and maintaining suitable stocking rates and planting erosion resistance grass and shrubs

Approaches to Soil Conservation

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Forest Land:

o Forest provide excellent protection of the soil against erosiono Increase erosion occur when the land change to agriculture, illegal logging, land clearance, mining or grazingo Conservation strategy: reforestation and agro-forest

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Methods of Soil and Water Conservation Practices

1. Vegetative Method Crop rotation Cover crops (Green manure), Mulching

Agro forestry2. Mechanical Method Conservation tillage Contour bund Terrace3. Chemical Method Soil conditioner

1. Agronomic Methods Crop rotation Cover crops (Green manure)

Strip cropping Multiple cropping

Mulching Revegetation Agro forestry

2. Soil Management Conservation tillage Soil stabilizer

3. Mechanical Method Contour bund Terrace

Waterways

(Arsyad, 2010)

(Morgan, 2006)

Vegetative Method/ Agronomic Practices

o Soil completely covered with vegetation is ideal condition to absorbed moisture and resist erosion

o The reasons: (a) reduce direct impact of rain on soil surface, (b) reduce speed of water flowing, (c) increase soil organic matter favor infiltration of water

o Examples: Crop rotation Cover crops (Green manure)

Strip cropping Multiple cropping

Mulching Revegetation Agro forestry

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1. Crop Rotation

What it is?:• A system in which different crops are

grown in recurrent succession on a single piece of land

• Long-term effect of rotation is significant: on 4o slope, erosion from continuous corn was 44 t/ha vs 6 t/ha from rotation.

• After 100 years, land under continuous corn had only 44% as much top soil as permanently under grass, whereas land under rotation had 70%

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Crop Rotation

How it works? • Objective: to preserve

productivity and yield• Rotate cereals (small grain, grass)-

legumes or legume-grass mixture• Types of rotation depends on soil

type, economic condition and cropping system/region

• Rotation crops covering land can protect soil from rain drops

• Soil organic matter from crop residue can enhance soil fertility